Multichannel Seismic Study of the Deep Structure of a Cordilleran Orogen: The Southernmost Andes

安第斯造山带是由构造和岩浆作用形成的山脉的典型例子，这些作用主要是由于大洋岩石圈俯冲到大陆边缘之下。然而，对山脉和大陆边深层结构的了解仅以1960年代获得的有限的地震折射剖面图为依据。安第斯山脉南部的地表地质测绘表明，山脉带是由大陆地壳的增厚和缩短产生的，这是对俯冲相关构造作用的反应，南美洲下面的纳斯卡板块的俯冲，以及与俯冲相关的岩浆活动。目前建议的赔偿金将用于支持利用海洋多通道地震反射技术研究安第斯山脉下的地壳结构。将在横贯安第斯山脉的峡湾以及邻近大陆架地区采集数据。将把这些数据与其他关于山脉下地壳结构的研究进行比较，以检验山脉形成的模型，并审查大陆地壳演变的假设。这是一个合作项目，涉及德克萨斯大学和拉蒙特-多尔蒂地质观测站的科学家。现场数据将在康拉德号上获得。

The Andean orogen is the type example of a mountain range formed by tectonic and magmatic processes resulting primarily from the subduction of oceanic lithosphere beneath a continental margin. Knowledge of the deep structure of the mountain range and continental margin, however, is based on only limited seismic refraction profiles obtained in the 1960s. Surface geologic mapping in the southern Andes indicates that the mountain belt has been produced by both thickening and shortening of the continental crust in response to subduction related tectonism, underthrusting of the Nazca Plate beneath South America, and resulting magmatic activity related to this subduction. The present recommended award will support a study of the crustal structure beneath the Andes using marine multichannel seismic reflection techniques. Data will be acquired in fjords which traverse the Andean range, as well as in the adjacent continental shelf areas. These data will be compared to other studies of crustal structure beneath mountain ranges to test models for their formation and to examine hypotheses for the evolution of the continental crust. This is a cooperative project involving scientists at the Univ. of Texas and Lamont-Doherty Geological Observatory. Field data will be acquired aboard the R.V. Conrad.