Basin and Range Geoscientific Experiment (BARGE)

小行星9219939 BARGE是对地球大陆岩石圈区域的综合、多学科调查，该区域在高度延伸的地形和构造稳定块体之间存在突变边界。 本研究的主要研究目标是利用岩石圈最上部大应变梯度的“自然实验”来了解莫霍面和其他深部不连续面如何对伸展作出响应，从而量化岩石圈大水平应变与各水平垂直运动之间的关系，这些水平运动受等厚线控制。 通过在盆岭省进行地质测绘，已经确定了一些这样的区域。 其中，科罗拉多高原的西部边缘是实现我们目标的最合适的例子。 它具有以下优点：（1）简单，（2）地质背景指示了一个简单的前伸展地壳结构，（3）一个很好理解的大规模伸展运动学历史，（4）一个简单的前伸展地壳结构，（5）一个简单的前伸展地壳结构。也许最重要的是，（4）一个适合于深入地球物理研究的大型内陆水道，米德湖，在地质学研究可以确定地壳在伸展过程中隆起的界限的精确位置上横切边界。 主要调查人员正在整合地质和地质年代学研究、海洋多道地震反射剖面、协调的陆地和海洋地震折射剖面以及重力建模，以揭示海洋的运动学和动力学。 岩石圈对剧烈伸展应变的响应 BARGE项目地质部分的主要目标已接近完成。 主要目的是通过地质测绘、岩石学和热年代学研究以及对构成黄金丘构造块体大部分的元古代结晶基底的古地磁研究，确定该构造块体在地壳中的大规模伸展前构造特征。 BARGE的地球物理部分比地质部分晚一年获得资金。 由于后勤方面的意外延误，地球物理实验将于1994年初进行，即在研究的地质部分的赠款到期后将近一年。 本项目涉及驳船地质部分的适度延续，主要目标有两个： 1)对Gold Butte和邻近的小断块，特别是断块的最高部分（主要上地壳断裂带与高分辨率反射线相交处）进行额外的地质测绘; 2）PI参与地球物理实验，包括解释结果和准备出版手稿。 ***

9219939 Wernicke BARGE is an integrated, multi-disciplinary investigation of a region of the earth's continental lithosphere where an abrupt boundary exists between highly extended terrain and a tectonically stable block. The main research objective of this study is to use the "natural experiment" of a large strain gradient in the uppermost part of the lithosphere to understand how the Moho and other deep discontinuities respond to extension, thus quantifying how large horizontal strains of the lithosphere relate to vertical motions at various levels, controlled by isostasy. A number of such regions have been identified by geological mapping in the Basin and Range province. Of these, the western margin of the Colorado Plateau is the best suited example for accomplishing our objective. It has the virtues of (1) abruptness; (2) a geologic setting that indicated a simple pre-extensional crustal structure; (3) a well-understood large-scale extensional kinematic history; and perhaps most importantly, (4) a large inland waterway suitable for deep geophysical studies, Lake Mead, that transects the boundary in precisely the location where geological studies can place bounds on crustal uplift during extension. The Principal Investigators are integrating geological and geochronologic studies, marine multi-channel seismic reflection profiling, coordinated land and marine seismic refraction profiling, and gravity modeling to unravel the kinematic and dynamics of the lithosphere's response to severe extensional strain. The main objective of the geologic portion of the BARGE project are nearing completion. The primary objective was to characterize the large-scale pre-extensional configuration of the Gold Butte structural block in the crust through geologic mapping, a petrologic and thermochronometic studies, and paleomagnetic studies of the Proterozoic crystalline basement that comprises the bulk of the block. The geophysical component of BARGE was fun ded a year later than the geological portion. Due to unforseen logistical delays, the geophysical experiment will be conducted in early 1994, nearly a year after the expiration of the grant for the geological portion of the research. This project involves a modest continuation of geological portion of BARGE with two principal objectives: 1) Additional geologic mapping of the Gold Butte and neighboring small fault blocks, in particular the uppermost part of the block where major upper crustal fault zones intersect the high-resolution reflection lines; 2) Participation of the PI in the geophysical experiment, including interpretation of results and preparation of manuscripts for publication. ***