COLLABORATIVE RESEARCH: Thermochronologic Evidence for Uplift and Unroofing of the Olympic Mountains

华盛顿州西北部的卡斯卡迪亚会聚边缘标志着北美和胡安德富卡板块之间的俯冲边界。奥运山由始新世至中新世的逆冲组合组成，构造上覆盖始新世玄武岩和始新世至中新世碎屑岩。这些岩石的抬升发生在中新世晚期。这些观测和现有的裂变径迹数据导致了一种构造模型，该模型涉及到吸积和底侵，然后在吸积继续的同时抬升。该项目将测试两种终端成员对隆起的时间和样式的解释，简单的穹隆或大规模的正断层。方法包括裂变径迹测年和结构分析。这些结果应该有助于理解活跃的会聚造山带抬升的原因。

The Cascadia convergent margin in northwest Washington State marks the subduction boundary between North America and the Juan de Fuca plate. The Olympic mountains consist of an assemblage of Eocene to Miocene thrusts structurally overlain by Eocene basalts and Eocene to Miocene clastic rocks. Uplift of these rocks occurred during the late Miocene. These observations and available fission track data have resulted in a tectonic model involving accretion and underplating followed by uplift while accretion continues. This project will test between two end-member explanations for the timing and style of the uplift, simple doming or large scale normal faulting. Methods include fission track dating and structural analysis. Results should help understanding causes of uplift in active convergent orogens.