Stratigraphy and Facies Architecture of Parasequences with Examples from the Spring Canyon Member, Blackhawk Formation, Utah
Stratigraphy and Facies Architecture of Parasequences with Examples from the Spring Canyon Member, Blackhawk Formation, Utah
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准层序的地层学和相结构，以犹他州 Blackhawk 组 Spring Canyon 段为例
DOI：
10.1306/m64594c3
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发表时间：
1995
影响因子：
1.4
通讯作者：
J. Wagoner
中科院分区：
文献类型：
--
作者：
D. Kamola;J. Wagoner
上白垩统 Blackhawk 组的 Spring Canyon 段很好地说明了准层序结构和海相与非海相地层中准层序边界的性质。准层序和准层序组是地层序列，是层序的组成部分。在海相地层中，准层序是海岸线向盆地进积的结果，通常较浅且向上变粗；在非海相中，准层序显示出明显的垂直相序列，始于泻湖填充沉积物，终于淡水煤。泛滥面（准层序边界）表明水深突然增加，并伴有轻微的海底侵蚀和非沉积，将准层序组内的各个准层序分开。准层序边界是一个连续的单一表面，可以从沿海平原的上倾延伸到远端陆棚的下倾。准层序边界根据观测位置的不同而具有不同的物理表达，并且能够将非海相/边缘海相岩石与同一准层序内的同期海相地层进行关联。准层序演化和沉积重建依赖于层序地层概念的应用。 Spring Canyon 成员文档准层序表达式中的露头示例。波浪主导的滨面砂岩和河流主导的三角洲砂岩均横向存在于同一准层序的海相部分。两者都以洪水事件结束，其特征是相迅速向陆地移动，没有海侵滞后。许多边缘海洋和非海洋亚环境横向存在于同一准层序内。准层序边界提供了
Parasequence architecture and the nature of parasequence boundaries in marine to nonmarine strata are well illustrated in the Spring Canyon Member of the Upper Cretaceous Blackhawk Formation. Parasequences and parasequence sets are stratal successions which are the building blocks of sequences. In marine strata, parasequences result from basinward progradation of the shoreline, and typically shallow and coarsen upward; in the nonmarine, parasequences show a distinct vertical facies succession which begins with lagoon-fill deposits and ends with freshwater coals. A flooding surface (parasequence boundary), indicating an abrupt increase in water depth, accompanied by minor submarine erosion and nondeposition separates individual parasequences within a parasequence set. The parasequence boundary is a continuous, single surface that can be traced from updip in the coastal plain to downdip in the distal shelf. The parasequence boundary has different physical expressions depending on where it is observed, and enables correlation of nonmarine/marginal marine rocks to coeval marine strata within the same parasequence. Parasequence evolution and depositional reconstruction is dependent on the application of sequence stratigraphic concepts. Outcrop examples from the Spring Canyon Member document parasequence expression. Both wave-dominated shoreface sandstone and river-dominated deltaic sandstone exist laterally in the marine portion of the same parasequence. Both are terminated by a flooding event marked by a rapid landward shift in facies, with no transgressive lag. A number of marginal marine and nonmarine subenvironments exist laterally within the same parasequence. The parasequence boundary provides a