南海天然气水合物成矿条件与找矿前景

天然气水合物是一种新近发现的能源矿产,世界各国都非常重视对它的调查研究。南海是西太平洋天然气水合物成矿带的重要组成部分,具备良好的成矿条件和找矿前景,并已发现一系列地球物理和地球化学找矿标志,如模拟海底反射层标志、孔隙水氯离子浓度降低标志、卫星热红外增温异常、甲烷含量异常和热释光异常等,是我国最有希望的找矿远景区。

GAS HYDRATE IN THE SOUTH CHINA SEA:BACKGROUND AND INDICATORS

Gas hydrate has become the focus of international interest over the past few years because of its abundance and its potential importance as (1) new energy resources,(2) controlling factor of global climatic change,and (3) trigger of sea floor instability.The South China Sea is one of marginal seas in the western Pacific.It is well known for their abundant oil and gas reserves,but only a little work has been done on gas hydrate.However,geological background,gas resource,temperature and pressure are good to form gas hydrate.Recently,the multichannel seismic profiles were rechecked and some bottom simulating reflectors (BSR) as well as blanking zones were identified.Some high temperature anomalies above the sea surface were discovered from satellite thermal infrared images,which is probable related to gas hydrate or gas seeps.Furthermore,high methane concentration of sediments and low chlorinity anomalies in interstitial water,which regarded to be indicators of gas hydrate,were also found from Site 1146,ODP leg 184.Moreover,the hydrocarbon anomalies and radioactive anomalies of shallow sediments were recognized.Therefore,it is quite probable that gas hydrates may occur in the South China Sea.