现代地质工作重要发展领域:“十一五”期间勘查地球化学评述

摘要

The national geochemical mapping projects had been conducted continually by China Geological Survey during the Eleventh Five-Year Period,including the Regional Geochemistry-National Reconnaissance (RGNR) Project for mineral exploration and the Multi-Purpose Regional Geochemical Survey Project (MPRGS) for environmental protection.Significant prospecting achievement had been made in the area of regional geochemical exploration.The survey area of 829300 km2 had been completed (cumulative 7566200 km2 completed).4708 anomalies and 411 mineral deposits and occurrences were found,including 273 non-ferrous mineral deposits.Geochemical assessments of mineral resource were carried out.The prospecting targets and resource potential were quantitatively forecasted through the establishment of typical deposit geochemical anomaly model.In the area of Multi-Purpose Regional Geochemical Survey Project (MPRGS),the survey area of 265600 km2 were completed (cumulative 1656600 km2 completed).The ecological geochemical evaluation system was established for the first time,which focused on the origin,migration-transformation,ecological effects and changing trends of the heavy metals.Land quality geochemical evaluation showed that the lands with excellent quality and with good quality accounted for 53％ and 33％ respectively.The lands with poor quality are distributed in the economically developed region.The research on soil organic carbon has shown that the average organic carbon density of the topsoil (0-0.2 m) in the areas covered by Multi-Purpose Regional Geochemical Survey was only 3186 t/km2.With impressive achievements made in the Eleventh FiveYear Period,many important research frontiers or fields on mineral resources and environment protection are formed such as mineral resource potential assessment,ecological geochemistry,land quality assessment,global carbon cycle,and so on.%“十一五”期间(2006-2010年),国土资源部中国地质调查局继续推进区域化探与多目标区域地球化学调查计划.在区域化探方面,完成调查面积82.93万km2(累计完成756.62万km2),发现异常4 708处,经验证发现各类矿产411处,其中有色金属矿产273处,占66.4％,取得重大找矿突破.开展矿产资源地球化学评价,通过建立典型矿床地球化学异常模式,来圈定找矿靶区和进行资源潜力定量预测.在多目标区域地球化学调查方面,完成调查面积26.56万km2(累积完成165.66万km2),建立生态地球化学评价体系,主要针对重金属元素成因来源、迁移转化、生态效应与变化趋势进行较为全面和深入的研究.土地质量地球化学评价表明,中国土地达到优质级占53％,优良级占33％,较差等级主要分布在中东部经济社会发达地区.土壤有机碳研究表明,全国表层土壤(0～0.2 m)平均碳密度仅为3 186 t/km2,且各地区碳密度变化幅度较大,说明中国土壤有机碳处于低水平和不稳定状态.“十一五”期间勘查地球化学针对重大资源与环境问题,深化和延拓地质工作内涵,逐步形成矿产资源评价、生态地质科学研究、土地质量与生态评价、全球变化科学研究及基础地学研究等现代地质工作若干重要发展领域.