tag:blogger.com,1999:blog-32001291384095387032024-03-05T13:06:38.683-10:00Knowledge FlocsCathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.comBlogger15125tag:blogger.com,1999:blog-3200129138409538703.post-12092180265113208462012-05-06T18:10:00.000-10:002012-06-04T19:32:43.421-10:00Accretionary Wedge 46: Geology, Life and Civilization<div dir="ltr" style="text-align: left;" trbidi="on">
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This month's Accretionary Wedge was inspired by two events demonstrating the interplay between geology and civilization. First was a segment from 'How the Earth Made Us' narrated by <a href="http://en.wikipedia.org/wiki/Iain_Stewart_%28geologist%29">Prof. Iain Stewart</a>. The snippet I saw suggested that without the Carboniferous coal deposits the industrial revolution would not have happened (<a href="http://www.youtube.com/watch?v=akz48vcYTBc&feature=relmfu">from about 19 minutes</a>). The second is that I have recently moved to the Outback, Australia, where mineral wealth is often the driving force behind the establishment of communities. The fortunes of these settlements follows the boom and bust nature of the minerals industry.<br />
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From these two observations sprang the topic for this month’s Accretionary Wedge; Geology, Life and Civilization. How has life or civilisation been affected by geology or how has geology been affected by life? Do not feel restricted to human-centric themes. This topic can range from global scale events such as the Great Oxidation Event to the fortunes of small mining communities. <br />
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I'll aim to put a summary post up at the beginning of June. Enjoy.<br />
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<b>Update: </b>Thank you all for the wonderful submissions. I'll get the summary post up before Friday (Australian EST).<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_eqEPJjPpkwSr9nJiq0HGCjxIHYg-QysRotmLYTdJAS8n4-1-yYMyrxZRIswIB8SwpFr3mNaPg6oAOUEfcnBy2rkdtyi47-owPXoFUU1zRhytpMd_2sWIKjiOpCLJtY-9XUIdwfzkM4sU/s1600/IMG_0137.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="476" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_eqEPJjPpkwSr9nJiq0HGCjxIHYg-QysRotmLYTdJAS8n4-1-yYMyrxZRIswIB8SwpFr3mNaPg6oAOUEfcnBy2rkdtyi47-owPXoFUU1zRhytpMd_2sWIKjiOpCLJtY-9XUIdwfzkM4sU/s640/IMG_0137.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Decorative island in the abandoned town, Mary Kathleen, Queensland</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiywLYwTGCZkyDnhwNwXl1QH16nIigrIFBr0nwb1PFCm76RSdV7HNdbyLrtH4beJFcDyRqtpflt5rPCBeb98HJ8_elDaE8EvrmY-6O4Zjv9roPn-SsmG6NzTenJXXvQ4mloByDFcnRTZEoc/s1600/IMG_0149.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="476" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiywLYwTGCZkyDnhwNwXl1QH16nIigrIFBr0nwb1PFCm76RSdV7HNdbyLrtH4beJFcDyRqtpflt5rPCBeb98HJ8_elDaE8EvrmY-6O4Zjv9roPn-SsmG6NzTenJXXvQ4mloByDFcnRTZEoc/s640/IMG_0149.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Abandoned uranium mine, Mary Kathleen, Queensland</td></tr>
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<br /></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com14tag:blogger.com,1999:blog-3200129138409538703.post-45925087753041274132012-02-08T03:07:00.000-10:002012-02-08T03:07:57.301-10:00Wednesday Rocks: #5<div dir="ltr" style="text-align: left;" trbidi="on">I've been in the lab so today's Wednesday Rocks is a teaser. The first photo is of the of the Brandberg, Namibia's highest mountain. The second photo is one of the perks of pottering around looking at rocks in Namibia, Desert Elephants. <br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjK1zSO3AEG4HLIH6bRjV63Dtol7jIN6YCRLuczilOJ5a8ahzUVPfcjuEil8nutgdDNTOovaPDKN3wwueYcfxec2Fd9_tC_YeB8_ml0ND6k9PBNMiQCrcXd8M0Az_RmGmUTMJnFctKW-dD7/s1600/00009.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjK1zSO3AEG4HLIH6bRjV63Dtol7jIN6YCRLuczilOJ5a8ahzUVPfcjuEil8nutgdDNTOovaPDKN3wwueYcfxec2Fd9_tC_YeB8_ml0ND6k9PBNMiQCrcXd8M0Az_RmGmUTMJnFctKW-dD7/s640/00009.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Brandberg granite. </td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2p4dFnZm4w_Y5AL6U3XT3mOmtBss2nKdhkUIqxQtg88iEoBGYk4it0ZcdVRcECnPNHLxBpI5ch8rNOW3DMCpEl4u3jegRNbrKoCcBQWXeAoM_D-mIHJyvDNIUa4NMU6hQMbSzhNJBH_TL/s1600/00039.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2p4dFnZm4w_Y5AL6U3XT3mOmtBss2nKdhkUIqxQtg88iEoBGYk4it0ZcdVRcECnPNHLxBpI5ch8rNOW3DMCpEl4u3jegRNbrKoCcBQWXeAoM_D-mIHJyvDNIUa4NMU6hQMbSzhNJBH_TL/s640/00039.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Desert Elephants, Ugab River. </td></tr>
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</div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-8942350734081989972012-02-01T04:35:00.000-10:002012-02-01T04:35:23.011-10:00Wednesday Rocks: #4<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">The petrified forest in Namibia's Erongo Region is the result of glacial outwash at the end of a Carboniferous-Permian, Gondwana wide glaciation. The trees are Dadoxylon Arber, an extinct conifer and reach lengths of about 45m (Wikipedia). They are preserved in a palaeo-river channel and recent erosion has uncovered many of the fossilised conifers (Wikipedia). This is evident in the multitude of handwritten 'Petrified Forest' signs along the road from Twyfelfontein to Khorixas. The official park employs people from the area as guides who explain a bit about the geology and botany as you wonder through the silicified trees. The photos below are from the official forest park.</span></span></div><br />
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<div style="font-family: Arial,Helvetica,sans-serif;"><span style="font-size: x-small;"><a href="http://translate.google.com/translate?hl=en&sl=it&u=http://it.wikipedia.org/wiki/Foresta_Pietrificata&ei=3D4pT6OeJNSgiQfEnPzfAg&sa=X&oi=translate&ct=result&resnum=4&ved=0CEMQ7gEwAzgU&prev=/search%3Fq%3DThe%2Broadside%2Bgeology%2Bof%2BNamibia%2Bdownload%26start%3D20%26hl%3Den%26client%3Dubuntu%26hs%3DR3v%26sa%3DN%26channel%3Dfs%26biw%3D1366%26bih%3D592%26prmd%3Dimvnsb">Petrified Forest - Wikipedia</a> </span></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><span style="font-size: x-small;">All Photos were taken by Sameer Morar. </span></div><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial,Helvetica,sans-serif;">This fragment is about 15cm across</span></td></tr>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial,Helvetica,sans-serif; font-size: x-small;">Michael, our guide, and I for scale. I'm 1.69m</span></td></tr>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial,Helvetica,sans-serif;">The knot Michael was pointing at with his stick</span></td></tr>
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</div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-25057330745071804732012-01-25T04:53:00.000-10:002012-01-25T04:53:50.168-10:00Wednesday Rocks: #3<div dir="ltr" style="text-align: left;" trbidi="on"><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">As this Wednesday Rocks being posted 40 minutes into Australia Day (Thursday 26th January) it's fitting that the subject is Australian.</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><br />
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<tr><td style="text-align: center;"><span style="font-size: small;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaG7ZRx1vVtFsoqb5LK3Fisf6T4dYOv1lJUcBG2bWn-4Mor7o-MZUjYuaWysItGKddS6WhFDVpikKB5tEsUgsntFbop4XC6uYOFiOiInmlzJ5uxC9-oycNg84lvHyNTb9gwMvpwSZspFQs/s1600/DSCN3845.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaG7ZRx1vVtFsoqb5LK3Fisf6T4dYOv1lJUcBG2bWn-4Mor7o-MZUjYuaWysItGKddS6WhFDVpikKB5tEsUgsntFbop4XC6uYOFiOiInmlzJ5uxC9-oycNg84lvHyNTb9gwMvpwSZspFQs/s640/DSCN3845.JPG" width="480" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Natural Bridge</span></td></tr>
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</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">In November 2011 we took a drive south of Brisbane into the SE Queensland / NE New South Wales Hinterland (-28.202768,153.249664 - just enter the coordinates into the Google Maps search bar). Our exploring took us to Natural Bridge in the Springbrook National Park </span><span style="font-size: small;">(I keep seeing Springbok but that's a result of my eight years living in South Africa)</span><span style="font-size: small;">. The rocks at Springbrook are part of a ~20Ma shield volcano which forms the Tweed Province, a series of basalt and rhyolite lava flows. Natural Bridge is an erosional feature formed behind a waterfall (Willmott, et al. 1981). </span></div><div style="font-family: Arial,Helvetica,sans-serif;"><span style="font-size: small;"><br />
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<tr><td style="text-align: center;"><span style="font-size: small;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtvV3iN6lymrgzWJXx42MG-GkBoyKV_ytww04VRS-WF1TX-E8rj1WVwlJv4dpWQd8WxJumfsZd_8fckI5PVjgU52e3rY-PpDIx2iBdkx1oBtVeaBKaf-NMeJGLI1oqhbN06pnInjNd7oVO/s1600/DSCN3880.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtvV3iN6lymrgzWJXx42MG-GkBoyKV_ytww04VRS-WF1TX-E8rj1WVwlJv4dpWQd8WxJumfsZd_8fckI5PVjgU52e3rY-PpDIx2iBdkx1oBtVeaBKaf-NMeJGLI1oqhbN06pnInjNd7oVO/s640/DSCN3880.JPG" width="480" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">A river runs through it, the top of the waterfall.</span></td></tr>
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</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">I assume that the formation is the result of a <a href="http://en.wikipedia.org/wiki/Giant%27s_kettle">pothole or kettle</a> forming behind the lip of the waterfall, as evident in the photo above. The rocks possibly faced a four-pronged attack from above, the pothole, below, the falling water eroding the rocks at base of the falls, water eroding joints and fractures in the rocks and then continued erosion by the waterfall. However, these processes are not something I've looked at in detail for a couple of years so feel free to drop suggestions in the comments box.</span></div><br />
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</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">The cave at Natural Bridge is 46m long, 26m wide and 6m high (Webb, et al). It is famous for glow-worms and bats neither of which were in residence on our visit.</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;"><br />
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<a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CD8QFjAD&url=http%3A%2F%2Fwww.vulcanospeleology.org%2Fsym03%2FISV3x12.pdf&ei=mhMgT9-LLcTsmAXi67ygDg&usg=AFQjCNHkVkibcDsTHtKI5OgwITHRw0iWYA&sig2=HDSY_s7dMkW6L7Nv9Ol2nQ">Webb, J.A., Joyce, E.B. and Stevens, N.C. Lava Caves of Australia</a></span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: x-small;">Willmott, W.F, Webb, J.A. and Wade, M. (Eds), 1981. Geological Sites in Southeast Queensland, Report 2. Geological Elements of the National Estate in Queensland, Geo. Soc. Aust. Inc. Queensland division, Brisbane, pp 119. </span></div><div style="font-family: Arial,Helvetica,sans-serif;"><span style="font-size: small;"><br />
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<tr><td class="tr-caption" style="font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: small;">Tweed Valley</span></td><td class="tr-caption" style="text-align: center;"><br />
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</tbody></table><div style="font-family: Arial,Helvetica,sans-serif;"><span style="font-size: small;">Happy Australia Day!! :)</span></div></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-77602538087083116612012-01-18T05:37:00.001-10:002012-01-18T20:15:12.606-10:00Wednesday Rocks: #2<div dir="ltr" style="text-align: left;" trbidi="on"><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">Whakarewarewa </span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;"><br />
</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">As I have mentioned <a href="http://knowledge-flocs.blogspot.com/2011/12/auckland-volcanic-field.html">before</a>, New Zealand's North Island is rife with volcanic activity. I spent part of December and January on the North Island and part of that time was spent camping near Rotorua. Rotorua is part of the Taupo Volcanic Zone. Volcanism here is related to the subduction of the Pacific Plate beneath the Australian/Indian (depending on your source) plate. The volcanic zone has four recent andesite or dacite calderas which are, in order from west to east; Taupo, Maroa, Okataina and Rotorua. Maroa is the largest and Rotorua is the smallest (Cole, 1984). These calderas are situated in the Taupo-Rotorua depression and evidence suggests that the depression is the result of extension (Cole, 1984). </span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;"><br />
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</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">The photos below are from the <a href="http://www.whakarewarewa.com/">Whakarewarewa Geothermal Village</a> which is the happy marriage of New Zealand culture and geology. The village is home to the Tuhourangi/Ngati Wahiao people who use the geothermal springs for cooking, bathing and hot water. The village has been open to visitors since the beginning of the 19th Century and is definitely worth a visit. The people of the village are fantastic and the guides very knowledgeable. While we were at Whakarewarewa we had a hangi, a traditional Moari meal cooked using hot stones. At Whakarewarewa the hangi is unique as it is cooked using the heat from the geothermal system. One of the geothermal pools is also used for cooking. Food is placed in a basket which is lowered into the pool for about 7 to 15 minutes, depending on what's being cooked. </span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;"><br />
</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;"> The geothermal footprint at Rotorua is extensive with hot springs occurring on both the northern and southern shores of Lake Rotorua. Whakarewarewa is situated on the southern shore and the hot water found here ranges from about 90 - 110C. The composition of the hydrothermal waters at Rotorua suggests that there are three related hydrothermal cells. Whakarewarewa and a hydrothermal system which surfaces beneath Lake Rotorua are the hottest reaching temperatures in excess of 250C, at depth. The water flowing to the north of the lake is cooler at 220C. Ions dissolved in the hydrothermal fluids suggest that they interact with basalt and/or rhyolite at depth with basalt being the probable heat source for the thermal waters (Giggenbach and Glover, 1992). </span></div><div style="text-align: justify;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;">References:</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;">Cole, J.W. 1984. Taupo-Rotorua depression: an ensialic marginal basin of North Island, New Zealand. Geo. Sco. London, Special Pub. p 109-120.</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;">Giggenbach, W.F. and Glover, R.B. 1992. Tectonic regime and major processes governing the chemistry of water and gas discharges from the Rotorua Geothermal Field, New Zealand. Geothermics pp 121-140</div><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">Parekohuru, most of the hot water used at Whakarewarewa comes from this spring. It is also the cooking pot.</span></span></td></tr>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">Pohutu, Big Splash, Geyser (I think)</span></span></td></tr>
</tbody></table><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisllg_xzcf_5ITXjROZlNYv0pmfKT5kNpqkQSkKQawvZMVyJjJzQTbSp6dwHVZWPcu1cjD8HQbtEUhNo38stGPX72tE29FGHgdrNh76XZMkdwr1ej5p7fNyk-8kK_tcrQfpPRb5-docMnl/s1600/DSCN4281.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"> </a></div><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">Whakarewarewa Village with Rotorua in the background</span></span></td></tr>
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgV6996fwFzKz8CKMKWy28OyswaYiELusdlCrwVbbq2boGgutIbMBDPy6uNXzWFe2NNi-cGB9nmCqMAA764nGHY-PXF6K29B76Jc3dXm2d5Eod2Tk5sE-eDcspXCVaiNk0umROGbLCtenX4/s1600/20111227_16_11_28_julian.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></div><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">Mud pool with gas bubbles. Photo by Julian Joyce.</span></span></td></tr>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgV6996fwFzKz8CKMKWy28OyswaYiELusdlCrwVbbq2boGgutIbMBDPy6uNXzWFe2NNi-cGB9nmCqMAA764nGHY-PXF6K29B76Jc3dXm2d5Eod2Tk5sE-eDcspXCVaiNk0umROGbLCtenX4/s1600/20111227_16_11_28_julian.jpg" style="margin-left: 1em; margin-right: 1em;"></a><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><span style="font-family: Arial,Helvetica,sans-serif;">The hangi meal, cooked with the wonders of geothermal energy :) and very tasty</span></span></td></tr>
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</div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-29390768096637963612012-01-11T04:16:00.000-10:002012-01-11T04:16:38.537-10:00Wednesday Rocks: #1<div dir="ltr" style="text-align: left;" trbidi="on"><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">Wednesday rocks will be my regular mid-week post of a cool, in my opinion, geo-related photo with a bit of an explanation. </span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;"><br />
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Today's image is from the Cape Fold Belt (CFB), which is a mini meme started by Brian Romans of <a href="http://www.wired.com/wiredscience/2011/12/friday-field-photo-162-folded-quartzite-in-the-cape-fold-belt/">Clastic Detritus</a> with posts by Evelyn Mervine of <a href="http://blogs.agu.org/georneys/2011/12/27/monday-geology-picture-a-glimpse-of-the-cape-fold-belt-through-a-car-window/">Georneys</a> and Callan Bentley of <a href="http://blogs.agu.org/mountainbeltway/2011/12/23/friday-fold-a-wrinkled-mountain-in-hermanus/">Mountain Beltway</a>. </span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;">The CFB extends for roughly 500km from Port Elizabeth to Cape Town where it takes a 90 degree turn northwards and can be followed for about 350km to Vanrhynsdorp. From the air the rocks of the CFB form very distinctive ridges which I'd always watch out for when flying to Cape Town. I get bored during flights so seeing the familiar folds and ridges of the Cape Mountains is a nice reprieve from the monotony of the Karoo. There is a cool Landsat image of the CFB <a href="http://jeanine.engelbrechtonline.net/blog/2010/01/08/cape-fold-belt/">here</a> posted by Jeanine Engelbrecht. </span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="font-size: small;"><em></em></span></div><em><br />
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<tr><td class="tr-caption" style="text-align: center;">Near vertical bedding of the Carboniferous Witteberg Group. Mudstone layers <br />
have been preferentially weathered leaving two sandstone ridges. <br />
The photo is fom the hills behind Ladismith, Western Cape, South Africa </td><td class="tr-caption" style="text-align: center;"><br />
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</div></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-67349849909735662972012-01-06T20:37:00.000-10:002012-01-06T20:37:31.146-10:00Learning Geology Online: Sifting The Fake From The Genuine<div dir="ltr" style="text-align: left;" trbidi="on"> <style type="text/css">
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<div style="margin-bottom: 0cm;">This may seem like a random topic. But I come from a education system where the academic year begins now or within the next month and with all the talk about the <a href="http://all-geo.org/highlyallochthonous/2012/01/how-useful-are-lectures-really/">importance of lectures</a> it seemed natural.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">Many people are interested in how the Earth works. They have become interested in rocks by reading geology blogs, moving to areas with rocks visibly mangled by tectonic forces or hearing about volcanoes, earthquakes and climate change on the news. The information from blogs is like dipping one's toe in the water, mangled rocks are just plain confusing and the media often gets things wrong. People interested in Earth processes and geology may be left wanting more. </div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">My sisters are studying by correspondence through the University of South Africa (UNISA). This has made me curious about this as an option for geology. Can one study geology by correspondence or online? The advantages of distance learning are; it is perfect for people who can only study part time and it tends to be cheaper than physically being on campus. On the other hand one has to be very self motivated and disciplined and there are no lectures or lecturers to guide one. Yes emails are answered but there is nothing quite like one on one contact when one is struggling with a concept. Added complications when studying geology by correspondence are field work and practicals. I have found that students struggle with concepts such as mineral cleavage or visualising things in 3D (yes the layers on Table Mountain do indeed go all the way through the mountain). My one sister did chemistry and zoology through UNISA (she's now studying psychology) so the practical side is not impossible. She did her chemistry practicals in the chemistry labs at the University of Namibia and the zoology practicals in Potchefstroom, South Africa. So I know that studying science via correspondence is doable. But are there options for people interested in geology? And if yes what are they? </div><div style="margin-bottom: 0cm;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgD84PN5sR0dH2_QEGtTLR4lHYj7lUHC5vTnig2enXOrMxhwHupw6O1j2RdFAamyfw9ZACheD4ySvyL6Tgnb3w2Baw70Wa_7KElqsX4CkFp5ytLKrxxpmba1yhwtbAPI0B5RFQB4jHdD-Fn/s1600/DSC07501.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgD84PN5sR0dH2_QEGtTLR4lHYj7lUHC5vTnig2enXOrMxhwHupw6O1j2RdFAamyfw9ZACheD4ySvyL6Tgnb3w2Baw70Wa_7KElqsX4CkFp5ytLKrxxpmba1yhwtbAPI0B5RFQB4jHdD-Fn/s640/DSC07501.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Table Mountain, Cape Town, South Africa. Taken from Lion's Head.</td></tr>
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</div><div style="margin-bottom: 0cm;">From my googling there seems to be two options 1) a degree in geology by distance learning and 2) free courses which teach the basic principles but do not result in a geology degree. I have also discovered that this is more complex than I had at first thought so I am going to cover distance learning in a series of blog posts. I shall evaluate the different free courses and then potential degree options by country. In this post I shall tackle how to choose an institution.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">Important questions to ask yourself are: what do I expect to gain from this course/degree? Do I want to be a geologist or do I just want an introduction so that I understand the basics? If I want to be a geologist will this degree make me employable as a geologist? Is the organisation offering the course a real accredited institution? </div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">The last two questions are linked. A degree from a genuine institution should make one employable as a geologist. Determining the legitimacy of an online institution can be easy in some cases and difficult in others. Courses from the Massachusetts Institute of Technology (MIT) or Birkbeck University of London are probably legit. Courses from University Degree Program are probably not. Personally I would use four steps to determine the legitimacy of an online university which I have listed below. If you can think of any of any others feel free to add them in the comments section.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">1) Is the institution accredited by a valid organisation? </div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">Wikipedia has a wonderful list of <a href="http://en.wikipedia.org/wiki/List_of_unaccredited_institutions_of_higher_education">dodgy institutions</a> (interestingly/unsurprisingly a fair number of them have theology in the title). Wikipedia also makes life easy by listing all the bodies which can <a href="http://en.wikipedia.org/wiki/List_of_recognized_accreditation_associations_of_higher_learning">legally</a> decide whether an institution is accredited or not. Although the Central Council of Homoeopathy is on this list! To complement the list of accredited accreditors Wikipedia has a list of <a href="http://en.wikipedia.org/wiki/List_of_unrecognized_higher_education_accreditation_organizations#I">non-accredited</a> accreditors.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">While I have linked to Wikipedia here, remember the lists are probably incomplete so use them as a starting point for your search.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">2) What is their course work/syllabus? </div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">Courses about plate tectonics, mineralogy and petrology are a good start. Courses about Noah's Flood are an obvious red flag.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">3) Check the staff.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">Who works at the institution? Where did they get their degree from? What are their research interests? Have they published any journal articles? Which journals have they published in?</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">4) To make doubly sure you can check with on organisation you trust.</div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;"><a href="" name="IARC Recognised Institution"></a><a href="" name="IARC Course Accredited"></a> Geological surveys and societies are a good places to go. The Geological Society of London a list of <a href="http://www.geolsoc.org.uk/gsl/pid/2812;jsessionid=F4E703FACF4CC6ECD9A771032AC5294C">accredited UK institutions</a>, for example. If there is nothing on their website you can contact your local survey and ask them if the online institution you are thinking of enrolling with is valid. </div><div style="margin-bottom: 0cm;"><br />
</div><div style="margin-bottom: 0cm;">Once you have determined that the institution is genuine the next step is looking at the courses offered in more detail. This will be the topic of my next post about online learning.</div></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com2tag:blogger.com,1999:blog-3200129138409538703.post-51276331183510711952012-01-05T02:09:00.001-10:002012-01-05T02:17:38.995-10:00Windhoek's Weird Weather<div dir="ltr" style="text-align: left;" trbidi="on"><style type="text/css">
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<div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"><a href="http://ron.outcrop.org/blog/?p=1432">Ron Schott is hosting the latest Accretionary Wedge</a>. He is asking us to recall the most memorable/significant geologic event that we have directly experienced. I have lived my life in very geologically stable places so this topic may seem a bit odd as my first entry for the Accretionary Wedge. There has been some neo-tectonic activity with small earthquakes in Namibia and the Western Cape, South Africa, but I have not felt any. There was also apparently an earthquake near Cape Town in my first year at university. I didn't feel that one either. I have traipsed across active faults and volcanoes but fortunately non ruptured or erupted while I was there. The youngest volcano I've lived next to is Regenstein, on the outskirts of Windhoek, and that last erupted in the early tertiary (the only age I can find; Pirajno, 1994) and is extinct. When it comes to geologic hazards, I have lived a sheltered life.</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"><br />
</span> </div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;">My sister-in-common-law and her husband used to live in Christchurch. It was scary when we couldn't contact them during the 22-Feb-2011 earthquake. Fortunately they were ok, although, their office buildings have been either demolished or condemned. There was a slim chance that we would be spending this christmas in Christchurch. However, they moved the week before we arrived in New Zealand. They now live on the North Island and I am charged with keeping them abreast of volcanic developments. My Partner was in Christchurch for the boxing day earthquake 2010 and in Brisbane during the floods in January 2011 (he just missed the cyclone). Me? I was in nice, stable and politicians aside, non-crazy Southern Africa. Windhoek, Namibia to be precise. What could I possibly experience in Windhoek that would fit the guidelines of Accretionary Wedge #41?</span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"><br />
</span> </div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;">Windhoek is supposed to have an average rainfall of about 350mm per year. Normally we are grateful for rain. We might even consider investigating the merits of rain-dancing. When Windhoek rivers flow many (most?) people in Windhoek go down to the banks to watch the standing waves go by and children play in the parts flowing slowly. Summer in Windhoek, you see, is usually hot and dry. </span></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivRntCxA1q4x83-MNbpQgeWcYk2AgyZNfeDXyKgG7WYsZZ4rZHoHCQjvTdwu6d0eG79txxubHUVkqRUDFxdd2kSJ0QEqRwJkMg3EwQIskPJxDc28Uwo6ni_KCQILTDM8Nl5SeHbsas2iv2/s1600/DSCN0037.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivRntCxA1q4x83-MNbpQgeWcYk2AgyZNfeDXyKgG7WYsZZ4rZHoHCQjvTdwu6d0eG79txxubHUVkqRUDFxdd2kSJ0QEqRwJkMg3EwQIskPJxDc28Uwo6ni_KCQILTDM8Nl5SeHbsas2iv2/s640/DSCN0037.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The hills on the southern edge of Windhoek. December 2010</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2mSJhnp6GOg8P2ZGce0Wptt-ckdauOiiBchPp2DegaWBLgZm3atO-zpdP97pStk0H1Sijm2qpTxK8Xft5lK-b0T9H6sB1vePEL30rUCzwXgAKofFmExNg_Ao7c4auU-iMtTBKN0jH-N48/s1600/DSCN0044.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2mSJhnp6GOg8P2ZGce0Wptt-ckdauOiiBchPp2DegaWBLgZm3atO-zpdP97pStk0H1Sijm2qpTxK8Xft5lK-b0T9H6sB1vePEL30rUCzwXgAKofFmExNg_Ao7c4auU-iMtTBKN0jH-N48/s640/DSCN0044.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Not very green and not much grass to speak of. December 2010. Jill Russell <br />
(aka Jilly Bean) smiling at the camera</td></tr>
</tbody></table><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"></span> </div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;">In January last year it was different. Last year we had <a href="http://weather.namsearch.com/Windhoekrainhistory.php">383.6mm</a> of rain in January alone. By the start of winter Windhoek had had over 1000ml of rain! By the start of winter we were all rather damp and sick of rain. Our roads were full of pot-holes and in some cases washed away all together. There are three bridges, I know of, across the Klein Windhoek River, Windhoek's main river. The roads the river crosses tend to be added to its sediment load. </span></div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"><br />
</span> </div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;">This unusual rainfall occurred across the country. There was flooding in the North. The Sesriem Canyon was full of water and Sossusvlei was flooded in the South. I spent a weekend in Henties Bay. It rained on our first night. Henties Bay is in the desert. Rivers in Windhoek and across Namibia were still flowing in May. Unheard of! Then in winter it actually snowed. Just a dusting in Windhoek and a bit heavier in the South. It last snowed in Namibia in about 1995. </span></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjycFlaW9tMFNhqsA1xQDnGp7IYvmP7d6pA3h92yqmAjoTmm4-P9P481cEycrKovu0-6vWSjq2jdv5xT1ByAUKt1E2O7VONKJAOXcs7RSVH8Bg6a6EU2X5IoPw9his4LxWBUl56QFJUV5ki/s1600/DSCN0572.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjycFlaW9tMFNhqsA1xQDnGp7IYvmP7d6pA3h92yqmAjoTmm4-P9P481cEycrKovu0-6vWSjq2jdv5xT1ByAUKt1E2O7VONKJAOXcs7RSVH8Bg6a6EU2X5IoPw9his4LxWBUl56QFJUV5ki/s640/DSCN0572.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Exactly the same slope as the first picture. January 2011</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi70oQXpP2WYvhuXUxeXYNgu8_f1a0Ki9B62jEO-95dYaVMP7Ce_n4zsnIhOgK6wpIkabmt2TiGtfvQ9Bx72QdwaqDJiEnZLtfeG6VpCjMcFPmu6y2AauLINAeMC2w-D4ctef3v2ULDx64Y/s1600/DSCN0574.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi70oQXpP2WYvhuXUxeXYNgu8_f1a0Ki9B62jEO-95dYaVMP7Ce_n4zsnIhOgK6wpIkabmt2TiGtfvQ9Bx72QdwaqDJiEnZLtfeG6VpCjMcFPmu6y2AauLINAeMC2w-D4ctef3v2ULDx64Y/s640/DSCN0574.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The hills on the southern edge of Windhoek, January 2011</td></tr>
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</div><div style="font-family: Arial,Helvetica,sans-serif; text-align: justify;"></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;">And there you have it the most significant earth science related event I have experienced directly, to date. As for Windhoek? So far this summer has been business as usual, piping hot and dry, with all the people I know in Windhoek looking at the sky, searching for the welcome glint of a cloud.</span></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;">Pirajno, F. 1994. </span><span style="font-size: small;">Mineral resources of anorogenic alkaline complexes in Namibia: A review. Australian Journal of Earth Sciences, pp. 157-168.<br />
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</div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;">More photos from Windoek. These are of Avis Dam on the eastern edge of the city.</span></div><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglfaWdAH7GeTgVLlyWmN5b9d9lZngA2tjBUPpi5Y-XjO7RsoTwjWHMIoWN5hxUtuRBJF70RJOBkmUi3GKafAHJc2kHu6SM23J7ovAhRnZTjf3ljaNdnjJwTuqmY7VLTgU3gVtjOcC7AFN-/s1600/DSCN0005.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglfaWdAH7GeTgVLlyWmN5b9d9lZngA2tjBUPpi5Y-XjO7RsoTwjWHMIoWN5hxUtuRBJF70RJOBkmUi3GKafAHJc2kHu6SM23J7ovAhRnZTjf3ljaNdnjJwTuqmY7VLTgU3gVtjOcC7AFN-/s640/DSCN0005.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Avis Dam flood plain, Windhoek, December 2010</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj16JtI3ow_3_9A-6PyH4WuyQnigq_A-dzTSZATzWzwT_lA8FCEunqDN5uvF9Z07rN8DAkLAHYhgbwKw2sGb3ldqG1v4eF9-VZqKN50gvEUWkFBESXqvf1bCoZaZdJCA_ZOsGU2t12aiCgg/s1600/DSCN2412.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj16JtI3ow_3_9A-6PyH4WuyQnigq_A-dzTSZATzWzwT_lA8FCEunqDN5uvF9Z07rN8DAkLAHYhgbwKw2sGb3ldqG1v4eF9-VZqKN50gvEUWkFBESXqvf1bCoZaZdJCA_ZOsGU2t12aiCgg/s640/DSCN2412.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Avis Dam flood plain, Windhoek, January 2011</td><td class="tr-caption" style="text-align: center;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzgE74h9Uxd3hdklN-PLgDdFDIKDkiQBGkbzHJ3_6C6LPX1uuvAzwn32FxY2Ej_xsABQ5lh6koxykkpwPHYUiL9B1JBntcoQ5DkChchodaNREjQI0IdrhV7pWDKf0iUjvt36oEB2Sso7kl/s1600/DSCN0014.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzgE74h9Uxd3hdklN-PLgDdFDIKDkiQBGkbzHJ3_6C6LPX1uuvAzwn32FxY2Ej_xsABQ5lh6koxykkpwPHYUiL9B1JBntcoQ5DkChchodaNREjQI0IdrhV7pWDKf0iUjvt36oEB2Sso7kl/s640/DSCN0014.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Rail bridge, and river feeding Avis Dam. Windhoek, beginning of January<br />
2011</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO4sGId7aXkNS86o5V6kw3kYpV2WYS-IMCZgmppF3h6tzJJhiaeq8_ZZBVbLdrEdYsaTnC5Sk_Jq1liWki_Cj0Nb81C-syBnrjrZU5EaaK9zAyjL_E3hjIVfvgA8cLp479OJbY6Kftj-Hp/s1600/DSCN0359.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO4sGId7aXkNS86o5V6kw3kYpV2WYS-IMCZgmppF3h6tzJJhiaeq8_ZZBVbLdrEdYsaTnC5Sk_Jq1liWki_Cj0Nb81C-syBnrjrZU5EaaK9zAyjL_E3hjIVfvgA8cLp479OJbY6Kftj-Hp/s640/DSCN0359.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">River flowing into Avis Dam. Windhoek, 22 January 2011</td></tr>
</tbody></table><div style="font-family: Arial,Helvetica,sans-serif; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"> </span></div></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-88838826183610198732011-12-22T16:08:00.000-10:002011-12-22T16:08:36.075-10:00Happy # insert relevant holiday here # to you all<div dir="ltr" style="text-align: left;" trbidi="on">I'm off camping for the next week. So here are some picture from Augrabies National Park, South Africa. The river guilty of carving the canyon is the Orange River :) These were taken in 2006 when we went on the University of Cape Town's epic Honours field trip. These two photos were taken by Nic Laidler and appear here with his permission.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnCYf5bnzqEg_L6RcISF5feUlz1QdVe9VFsSsuchL5NzeLJ58qXj_q4VrFa6fw2gRIMj6-OqFFha0QRU-AmCPYhpAptRDrqWSdMfNYL6jJ4ykNPF4U7MDqOzB03H4fV1yNHA_ys8N1wpbt/s1600/DSC02439.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnCYf5bnzqEg_L6RcISF5feUlz1QdVe9VFsSsuchL5NzeLJ58qXj_q4VrFa6fw2gRIMj6-OqFFha0QRU-AmCPYhpAptRDrqWSdMfNYL6jJ4ykNPF4U7MDqOzB03H4fV1yNHA_ys8N1wpbt/s640/DSC02439.JPG" width="640" /></a></div><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQZsdbLWufo2B8PnEZnGo92yMOfBTzoMwETRARtsAL8fkDaotgrh_2xYHyL4m64FyWTPVAU0ToJklEixTAUfg2Lb7HrepuBKqBkkBvzZgdpiBhxgXuGZwXgZPZV6FDEl8RotvsFRs6RIR8/s1600/DSC02444.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQZsdbLWufo2B8PnEZnGo92yMOfBTzoMwETRARtsAL8fkDaotgrh_2xYHyL4m64FyWTPVAU0ToJklEixTAUfg2Lb7HrepuBKqBkkBvzZgdpiBhxgXuGZwXgZPZV6FDEl8RotvsFRs6RIR8/s640/DSC02444.JPG" width="640" /></a></div><br />
This video is from January this year (2011) when Southern Africa had an unusually large amount of rain.<br />
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<div class="separator" style="clear: both; text-align: center;"><object width="320" height="266" class="BLOGGER-youtube-video" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,40,0" data-thumbnail-src="http://0.gvt0.com/vi/19GiAHP_0NA/0.jpg"><param name="movie" value="http://www.youtube.com/v/19GiAHP_0NA&fs=1&source=uds" /><param name="bgcolor" value="#FFFFFF" /><embed width="320" height="266" src="http://www.youtube.com/v/19GiAHP_0NA&fs=1&source=uds" type="application/x-shockwave-flash"></embed></object></div><br />
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And last but not least, have a fantastic festive season and a wondrous new year!<br />
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</div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-74287763783748381692011-12-21T03:04:00.007-10:002012-01-28T21:10:44.840-10:00Aussenkehr<div dir="ltr" style="text-align: left;" trbidi="on"><style type="text/css">
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<div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif; font-size: small;">Last year September (2010) I was part of a group hiking the Fish River Canyon. On the way to the canyon, driving north from Cape Town, three of us stopped off in <a href="http://www.aussenkehr.com/">Aussenkehr</a>, just North of the Orange River. It is an area I have only ever driven past and a cursory Google search was unenlightening so I didn't really know what to expect. All I can say is 'what a nice surprise!'. The crags at Aussenkehr are part of the Karoo Large Igneous Province (LIP) with similar ages and geochemistry (Richardson, 1979 and 1984; Reid and Rex, 1994; Marsh, et al. 1997). The Karoo LIP covered and/or intruded most of Southern Africa and part of Antarctica, the Ferrar-Province, current estimates for the size of the LIP are around 3 000 000km</span><span style="font-size: small;"><sup><span style="font-family: Arial,sans-serif;">2</span></sup></span><span style="font-family: Arial,sans-serif; font-size: small;"> (Jourdan, et al. 2007). Outcrops of the Karoo LIP can be found in Botswana, Malawi, Mozambique, Namibia, South Africa, Zamibia and Zimbabwe with unconfirmed occurrences in Angola (Jourdan, et al. 2007).</span></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8ffPCclB2FjixUO_Sjnep0VqBMAcuK4vh0wS9yYA4e5NblGRTDedlYgboKA7IX20Bhyphenhyphen0a-N7L8dXRr-5mWRP53nXx69U7bdsF4Jj7Q1fhljNTLEWYd5M_TxplIZgRiKU1LwYvE6yPTC2F/s1600/location.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="390" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8ffPCclB2FjixUO_Sjnep0VqBMAcuK4vh0wS9yYA4e5NblGRTDedlYgboKA7IX20Bhyphenhyphen0a-N7L8dXRr-5mWRP53nXx69U7bdsF4Jj7Q1fhljNTLEWYd5M_TxplIZgRiKU1LwYvE6yPTC2F/s400/location.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Location of Aussenkehr; the 'A' marks the spot. Image from <br />
Google Maps</td></tr>
</tbody></table><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif; font-size: small;">Much of the present surface expression of the Karoo LIP in Namibia is restricted to sills and dykes. The Aussenkehr rocks are part of the Tandjiesberg dolerite (diabase) sill complex, which has at least 55km of outcrop and is between 80 and 110m thick. The sill consists of two units, the upper and lower sill (Richardson, 1979 and 1984; Reid and Rex, 1994). The columnar jointing in the dolerite cliffs make for some fantastic climbing. I need to go back to do some actual climbing, at the time I was to distracted by the scale of the dyke, clambering over the rocks and hitting things with my geopic. </span></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixuGt7C2b5jmgvzPrgjZbkMrL4j-KGfnJ2D5EJHRhyphenhyphenla2lFRWPOsznOEmlpIYe1S8Eqn_iKWhODZlyG5eGF791LkCB-2sse5HrF-o0sRZ0D-PXNVmZBeoX-_RA5NtGS1GqHZdDD9J74KF8/s1600/DSC07757.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixuGt7C2b5jmgvzPrgjZbkMrL4j-KGfnJ2D5EJHRhyphenhyphenla2lFRWPOsznOEmlpIYe1S8Eqn_iKWhODZlyG5eGF791LkCB-2sse5HrF-o0sRZ0D-PXNVmZBeoX-_RA5NtGS1GqHZdDD9J74KF8/s640/DSC07757.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">My partner, taking full advantage of the columnar joints</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_eeRENx9iabgF_DNuf4DTe3bNzckcC2fTx_sFeuUdVxFHMPiztENQbmVZ6OIXwuimgttqcBm6EjO6epgdcvcFaaCkGCspqfcgyTu6vMdKwUD1MB1eFR19oBkq6ob2drjtYn8f0-UTjegJ/s1600/DSC07759.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_eeRENx9iabgF_DNuf4DTe3bNzckcC2fTx_sFeuUdVxFHMPiztENQbmVZ6OIXwuimgttqcBm6EjO6epgdcvcFaaCkGCspqfcgyTu6vMdKwUD1MB1eFR19oBkq6ob2drjtYn8f0-UTjegJ/s640/DSC07759.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The vertical extent of the sill was rather impressive, car for scale</td></tr>
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</div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif; font-size: small;"><i>The geology/geochemistry</i> </span></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif; font-size: small;">The lower sill, relative to the upper sill, is enriched in incompatible* elements, e.g. Rb, Zr and Y and depleted in compatible** elements such as MgO, indicating that the lower sill has a slightly more evolved*** composition than the upper sill. Trends and ratios between these elements indicate that the two sills could be related by fractional crystallisation (Reid and Rex, 1994). </span> </div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"><br />
</span> </div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;">*Elements which are not easily incorporated into the crystal structure of the major rock forming minerals, in the case of a mafic magma these minerals are olivine, pyroxene and plagioclase feldspar.</span></span></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;">**Elements which are either major constituents or easily incorporated into the crystal structure of major rock forming minerals.</span></span></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;">***As minerals are crystallised out of a magma they remove elements from the magma. This results in the composition of the magma changing. The concentration of incompatible elements increases while the compatible element concentrations decrease. The remaining liquid has a more evolved composition.</span></span></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"><br />
</span> </div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif; font-size: small;">The upper sill has a fine-grained chilled margin caused by the initial contact with the country rock. This is usual for large igneous bodies intruding much colder rock. From the edge to the centre of the sill the grain-size increases as the magma had more time to cool and form larger crystals. The sill groundmass consists of plagioclase, pyroxene and opaque minerals (e.g. iron oxides and/or sulphides depending on whether the magma is oxidised or not) and the microphenocrysts present are plagioclase, augite and olivine (petrography; Richardson, 1979). Richardson (1979) identified changes in magma chemistry and phenocryst concentrations and composition from the edge to the centre of the sill. Often chemical and mineral zoning in sills is caused by minerals settling to the bottom of the magma due to gravity. However, the pattern of chemical change and lack of mineral layering normally associated with gravitational settling, in upper sill, argues against this as a mechanism for the chemical changes (Richardson, 1979). The internal chemical variation observed is also inconsistent with fractional crystallisation, assimilation and multiple intrusions of magma. The chemical zoning is continuous along the 20km length sampled by Richardson (1979) and is attributed it to the migration of phenocrysts to the centre of the sill, flow differentiation. Similar differentiation has been observed in Hawaii in the Makaopuhi lava lake (Moore and Evans, 1967). The lower sill has not been described in much detail or at least I couldn't find the journal article describing it.</span></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdp-4S1gTw-LFNEs7rxxS1OnFkccfPtZsaqnECQQu0fYxXgciT6q_M0qfd4RCmMHfLB1DWKn5e7KnINH-rI8n0Oho1Tl0BpU8vezxvObiTrdolpJ12Do7aclF-SW9qZJ8U9CE9wPDCIfT_/s1600/Phenocryst+groundmass.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="298" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdp-4S1gTw-LFNEs7rxxS1OnFkccfPtZsaqnECQQu0fYxXgciT6q_M0qfd4RCmMHfLB1DWKn5e7KnINH-rI8n0Oho1Tl0BpU8vezxvObiTrdolpJ12Do7aclF-SW9qZJ8U9CE9wPDCIfT_/s400/Phenocryst+groundmass.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Just to demonstrate the difference between phenocryst and <br />
groundmass. This is from a quartz porphyry dyke. <br />
A phenocryst is a large/larger crystal in a fine-grained <br />
groundmass. In this image the phenocryst is quartz.</td></tr>
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</div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><a href="http://www.blogger.com/post-edit.g?blogID=3200129138409538703&postID=7428776378374838169&from=pencil" name="queryn"></a> <span style="font-family: Arial,sans-serif; font-size: small;">T</span><span style="font-family: Arial,sans-serif; font-size: small;">here is an unsolved</span><span style="font-family: Arial,sans-serif; font-size: small;"> </span><span style="font-family: Arial,sans-serif; font-size: small;"><span style="font-weight: normal;">conundrum for the sills in Namibia. No feeder dykes have been observed so how did magma originating near the east coast of South Africa travel so far? Reid and Rex (1994) analysed the largest and most prominent dyke in the area, the Mehlberg dyke, to determine if it was the magma conduit for the large Tandjiesberg sill complex. Chemical composition and age ruled out this option. The dyke is 133Ma and has a higher silica content than the sill (Reid and Rex, 1994). The connecting sills and dykes between the Karoo rocks in South Africa and those in Namibia have yet to be identified or perhaps they have already been eroded away.</span></span></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-size: small;"><br />
</span> </div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><i><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">References</span></span></span></i></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">Jourdan, F., Feraud, G., Bertrand, H., Watkeys, M.K. And Renne, P.R. 2007. Distinct brief major events in the Karoo Large Igneous Province clarified by new 40Ar/39Ar ages on the Lesotho basalts. Lithos, pp 195-209</span></span></span></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">Marsh, J.S., Hooper, P.R., Rehacek, J., Duncan, R.A., Duncan, A.R., 1997. Stratigraphy and age of Karoo basalts of Lesotho and implications for correlation within the Karoo igneous province. In: Mahoney, J.J., Coffin, M.F. (Eds.), Large Igneous Province: Continental, Oceanic and Planetary Flood Volcanism. Geophysical Monograph series, Washinton D.C., pp. 247–272</span></span></span></div><div style="text-align: justify;"></div><style type="text/css">
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<div align="JUSTIFY" style="line-height: 150%; margin-bottom: 0cm;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">Moore, J. and Evans, B. 1967, The role of olivine in the crystallization of prehistoric Makaopuhi lava lake, Hawaii: Contributions to Mineralogy and Petrology , pp. 202-223 </span></span></span> </div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><a href="http://web.uct.ac.za/depts/geolsci/people/staff/dlr.html#publications"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">Reid, D.L. and Rex, D.C. 1994. Cretaceous dykes associated with the opening of the South Atlantic: the Mehlberg dyke, north Richtersveld. South African Journal of Geology, pp 135-145</span></span></span></a></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">Richardson,S.H. 1979. Chemical differentiation induced by flow differentiationin an extensive Karoo dolerite sheet, Southern Namibia. Geochem.Cosmochim. Acta, pp 1433-1441</span></span></span></div><div style="text-align: justify;"></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">Richardson, S.H. 1984. Sr, Nd and O isotope variation in an extensive Karoo dolerite sheet, southern Namibia. Special Publication, Geological Society of South Africa, pp 289-294</span></span></span></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><br />
</div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">If anyone is interested in reading about geochemistry and how it all works this online text book by <a href="http://www.geo.cornell.edu/geology/classes/geo455/Chapters.HTML">William White</a> isn't bad. </span></span></span></div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><br />
</div><div style="line-height: 150%; margin-bottom: 0cm; text-align: justify;"><span style="font-family: Arial,sans-serif;"><span style="font-size: x-small;"><span style="font-weight: normal;">Some more photos from the crags </span></span></span></div><div style="text-align: justify;"></div><div align="JUSTIFY" style="line-height: 150%; margin-bottom: 0cm;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgynvh6_uMcfgy1rhe9YaQfDIms6Q3ATQUowEY6el4nguO6_wuH3Ub-k7h4zWrrN4UX3_uelPYyN17OdFxO4lOfkWpE9wswi2TTm9wtXbKFbV1AG2U7FDQTaNE7sxoapQXtOH-4j3tggb3w/s1600/DSC07815.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgynvh6_uMcfgy1rhe9YaQfDIms6Q3ATQUowEY6el4nguO6_wuH3Ub-k7h4zWrrN4UX3_uelPYyN17OdFxO4lOfkWpE9wswi2TTm9wtXbKFbV1AG2U7FDQTaNE7sxoapQXtOH-4j3tggb3w/s640/DSC07815.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Cool village on the bank of the Orange River. The Spar shop was reasonably stocked and having<br />
forgotten my hairbrush in Cape Town it was most useful!</td></tr>
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</div></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-46635067988353329602011-12-16T04:39:00.001-10:002012-01-07T20:05:11.097-10:00Friday geology photos: Fish River Canyon<div dir="ltr" style="text-align: left;" trbidi="on"><style type="text/css">
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<div style="margin-bottom: 0cm; text-align: justify;">The Fish River Canyon is one of Namibia's many wonders. The canyon is marketed as the second biggest in the world after the Grand Canyon. At 550m maximum depth and 160km long it is definitely a baby compared to the Grand Canyon but the Fish, as it is affectionately known, is a fantastic place in its own right. The first photo is from the view point at Hobas, which is the starting point of the Fish River hiking trail. The trail is 65 to 90km depending on whether you stick to the river course or cut across the meanders. The latter is far more fun, cool rocks and the added bonus of a break from the sand. The canyon is open to hikers from May to September each year. Flash flooding and high summer temperatures make it dangerous to hike from October to April. The photos below were taken when I hiked the canyon in September last year (2010).</div><div style="text-align: justify;"></div><div style="margin-bottom: 0cm; text-align: justify;"><br />
</div><div style="margin-bottom: 0cm; text-align: justify;"><i>The geology in brief</i></div><div style="margin-bottom: 0cm; text-align: justify;"></div><div style="text-align: justify;"></div><div style="margin-bottom: 0cm; text-align: justify;">Doming related to the African Superswell is thought to have resulted in the Fish incising its bed. There are beautiful exposures of the nonconformity between the ~550-750Ma sediments of the Nama group and the +1000Ma Gordonia Subprovince, migmitites and granite gneisses. These rocks are cut by two sets of <a href="http://en.wikipedia.org/wiki/Diabase">dolerite (diabase)</a> dykes one associated with break-up of Rhodina, which abuts against the Nama sediments. The second is related to the break-up of Gondwana. These are the youngest rocks in the canyon. </div><div style="margin-bottom: 0cm;"><br />
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<tr><td class="tr-caption" style="text-align: center;">View from Hobas look out point</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy09Sd_yQ4RDBYicdB_MARhFpacGvN8BHC74rO_-h-c0hzrKZ6ptHjOKYcGF5HkVVUOfkkdyf4X3IG6mKyJqSvOF6HpH-bpvONtVmdAEDRHETYpKJ13fB0ZnSCOvi1x6FoktkjiSoEhFlq/s1600/DSC07862.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy09Sd_yQ4RDBYicdB_MARhFpacGvN8BHC74rO_-h-c0hzrKZ6ptHjOKYcGF5HkVVUOfkkdyf4X3IG6mKyJqSvOF6HpH-bpvONtVmdAEDRHETYpKJ13fB0ZnSCOvi1x6FoktkjiSoEhFlq/s640/DSC07862.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Migmatite :)</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVc3ZFluvh8ORM5WlWNaYggfYauhmfxJ2sfScN0N9wsD3Zd5VMHql_ZcG2hsX9Iq6UkP4TUeEjW8anQy09y3JCYAGhS5SxlAa-Sew0O_VWl7mYelCPI9pWfLRY-G67Pou-Y9Ibt67m6bHe/s1600/DSC07885.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVc3ZFluvh8ORM5WlWNaYggfYauhmfxJ2sfScN0N9wsD3Zd5VMHql_ZcG2hsX9Iq6UkP4TUeEjW8anQy09y3JCYAGhS5SxlAa-Sew0O_VWl7mYelCPI9pWfLRY-G67Pou-Y9Ibt67m6bHe/s640/DSC07885.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Noncomformity between the Nama sediments (top) and the Gordonia migmitites (bottom) <br />
The dark band is one of the older dolerite dykes </td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_BZk9r6bH9pCD75WJRJzhELGIFc3oTWyWcBCgo5HQOp0I8KE1sEyVBM36s9f-lRNm0BMswjLNhiR9lEGD6PqQhXM-77y8TA6r9JOHT51wsoPoDNptAZByv7J6efEW3A3jJYy6OBQvWV1L/s1600/DSC07883.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_BZk9r6bH9pCD75WJRJzhELGIFc3oTWyWcBCgo5HQOp0I8KE1sEyVBM36s9f-lRNm0BMswjLNhiR9lEGD6PqQhXM-77y8TA6r9JOHT51wsoPoDNptAZByv7J6efEW3A3jJYy6OBQvWV1L/s640/DSC07883.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Desert horses. They are the descendants of escapees once owned by the German colonisers.</td></tr>
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</style> </div><div style="margin-bottom: 0cm;">Grunert, N., (2000) Namibia - fascination of geology: A travel handbook. Klaus Hess Publishers, pp 176</div></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-36687040741347368222011-12-15T01:24:00.000-10:002011-12-15T01:24:42.830-10:00Photo week continued: St Lucia<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;">Following <a href="http://blogs.agu.org/georneys/2011/12/12/monday-geology-picture-a-gorgeous-cape-town-inselberg/">Evelyn, from Geoneys</a>, fantastic idea of a week of geology photos here is my second instalment.<br />
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St Lucia is one of the windward islands in the lesser Antilles, West Indies. I have fond memories of this beautiful island as not only is it the location of my sister-in-common-law and her husband's wedding, it was also my first trip to an active volcano. Until my visit to the Soufrière Volcanic Centre I had only ever traipsed around the innards of long extinct volcanoes. To visit a place where the last eruption was a mere 20 000 years ago with a hydrothermal system still bubbling away was a real treat. Hydrothermal systems are of particular interest to me as I have spent the last four years studying their fossil remnants. To see what my 144 to 133Ma rocks may have looked like was exciting. Volcanism in the Lesser Antilles is related to the subduction of the North American Plate beneath the Caribbean Plate. The rocks of St Lucia are mafic to intermediate ranging from basalt to andesite. Below is a series of photos from the Soufrière Volcanic Centre showing the (probably) 40 000 year old crater, town of Soufrière, Sulfer Springs hydrothermal vents and the Diamond falls.</div><div style="text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmmw6aMP4XvE31j5qdyt637Bw7qQt9dUxz5cezrPssi_i-QN1u_AGNFC9vOIse0LpHQy6taXjrmIwNdGpL7iVJYpE3eINte2vfijtvt804U1M_Dc6pkik6CAdIvvv4tbHCW9hAc0WCld2b/s1600/f20080510-121342_sam_sony.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmmw6aMP4XvE31j5qdyt637Bw7qQt9dUxz5cezrPssi_i-QN1u_AGNFC9vOIse0LpHQy6taXjrmIwNdGpL7iVJYpE3eINte2vfijtvt804U1M_Dc6pkik6CAdIvvv4tbHCW9hAc0WCld2b/s640/f20080510-121342_sam_sony.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The town of Soufriere nestled in the Qualibou/Soufriere caldera. The peaks behind the town are the<br />
Gros and Petit Piton </td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFn-dkWeGPZtTMcF821N5MXOQjLSWLS355oKI4L4XSn_E03PgegtrkeaLloAck289LnpwR2EznqpdLeAQec_iDQ1tW5kTt6Dq9xz8ITf0PvkXzWlatOLPWEVaLkCJKzM4pFD4thYxciCE8/s1600/f20080510-121537_sam_sony.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFn-dkWeGPZtTMcF821N5MXOQjLSWLS355oKI4L4XSn_E03PgegtrkeaLloAck289LnpwR2EznqpdLeAQec_iDQ1tW5kTt6Dq9xz8ITf0PvkXzWlatOLPWEVaLkCJKzM4pFD4thYxciCE8/s640/f20080510-121537_sam_sony.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Sulphur Springs from a distance </td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAjM1P-3YwJ6wQzAQ_zuvyp4XueuWIja0YD6P1JwCMeqLhAhqq8KL64PeIHvAzKXlLJy5HlgIoX2K8zttydwpIzsLak9DOjxt98AR7u-GMETo8NceIAinx7sAqELv-TVKE6khI1NqTpFgb/s1600/f20080510-125501_sam_sony.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAjM1P-3YwJ6wQzAQ_zuvyp4XueuWIja0YD6P1JwCMeqLhAhqq8KL64PeIHvAzKXlLJy5HlgIoX2K8zttydwpIzsLak9DOjxt98AR7u-GMETo8NceIAinx7sAqELv-TVKE6khI1NqTpFgb/s640/f20080510-125501_sam_sony.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Sulphur Springs bubbling away. The dark colour is caused by iron and sulphur reacting</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQKotWDvQ3zDmTetNE4N26UpmTAL_dRF_BiXLXWsQyaIdb0WGQ3l1Y9sKxTmwPfF1dHE3-7eJngyAtkl1pa70QdzXV162ZBTRFYdk_ALCFLpcyDrKkRK0xEYDsUciQKWbhT9KCcI977EfE/s1600/f20080510-131223_sam_sony.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQKotWDvQ3zDmTetNE4N26UpmTAL_dRF_BiXLXWsQyaIdb0WGQ3l1Y9sKxTmwPfF1dHE3-7eJngyAtkl1pa70QdzXV162ZBTRFYdk_ALCFLpcyDrKkRK0xEYDsUciQKWbhT9KCcI977EfE/s640/f20080510-131223_sam_sony.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Little mud eruptions</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjU9zYsYTaOI8WT-VSzL2I-q8q3xhzh9VkO2it9i0VF6GNEI4nTx96t6nBvPp9-3B6j5Bx3aEwIkNI2Yw9Bog_TPMeV36UHJoHo8vBF5em-kVpTD1jjybMpVpL_klHQoTzxHelOCsmpwKjK/s1600/f20080510-163612_sam_sony.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjU9zYsYTaOI8WT-VSzL2I-q8q3xhzh9VkO2it9i0VF6GNEI4nTx96t6nBvPp9-3B6j5Bx3aEwIkNI2Yw9Bog_TPMeV36UHJoHo8vBF5em-kVpTD1jjybMpVpL_klHQoTzxHelOCsmpwKjK/s640/f20080510-163612_sam_sony.jpg" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Diamond Falls, the Botanical Gardens. The water is mineral rich and the colours<br />
are caused by these minerals precipitating out of solution onto the rock face</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQSqnQrnk2zPEnZQ8qIWrIZzr4E2-hS5llTjvUS1n8AUe4clq2ofCoM-99qKZzIZfPDNHXL20HUafEK4S1b3Y1C5Ci0Zb811OChwm33zAu84SJDsm5qEXyKGwvHbb1eEcdkLRUz-y8ubsa/s1600/f20080510-173754_sam_sony.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQSqnQrnk2zPEnZQ8qIWrIZzr4E2-hS5llTjvUS1n8AUe4clq2ofCoM-99qKZzIZfPDNHXL20HUafEK4S1b3Y1C5Ci0Zb811OChwm33zAu84SJDsm5qEXyKGwvHbb1eEcdkLRUz-y8ubsa/s640/f20080510-173754_sam_sony.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Grand Piton, I never got close enough to look at the rocks but one source I've found says the pitons are<br />
volcanic cones.</td><td class="tr-caption" style="text-align: center;"><br />
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</div>Reference:<br />
<br />
<a href="http://soufrierefoundation.org/about-soufriere/geology">Geology of Soufrier</a></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-2709813113723207932011-12-14T03:15:00.001-10:002011-12-14T10:00:27.169-10:00Week of Photographs<div dir="ltr" style="text-align: left;" trbidi="on">Jumping on the <a href="http://blogs.agu.org/georneys/2011/12/12/monday-geology-picture-a-gorgeous-cape-town-inselberg/">week of field photos</a> bandwagon (albeit three days late) here are three photos from around Namibia. Enjoy :)<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEje-9NSQ2pAUMM2bpK_aifDbZPB_EEsjPYfvzq4eFOb1pJe6menTA2Et0qgQnlz2z5YE9ykusWl64vglygQo7vohvJRImBzQfBoEy0ww21AaTYSp4y1aTYMRgxwXY4FTnpA3pnjBmJOwjNL/s1600/00022.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEje-9NSQ2pAUMM2bpK_aifDbZPB_EEsjPYfvzq4eFOb1pJe6menTA2Et0qgQnlz2z5YE9ykusWl64vglygQo7vohvJRImBzQfBoEy0ww21AaTYSp4y1aTYMRgxwXY4FTnpA3pnjBmJOwjNL/s640/00022.jpg" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Desert pavement and Welwitschia, NW Namibia<br />
roughly 10km from Brandberg</td><td class="tr-caption" style="text-align: center;"></td><td class="tr-caption" style="text-align: center;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOp63QjjuwdH9nDY2aahpb3R4dKwBWUIu_kL6lCDRO7r6otspWPex8y2s87YgwvFTwC1LcamZdRFP0nPKi2D569y6Tm6Dn0nOB4nBusQvAJCLkWKfrbKRa0zYtMYiADWfbkhpE7eGUnq2V/s1600/DSC00675.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOp63QjjuwdH9nDY2aahpb3R4dKwBWUIu_kL6lCDRO7r6otspWPex8y2s87YgwvFTwC1LcamZdRFP0nPKi2D569y6Tm6Dn0nOB4nBusQvAJCLkWKfrbKRa0zYtMYiADWfbkhpE7eGUnq2V/s640/DSC00675.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Sossusvlei, dried water channels, Southern<br />
Namibia</td><td class="tr-caption" style="text-align: center;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9P6XnhJ5yG5_7EyCIa8aX2EYdjQF9CVSnHOI650nTh-_JpYj61TdAKBuHjEDWGXV9M8cwmuEB8hOOIYujlRzulmSlVzpRn27oc5gFOcMLGoV3u3ukXrVj_5qPPKpeT4vM6hRqwiA7VWKH/s1600/DSC07820.JPG" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9P6XnhJ5yG5_7EyCIa8aX2EYdjQF9CVSnHOI650nTh-_JpYj61TdAKBuHjEDWGXV9M8cwmuEB8hOOIYujlRzulmSlVzpRn27oc5gFOcMLGoV3u3ukXrVj_5qPPKpeT4vM6hRqwiA7VWKH/s640/DSC07820.JPG" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Fish River Canyon, Southern Namibia. The Rocks above the unconformity are <br />
from the 750-550Ma Nama Supergroup. Below the unconformity <br />
are rocks from the +1000Ma Gordonia subprovince</td></tr>
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I shall describe the geology of these areas in future posts. My posting schedule will probably be a cool mid week photo with description and a nice long post on the weekend.<br />
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</div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0tag:blogger.com,1999:blog-3200129138409538703.post-90371221043049142272011-12-10T21:36:00.000-10:002011-12-10T21:36:26.818-10:00Auckland Volcanic Field<div dir="ltr" style="text-align: left;" trbidi="on"><style type="text/css">
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<div class="western" lang="en-AU" style="text-align: justify;"> New Zealand's North Island is underrated as a geological wonder. Yes the South Island has mountains and glaciers and faults and, and, and... But the North Island has volcanoes (Figure 1) including the ‘supervolcano’ under Lake Taupo. Having spent all of my life living in geologically stable places I am rather excited that Auckland, where I'll be for part of December, is only a few hours drive from the Taupo Volcanic Zone. This week I discovered that I won’t actually have to drive very far to reach one of the North Islands many volcanoes. Auckland, it turns out, is sitting in a volcanic field (Figure 2). I shall be able to roll out of bed into the <a href="http://www.stuff.co.nz/national/6081952/Study-predicts-6km-Auckland-ring-of-death">‘6km ring of death’</a>. How exciting! Scaremongering aside what is the Auckland Volcanic Field all about? </div><div style="text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3fvYJvMxgSl4Mld6IxbxwJB0522XMTaTVwetyy1FQ5_vWbxEqUoBkZbqYjKmzpPJgm2BlwlBe45ySk4bT7pdVLHZbQtUjLdNChvSbwJCqlFcnEiE-uTAXaeBTeXIxFfVjZeJ151ghysiQ/s1600/Map_new_zealand_volcanoes.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3fvYJvMxgSl4Mld6IxbxwJB0522XMTaTVwetyy1FQ5_vWbxEqUoBkZbqYjKmzpPJgm2BlwlBe45ySk4bT7pdVLHZbQtUjLdNChvSbwJCqlFcnEiE-uTAXaeBTeXIxFfVjZeJ151ghysiQ/s640/Map_new_zealand_volcanoes.gif" width="332" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Figure 1: Locations of the many volcanoes on <br />
New Zealand's North Island</td></tr>
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</div><div class="western" lang="en-AU" style="text-align: justify;"> The Auckland Volcanic Field is related to a hotspot located beneath the North Island. Excess heat from the hot spot caused small volumes (<0.4 km<sup><span style="font-size: x-small;">3</span></sup>) of magma to form which rose to the surface resulting in <a href="http://volcano.oregonstate.edu/education/hawaii/small_struct/vents/p_vents.html">phreatomagmatic</a> and magmatic eruptions [1-3, 5-7]. The field has an areal extent of approximately 360 km<sup><span style="font-size: x-small;">2 </span></sup>[1-3, 5-8] and to date between 3 to 4 km<sup><span style="font-size: x-small;">3</span></sup> of material, mostly <a href="http://en.wikipedia.org/wiki/Trachybasalt">trachybasalt</a> and <a href="http://en.wikipedia.org/wiki/Basanite">basanite</a>, has been erupted. Approximately 60% of this material is associated with Rangitoto, the youngest volcano (600-700yrs). It is also one of the few to have erupted more than once [1-8]. Onset of the volcanism is unclear. Radiocarbon and thermoluminescence give maximum ages of 141 ka whereas K-Ar ages are variable, affected by excess Ar, with a maximum age of 250 ka [2]. However, it has been noted that the frequency and magnitude of the Auckland eruptions have increased over time [2, 3, 6, 8 & 9]. </div><div class="western" lang="en-AU" style="text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkeISmYxGIrgJviWVCQbJwOwWnCKvxJbRMLn3qPe1bU3FNV4f-bHEOCYyKDftA5j01E6OnJYI8rhFzSHue0f3LbtoHGyXjA_eo51PHl3r80yPFzFRr7WdjgfMrznfIwLdFY1sh-txRtA0o/s1600/AVF.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkeISmYxGIrgJviWVCQbJwOwWnCKvxJbRMLn3qPe1bU3FNV4f-bHEOCYyKDftA5j01E6OnJYI8rhFzSHue0f3LbtoHGyXjA_eo51PHl3r80yPFzFRr7WdjgfMrznfIwLdFY1sh-txRtA0o/s400/AVF.jpg" width="273" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Figure 2: Volcanic centres of the Auckland <br />
Volcanic Field. From Ruaumoko website</td></tr>
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There are about 50 eruptive centres in the Auckland Volcanic Field (Figure 2), most of which are monogenetic, one eruption cycle [1-3, 5-8]. Thirty-five of the volcanoes show evidence of phreatomagmatic eruptions, 11 of these are only tuff rings expressed as <a href="http://en.wikipedia.org/wiki/Maar">maars</a>. Twenty-four of the 35 have three phases, an early tuff ring surrounding a later stage scoria cone which is finally breached by lava flows [1 & 5]. There are also small shields (Rangitoto), 'frozen' lava lakes and plugs in present. The volcanic structure is dependent on magma-water interaction and the duration of the eruption [5 & 6]. The majority of the Auckland volcanoes erupted on land therefore, aquifers, lakes and rivers are thought to be the dominant water source for the phreatomagmatic eruptions [1]. The country rock in the north of the field is Mesozoic <a href="http://en.wikipedia.org/wiki/Greywacke">greywacke</a> and 0-1km thick Miocene <a href="http://en.wikipedia.org/wiki/Flysch">flysch</a> while in the south it is Pliocene - Pleistocene sands and silts which are a few metres thick [1]. Aquifers are mainly associated with the Pliocene - Pleistocene sediments but they do occur in the fractured parts of the Miocene flysch [1]. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div><div class="western" lang="en-AU" style="text-align: justify;"> The lack of exact ages and the monogenetic character of the Auckland Volcanic Field volcanoes means that it is almost impossible to determine patterns [2]. This uncertainty has resulted in various studies and simulations with the aim of mitigating casualties in a future eruption [2 - 4, 6, 8 & 9]. The <a href="http://www.stuff.co.nz/national/6081952/Study-predicts-6km-Auckland-ring-of-death">article</a> which drew my attention to the Auckland Volcanic Field is in response to Sandri, et al (2011) which assesses the risk associated with a future eruption in Auckland. In 2008 the New Zealand government ran 'Exercise Ruaumoko'. This is a similar concept to California's 'Shake Out' except Ruaumoko only involves government agencies. During the Ruaumoko simulation it was assumed that the initial base surge would have a 1-3km run-out [3, 4 & 9]. However, further research combined with modelling done by Sandri, et al (2011) suggest that the run-out is larger. The purpose of the Sandri, et al (2011) was to assess the future risk of the Auckland Volcanic Field and create a volcanic hazard map for potential new vents. The study had two aspects a long-term hazard map and a short-term simulation similar to the Ruaumoko exercise.</div><div style="text-align: justify;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq4jYX326IziaUj1sZWeegb6Vk-e4XnfmYXn_mOLMs0rYRDSsQVQ400M_T66VJ-C4C6-2ZWMnZtAf_Do6EFPst49vV-VVZ1WipRdFC0o5FQB9ay-Q2wa9GEAAOCPWDC_XIYMNYk-zlmlEW/s1600/Mt+Eden.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="332" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq4jYX326IziaUj1sZWeegb6Vk-e4XnfmYXn_mOLMs0rYRDSsQVQ400M_T66VJ-C4C6-2ZWMnZtAf_Do6EFPst49vV-VVZ1WipRdFC0o5FQB9ay-Q2wa9GEAAOCPWDC_XIYMNYk-zlmlEW/s400/Mt+Eden.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Mount Eden. From the Ruaumoko and GSN websites</td></tr>
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</div><div class="western" lang="en-AU" style="text-align: justify;"></div><div class="western" lang="en-AU" style="text-align: justify;">References:</div><div class="western" lang="en-AU" style="text-align: justify;"><span style="font-size: small;">1: Allen, S.R., Bryner, V.F., Smith, I.E.M. and Ballance, P.F. 1996: Facies analysis of pyroclastic deposits within basaltic tuff-rings of the Auckland Volcanic Field, New Zealand. New Zealand Journal of Geology </span>and Geophysics, pp 309-327</div><div class="western" lang="en-AU" style="text-align: justify;">2: Cassidy, J. and Locke, C. A. 2004: Temporally linked volcanic centres in the Auckland Volcanic Field. New Zealand Journal of Geology and Geophysics, pp 287-290</div><div class="western" lang="en-AU" style="text-align: justify;">3: Lindsay, J., Marzocchi, W., Jolly., G., Constantinescu, R., Selva, J and Sandri, L. 2010: Towards real-time eruption forecasting in the Auckland Volcanic Field: application of BET-EF during the New Zealand National Disaster Exercise ‘Ruaumoko’. Bull. Volcanology pp 185-204</div><div class="western" lang="en-AU" style="text-align: justify;">4: Sandri, L., Jolly, G. and Lindsay, J. 2011: Combining long- and short-term probabilistic volcanic hazard assessment with cost-benefit analysis to support decision making in a volcanic crisis from the Auckland Volcanic Field, New Zealand. Bull. Volcanology pp 1-19</div><div class="western" lang="en-AU" style="text-align: justify;">5: Shane, P. and Smith, I., 2000: Geochemical fingerprinting of basaltic tephra deposits in the Auckland Volcanic Field. New Zealand Journal of Geology and Geophysics, pp 569-577</div><div class="western" lang="en-AU" style="text-align: justify;"><a href="http://www.arc.govt.nz/environment/volcanoes-of-auckland/volcanic-formation.cfm">6: Auckland Council webpage</a></div><div class="western" lang="en-AU" style="text-align: justify;"><a href="http://www.gns.cri.nz/Home/Learning/Science-Topics/Volcanoes/New-Zealand-Volcanoes/Auckland-Volcanic-Field">7: Auckland Volcanic Field page and Rangitoto fact sheet, GSN website</a></div><div class="western" lang="en-AU" style="text-align: justify;"><a href="http://en.wikipedia.org/wiki/Auckland_Volcanic_Field">8: Wikipedia </a></div><div class="western" lang="en-AU" style="text-align: justify;"><a href="http://www.exerciseruaumoko.co.nz/">9: Exercise Ruaumoko webpage</a></div><div style="text-align: justify;"><br />
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<div class="western" lang="en-AU">The papers form the <a href="http://www.tandfonline.com/loi/tnzg20">New Zealand Journal of Geology and Geophysics</a> are open access </div></div>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com3tag:blogger.com,1999:blog-3200129138409538703.post-39718490377250902352011-12-01T03:25:00.000-10:002011-12-01T03:25:33.337-10:00Testing<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOxIDUftzuNTX6F_ODcQXaT32nY1uDVVnRqKIhXFO9g5DJ1YJ6qK7kV1BKu6mNTxd8eZZYtXNQWpgiShBRdMvxNXlAJ5NptazwPQ35KT3gxL7cb-2Pz4QuT3HkMAuvYbdaEGqvbw6yEgY2/s1600/00104.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOxIDUftzuNTX6F_ODcQXaT32nY1uDVVnRqKIhXFO9g5DJ1YJ6qK7kV1BKu6mNTxd8eZZYtXNQWpgiShBRdMvxNXlAJ5NptazwPQ35KT3gxL7cb-2Pz4QuT3HkMAuvYbdaEGqvbw6yEgY2/s320/00104.jpg" width="240" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Chapman's Peak Drive unconformity between the <br />
Graafwater formation(top) and the Cape Granite (bottom)</td></tr>
</tbody></table>Cathttp://www.blogger.com/profile/15097541679218959806noreply@blogger.com0