Collaborative Research: The Neoproterozoic and Cambrian of the Tethyan Himalaya: A Test of Models of Core Gondwanan Construction

合作研究：特提斯喜马拉雅新元古代和寒武纪：冈瓦纳核心构造模型的检验

• 批准号: 9980426
• 负责人: Nigel Hughes
• 金额: $ 10.07万
• 依托单位: University of California-Riverside
• 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 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9980426&HistoricalAwards=false
• 关键词: Collaborative; Research; Neoproterozoic; Cambrian; Tethyan

EAR 9980376 MyrowEAR 9980426 HughesCollaborative Research: THE NEOPROTEROZOIC AND CAMBRIAN OF THE TETHYAN HIMALAYA: A TEST OF MODELS OF CORE GONDWANAN CONSTRUCTIONThe nature and timing of the assembly of core Gondwanaland remains a matterof vigorous debate. The traditional view is that East Gondwana, consistingof India, Australia and Antarctica collided with the combined Africancratons (Kalahari and Congo) as one block sometime during the lateNeoproterozoic. An alternative model suggests that the accretion of EastGondwana to the African craton was a two part process. In this model, Indiabroke off from Australia and Antarctic, swept across the Mozambique Ocean,and collided with the African craton at approximately 680 Ma. This waspurportedly followed sometime later by collision of Australia/Antarcticaaround 550 to 530 Ma. Our study of the Tethyan Himalaya will test tectonicmodels of the assembly of core Gondwanaland using a combined stratigraphic,macrofaunal and sedimentological approach. Of primary importance is thestratigraphic signature of sediment input from adjacent orogenic belts. Arecord of major increases of siliclastic sediment, with abrupt changes inpaleocurrents would accompany orogenesis. A key component of the proposedmodels is that they have predictable patterns of detrital zircon ages. ALate Cambrian-Early Ordovician tectonic event is recorded in the TethyanHimalaya and in other places in East Gondwanaland. The nature of this eventis unclear, but two possibilities include: (1) it represents a somewhatdelayed expression of the Australia/Antarctica collision in the two-stagemodel, or (2) it represents the docking of an outboard microcontinent(e.g., the Lhasa Block of Tibet) subsequent to the formation of coreGondwanaland. The biostratigraphic patterns of trilobites provide the basisof testable predictions of these hypotheses. In the first case, we expectto find a stratigraphic increase in similarity in faunas between India andthe rest of East Antarctica throughout the Cambrian. If faunal similaritywith the rest of East Gondwana was constant throughout thetrilobite-bearing Cambrian, we may infer that Gondwanan construction wascomplete prior to 520 Ma. In addition, if the ~500 Ma tectonic event in theTethyan Himalaya records microcontinental collision, then theidentification of the outboard terrane may be approached throughbiogeographic patterns established in this study. Myrow's RUI proposal willinvolve undergraduates at Colorado College as junior collaborators in allcomponents of the research. This will provide a much-needed opportunity forstudents to experience scientific research in diverse geographical andcultural environments. A key aspect of this proposal is the close researchcollaboration with Indian and Chinese scientists.

电话：[phone] Hughes合作研究：特提斯喜马拉雅的新元古代和寒武纪：冈瓦纳大陆核心板块聚合模型的检验冈瓦纳大陆核心板块聚合的性质和时间仍然是一个激烈争论的问题。传统的观点认为，东冈瓦纳，包括印度，澳大利亚和南极洲碰撞的联合非洲大陆（喀拉哈里和刚果）作为一个块在晚新元古代的某个时候。另一种模型认为，东冈瓦纳大陆向非洲克拉通的增生是一个两部分的过程。在这个模型中，Indiabroke离开澳大利亚和南极，横扫莫桑比克海洋，并在大约680 Ma与非洲克拉通相撞。据说，这之后的某个时候，澳大利亚/舌tica碰撞约550至530 Ma。我们对特提斯喜马拉雅的研究将使用地层学、大型动物群和沉积学相结合的方法来检验核心冈瓦纳大陆集合体的构造模型。最重要的是来自邻近造山带的沉积物输入的地层特征。硅质沉积物大量增加的记录，伴随着古水流的突然变化，将伴随着造山作用。提出的模型的一个关键组成部分是，它们具有可预测的碎屑锆石年龄模式。在特提斯-喜马拉雅和东冈瓦纳大陆的其他地方记录了寒武纪-早奥陶世的构造事件。这一事件的性质尚不清楚，但有两种可能性：（1）它代表了两阶段模型中澳大利亚/南极洲碰撞的延迟表达，或者（2）它代表了外侧微大陆的对接（例如，西藏拉萨地块）的核心冈瓦纳大陆形成之后。三叶虫的生物地层模式为这些假说提供了可检验的预测基础。在第一种情况下，我们期望在整个寒武纪期间发现印度和南极洲东部其他地区之间的动物群相似性的地层增加。如果在整个含三叶虫的寒武纪，与东冈瓦纳大陆其他地区的动物群相似性是恒定的，我们可以推断冈瓦纳大陆的构造在520 Ma之前就完成了。此外，如果特提斯喜马拉雅地区~500 Ma的构造事件记录了微大陆碰撞，那么，通过本研究建立的地质模式，可以探讨外大陆碰撞的识别问题。Myrow的RUI计划将把科罗拉多学院的本科生作为研究所有组成部分的初级合作者。这将为学生提供一个在不同地理和文化环境中体验科学研究的急需机会。这项提议的一个关键方面是与印度和中国科学家的密切研究合作。