The role of turbidites on compaction and dewatering of underthrust sediments at the toe of the northern Barbados accretionary prism: new evidence from Logging While Drilling, ODP Leg 171A
The role of turbidites on compaction and dewatering of underthrust sediments at the toe of the northern Barbados accretionary prism: new evidence from Logging While Drilling, ODP Leg 171A
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浊积岩对巴巴多斯北部增生棱柱趾部逆冲沉积物压实和脱水的作用：来自随钻测井的新证据，ODP Leg 171A
DOI：
10.1016/s0012-821x(00)00078-9
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
T. Tokunaga
中科院分区：
文献类型：
--
作者：
T. Tokunaga
最近从ODP 171A航次获得的随钻测井数据集使钻井地点之间的沉积物的详细相关性和它们之间的体积密度变化的估计成为可能。在这项分析中，三种不同的岩性从底冲沉积物的巴巴多斯增生棱镜拿起和体积应变进行了计算，通过比较体积密度的相关间隔。结果表明，浊积岩中的互层泥岩经历了较大的体积应变，而块状粘土岩则没有。由于横向连续的砂岩起到了有效排水的作用，因此，被相对高渗透性砂岩上下夹持的泥岩层被解释为经历了脱水。俯冲带中浊积岩砂岩的存在以及暖流体沿着砂岩的迁移可能解释了为什么在浊积岩砂岩存在的672号站点洋底观察到高热流，而在没有浊积岩沉积的543号站点则没有。
Recently obtained Logging While Drilling data sets from ODP Leg 171A enable a detailed correlation of sediments among drill sites and an estimate of the change of bulk densities among them. In this analysis, three different lithologies from the underthrust sediments of the Barbados accretionary prism were picked up and volumetric strains were calculated by comparing bulk densities of correlated intervals. Results showed that the interbedded mudstones in turbidites have experienced larger volumetric strain while massive claystones have not. The mudstone beds, sandwiched both above and below by relatively highly permeable sandstones, are interpreted to have undergone dewatering because laterally continuous sandstones have acted as effective drains for dewatering. The existence of the turbidite sandstones in the underthrust package and the migration of warm fluid along the sandstones might explain why high heat flow is observed at the ocean floor at Site 672, where turbidite sandstones exist, but not at Site 543, where turbidites were not deposited.