Lithology Dependence of Porosity in Slope and Deep Marine Sediments
Lithology Dependence of Porosity in Slope and Deep Marine Sediments
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斜坡和深海沉积物中孔隙度的岩性依赖性
DOI：
10.2110/jsr.2011.60
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发表时间：
2011
影响因子：
2
通讯作者：
Danielle Odette
中科院分区：
文献类型：
--
作者：
M. Kominz;Kyle Patterson;Danielle Odette
11个大洋钻探项目分支和53个地点的孔隙度数据汇编表明，深海到上坡沉积物中的压实作用至少部分是埋藏深度和岩性的函数。总体孔隙率从4%到94%不等。尽管孔隙度范围很广，但随着深度的增加，孔隙度呈指数下降的趋势。根据颗粒大小和成分，对以六种岩性为主(90%~100%)的样品进行比较，揭示了压实作用与岩性的相关性，但生物粉砂和碎屑砂除外。在前一种情况下，这可能部分是由于钙质和硅质纳米化石的混合。粘土大小的碎屑沉积物显示出明显的变化，从顶部172m的孔隙度迅速减少(孔隙度=82.7e−深度/430)到下面的孔隙度损失不太明显(孔隙度=61.4e−深度/1671)。其余岩性，粉砂(孔隙度=75.5e−深度/1091)、生物砂岩(孔隙度=88.5e−深度/1338)和泥晶岩(孔隙度=69.5e−深度/1235)显示出良好到强烈的孔隙度随深度的指数递减。考虑到这部作品中使用的岩性不那么纯粹，这些关系可以与文学研究相媲美。粉土的压实曲线是独一无二的；以前没有关于孔隙度的研究将粉土与其他颗粒大小区分开来。大多数沉积物样品的粒度大小和类型都不同。利用基于岩性的孔隙度-深度关系，对用于反剥离的混合岩性沉积物的4种解压方法进行了验证。所有方法得到的孔隙度估计值都与观测值高度相关，相关系数从0.629到0.686不等。这些已经使用了多年的方法第一次被证明是有效的。
Abstract Compilation of porosity data from 11 Ocean Drilling Program legs and 53 sites show that compaction in deep marine to upper-slope sediments is, at least in part, a function of both burial depth and lithology. Overall porosities range from 4 to 94%. Despite the broad range of porosities, there is an exponential trend toward decreasing porosity with depth. Comparison among samples dominated (90 to 100%) by each of six lithologies, based on grain size and composition, reveals the lithology dependence of compaction, except for biogenic silt-size sediments and clastic sands. In the former case, this may, in part, be due to mixing of calcareous and siliceous nannofossils. Clay-size clastic sediments show a clear change from rapid porosity reduction in the top 172 meters (porosity = 82.7 e−depth/430) to less pronounced loss of porosity below (porosity = 61.4 e−depth/1671). The remainder of the lithologies, silt (porosity = 75.5 e−depth/1091), biogenic sand (porosity = 88.5 e−depth/1338) and micrite (porosity = 69.5 e−depth/1235) show a good to strong exponential reduction of porosity with depth. These relations compare well with literature studies, taking into account the less pure nature of the lithologies used in this work. The silt compaction curve is unique; no previous studies of porosity separated silt from other grain sizes. Most sediment samples are of mixed grain sizes and types. The lithology-based porosity-depth relations were used to test four approaches to decompaction in mixed-lithology sediment used in backstripping. All methods generated porosity estimates that correlated strongly to the observed values, with correlation coefficients ranging from 0.629 to 0.686. These methods that have been used for years are, for the first time, shown to be valid.