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

9725035 Pavlis板块构造学中一个挥之不去的争议围绕着大陆地壳在碰撞带中相互作用的方式。争论的中心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，圣埃利亚斯碰撞区包括北美最大的高山集中区。对该地区的传统解释是大陆微板块(雅库塔特地块)与北美板块汇聚。另一种假设认为，滑移被划分为允许跨压边界的走滑分量和收缩分量，并且不涉及微板。帕夫利斯和布鲁恩的这项研究将通过寻找第二个假设的预测来检验这些假设。特别是，将进行野外测绘和构造分析，以评估预测的走滑断裂上的近期活动，并将分析近海地震反射资料，以寻找预测的离岸褶皱和冲断带中的变形。这些结果将直接关系到阿拉斯加这一争议的解决，但也将揭示一般性的结果，这些结果将允许对海侵板块边界的行为进行概括。

9725035 Pavlis 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.