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首页> 外文OA文献 >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.地层对离散新元古代冰川作用的限制以及冰川作用与埃迪卡拉进化之间的关系。 II。内华达州春山脉西北部的Kwichup spring推力：对大幅度延伸的影响以及Cordilleran冲断带的结构

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Part I: Stratigraphic constraints on the number of discrete neoproterozoic glaciations and the relationship between glaciation and ediacaran evolution.ududStratigraphic 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. This record of two to three glaciations matches the global Neoproterozoic glacial record. The incised valleys provide the youngest evidence for large-scale Neoproterozoic glaciation in the western United States. Correlation of the Johnnie valleys with incised valleys in the uppermost Caddy Canyon Formation of Idaho and Utah shows that this glaciation occurred before 580 Ma. These findings suggest that diverse Ediacaran faunas post-date the youngest major Neoproterozoic glaciation by tens of millions of years.ududSecond, 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 area and north of Las Vegas Valley.ududCorrelation 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 at least in part Permo-Triassic in age, and may represent a foreland fold and thrust belt which developed inboard of the Golconda allochthon during its emplacement.ududPart II: The Kwichup Spring thrust in the northwestern Spring Mountains, Nevada : implications for large-magitude extension and the structure of the Cordilleran thrust belt.ududApproximately 170 km(2) of new mapping in the northwestern Spring Mountains reveals contractile structures related to a regional thrust fault called the Kwichup Spring thrust. The Kwichup Spring thrust involves at least 1.4 km of stragraphic throw. Along much of its length, the Kwichup Spring thrust has been reactivated or excised by a normal fault.ududStratigraphic and structural evidence suggest that the Kwichup Spring thrust correlates with the Montgomery thrust in the Montgomery Mountains. Correlation of these two thrusts requres a reappraisal of the geometry of the Cordilleran thrust belt in Nevada and southeastern California. The Kwichup Spring - Montgomery thrust probably correlates with either the Clery thrust in the Funeral Mountains or the Panamint thrust in the Panamint Mountains. Both possible correlations require large (>115 km) west-northwest translation of the Panamint and Cottonwood Mountains with respect to the Spring Mountains during Neogene extension.ududBefore this large-scale translation, the Panamint and Cottonwood Mountains were positioned along the southern projection of the Central Nevada thrust belt of Taylor and others (1993). Since contractile structures in the Cottonwood Mountains are Permo-Triassic, the Central Nevada thrust belt may be at least in part Permo-Triassic.ud
机译：第一部分：新元古代不连续冰川数量的地层限制以及冰川作用和埃迪卡拉峰演化之间的关系。 ud ud死亡谷地区的地层和结构观测提供了对两个热点问题的新见解。首先，地层学观察可以更好地理解新元古代不连续冰川的数量以及冰川作用与首批动物多样化之间的关系。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。该记录有两到三个冰川，与全球新元古代冰川记录相吻合。切开的山谷为美国西部大规模的新元古代冰川形成提供了最年轻的证据。爱达荷州和犹他州最上段的球童峡谷地层的约翰尼山谷与切开的山谷之间的相关性表明，这种冰川作用发生在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。 ud ud其次，结构和地层观测为死亡谷扩展域的扩展幅度提供了新的限制。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，但最合理的相关性需要在死亡谷地区和拉斯维加斯谷地以北大幅度扩展。 ud ud西北斯普林山脉和Spectre山脉中的收缩构造与Permo-Triassic构造的相关性卡顿伍德山脉可能在卡顿伍德山脉的Permo-Triassic逆冲带和内华达中部逆冲带之间提供联系。内华达中部逆冲带可能至少部分是三叠纪时代的，并且可能代表前陆褶皱和逆冲带，它是在戈尔康达异地冲动就位时在内侧发展的。内华达州斯普林斯山：对大范围扩展和科迪勒拉逆冲带结构的影响。 ud ud西北斯普林斯山中约170 km（2）的新地图显示了与区域性逆冲断层有关的收缩结构，称为Kwichup Spring推力。凯普苏普泉的推力至少涉及1.4 km的地层投掷。沿其大部分长度，凯奇普普斯逆冲推力已被正常断层重新激活或切除。 ud ud结构和结构证据表明，凯奇普普斯逆冲推力与蒙哥马利山脉的蒙哥马利推力有关。这两个推力的相关性要求对内华达州和加利福尼亚东南部的山脉推力带的几何形状进行重新评估。 Kwichup Spring-Montgomery逆冲可能与the仪山的Clery逆冲或Panamint山脉的Panamint逆冲有关。两种可能的相关性都需要在新近纪扩展期间相对于春山山脉对Panamint和Cottonwood山进行大的（> 115 km）西西北偏西转换。 ud ud在进行大规模转换之前，Panamint和Cottonwood山是在南部定位泰勒等人在内华达州中部逆冲带的投影图（1993年）。由于三叶杨山区的收缩构造是Permo-Triassic，所以内华达中部逆冲带可能至少是Permo-Triassic的一部分。 ud

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    Abolins Mark Joseph;

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