海洋科学Issue(4)：81-87,7.
南海中央海盆扩张期后海山链岩浆活动的热模拟研究
The thermal simulation of magma activities of the seamount chain after
摘要
Abstract
On the basis of the gravity data, magnetic data, bathymetric data, rock sample analysis data (crustal structure and the thermal parameters) and the FEM numerical simulation, we researched the relation among the viscosity, melting and migration issues beneath the Zhenbei-Huangyan seamount chain. The result of our analysis was the viscosity was controlled by pressure and temperature but it increase with thermal dissipation and melting dehydration or decrease caused by the residual magma. According to the result, we designed three different viscos-ity structure models. The calculation results showed that the maximum melting rates of the three vertical viscosity structure models in the mantle melting zone were all bigger than 20%~25%. The melting degree of the magma ac-tivities was related to the mantle thermal structure, melting latent heat and water content, meanwhile it was affected by the expansion rate. For example, the melting rate of the slow spreading ridges slower lower than others. After the spreading period, the magma vertically rose to the top interface of the melting zone mainly by the decompression melting buoyancy, and migrated to the ridge axis along the dumping area. We discussed the factors which affected the melting and migration. With the increase of the distance to the ridge axis, the potential melting degree became lower. Thus we can come to a conclusion that during the peak spreading period of the South China Sea’s central basin, the area which was 10 km below the seamount chain had the condition to form the tholeiitic magma;at the end of the spreading period, the area in the depth of 25 km had the condition to form alkaline basalt magma.关键词
南海珍贝-黄岩海山链/扩张期后岩浆活动/黏性结构/减压熔融与上浮Key words
Zhenbei-Huangyan seamount chain in the South China Sea/magma activities after the spreading period/viscosity structure/decompression melting and buoyancy分类
天文与地球科学引用本文复制引用
林巍,张健,李家彪..南海中央海盆扩张期后海山链岩浆活动的热模拟研究[J].海洋科学,2013,(4):81-87,7.基金项目
国家自然科学基金(41174085) （41174085）
国家重点基础研究发展计划“973”课题(2007CB411704) （2007CB411704）
