Kinematic Linkages Among Extrusion, Fold-thrust Shortening, and Foreland Basin Evolution During Early Continental Collision, Zagros Mountains, Iran

这项研究的主要调查人员正在进行一项为期三年的扎格罗斯褶皱冲断带及其邻近的高扎格罗斯地质史的研究。目的是确定(1)孕震的地壳规模的右行断裂(最近的主要断裂)和(2)与阿拉伯构造板块汇聚欧亚板块有关的变形过程中薄皮褶皱冲断带的相对作用和相互作用。与以前的研究相反，正在进行的研究表明，这两个构造元素可能形成一个运动学上相互联系的系统，并且在过去大约1000-2000万年的板块碰撞期间同时活动了很长一段时间。欧亚-阿拉伯大陆碰撞是世界上最年轻的碰撞，为研究早期构造过程提供了机会，这些构造过程强烈地叠加在阿尔卑斯山、喜马拉雅山脉和阿巴拉契亚山脉等较老的碰撞山带上。褶皱-逆冲变形的时间记录存在于扎格罗斯广泛的、超暴露的前陆盆地沉积中，包括横切构造、重叠的应变标志以及与断裂和褶皱同步沉积的沉积物。该项目采用了地层学和构造分析，包括重要的新野外数据收集，用于确定关键岩石单元低温热历史的同位素年龄测定，以及应用于沉积地层测年的磁学方法。这项对伊朗扎格罗斯系统的研究通过描述早期碰撞期间的变形、沉积、侵蚀和岩浆事件的序列，并对它们的发展速度提供强烈的时间限制，提高了对早期大陆-大陆碰撞中的构造过程的理解。这项研究还探讨了如何根据更演化和更复杂的碰撞山带的地质记录来确定大陆碰撞开始的年龄这一一般性问题。

The principal investigators of this study are conducting a three-year study of the geologic history of the Zagros fold-thrust belt and adjacent High Zagros. The goal is to determine the relative roles and interactions of (1) a seismogenic, crustal-scale, dextral fault (the Main Recent Fault) and (2) the thin-skinned fold-thrust belt during deformation related to the Arabian tectonic plate converging with the Eurasian plate. Ongoing research suggests, contrary to previous studies, that these two structural elements may form a kinematically linked system and were active contemporaneously for a significant period of time during the plate collision over the last approximately 10-20 million years.The Eurasian-Arabian continental collision is the world's youngest and provides opportunities to study early structural processes that are strongly overprinted in older collisional mountain belts such as the Alps, Himalaya, and Appalachians. A temporal record of fold-thrust deformation resides within the extensive, superbly exposed foreland-basin deposits of the Zagros, including crosscutting structures, overlapping strain markers, and sediments deposited synchronously with faulting and folding. The project employs stratigraphic and structural analysis, and includes significant new field data collection, isotopic age dating to determine the low-temperature thermal history of key rock units, and magnetic methods applied to dating sedimentary strata.This research on the Zagros system of Iran is improving understanding of tectonic processes in early continent-continent collision by characterizing the sequence of deformational, depositional, erosional, and magmatic episodes during early collision and providing strong timing constraints on their rates of development. The study is also addressing the general question of how the age of onset of continental collision is determined from the geologic record of more evolved and more complex collisional mountain belts.