COLLABORATIVE RESEARCH: Alternating Contraction and Extension During the Late Mesozoic to Early Cenozoic, Northwestern Utah

9317044 Hoisch理论和物理模型以及野外研究表明，在收缩造山带内部可以发育包括收缩和伸展交替的复杂构造历史，在造山带发育过程中，这从本质上减缓了地壳厚度。本项目将尝试通过使用位于犹他州西北部的Raft河和Grouse Creek山脉的Sevier造山带腹地的中地壳暴露来测试这些模型。这项工作将涉及构造测绘、变质热气压测量、P-T-t路径建模和几种地质年代学技术。本研究将探讨该地区变形史的几个组成部分，并测试中生代区域收缩和造山后伸展期间中地壳演化的几种现有模型。它还将有助于联系腹地与前陆冲断带之间可能的同期变形。＊＊＊

9317044 Hoisch Theoretical and physical models as well as field studies suggest that complex structural histories involving alternating contraction and extension can develop within the interior of contractional orogenic belts, essentially moderating crustal thickness during the growth of the orogenic belt. This project will attempt to test these models by use of mid-crustal exposure of the hinterland of Sevier Orogen in the Raft River and Grouse Creek Mountains of northwestern Utah. The work will involve structural mapping, Metamorphic thermobarometry, P-T-t path modeling, and several geochronologic techniques. This study will address several components of the deformation history of the area and test several existing models for middle crustal evolution during Mesozoic regional contraction and post-orogenic extension. It will also help link the possible coeval deformations between the hinterland and the foreland thrust belt. ***