Distribution of the Bottom-Simulating Reflector in the Offshore Taiwan Collision Zone
Distribution of the Bottom-Simulating Reflector in the Offshore Taiwan Collision Zone
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DOI：
10.3319/tao.1998.9.4.779(taicrust
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发表时间：
1998-12
影响因子：
0.8
通讯作者：
W. Chi;D. Reed;Char‐Shine Liu;Neil Lundberg
中科院分区：
文献类型：
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作者：
W. Chi;D. Reed;Char‐Shine Liu;Neil Lundberg
台湾西南部近海是台湾山带最早侵入中国大陆边缘的地区。吕宋弧向中国大陆边缘的西北向汇聚，导致台湾西南部近海褶皱冲断堆积成厚层沉积物。在该地区普遍观察到泥底辟和海底模拟反射层（BSR）。在野外实验中，利用海洋研究所研制的热探针，利用台湾大学研制的热探针，在台湾西南海域进行了十四次现场热流测量，结果表明：（1）在泥底辟区，温度、温度梯度和热导率异常，热流值较高，泥底辟明显受深部流体运移的影响，在泥底辟侧翼发现的低热流值可能是含气泥角砾岩热导率低的结果。(2)To应用天然气水合物温度-压力相图从BSR中导出温度梯度，如果我们推测天然气在纯水中的组成为90%甲烷和10%乙烷，则得到的温度梯度与原位测量的温度梯度相比接近（仅小6.3%）。
The area offshore from southwest Taiwan is where the Taiwan mountainbelt first encroaches on the Chinese continental margin.The northwestwardconvergence of the Luzon Arc towards the Chinese continentalmargin has resulted in stacking of thick sediments in terms of folds andthrusts off southwest Taiwan.Mud diapirs and bottom simulating reflectors(BSRs)are commonly observed in this region.During the field experiment,the heat probe developed by the Instituteof Oceanography,National Taiwan University is found to be efficient anddurable.Using the newly designed heat probe,we have conducted fourteenin situ heat flow measurements off southwest Taiwan.The results showthat:(1)Temperatures,temperature gradients,and thermal conductivitiesare anomalous and heat flows are higher above the area where muddiapirs appear.The mud diapirs are apparently influenced by relevant deepfluid migration through the pore spaces.The low heat flow found on theflank of a diapir probably results from the low thermal conductivity ofmud breccia containing gas.(2)To apply the gas hydrate temperature-pressurephase diagram to derive temperature gradients from BSRs,if we speculatea gas composition of 90 percent methane and 10 percent ethane in purewater,a close estimation of the temperature gradient(only 6.3 percent less),compared with that measured in situ,is obtained.