Statistical Analysis of Bed-Thickness Patterns in a Turbidite Section from the Great Valley Sequence, Cache Creek, Northern California
Statistical Analysis of Bed-Thickness Patterns in a Turbidite Section from the Great Valley Sequence, Cache Creek, Northern California
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北加州卡什溪大山谷层序浊积岩剖面的床厚模式统计分析
DOI：
10.2110/jsr.66.900
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发表时间：
1996
影响因子：
2
通讯作者：
Tom Williams
中科院分区：
文献类型：
--
作者：
C. Murray;D. Lowe;S. Graham;P. A. Martinez;J. Zeng;A. Carroll;Rónadh Cox;M. Hendrix;C. Heubeck;Donald R. Miller;I. Moxon;E. Sobel;J. Wendebourg;Tom Williams
摘要：本文探讨了运用一种基于蒙特卡罗的游程分析方法来分析浊积岩序列中是否存在不对称的层厚旋回。沃尔德伦检验可用于识别以向上变厚或向上变薄旋回为主的序列，但不能同时识别这两种情况。我们对游程分析的改进提供了一种稳健的技术，它能够表明局部厚度趋势的存在，这些趋势不同于随机序列中所预期的趋势，并且可用于评估向上变厚和向上变薄旋回的相对重要性。作为一个案例研究，对加利福尼亚北部卡什溪沿岸的大峡谷群上白垩统赛茨组236米的地层进行了详细测量和描述。该剖面先前被解释为一系列以不对称向上变厚旋回为特征的进积海底扇叶状体沉积。沃尔德伦检验的应用表明，该剖面并非如先前所述以向上变厚旋回为主。蒙特卡罗游程分析表明，小规模向上变薄旋回与向上变厚旋回同样常见。海底扇叶状体的简单进积并不能充分解释该剖面中所见的厚度模式。将蒙特卡罗游程分析应用于其他浊积岩剖面，对于浊积岩层厚旋回的定量识别和比较将是有用的，这应该会促使更好的浊积岩相模式的发展。
ABSTRACT This paper explores the use of a Monte Carlo adaptation of runs analysis to analyze turbidite sequences for the presence of asymmetric bed-thickness cycles. Waldron's test can be used to identify sequences that are dominated by either upward-thickening or upward-thinning cycles, but not both. Our adaptation of runs analysis provides a robust technique that can indicate the presence of local thickness trends that are different from those expected in random sequences, and can be used to evaluate the relative importance of upward-thickening and upward-thinning cycles. As a case study, 236 m of the Upper Cretaceous Sites Formation in the Great Valley Group were measured and described in detail along Cache Creek in northern California. This section had been previously interpreted as a s ccession of prograding submarine-fan-lobe deposits marked by asymmetric upward-thickening cycles. Application of Waldron's test indicates that the section is not dominated by upward-thickening cycles, as previously suggested. Monte Carlo runs analysis demonstrates that small-scale upward-thinning cycles are as common as upward-thickening cycles. The simple progradation of submarine fan lobes does not adequately explain the thickness patterns seen in the section. Application of Monte Carlo runs analysis to other turbidite sections would be useful for quantitative identification and comparison of turbidite bed-thickness cycles, which should lead to development of better turbidite facies models.