摘要
Abstract
The widespread potash deposits account for one of the most important evaporate deposits in the world,which have reserves of 3.5 billion tons.They are distributed in Canada,Belarus,Russia,China,the United States,Chile and Germany.This paper analyzed the spatial and temporal distribution of global potash deposits and proposed that they were mainly formed in the form of solid mineral resources in marine and marine-terrigenous evaporative basins in northern hemisphere.Devonian,Jurassic,Cretaceous,Permian and Cambrian are the world's most important potassium metallizing eras.Among them,Paleozoic eras are characterized by large-scale potash deposits,which were usually located in large intra-plate or inter-plate rift zones.Mesozoic and Cenozoic potash deposits are also found in plate boundary foreland settings.By means of tectonic plate reconstruction,ancient geography and climate analysis,three factors that contributed to the spatial and temporal distribution of global potash deposits are proposed.(1) Climatic Paleozone.Dry climate are favorable condition for potash deposits.(2)Global Sea Level Fluctuation.Marine regression is beneficial for potash deposition,most of which occurred when the sea level were slightly fluctuated.(3)Tectonic Setting.Orogenic activities are destructive for the formation of potash deposit.We further discussed the reason why Chinese potash resources are widespread but small in scale.We proposed that during the global major potash depositing periods,North China,South China and Tarim plates were not in arid zone or covered by shallow sea.Therefore,they are not favorable for the formation of large potash deposits.关键词
钾盐资源/全球分布/古板块位置/构造成因Key words
potash resource/global distribution/plate setting/tectonic genetic分类
天文与地球科学
