Basin and Range Geoscientific Experiment (BARGE)

盆地和山脉地球科学实验（BARGE）

• 批准号: 9019357
• 负责人: John Mutter
• 金额: $ 104.7万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-09-01 至 1996-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9019357&HistoricalAwards=false
• 关键词: Basin; Range; Geoscientific; Experiment; BARGE

This project involves an integrated, multi-disciplinary investigation to quantify how the deep continental crust and uppermost mantle respond to extension, and to thus establish how large horizontal strains of the lithosphere relate to vertical motions controlled by isostasy. The principal investigators plan to use the "natural experiment" of a large strain gradient in the uppermost part of the lithosphere associated with the abrupt boundary between highly extended terrain and a tectonically stable block. They have chosen the western margin of the Colorado Plateau to study. It is ideally suited for accomplishing their research objectives for several reasons: (1) the transition is particularly abrupt here; (2) the geologic setting indicates a simple pre- extensional crustal structure; (3) it has a well-understood large- scale extensional kinematic history; (4) the large inland waterway of Lake Mead provides a unique environment in which to perform deep geophysical studies that transect the boundary in precisely the location where geological studies place bounds on crustal uplift during extension. They propose to integrate geological and geochronologic studies, "marine" multi-channel seismic reflection profiling in the lake itself, integrated with land-based recordings on an array on three-component seismometers to provide control on seismic velocity structure and to develop tomographic images of the region which, together with gravity modeling will allow them to unravel the kinematics and dynamics of the lithosphere's response to severe extensional strain.

该项目涉及一项综合的多学科调查，以量化大陆深部地壳和最上地幔对伸展的反应，从而确定岩石圈的大水平应变与由均衡作用控制的垂直运动之间的关系。主要研究人员计划在岩石圈最上方进行大应变梯度的“自然实验”，该实验与高度伸展的地形和构造稳定的地块之间的陡峭边界有关。他们选择了科罗拉多高原的西缘进行研究。由于以下几个原因，它非常适合于完成他们的研究目标：(1)这里的过渡特别突然；(2)地质背景表明了简单的前伸展地壳结构；(3)它有广为人知的大规模伸展运动史；(4)米德湖的大型内河航道为进行深入的地球物理研究提供了独特的环境，这些研究正好在地质研究确定伸展期间地壳隆起界限的位置横切边界。他们建议综合地质学和地质年代学研究，即湖泊本身的“海洋”多道地震反射剖面，与三分量地震仪阵列上的陆上记录相结合，以控制地震速度结构，并开发该区域的层析图像，与重力模拟一起，使他们能够揭示岩石圈对严重伸展应变的运动学和动力学。