首页> 外文学位 >NEOGENE TECTONICS AND PALEOGEOGRAPHY OF THE SOUTHWESTERN GREAT BASIN, CALIFORNIA (RANGE, INYO COUNTY, CRUSTAL EXTENSION).
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NEOGENE TECTONICS AND PALEOGEOGRAPHY OF THE SOUTHWESTERN GREAT BASIN, CALIFORNIA (RANGE, INYO COUNTY, CRUSTAL EXTENSION).

机译:加利福尼亚西南大盆地的新近纪构造和古地理(范围,印诺县,地壳扩展)。

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摘要

This study characterizes crustal extension in the southwestern Great Basin, California, in terms of the timing of its inception, its evolution, and the areas of present activity through an examination of volcanic activity, timing and orientations of structural features, and sedimentary rock types and source areas. Inception of Basin and Range activity generally proceeded across the study area from east to west. Normal faulting and west-northwest extension may have begun by 20 million years ago in the Death Valley area. About 13 million years ago igneous activity, faulting, and eastward tilting became widespread in areas east of Panamint Valley. West of the Panamint Range detailed study of the Darwin Plateau volcanic field, at the north end of the Argus and Coso Ranges, reveals that igneous activity began about 7.7 million years ago, with eruptions onto a generally flat erosion surface. The peak of volcanism occurred between 5 and 6 million years ago, when the earliest normal faulting also was recorded on the plateau. Faults and dikes indicate that west-northwest extension has been dominant, except during a period of east-northeast extension that lasted at least from 5.7 to 5.3 million years ago. A paleomagnetic study shows that no significant rotation has occurred in the eastern Darwin Plateau. Between three and four million years ago Basin and Range tectonic activity began in the Coso and Saline Valley volcanic fields, south and north of the Darwin Plateau area. At this time the present basins and ranges were developing throughout the southwestern Great Basin. Volcanic activity continued into late Quaternary time in the Coso Range and Owens Valley.; West-northwest extension has been dominant in Neogene time over the entire southwestern Great Basin. Present-day extension over the entire region is also oriented west-northwest, as evidenced by earthquake fault-plane solutions, young faults, and geodetic strain measurements. Right-lateral strike-slip faults trending north-northwest have played a major role in accommodating strain in the southwestern Great Basin. The main pulse of uplift, tilting, and volcanism east of the Panamint Range began when the Mendocino fracture zone was positioned at the latitude of the southern end of Death Valley (13 m.y. ago). A westward shift in volcanic and tectonic activity closely corresponds to a change in relative motion between the Pacific and North American plates (4-6 m.y. ago).
机译:这项研究通过研究火山活动,构造特征的时间和方向以及沉积岩的类型和特征,描述了加利福尼亚州大盆地西南部地壳扩展的开始时间,演化和当前活动范围。源区域。在整个研究区域内,盆地和山脉活动的开始总体上是从东到西进行的。正常的断层和西北偏西扩展可能已经在2000万年前在死亡谷地区开始。大约一千三百万年前,在Panamint山谷以东的地区,火成活动,断层和向东倾斜变得很普遍。在Panamint山脉以西对Argus和Coso山脉北端的达尔文高原火山场进行的详细研究表明,火成活动始于大约770万年前,爆发时是在大致平坦的侵蚀面上。火山活动的高峰发生在5到600万年前,当时高原也记录了最早的正常断层。断层和堤坝表明,东西向西北延伸一直占主导地位,除了在至少从5.7到530万年前持续的东西向东北延伸期间。一项古磁研究表明,在达尔文高原东部没有发生明显的自转。在三到四百万年前,盆地和山脉的构造活动开始于达尔文高原地区南北的科索和盐谷火山田。这时,整个西南大盆地正在发育目前的盆地和山脉。火山活动一直持续到第四季度末的科索山脉和欧文斯山谷。在整个西南大盆地,新近纪以来,西北向的扩张一直占主导地位。如今,整个区域的延伸方向也是西北偏西,这由地震断层平面解,年轻断层和大地应变测量证明。西北偏北走向的右走向走滑断层在适应西南大盆地的应变中起了重要作用。 Panmenint山脉以东的主要隆升,倾斜和火山爆发是在Mendocino断裂带位于死亡谷南端的纬度(13年前)之后开始的。火山活动和构造活动向西移动与太平洋板块和北美板块之间的相对运动变化(4-6 y.y.)非常接近。

著录项

  • 作者单位

    Stanford University.;

  • 授予单位 Stanford University.;
  • 学科 Geology.
  • 学位 Ph.D.
  • 年度 1985
  • 页码 229 p.
  • 总页数 229
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;
  • 关键词

  • 入库时间 2022-08-17 11:51:10

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