Late Mesozoic(?)-Mid Cenozoic Hinterland Extension: Black Pine Mountains, Idaho and Raft River Mountains, Utah

薄皮逆冲带腹地的水平伸展被认为是地壳缩短和增厚以及由此产生的地形抬升的自然结果。大多数例子来自现代造山带，而古代造山带几乎没有证据。这项研究将探索爱达荷州南部神秘的、年轻的、顶部向西的断层的延伸，这些断层似乎与晚白垩世的拉拉米挤压同时发生。利用39Ar/40Ar定年和伊利石结晶度和牙形石CAI重建热态来确定断层的运动和时间。研究结果将确定该地区伸展构造的时间和运动规律，并将对冲断带腹地地壳的缩短、增厚、地形隆起、侵蚀和伸展之间的关系产生影响。

Horizontal extension in the Hinterland of a thin-skinned thrust belt has been proposed as a natural consequence of crustal shortening and thickening and resulting topographic uplift. Most examples are known from modern orogens and ancient belts have yielded little evidence. This study will explore a suggestion of extension in the enigmatic, younger-over-older, top-to-the-west faults in southern Idaho that appear to be contemporaneous with Late-Cretaceous Laramide compression. The fault motion and timing will be addressed by 39Ar/40Ar dating and by reconstructing the thermal regime by illite crystallinity and conodont CAI. Results are expected to define the timing and kinematics of extensional tectonics in this region, and will bear on the relations among crustal shortening, thickening, topographic uplift, erosion and extension in the hinterland of thrust belts.