Collaborative Research: Permian-Triassic Basin History of Southern Victoria Land and the Darwin Mountains

合作研究：维多利亚州南部土地和达尔文山脉的二叠纪-三叠纪盆地历史

• 批准号: 9909749
• 负责人: Rosemary Askin
• 金额: $ 22.05万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9909749&HistoricalAwards=false
• 关键词: Collaborative; Research; Permian; Triassic; Basin

9909749AskinThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a collaborative sedimentological, palynological, and paleomagnetic study of Permian and Lower Triassic strata in southern Victoria Land (SVL) and the Darwin Mountains (DM), Antarctica. Results of the study will help constrain the paleoenvironmental, tectonic, biotic, and paleogeographic histories of southern Pangea and provide a unique polar view of the world during an icehouse to greenhouse transition.The assembly and drift of Pangea resulted in heightened orogenic activity and associated development of numerous depositional basins. One of the largest basins was the 10,000+ km long "Gondwanide foredeep" that extended across southern South America, South Africa, the Falkland Islands, Antarctica, and Australia. Antarctica's centralized location between South Africa and Australia, make SVL and DM key areas for testing paleogeographic and paleoclimatic models.Upper Paleozoic and Lower Mesozoic rocks in SVL and DM were deposited during Gondwanaland's drift across the south pole. Based on present plate reconstructions, SVL and DM were located higher than 75 degrees south latitude from 320 to 210 Ma. Despite the putative high latitude position, SVL and DM sedimentary successions record a change from Lower Permian glacial deposits, to Permian fluvial coal measures, to Lower Triassic non-carbonaceous fluvial deposits, and finally to Middle and Upper Triassic fluvial coal measures, with well-developed vegetation during much of this time. Present climatic simulations suggest seasonal climatic extremes within Pangea's polar interior. Discrepancies between the geological evidence and the climate simulations need to be resolved, and may be magnified by incomplete understanding of the influence of paleotopography, large lakes, and river systems at the time of deposition, as well as by incomplete documentation of paleoenvironmental conditions. Furthermore, Late Permian and Triassic mean pole positions for Gondwanaland are not tightly constrained. Paleomagnetic signatures will be recovered from Permian and Triassic petrified wood, silicified peat, and coal, which were cemented during early diagenesis (preliminary results indicate stable remnant magnetizations). Palynological analyses will provide time control for the succession.Objectives of this study include:1) Determination of a late Paleozoic glacial/deglaciation history for SVL and DM as Gondwana drifted over the south pole,2) Documentation of Permian strata as a means to better understand the environments of high latitude fluvial coal-bearing deposits,3) Documentation of Triassic lithofacies as a means to better understand high latitude conditions during the Early to Middle Triassic "coal gap" interval,4) Providing a well-constrained stratigraphic framework for the Permian to lower Triassic succession,5) Testing the diachronous and inversion tectonic models for the Panthalassan Margin of southwestern Pangea, and6) Constructing better paleogeographic models for Gondwana by obtaining new Gondwana reference poles for the Permian and Triassic.

9909749 Askin该奖项由极地计划办公室南极地质和地球物理计划提供，支持对南极洲维多利亚地南部（SVL）和达尔文山脉（DM）的二叠纪和下三叠纪地层进行沉积学、孢粉学和古地磁学的合作研究。研究结果将有助于限制古环境，构造，生物和古地理的历史，南盘古大陆，并提供了一个独特的极地世界观在冰库到温室transition.The组装和漂移的盘古大陆导致了造山活动的加剧和许多沉积盆地的发展。最大的盆地之一是10，000多公里长的“冈瓦纳前渊”，横跨南美洲南部，南非，福克兰群岛，南极洲和澳大利亚。南极洲位于南非和澳大利亚之间的中心位置，使SVL和DM成为验证古地理和古气候模型的关键地区，SVL和DM中的上古生界和下中生代岩石是冈瓦纳大陆漂移越过南极的过程中沉积的。根据现今的板块重建，SVL和DM在320 - 210 Ma位于南纬75度以上。尽管假定的高纬度位置，SVL和DM沉积序列记录的变化，从下二叠世冰川沉积，二叠纪河流煤层，下三叠世非碳河流沉积，最后到中，上三叠世河流煤层措施，与发达的植被在这段时间的大部分。目前的气候模拟表明，在盘古大陆的极地内部存在季节性的极端气候。地质证据和气候模拟之间的差异需要解决，并可能被放大的古地形，大型湖泊和河流系统的影响，在沉积时的不完整的理解，以及不完整的古环境条件的文件。此外，晚二叠世和三叠纪的冈瓦纳大陆的平均极点位置没有严格的约束。将从二叠纪和三叠纪的石化木、硅化泥炭和煤中恢复古地磁特征，这些化石木、硅化泥炭和煤在早期成岩作用期间被胶结（初步结果表明残余磁化稳定）。孢粉分析将为演替提供时间控制。本研究的目的包括：1）确定冈瓦纳大陆漂移到南极时SVL和DM的晚古生代冰川/冰消历史，2）记录二叠纪地层作为更好地了解高纬度河流含煤沉积环境的手段，3）记录三叠纪岩相作为更好地了解早至中三叠世“煤隙”期间高纬度条件的手段，4）为二叠纪至下三叠世序列提供约束良好的地层框架，（5）检验泛大陆西南缘的穿时和反转构造模式;（6）通过获得新的冈瓦纳二叠纪和三叠纪参考极，建立更好的冈瓦纳古地理模式。