Collaborative Research: Kinematics and Timing of Early Paleozoic Tectonic Events In the Easternmost Precordillera Terrane, Argentina:An Evaluation of Gondwana-Laurentia Interaction

最近在重建过去板块构型方面的主要进展之一是认识到阿根廷的Precordillera Terrane是从今天的北美的Ouachita EmBay派生(裂解)的，从而提供了一个罕见的准确了解外来地体来源的例子。然而，裂谷的时间和随后与冈瓦那碰撞的时间是有问题的，这对古生代重建至关重要。以前，碰撞的时间被认为是中到晚奥陶世，基于碳酸盐平台淹没的时间，推测是通过大陆边缘的近距离接近和俯冲。然而，最近的研究表明，碳酸盐平台的溺水是由于与裂谷相关的下沉，如果正确的话，那么它的年代是来自北美的裂谷，而不是随后与冈瓦那的碰撞。该项目旨在通过辐射测量方法测定裸露缝合带岩石的碰撞年代，包括在与碰撞有关的几个阶段或脉冲变形期间和之后侵入的岩浆体。结果将澄清前纪的到达时间，这将是建立古生代板块位置历史的关键数据。

One of the major recent advances in reconstructing past plate configurations was the recognition that the Precordillera Terrane of Argentina was derived (rifted from) the Ouachita embayment of present day North America, thus providing a rare example of knowing exactly where an exotic terrane came from. However, the timing of the rifting and the timing of the subsequent collision with Gondwana, critical to Paleozoic reconstructions is problematic. Previously the timing of the collision was thought to Middle to Late Ordovician based on when the carbonate platform drowned, presumably by close approach and subduction of the continental margin. However, more recent work suggests that the drowning of the carbonate platform was due to rift-related subsidence, and if correct, dates the rifting from North America, not the subsequent collision with Gondwana. This project aims to date the collision by radiometric methods from rocks in the exposed suture zone, including magmatic bodies that intruded during and after the several phases or pulses of collision-related deformation. Results will clarify the arrival time of the Precordillera, data that will be critical in establishing a Paleozoic plate position history.