Basin and Range Geoscientific Experiment (BARGE)

盆地和山脉地球科学实验（BARGE）

• 批准号: 9219939
• 负责人: Brian Wernicke
• 金额: $ 4.21万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-15 至 1994-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9219939&HistoricalAwards=false
• 关键词: Basin; Range; Geoscientific; Experiment; BARGE

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. ***

9219939韦尼克驳船是对地球大陆岩石圈的一个区域进行的综合、多学科的调查，在那里，高度延伸的地形和构造稳定的地块之间存在陡峭的边界。这项研究的主要目的是利用岩石圈顶部大应变梯度的“自然实验”来了解莫霍面和其他深部不连续面对伸展的响应，从而量化岩石圈的大水平应变与受均衡控制的不同水平的垂直运动的关系。在盆地和山脉省的地质制图中已经确定了一些这样的地区。其中，科罗拉多高原的西缘是实现我们目标的最合适的例子。它具有以下优点：(1)突发性；(2)表明简单的伸展前地壳结构的地质背景；(3)广为人知的大规模伸展运动学历史；以及(4)可能最重要的是，适合进行深部地球物理研究的大型内陆水道米德湖，它横切边界，正好位于地质研究能够对伸展时的地壳隆起划定界限的位置。首席调查人员正在综合地质和地质年代学研究、海洋多通道地震反射剖面图、协调陆地和海洋地震折射剖面图以及重力模拟，以揭示岩石圈对严重伸展应变的运动学和动力学响应。驳船工程地质部分的主要目标已接近完成。主要目的是通过地质填图、岩石学和热年代学研究以及构成地块主体的元古界结晶基底的古地磁研究，表征地壳中金巴特构造块的大规模伸展前构造形态。驳船的地球物理部分比地质部分晚了一年。由于不可预见的后勤延误，地球物理实验将于1994年初进行，也就是研究的地质部分赠款到期近一年之后。该项目涉及适度延续驳船的地质部分，其主要目标有两个：1)对金巴特和邻近的小断块进行额外的地质填图，特别是在该地块的最顶部，即主要的上地壳断裂带与高分辨率反射线相交的地方；2)让国际地球物理研究所参与地球物理实验，包括解释结果和编写出版手稿。***