华南陆块钨和锡的地球化学时空分布

摘要

Based on tungsten and tin analytical data from stream sediments of 1∶200000 Regional Geochemistry-National Reconnaissance Project and the study of elemental abundance of crust and rocks in the eastern part of China,the temporal and spatial distribution characteristics of tungsten and tin in South China Continent（SCC） are discussed in this paper.On the temporal distribution,the high background contents of tungsten and tin in SCC are distributed in the South China Orogenic Belt and Coastal Volcanic Rocks Belt of Cathaysia Block,in the lower Yangtze Platformal Fold Belt and the Jiangnan Earth Axis of the Yangtze Block,in east of the Yueyang-Huaihua-Guilin-Wuzhou-Maoming and south of Yangtze River.The concentrated distribution area of high contents of tungsten and tin in Nanling Region corresponds with important tungsten and tin orefield in China and the world as a whole,which occurred in the metallogenic domain of South China Mesozoic great granite province.On the lithology,alkalic feldspar granite and syenogranite,slate,phyllite and schist in basement in the southeast part of South China Block are characterized by high background contents of tungsten and tin.On the temporal distribution,the sandstones and mudstones in basement and cover from the Mesoproterozoic era are enriched in tungsten and tin;the extensive granitoid volcanic-intrusive activities during the Indosinian and Yanshanian periods,in which the alkalic feldspar granite and syenogranite enriched in tungsten and tin played the main parts,reached a climax in the late stage of crustal evolution.These brought about the distribution of high background contents of tungsten and tin,and formed the geochemical domain.In addition,strong metallogenesis and a lot of middle-large deposits of tungsten and tin widespread in the southeast part of SCC led to forming plentiful regional geochemical anomalies and local geochemical anomalies of tungsten and tin.%以1∶20万区域化探全国扫面计划水系沉积物和中国东部地壳与岩石元素丰度研究W、Sn分析数据为基础,探讨了华南陆块W、Sn的时空分布特征。从空间分布上看,华南陆块W、Sn的高含量主要分布在华南陆块东南部,即岳阳—怀化—桂林—梧州—茂名以东、长江以南广大地区的华夏地块华南造山带和东南沿海火山岩带与扬子地块下扬子台褶带和江南地轴;而南岭地区则是华南造山带W、Sn高含量的集中分布区,与华南中生代大花岗岩省成矿域产出的中国乃至世界重要的W、Sn矿产地相一致。从岩性上看,华南陆块东南部基底碱（正）长花岗岩、板岩、千枚岩、片岩以W、Sn背景含量高为特点。从时间分布上看,华南陆块东南部自中元古代以来形成的基底和盖层中砂岩和泥岩富含W、Sn,在地壳演化后期以富含W、Sn的碱（正）长花岗岩为主体的印支—燕山期大面积花岗质岩浆火山-侵入活动达到高峰,造成华南陆块东南部W、Sn高背景含量的分布,形成巨大的W、Sn地球化学域。加之,华南陆块东部W、Sn成矿作用强烈,与W、Sn有关的中大型矿床密集分布,从而导致大量W、Sn区域地球化学异常和局部地球化学异常的形成。