Significance of Vertical Tectonics in Convergent Margins; Evidence from Post-Accretion Strains and Uplift Rates

会聚板块边界是地球上构造最活跃的区域之一，长期以来一直被认为是大陆边缘或海底沉积物可以俯冲到很深的区域。然而，关于这些沉积物在增生棱柱和大陆碰撞带中的抬升过程，人们了解的要少得多。本项目将测试两个关于吸积棱柱抬升机理的端元模型：1)底侵，其中吸积棱柱为剥离的沉积物提供刚性支撑；或2)棱柱内的穿透性变形，因为沉积物在脚趾处吸积。这些模型将利用阿拉斯加州科迪亚克岛科迪亚克增生杂岩的后吸积应变和抬升历史进行测试。这些结果将有助于阐明如何在吸积棱镜中实现隆起。

Convergent plate boundaries are one of the earth's most tectonically active regions and they have long been recognized as zones where continental margin or ocean floor sediments can be subducted to great depths. However much less has been learned about the processes responsible for uplift of these sediments in accretionary prism and continental collision zones. This project will test two end-member models concerning the mechanics of uplifting accretionary prisms: 1) underplating, where the accretionary prism provides a rigid backstop for the offscraped sediments or 2) penetrative deformation within the prism as sediments are accreted at the toe. These models will be tested by using the post-accretion strain and uplift history of the Kodiak accretionary complex, Kodiak Island, Alaska. Results will help clarify how uplift is accomplished in accretionary prisms.