COLLABORATIVE RESEARCH: The Fairweather-St. Elias Orogenic System: A Slip Partitioned Transpressional Orogen

小行星9725339 板块构造学中一个挥之不去的争论围绕着大陆地壳在碰撞带中的相互作用方式。 争论的焦点是，应变是否以及如何在几个可能的地壳块体之间或周围分配。 在阿拉斯加东南部的圣伊莱亚斯碰撞区包括北美最大的高峰集中区。 对这一区域的传统解释是，一个大陆微板块（雅库塔特板块）正在与北美板块汇合。 另一种假设认为，滑动被划分为一个走滑分量和收缩分量允许一个压扭边界和微板不参与。 帕夫利斯和布鲁恩的这项研究将通过寻找第二种假设的预测来检验这些假设。 特别是，将进行野外测绘和结构分析，以评估预测的走滑断层最近的活动，并将分析检查离岸海岸地震反射数据，以寻找预测的离岸海岸褶皱和冲断带的变形。 这些结果将直接影响到阿拉斯加争议的解决，但也将揭示一般性的结果，这将允许概括一般的横推板块边界的行为。

9725339 Bruhn A lingering controversy in plate tectonics surrounds the way in which continental crusts interact in collision zones. The arguments center on if and how strain is partitioned among or around several possible crustal blocks. In southeast Alaska the St. Elias collision region includes the largest concentration of high peaks in North America. The conventional explanation for this region is that a continental microplate (the Yakutat block) is converging with the North American plate. An alternative hypothesis holds that slip is partitioned into a strike-slip component and a contractional component allowing a transpressional boundary and that microplates are not involved. This Pavlis and Bruhn study will test these hypotheses by looking for the predictions of the second. In particular, field mapping and structural analysis will be done to evaluate recent an active motion on the predicted strike-slip faults, and examining off-shore seismic reflection data will be analyzed to look for deformation in the predicted off shore fold and thrust belt. The results will bear directly on the resolving the controversy here in Alaska, but will also reveal generic results that will allow generalizing about the behavior of transpressive plate boundaries in general.