高分辨层序地层学中A/S值量化方法的研究与讨论
摘要: 可容纳空间增加速率与沉积物供应速率的比，即A/S，作为高分辨率层序地层学研究中一个重要的参数，主要应用于划分地层旋回性。根据岩相特征对A/S值变化的响应，本文提出了A/S区间量化方法来确定A/S值。鉴于前人的研究成果，建立理想沉积模型，并对模型中的各种岩相分别赋值（由底部向顶部，ZYXWDCBA，分别为12345678）。根据沉积地层岩相值的变化，划分为基准面上升（岩相值向上增加）与下降（岩相值向上减小）两个区间，并定义单个区间内岩相值与底部岩相值的比值为该岩相地层的A/S值，同趋势区间岩相的A/S值相同。据此定义出的A/S值及其纵向变化意义与高分辨率层序地层中A/S值变化意义保持一致。应用本文提出的A/S值量化方法，对经典辫状河沉积岩相进行标准A/S量化研究，确立了各岩相的A/S值。应用于两个实例研究中确定A/S值，并利用A/S值来划分短期基准面旋回，与经典理论划分出的旋回特征具有较好的对比性，划分成果统一且操作简单，避免了同种沉积不同沉积旋回特征的划分方案。
Research and Discussion: an Approach to Quantitative A/S in High-Resolution Sequence Stratigraphy
Abstract: As a key parameter in high-resolution sequence stratigraphy, the ratio of accommodation to sediment supply, named A/S for short, has been used to divide stratigrahpic base-level cycles. However, A/S has been classified into unity, increasing, decreasing and below zero, without any real data. According to the record of litho-facies and its thickness responded to the variation of A/S, this paper proposes an approach, named A/S interval quantization principle within special interval, to quantify the real data of A/S. Based on the former research, we found real sedimentary model, and set number on each litho-facies within the model (from bottom to top, ZYXWDCBA, 12345678, respectively). According the numbers' changing, they are classified two intervals, base-level rising (number bigger upward) and base-level falling (number smaller upward). In each interval, we define the ratio, number of sediment litho-face to number of bottom sediment litho-face, as A/S data, and every A/S data of litho-face is the same. The A/S data and its vertical changing has the same meanings with which in high-resolution sequence stratigraphy. Applying the approach, we quantify A/S data on classic braided-river sedimentary litho-faces. With two practices, we found the A/S data on the former research, and based on which to classify short-term base-level cycle. Comparing with the former research, the division of base-level based on the approach has ideal similarity. At the same time, the division is single and operation-simple, which can avoid the phenomenon that different base-level division in the same sediment.
高分辨层序地层学中A/S值量化方法的研究与讨论[J]. 沉积学报, 2013, 31(6): 1088-1093.
| 引用本文: |
高分辨层序地层学中A/S值量化方法的研究与讨论[J]. 沉积学报, 2013, 31(6): 1088-1093.
|
Research and Discussion: an Approach to Quantitative A/S in High-Resolution Sequence Stratigraphy[J]. Acta Sedimentologica Sinica, 2013, 31(6): 1088-1093.
| Citation: |
Research and Discussion: an Approach to Quantitative A/S in High-Resolution Sequence Stratigraphy[J]. Acta Sedimentologica Sinica, 2013, 31(6): 1088-1093.
|
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