【摘要】 西南印度洋中脊(Southwest Indian Ridge, SWIR)热液区具有潜在发育的大规模硫化物矿床，当前正在开展SWIR硫化物矿产资源评价。测量分析硫化物和不同围岩的声速等物性特征是硫化物近底地震勘探资料处理和解释的基础。该文对西南印度洋中脊热液区的硫化物和围岩等样品进行了系统的物性测量，结合岩石物性(包括密度、孔隙度、P波速度)与矿物组成，深入分析了西南印度洋中脊热液区岩石声速变化特性及其影响因素。结果表明，SWIR热液区围岩的P波速度受到岩石骨架矿物、孔隙和围压的影响。由于岩石孔隙度总体偏小，对P波速度的影响并不显著，但围压的增加使岩石微裂缝和孔隙逐渐闭合，P波速度呈非线性指数变化。蚀变作用导致了矿物成分改变，是影响围岩声速的最关键因素。单一物性参数测量结果可能存在多解性，联合波速、密度、磁性和电性等多物性参数测量有利于岩性区分。该研究成果有助于识别硫化物和围岩，为我国西南印度洋合同区多金属硫化物地震勘探工作提供重要支撑。更多还原

【Abstract】 The hydrothermal fields of the Southwest Indian Ridge(SWIR) have the potential to develop large scale sulfide deposits, and the SWIR sulfide mineral resource evaluation is currently underway. Measurement and analysis of petrophysical characteristics such as P-wave velocity of sulfides and different host rocks are the basis for processing and interpretation of near-bottom seismic exploration data. Through the systematic measurement of the physical properties of sulfides and host rocks in the SWIR hydrothermal areas, we have analyzed the characteristics of rock P-wave velocity variation and its influencing factors by combining rock physical properties(including density, porosity, P-wave velocity) and minerals. The results show that the P-wave velocity of SWIR rocks is influenced by the rock skeleton minerals, pore space and confining pressure. Due to the overall small porosity of the rocks, the effect on P-wave velocity is not significant, but the increase of the confining pressure gradually closes the rock microfractures and pores, and the P-wave velocity varies non-linearly exponentially. The alteration causes the change of mineral composition, which is the most critical factor affecting the P-wave velocity of the confining rocks. The results of single physical parameter measurements may have multiple solutions, and the joint measurement of multiple physical parameters such as wave velocity, density, magnetic and electrical properties is beneficial for lithological differentiation. The research results help identifying sulfides and host rocks, and provide important support for the seismic exploration of polymetallic sulfides in the Southwest Indian Ocean contract area of China.更多还原