台灣西南海域手掌海脊天然氣水合物相關近海床構造之研究;The gas hydrate-related seabed features in the Palm Ridge off southwest Taiwan

NCUIR > College of Earth Sciences > Graduate Institute of Geophysics > Electronic Thesis & Dissertation > Item 987654321/71606

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Title:	台灣西南海域手掌海脊天然氣水合物相關近海床構造之研究;The gas hydrate-related seabed features in the Palm Ridge off southwest Taiwan
Authors:	蘇政緯;Su,Zheng-Wei
Contributors:	地球科學學系
Keywords:	天然氣水合物;側掃聲納;底質剖面;Gas hydrate;Side-scan sonar;Sub-bottom profiler
Date:	2016-07-01
Issue Date:	2016-10-13 13:22:04 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究使用高解析底拖側掃聲納（Side-scan Sonar）、高解析底拖底質剖面（Sub-bottom Profiler）、單音束水深儀（Single-beam Echo Sounder）、多音束水深地形（Multi-beam Echo Sounder）、多頻道反射震測（Multi-channel seismic reflection）與海底攝影（Seafloor video）。從側掃聲納及底質剖面影像上，發現有自生碳酸鹽礁、滲漏構造，在單音束水深儀影像上也發現大量的海床溢氣現象，而觀察到的天然氣水合物相關構造皆分布在手掌海脊的地形高區上，且在海底攝影也觀察到在自生碳酸鹽礁周圍有菌叢、貝屑與氣煙囪等化學自營性生物群落聚集。另外在底質剖面影像上，亦發現在此區域有大量的海底山崩堆積物分布，且分布位置上的BSR不連續，推測可能是近期才發生山崩事件，導致天然氣水合物穩定帶（Gas Hydrate Stability Zone）尚未平衡。另外，在R3.1背斜構造的近海床發現許多的正斷層及地塹構造，推測雖在深部是擠壓變形，但因拱起造成在近海床是張裂的現象。綜合觀察到的構造特徵顯示，在手掌海脊處有大量的甲烷氣體從深部地層移棲到近海床，並造成海底山崩事件發生。;The offshore area of the SW Taiwan is located in the convergence zone between the northern continental margin of the South China Sea and the Manila subduction complex. Our study area, the Palm Ridge, is located in the passive continental margin. According to the geophysical, geochemical and geothermal data, abundant gas hydrate may exist in the offshore area of SW Taiwan. In this study, we will study the relationship between the seabed features and the gas hydrate formation of the Palm Ridge. The data used in this study include high-resolution side-scan sonar images, sub-bottom profiles, single-beam echo sounder, multi-beam echo sounder, multi-channel seismic reflection and seafloor video in the Palm Ridge. Our re-sults show the existing authigenic carbonates, gas seepages and gas plumes are mainly distributed in the bathymetric high of the Palm Ridge. Seafloor photos shows the chemosynthetic communities (shells, bacteria mat and chimney). Numerous submarine landslides have occurred in the place where the BSR dis-tribution is not continuous. We suggest that it may be because of rapid slope failure, causing the change of the gas hydrate stability zone. We also found several faults on the R3.1 anticline structure east of the deformation front. These features imply that abundant deep methane gases have migrated to shallow strata, causing submarine landslides or collapse.
Appears in Collections:	[Graduate Institute of Geophysics] Electronic Thesis & Dissertation

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