Collaborative Research: Formation of Basement-involved Foreland Arches: An Integrated EarthScope Experiment

合作研究：涉及地下室的前陆拱门的形成：综合 EarthScope 实验

基本信息

批准号：
0843889
负责人：
Christine Siddoway
金额：
$ 13.44万
依托单位：
Colorado College
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2009
资助国家：
美国
起止时间：
2009-05-01 至 2013-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0843889&HistoricalAwards=false
关键词：
Collaborative Research Formation Basement involved

项目摘要

This EarthScope project, herein called the Bighorn Project, is an integrated geological and geophysical investigation of contractional basement-involved foreland arches. It addresses how these foreland arches form and how they are linked to plate tectonic processes. The research in the Rocky Mountain Bighorn Arch of northern Wyoming and southern Montana combines geological investigations of surface geometries and kinematic indicators with geophysical imaging of 3D crustal and upper mantle geometries from an active/passive seismic experiment. The resulting 4D (3D spatial and temporal), lithospheric-scale model of foreland arch deformation tests current hypotheses for basement-involved foreland thrust belts both in the Rockies and in active orogens of Asia and the Andes. These hypotheses include: 1) fault blocks defined by lithosphere-penetrating thrust faults, 2) subhorizontal detachment within the crust, 3) lithospheric buckling, and 4) pure shear lithospheric thickening. Our investigation to determine the mechanism driving basement-involved arch formation is advancing our understanding of continental lithospheric rheology. This three year (2009-12) collaborative project defines a lithospheric volume of 1.5 x106 km3 by integrating arch-scale upper crustal geometries derived from surface exposures and petroleum industry subsurface data (Eric Erslev, University of Wyoming; Christine Siddoway, Colorado College) with the results of a hybrid seismic experiment. The passive component of this experiment consists of a 1.25 year (2009-10) deployment of 27 broadband seismometers that densify the EarthScope transportable array (Megan Anderson, Colorado College), a 6.5 month deployment of 220 short period seismometers (Anne Sheehan, University of Colorado), and a 9 day deployment of 800 high frequency "Texan" seismometers (Kate Miller, University of Texas at El Paso). The active component consists of 9 shots (summer 2010) recorded by the above instruments and an additional 1600 "Texan" seismometers deployed for 5 days. These instruments are arrayed in a grid consisting of three SW-NE lines and two NW-SE lines with a total line length of 1000 km. Joint inversion of active and passive results defines crustal and upper mantle velocities and interface structures within the Bighorn Arch. These new seismic results are integrated (2010-12) within a GIS-based, 3D geospatial framework including data from exposures, geologic maps and industry subsurface data for the study area. Kinematic information from fracture transects (Erslev, Siddoway) and gravity modeling (Miller) is used to guide 3D, lithosphere-scale structural restorations to test the compatibility of different components in our 3D geometric model. The broader impact of the Bighorn Project partially lies in the development of fundamental methods for quantitative integration of geological and seismological research. In addition, the Bighorn Project involves a broad range of geoscientists, including one post-doctoral fellow, 4 graduate students, and 15 undergraduates, who will participate in IRIS and Keck Consortium sponsored research. The results have key implications for energy resources, allowing the prediction of open fractures that are critical to hydrocarbon production. The development of a dramatic animation showing the 4D structural development of the Bighorns Arch during the Laramide Orogeny provides important public outreach.

该地球景观项目称为大角项目，是对收缩地下室的前田拱门进行的综合地质和地球物理研究。它解决了这些前拱门如何形成的方式以及它们如何与板构造过程相关联。怀俄明州北部和南部蒙大拿州的落基山大角拱门进行的研究结合了对表面几何形状和运动学指标的地质研究，以及来自活跃/被动的地震实验的3D地壳和上地幔几何形状的地球物理成像。所得的4D（3D空间和时间），岩石圈尺度模型的前拱形变形测试测试了落基山脉和亚洲和安第斯山脉中的落基山脉和活跃的Ogens中的地下室涉及前陆的前线推力的当前假设。这些假设包括：1）由岩石圈穿透性推力断层定义的断层块，2）地壳内的下侧脱落，3）岩石圈屈曲，4）纯剪切岩石圈增厚。我们的调查以确定驱动基底围绕拱形的机制的调查正在促进我们对大陆岩石圈流变学的理解。这三年（2009-12）合作项目通过整合源自地面暴露和石油行业的地下地壳几何形状（Eric Erslev，Wyoming; Wyoming; Wyoming; Christine Siddoway College of Colorado College of Colorado College of Colorado College of a hybricsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsicsic osissicsicsicsicsiceciencics osissicsicsicsicsicsicsicsicsicsicsicsicssicssicssicssicssics osissicssics ossicsics oserface''的合作项目。 The passive component of this experiment consists of a 1.25 year (2009-10) deployment of 27 broadband seismometers that densify the EarthScope transportable array (Megan Anderson, Colorado College), a 6.5 month deployment of 220 short period seismometers (Anne Sheehan, University of Colorado), and a 9 day deployment of 800 high frequency "Texan" seismometers (Kate Miller, University of Texas在El Paso）。活跃组件由上述乐器记录的9张镜头（2010年夏季）和另外1600个“德克萨斯”地震仪仪组成5天。这些仪器以三个SW-NE线和两条NW-SE线的网格为准，总线长为1000 km。主动和被动结果的联合反转定义了大角弓内的地壳和上地幔速度和界面结构。这些新的地震结果已集成（2010-12），其中包括基于GIS的3D地理空间框架，包括来自研究区域的暴露，地质图和行业地下数据的数据。来自断裂样品（ERSLEV，Siddoway）和重力建模（Miller）的运动信息用于指导3D，岩石圈尺度的结构修复体，以测试我们3D几何模型中不同组件的兼容性。大角项目的更广泛的影响部分在于开发基本方法，用于定量地质和地震学研究。此外，该项目还涉及各种各样的地球科学家，其中包括一名博士后研究员，4名研究生和15名本科生，他们将参加Iris和Keck Consportium赞助的研究。结果对能源具有关键意义，从而预测了对碳氢化合物至关重要的开放性裂缝。戏剧性的动画的发展，显示了Laramide造口期间大角弓的4D结构发展提供了重要的公众外展。