The Co-evolution of Thin- and Thick-skinned Deformation Associated with Flat Subduction, Western Argentina

康奈尔大学的研究人员和他们的阿根廷同事正在研究薄皮和厚皮变形之间的关系，这是由于阿根廷西部的Precordillera-Sierras Pampeanas地区下面的海洋地壳的平板俯冲造成的。本研究的目标是制作一套地图，显示从2000万年前到现在的500万年间隔的综合速度场。这些图记录了从薄皮逆冲推覆和活跃岩浆活动到弧岩浆活动停止和与薄皮逆冲推覆同时期的前陆块体隆起（厚皮逆冲推覆）开始的运动学变化。这项工作涉及的实地工作相结合，以测量断层滑动生长地层，建设平衡的横截面，和运动学建模的速度场的每个时间增量。该研究为探讨板块俯冲过程中前陆变形的机制和驱动力提供了新的思路。此外，该研究正在积累关于大地测量方法（全球定位系统）确定的瞬时变形率与数百万年来测量的地质变形率之间关系的关键数据。这些数据也将有助于评估该地区地震危险性的人。

Researchers at Cornell University and their Argentine colleagues are studying the relationship between thin- and thick-skinned deformation due to flat slab subduction of oceanic crust beneath the Precordillera-Sierras Pampeanas region of western Argentina. The goal of this study is to produce a suite of maps that showing comprehensive velocity fields at 5 million year intervals from 20 million years ago to the present. These maps record the kinematic changes from thin-skinned thrusting and active magmatism to the cessation of arc magmatism and beginning of foreland block uplifts (thick-skinned thrusting) coeval with thin-skinned thrusting. The work involves a combination of fieldwork to measure fault slip in growth strata, construction of balanced cross sections, and kinematic modeling of the velocity field for each time increment. The research is providing insight into the mechanisms and driving forces of foreland deformation during flat slab subduction. Additionally, the research is accumulating critical data on the relationship of instantaneous deformation rates determined by geodetic methods (Global Positioning System) and geological deformation rates measured over millions of years. The data will also be useful to those evaluating seismic hazard in the region.