Jurassic geothermal landscapes and fossil ecosystems at San Agustin, Patagonia, Argentina
Jurassic geothermal landscapes and fossil ecosystems at San Agustin, Patagonia, Argentina
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DOI：
10.1144/0016-76492009-109
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发表时间：
2010-01-01
影响因子：
2.7
通讯作者：
Zamuner, Alba
中科院分区：
文献类型：
--
作者：
Guido, Diego M.;Channing, Alan;Zamuner, Alba
描述了阿根廷巴塔哥尼亚Deseado地块的San Agustin农场的一个广泛的、保存完好的晚侏罗世(约150 Ma)地热系统。这个矿床和以前在同一地区已知的其他矿床一起，部分填补了世界各地报道的新生代和零散的古生代温泉地区之间的相当大的差距。圣奥古斯丁矿床之所以新颖，是因为它代表了一片大(1.4公里(2))且几乎完整的地热景观。硅质温泉相，包括水下和水下，在其原始的空间和地质背景下并排暴露，设置在侵入流纹岩和河湖沉积之间。侏罗纪温泉保存了当地的整个生态系统，包括微生物、节肢动物、腹足类和植物，表现出拉格斯塔滕式的保存。尤其是植物保存，范围从腐烂的枯枝落叶到幼苗萌芽，再到具有完整解剖结构的生命取向的密林。圣奥古斯丁矿床具有现代温泉的一些生态、埋藏学和沉积学特征。由于它形成于被子植物之前的世界，它类似于苏格兰著名的与温泉有关的泥盆纪Rhynie Certs。它的不同之处在于具有极好的曝光性，因此可能有助于更好地理解地质记录中极端环境中生物信号的保存。
An extensive, well-preserved, Late Jurassic (c. 150 Ma) geothermal system at San Agustin farm in the Deseado Massif, Patagonia, Argentina, is described. This deposit, along with others previously known from the same region, partially fills a considerable gap between Cenozoic and scattered Palaeozoic hot spring localities reported worldwide. The San Agustin deposit is novel because it represents a large (1.4 km(2)) and nearly complete geothermal landscape. Siliceous hot spring facies, both subaerial and subaqueous, are exposed side by side in their original spatial and geological context, set amongst intrusive rhyolite denies and fluviolacustrine sediments. The Jurassic hot springs have preserved an entire local ecosystem containing microbes, arthropods, gastropods and plants exhibiting Lagerstatten-style preservation. Plant preservation, in particular, ranges from decayed litter, to seedling sprouts, and to dense stands in life orientation with intact anatomy. The San Agustin deposit shares some ecological, taphonomic and sedimentological characteristics with modem hot springs. As it formed in a pre-angiosperm world, it is akin to the famous hot spring-related Devonian Rhynie cherts of Scotland. It differs in having excellent exposure, and thus will probably contribute to a better understanding of biosignal preservation in extreme environments in the geological record.