摘要
对大巴山区内主要分布的早古生代地层中氟的分布规律进行了研究,结果表明:大巴山区地史时期形成的各单元地层岩石中普遍富氟。下寒武统鲁家坪组碳质板岩、黑色页岩、磷块岩中平均氟含量普遍超过800mg/kg,下志留统大贵坪组碳板岩氟含量也明显较高(1500mg/kg以上),这些地层分布区是大巴山区的氟富集区;奥陶系、中志留统及下志留统除大贵坪组外的各组地层氟含量也一般高于地壳平均含氟量;而震旦系、下寒武统箭竹坝组及中上寒武统地层氟含量一般低于500mg/kg,是大巴山区的相对低氟区。大巴山区早古生代石煤中氟含量普遍高于中国腐植煤的平均含氟量,其中紫阳蒿坪下志留统大贵坪组的石煤氟含量最高;其次是下寒武统石煤;中、上寒武统及奥陶系石煤含氟量最低。
Fluorine is widely distributed in rocks, which are the ultimate sources of fluorine in the environment. So it is necessary to study fluorine distribution in rocks especially in fluorine poisoning areas. The Daba mountainous region has severe endemic fluorosis. Most of outcropping bedrocks have high F content, about several times to tens of times greater than the average in the earth crust. Furthermore, strong weathering in the Daba region, which has a typical subtropical monsoon climate with rich heat and rainfall and landform characterized by mountains and hills, resulted in close relations between weath- ered bedrock and human health. In this paper, the F content and distribution in the strata of the Daba region are stud- ied, particularly F-rich strata. The results show that the Early Paleozoic strata in this re- gion are all rich in fluorine at large. Fluorine content is mostly more than 800 mg/kg in carbonaceous slate, black shale and phosphate rock of Lower Cambrian Lujiaping Forma- tion. Fluorine content is also high in carbonaceous slate of Lower Silurian Daguiping For- mation （more than 1500 mg/kg）, and the forementioned strata are classified into the high- fluorine zones in the Daba region. Fluorine contents of Ordovician and other formations of Mid-Lower Silurian strata are also higher than the average in the earth crust （550 mg/kg） but lower than 800 mg/kg. Fluorine contents Of Neoproterozoic, Lower Cambrian Jianzhuba Formation and Mid-Upper Cambrian strata are generally lower than 500 mg/kg, which are classified into the low-fluorine zones in the Daba region. The fluorine content of stone coal of Early Paleozoic in the Daba region is generally much higher than the average fluorine content of Chinese coals. The highest fluorine con- tent of stone coal occurs in Lower Silurian Daguiping Formation, the next in Lower Cam- brian, and the lowest in Mid-Upper Cambrian and Ordovician stone coal. Most Chinese stone coals are high-fluorine coals （〉800 mg/kg）, which are widely distributed in south- ern China short of ordinary coal resource, where stone coal is used as a local household fu- el easily to be exploited, so the usage of stone coal with high F concentration has brought severe fluorosis for local people.
出处
《地理研究》
CSSCI
CSCD
北大核心
2012年第8期1503-1511,共9页
Geographical Research
基金
国家自然科学基金项目(40872210
41172310)
"863"计划项目(2004AA601080
2006AA06Z380)
关键词
氟
地层
分布规律
大巴山区
fluorine
strata
distribution
Daba mountainous region
