Time and Mechanism(s) of Accretion of the Laurentia-Derived Argentine Precordillera to Western Gondwana: the Record in the Foreland

源自劳伦西亚的阿根廷前列迪勒拉沉积到冈瓦纳西部的时间和机制：前陆的记录

• 批准号: 0229522
• 负责人: William Thomas
• 金额: $ 10.15万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229522&HistoricalAwards=false
• 关键词: Time; Mechanism; Accretion; Laurentia; Derived

The Precordillera in northwestern Argentina is an exotic Laurentian (North American) terrane that collided with and was accreted to western Gondwana (South America). General consensus holds that the Precordillera was rifted from the Ouachita embayment of southern Laurentia, and the Precordillera arguably has the best-constrained original location of any known exotic continental terrane. For that reason, the Precordillera provides a place to address fundamental questions of mechanisms and rates of transfer of a continental terrane from one continent to another. In addition, the Precordillera may serve as model for processes and responses that characterize the collision of a microcontinent (small plate) with a continent. Finally, the history of the transfer of the Precordillera from Laurentia to Gondwana is an important constraint on global paleogeographic reconstructions.Even with the consensus both for the original location of the Argentine Precordillera in the Ouachita embayment and for collision of the Precordillera with western Gondwana, interpretations of the time of collision differ from Middle-Late Ordovician to Silurian-Devonian. Middle-Late Ordovician events are recognized in each of the interpretations, but those events are considered to represent collision with Gondwana in some interpretations and to represent rifting from Laurentia in others. New data gathered in this research help to constrain both the timing and mechanism(s) of collision of the Precordillera with Gondwana. This research integrates the history of subsidence and sedimentary filling of the Precordillera foreland basin in the context of temporal and mechanical links to the Famatina volcanic arc and a continental suture zone between the rocks of western Gondwana and the eastern Precordillera. Specifically, the research is examining the subsidence history of the basin, role of high-relief fault blocks as sources of carbonate olistoliths, significance of possible fault blocks for extension or transpression/transtension, provenance of igneous and metamorphic clasts, patterns of clastic sediment dispersal on Precordillera platform, relation of Famatina arch and suture zone to basin subsidence and sediment progradation on platform, and relation of succession to southern Laurentia.

位于阿根廷西北部的前科迪勒拉是一个外来的劳伦（北美）火山，与冈瓦纳（南美）西部相撞并增生。 普遍的共识认为，前科迪勒拉是从劳伦西亚南部的瓦希塔海湾断裂的，而前科迪勒拉可以说是任何已知的外来大陆板块中最受约束的原始位置。 因此，前科迪勒拉提供了一个场所，以解决机制和大陆移民从一个大陆向另一个大陆转移的速度等根本问题。 此外，前心脏地带可以作为一个过程和反应的模型，其特点是一个微大陆（小板块）与大陆碰撞。 最后，从劳伦特到冈瓦纳转移的历史是全球古地理重建的一个重要制约因素，即使阿根廷前心血管疾病的原始位置在Ouachita海湾和碰撞的前心血管疾病与西方冈瓦纳的共识，碰撞时间的解释不同，从中晚奥陶世志留纪-泥盆纪。 中晚奥陶世事件在每一种解释中都得到了承认，但这些事件在一些解释中被认为是与冈瓦纳大陆的碰撞，而在另一些解释中则被认为是劳伦提斯大陆的裂谷。 本研究收集的新数据有助于限制前心脏地带与冈瓦纳大陆碰撞的时间和机制。 这项研究整合了历史的沉降和沉积充填的前心前陆盆地的时间和机械联系的Famatina火山弧和大陆缝合带之间的岩石，冈瓦纳西部和东部前心前陆盆地。具体而言，研究正在检查盆地的沉降历史，高浮雕断块作为碳酸盐岩的来源的作用，可能的断块对于伸展或平移/平移张的意义，火成岩和变质碎屑的来源，前Cordillera平台上碎屑沉积物的分散模式，Famatina拱和缝合带与盆地沉降和平台上沉积物迁移的关系，以及与南劳伦提斯的继承关系。