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辐合缘标志着北美洲与胡安德富卡板块之间的俯冲边界。奥林匹克山脉由始新世至中新世逆冲构造组合组成，构造上覆盖始新世玄武岩和始新世至中新世碎屑岩。这些岩石的隆起发生在中新世晚期。这些观测和现有的裂变径迹数据得出了一个构造模型，包括增生和底沉积，然后在增生继续时隆升。该项目将对隆升的时间和样式的两种端元解释进行检验，是简单的穹隆还是大规模的正断层。方法包括裂变径迹定年和结构分析。研究结果有助于理解活动辐合造山带隆升的原因。

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.