金刚石碳同位素原位分析和元素分析应用于江苏金刚石砂矿物源研究

The north China craton (Mengyin in Shandong province and the Yangtze craton (Wafangdian in Liaoning Province) are the most important diamond producing areas in China. In Jiangsu province, there exists only tiny diamond placer such as in Xinyi area, but not any original deposits. Based on the data of well log, drill log, and accompanying minerals of diamond in studied area, we will analyze the provenance of this diamond placer mainly through geochemical method. The research includes in-situ analysis of diamonds using SIMS and element geochemical, for discussing the question of primary source of diamonds (from the north China craton or the Yangtze craton) and the secondary origin of diamonds. Through studying the Pleistocene Wangxu member in which diamonds exist, this secondary source study will confirm the location and type of the mother rocks, recover the palaeogeographic environment of Yi-Shu river basin where the diamond placer located. We aim to support important theory for finding the original deposits of diamonds or the diamonds placer, and to propose forecast of diamond deposits finding.

华北克拉通（山东蒙阴、辽宁瓦房店）和扬子克拉通（湖南沅水流域）是我国金刚石主要产区。江苏仅在新沂等地发现小型金刚石砂矿，至今未有金刚石原生矿找矿突破。本研究以江苏新沂地区金刚石砂矿为研究对象，立足研究区的录测井、钻井取心及金刚石伴生矿物等前人资料，主要通过地球化学方法对该金刚石砂矿进行深入的物源研究。本研究拟对研究区金刚石颗粒进行碳同位素原位分析（SIMS），探讨原生性来源，确定该区金刚石来自华北克拉通还是扬子克拉通；结合金刚石矿物组分研究成果，对赋存金刚石砂矿的研究区更新统王圩组沉积岩进行微量元素示踪，确定物源位置和母岩类型，恢复该区所处沂沭河流域的古地理环境，解决研究区金刚石砂矿的物源方向等次生性来源问题。在上述研究基础上，综合探讨研究区金刚石砂矿的物源，提出金刚石找矿方向预测，为江苏金刚石原生矿或砂矿的找矿工作提供理论支撑。

华北克拉通（山东蒙阴、辽宁瓦房店）和扬子克拉通（湖南沅水流域）是我国金刚石主要产区。江苏仅在新沂等地发现小型金刚石砂矿，至今未有金刚石原生矿找矿突破。本研究以江苏新沂地区金刚石砂矿为研究对象，立足研究区的录测井、钻井取心及金刚石伴生矿物等前人资料，主要通过地球化学方法对该金刚石砂矿进行深入的物源研究。确定该区金刚石来自华北克拉通还是扬子克拉通；结合金刚石矿物组分研究成果，对赋存金刚石砂矿的研究区更新统王圩组沉积岩进行微量元素示踪，确定物源位置和母岩类型，恢复该区所处沂沭河流域的古地理环境，解决研究区金刚石砂矿的物源方向等次生性来源问题。在上述研究基础上，综合探讨研究区金刚石砂矿的物源，提出金刚石找矿方向预测，为江苏金刚石原生矿或砂矿的找矿工作提供理论支撑。