Scientific Drilling of Mass-Transport Deposits in the Nankai Accretionary Wedge: First Results from IODP Expedition 333
Scientific Drilling of Mass-Transport Deposits in the Nankai Accretionary Wedge: First Results from IODP Expedition 333
复制标题
南开增生楔中物质传输沉积物的科学钻探：IODP 333 探险队的初步结果
DOI：
10.1007/978-94-007-2162-3_60
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发表时间：
2012
期刊：
影响因子：
6.7
通讯作者：
I. Scientists
中科院分区：
文献类型：
--
作者：
M. Strasser;P. Henry;T. Kanamatsu;M. Thu;G. Moore;I. Scientists
综合大洋钻探计划（IODP）第333远征队在日本西南近海南海增生楔的斜坡盆地的更新世至全新世序列中钻探并取芯。斜坡-盆地是下坡沉积物搬运的沉积中心，由若干块搬运沉积物组成，其中包括一个厚达180米的块搬运沉积物。恢复的剖面（海底以下0-315 m）记录了该活动构造背景下100万年的海底滑坡历史。我们介绍了来自C 0018站点的D/V Chikyu船载结果，包括岩石-生物-磁-和火山岩-地层学和物理性质数据。根据岩心目视描述和X射线CT扫描，确定了6个厚度为0.5 ~ 61 m的MTD。最厚的MTD也是最古老的（位于0.85和1.05 Ma之间），它与下面的桑迪浊积岩序列和上面包含几个MTD的含灰半长岩之间的岩性过渡相吻合。MTD内的变形样式是不均匀的：扰动沉积物的间隔在推断为保留原始连贯层理的间隔内互层。在三种情况下，MTD的底部由细粒沉积物内的剪切带确定。这些观察结果表明，滑塌和质量传输是由局部塑性变形。此外，块体运动是一个活跃的过程，正在塑造现今的海底，这一点可以从C 0018站点的许多表层滑塌疤痕和浅埋（推测为全新世MTD）的出现中得到证明。
Integrated Ocean Drilling Program (IODP) Expedition 333 drilled and cored a Pleistocene-to-Holocene succession of a slope-basin in the Nankai accretionary wedge, offshore southwest Japan. The slope-basin represents the depocentre for downslope sediment transport and comprises several mass-transport deposits (MTDs), including an up to 180 m thick MTD. The recovered section (0–315 m below seafloor) records ∼1 Million years of submarine landsliding history in this active tectonic setting. We present D/V Chikyu shipboard results from Site C0018, including litho- bio- magneto- and tephra-stratigraphy and physical properties data. Six MTDs of thickness ranging from 0.5 to 61 m were identified from visual core description and X-ray CT-scans. The thickest MTD is also the oldest (emplaced between 0.85 and 1.05 Ma) and it coincides with a lithological transition between a sandy turbidite sequence below, and ash-bearing hemipelagites comprising several MTDs above. The deformation style within the MTD is heterogeneous: intervals of disturbed sediments are interbedded within intervals inferred to retain original, coherent bedding. In three occurrences the base of the MTD is defined by a shear zone within fine-grained sediments. These observations suggest that slumping and mass-transport is dominated by localized plastic deformation. Furthermore, mass movements are an active process that is shaping the present-day seafloor, as evidenced by numerous surficial slump scars and the occurrence of a shallowly buried, presumably Holocene MTD at Site C0018.