COLLABORATIVE RESEARCH: The Cretaceous Strike-Slip Fault History of the Border Ranges Fault System: A Study of Translation and Transpression

走滑断裂作用在北科迪勒拉构造演化中起着重要作用，但许多走滑运动的时间、位置和机制尚不明确。先前的工作已经确定了沿阿拉斯加边界山脉断层白垩纪时期的主要右滑。初步证据表明，目前的侵蚀水平暴露了断层在运动时的脆性-韧性转变附近。最近的模型提出了在这个过渡时期，除了通常设想的陡峭的走滑分离外，走滑系统中还存在主要的亚水平分离。由于暴露地壳的深度和特殊的露头暴露，该地区提供了测试这些模型在走滑剪切带中亚水平分离作用的机会。研究结果有望适用于许多大型走滑带。

Strike-slip faulting has played a major role in the tectonic evolution of the northern Cordillera, however the timing, location and mechanisms of much of the strike-slip motion is not well established. Prior work has identified major dextral slip of Cretaceous age along the Border Ranges Fault, Alaska. Preliminary evidence indicates that the present level of erosion exposes the fault near the brittle-ductile transition at the time of motion. Recent models have proposed major subhorizontal detachments in strike-slip systems at this transition, in addition to the steep, strike-slip detachment normally envisioned. Because of the deep level of exposed crust and exceptional outcrop exposure this area affords the opportunity to test these models of the role of subhorizontal detachments in strike-slip shear zones. Results are expected to be applicable to many large-scale strike-slip zones.