腾冲山寨盆地特征及砂锡矿物质成分研究  

STUDY OF CHARACTERISTICS OF SHANZHAI BASIN AND MATERIAL COMPOSITION OF TIN PLACER,TENGCHONG COUNTY

作　　者：李舜贤[1] 陆永潮[1] 马进德 

机构地区：[1]中国地质大学武汉管理干部学院

出　　处：《云南地质》1991年第4期362-384,共23页Yunnan Geology

摘　　要：山寨盆地位于腾冲-梁河锡矿带小龙河含锡岩体的东侧。盆地中充填有第四纪湖相-冲积相厚层沉积,有砂锡聚集,局部富集成矿床。本文论述了该盆地的新构造背景、沉积特征和沉积相、砂锡矿物质成分等。 1.山寨盆地为-断陷盆地,并严格地受到NE和NW向两组断裂的控制,从而使盆地具菱形平面形态,并在盆内发育有NE、NW向展布的新生代地堑和地垒的基本格局。 2.控制山寨盆地发展演化有两个因素:一是第四纪新构造拉张运动和岩浆侵出;二是盆地西侧火山岩源区沉积物的大量供给。 3.盆地的沉积物可分出老湖相和新湖相。沉积相可分冲积扇相、扇三角洲相、湖泊相、河流相和沼泽相。 4.砂锡矿类型有:残坡积型,洪积型,洪冲积型,河床-河漫滩型,古河道型,湖积型。盆内聚锡的有利部位为:(1)盆缘同沉积断裂带内冲积扇复合体;(2)扇三角洲河口沙坝;(3)活跃湖泊边缘—湖滨带;(4)湖盆内古河道。 5.砂锡矿物组合和锡矿化程度在不同的流域中有不同的分布规律和成熟程度,与源区母岩成分及其搬运距离有着密切的关系。 6.不同流域的锡石矿物和脉石矿物特征和组合类型有明显的差异,据石英颗粒的表面特征可划分出上、中、下游河床和不同的河流阶地。The Shanzhai basin lies to the eastern side of Xiaolonghe tin-bearing rocks in the Tengchong-Lianghe tin mineralized zone. The basin was filled with thick sediments of Quaternary lake and alluvial facies and accumulated with tin placer which is locally enriched to be commercial deposit. This paper describes the neotectonic setting, sedimentary characteristics and facies as well as material composition of the tin placer in the basin. 1. The Shanzhai basin is a rift basin which is strictly controlled by two fault groups of NE and NW. Therefore the basin is of rhombus in plane shape, and its basic fame work consists of Cenozoic graben and horst of NE and NW. 2. The evolution of Shanzhai basin might be decided by two factors:(1) neotectonic tensil movement and magmatic extrusion of Quaternary; (2) a good supply of sediments from the volcanic rock source region in the western side of the basin. 3. The sediments in the basin can be distinguished into old and new lake facies. The sedimentary facies can be classified into alluvial fan, fan delta, lake, stream and swamp. 4. Types of the tin placer are: elluvial-deluvial, proluvial, proluvial---alluvial, riverbed—vallyflat, fossil stream channel and lacustrine. The Sn-rich zones in the basin usually are:(1)alluvial fan complexes in syndepositional fault zone along the basin margins; (2) river-mouth barrier of fan delta;(3) active lake margin-shore belt; (4) fossil stream channel within the lake basin. 5. Mineral assemblages and mineralized intensity of the tin placer are dif. ferent in distribution patterns and degree of maturity when they occur in dif-ferent valley reaches. They are closely related to the composition of the mother rocks and to the transported distance. 6. It is evidently different that the characteristics and the mineral assem-blages of the cassiterite and gangue occur in different vally reaches. According to surface features of the quartz particles, the riverbed of the upper, middle and lower reaches, and the different stream terraces can be divi

关 键 词：锡矿 砂矿 物质成分 山寨盆地 

分 类 号：P618.440.4[天文地球—矿床学]