Cyclostratigraphic and Ichnofacies Analysis of the Upper Albian Salmon Peak Formation, Maverick
Cyclostratigraphic and Ichnofacies Analysis of the Upper Albian Salmon Peak Formation, Maverick
复制标题
Maverick 上阿尔布安鲑鱼峰地层的旋回地层和岩相分析
DOI：
10.1306/7834dddc-1721-11d7-8645000102c1865d
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
J. L. Wilson
中科院分区：
文献类型：
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作者：
Laura C. Zahm;C. Kerans;J. L. Wilson
上Albian鲑鱼峰组由半深海陆棚内盆地沉积组成，位于Stuart City礁主走向后面，被Devils River石灰岩的高能碳酸盐斜坡边缘相向陆地（北部和西部）包围。三文鱼峰组上覆Del里约热内卢页岩，下覆McKnight组。鲑鱼峰组的顶部大致对应于阿尔巴尼亚/塞诺曼尼亚边界。萨尔蒙峰一直在国际边界和水资源委员会ID-22核心中，从德克萨斯州德尔里约热内卢附近的Val Verde县开始。对该岩心进行综合生物地层学、沉积学和时间序列分析，可以细化上阿尔bian碳酸盐岩台地-盆地体系的生物地层学和旋回地层学历史。116米（380英尺）厚的鲑鱼峰组被划分为：(1)无构造泥岩，(2)稀疏的Skolithos穴状泥岩至尾纹岩，(3)Thalassinoides或planololite类穴状富有机质泥岩至尾纹岩，(4)暗色层状富有机质有孔虫泥岩，(5)块状粗粒状尾纹岩至颗粒岩。在ID-22核心中可以识别出三重复合循环层次结构。1-2-3相和2-3-5相高频旋回与更富有机质、缺乏有机质的2-3-4相高频旋回交替形成中等规模旋回。在Maverick盆地，大尺度旋回作用的定义是高频旋回的不对称退积-递进叠加（McKnight中部至Salmon峰下部）和以退积和缺氧为主的上部包裹。微古生物学分析(4)显示了浮游和底栖有孔虫的丰度和多样性的波动，从而可以确定最大的洪水面，然后是陆架边缘进积。时间序列分析将观察到的岩相和生物相旋回置于一个年代地层格架中，这将有助于陆架与盆地的对比。
ABSTRACT The Upper Albian Salmon Peak Formation consists of hemipelagic intrashelf basin deposits positioned behind the main Stuart City Reef trend and surrounded landward (north and west) by high-energy carbonate ramp margin facies of the Devils River Limestone. The Salmon Peak Formation is overlain by Del Rio Shale and underlain by McKnight Formation. The top of the Salmon Peak Formation corresponds approximately to the Albian/Cenomanian boundary. The Salmon Peak is continuously cored in the International Boundary and Water Commission core ID-22 from Val Verde County, near Del Rio, Texas. Integrated biostratigraphic, sedimentologic, and time-series analysis of this core allows refinement of both biostratigraphic and cyclostratigraphic histories of this Upper Albian carbonate platform-to-basin system. The 116 meter (380 feet) thick Salmon Peak Formation is subdivided into: (1) structureless mudstone, (2) sparse Skolithos burrowed mudstone to wackestone, (3) Thalassinoides or Planolites-like burrowed organic-rich mudstone to wackestone, (4) dark laminated organic-rich foraminifera-bearing mudstone, and (5) massive coarse pelletal wackestone to grainstone. A three-fold compound cycle hierarchy is recognized in the ID-22 core. Facies 1-2-3 and 2-3-5 high-frequency cycles alternate with more organic-rich, starved 2-3-4 high-frequency cycles to define intermediate-scale cyclicity. Large-scale cyclicity is defined by a lower asymmetric retrogradational-progradational stacking of high-frequency cycles (middle McKnight through lower Salmon Peak) and an upper package dominated by retrogradation and decreased oxygenation in the Maverick Basin. Micropaleontologic analysis of facies (4) shows fluctuations in abundance and diversity of planktic and benthic foraminifera which allows identification of a maximum flooding surface followed by shelf margin progradation. Time series analysis places observed lithofacies and biofacies cycles in a chronostratigraphic framework that will aid in shelf-to-basin correlations.