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首页> 外文学位 >I. Stratigraphic constraints on the number of discrete Neoproterozoic glaciations and the relationship between glaciation and Ediacaran evolution. II. The Kwichup spring thrust in the northwestern Spring Mountains, Nevada: Implications for large-magnitude extension and the structure of the Cordilleran thrust belt.
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I. Stratigraphic constraints on the number of discrete Neoproterozoic glaciations and the relationship between glaciation and Ediacaran evolution. II. The Kwichup spring thrust in the northwestern Spring Mountains, Nevada: Implications for large-magnitude extension and the structure of the Cordilleran thrust belt.

机译：I.地层限制了新元古代不连续冰川的数量以及冰川作用与埃迪卡拉纪演化之间的关系。二。内华达州西北斯普林斯山脉的Kwichup春季逆冲作用：对大幅度伸展和科迪勒兰逆冲带结构的影响。

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摘要

Stratigraphic and structural observations in the Death Valley region provide new insights into two topical problems. First, stratigraphic observations provide a better understanding of the number of discrete Neoproterozoic glaciations and the relationship between glaciation and the diversification of the first animals. Detailed stratigraphic investigations reveal incised valleys within the Neoproterozoic Johnnie Formation. The size (>150 m) and regional extent of the valleys, and the carbon isotope signature of underlying carbonates show that the valleys are probably glacioeustatic in origin. The incised valleys help to complete the Neoproterozoic glacial record in the western United States. The incised valleys and a pair of glacial diamictites in the underlying Kingston Peak Formation represent two to three discrete Neoproterozoic glaciations. Correlation of the Johnnie valleys with incised valleys in the uppermost Caddy Canyon Quartzite of Idaho and Utah shows that the youngest major Neoproterozoic glaciation probably occurred before 580 Ma. These findings suggest that diverse Ediacaran faunas post-date the youngest major Neoproterozoic glaciation by tens of millions of years.; Second, structural and stratigraphic observations provide new constraints on the magnitude of extension in the Death Valley extended domain. These observations reveal a thrust fault in the northwestern Spring Mountains, NV. Correlation of this thrust fault with thrusts in other ranges constrains the translation of those ranges relative to the Spring Mountains. While these correlations are not unique, the most plausible correlations require large-magnitude extension in the Death Valley extended domain.; Correlation of contractile structures in the northwestern Spring Mountains and Specter Range with Permo-Triassic structures in the Cottonwood Mountains may provide a link between the Permo-Triassic thrust belt in the Cottonwood Mountains and the Central Nevada thrust belt. The Central Nevada thrust belt may be a Permo-Triassic foreland fold and thrust belt which developed inboard of the Golconda allochthon during its emplacement.
机译：死亡谷地区的地层和结构观测提供了对两个主题问题的新见解。首先，地层学观测可以更好地了解新元古代冰川的离散数量以及冰川作用与首批动物的多样性之间的关系。详细的地层调查显示，新元古代强尼组内的切谷。山谷的大小（> 150 m）和区域范围以及下层碳酸盐的碳同位素特征表明，这些山谷的起源可能是冰川恒流的。切开的山谷有助于完成美国西部的新元古代冰川记录。底层金斯敦峰组中的切开的山谷和一对冰川铁矾土代表了两到三个离散的新元古代冰川。爱达荷州和犹他州最上层的球童峡谷石英岩中的约翰尼山谷与切开的山谷之间的相关性表明，最年轻的主要新元古代冰期可能发生在580 Ma之前。这些发现表明，不同的埃迪卡拉动物群将最年轻的新元古代冰河时代推迟了几千万年。第二，结构和地层观测对死亡谷扩展域的扩展幅度提供了新的约束。这些观测结果揭示了内华达州西北斯普林山的逆冲断层。该推力断层与其他范围内的推力的相关性限制了这些范围相对于斯普林山脉的平移。尽管这些相关性不是唯一的，但最合理的相关性要求在死亡谷扩展域中进行大幅度扩展。西北春山和幽灵山脉的收缩结构与三叶杨的二叠系-三叠纪构造的相关性可能在三叶草的二叠系-三叠系逆冲带和内华达中部逆冲带之间建立联系。内华达中部冲断带可能是Permo-Triassic前陆褶皱和冲断带，该冲断带和冲断带是在Golconda异位隆起时向内侧发展的。

著录项

  • 作者

    Abolins, Mark Joseph.;

  • 作者单位

    California Institute of Technology.;

  • 授予单位 California Institute of Technology.;
  • 学科 Geology.
  • 学位 Ph.D.
  • 年度 1999
  • 页码 341 p.
  • 总页数 341
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;
  • 关键词

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