南秦岭早古生代地层含硒量及硒的分布规律  

Selenium Content and Distribution Pattern in the Palaeozoic strata in the Southern Qinling Mountains

作　　者：雒昆利[1] 潘云唐[2] 王五一[1] 谭见安[1] 

机构地区：[1]中国科学院地理科学与资源研究所 [2]中国科学院研究生院,北京100039

出　　处：《地质论评》2001年第2期211-217,共7页Geological Review

基　　金：煤炭工业部跨世纪学科带头人基金(编号2300213);陕西省自然科学基金(编号ISO3);国家重点基础研究发展规划项目(973)子课题(编号G1999022212-02)资助

摘　　要：本文对南秦岭大巴山区主要分布的早古生代地层各种岩石的含硒量的研究结果表明,含硒量与岩石的岩性和形成时代密切相关,与岩石的含碳量和含硫量成正线性关系。碳质板岩和石煤相对于其他类岩石的含硒量高,碳质板岩一般为6×10^(-6)～35×10^(-6),石煤的含硒量为8×10^(-6)～45×10^(-6);中、下寒武统和志留系大贵坪组的碳质板岩和石煤含硒量较高,可达30×10^(-6)。同时,下寒武统的含硒量远远大于早古生代其他层位同类岩石的平均含硒量,是同类岩石平均含量的5～10倍。如碳酸盐岩的含硒量为2×10^(-6)～4×10^(-6);细粒岩石的含硒量较粗粒岩石的含硒量高,下志留统陡山沟组的厚层状到中厚层状砂岩、粉砂岩和上寒武统的砾屑灰岩的含硒量相近,约0.05×10^(-6)～0.08×10^(-6),是本区最低的。因此,并非本区所有岩石都富硒。The content and distribution pattern as well as the source of the selenium in the early Palaeozoic strata of the southern Qinling and Daba regions are studied in this paper. The results show that the selenium content of the early Paleozoic strata is closely related with the age and lithologic characters of rocks, and is directly proportional to the carbon and sulphur contents in the rocks. The selenium content of carbonic slate is 6 ×10-6~35 × 10-6 and that of stone coal is 8×10-6~45 × 10-6, which are more abundant than other types of rocks in this region. The selenium content of the lower Cambrian strata is 5~10 times that of strata of other ages, and it is much higher than the average selenium content of the same type of rocks of the early Palaeozoic in other horizons, such as lower Cambrian limestone (selenium content: 2×10~6~4×10-6). Fine-grained rocks are more abundant in selenium than coarse-grained rocks. The selenium content of lower Silurian sandstone and fine sandstone as well as upper Cambrian gravel limestone are about 0. 05×10-6~0. 08× 10-6, which is the lowest in this region. So, one can see that not all rocks are rich in selenium in this region. The contemporaneous volcano activity brought plenty of selenium to the sedimentary basin and the absorption of algae and clay furthers such selenium enrichment. The bathyal stagnant environment is favourable for the preservation of selenium-rich algae and clay sediments. Rocks enriched in selenium the most are closely related to igneous rocks. Igneous rocks, carbonic slate or stone coal occurring in their contact zones have selenium content of 28×10-6~35× 10-6, which is higher than that of stone coal and carbonic slate far away from igneous rocks. The late-stage magmatic intrusion and tectonic movement readjusted the selenium content in rocks around structural positions or contact zones with igneous rocks to enrich the selenium in local areas, but no more selenium was added to the strata, so the average selenium content was not changed significant

关 键 词：南秦岭 早古生界 硒 分布规律 大巴山 微量元素 富集 

分 类 号：P534[天文地球—古生物学与地层学]