| 论元古界矿源层 |
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| 引用本文： | 李英.论元古界矿源层[J].地球科学与环境学报,1989(4). |
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| 作者姓名： | 李英 |
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| 作者单位： | 西安地质学院地勘系 |
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| 摘 要： | 本文依据众多已知的矿床实例,说明元古宙不仅是重要的成矿时代,而且成为显生宙成矿的重要矿源层。“元古界矿源层”的概念可以把成矿作用的演化与大陆壳的演化联系起来,指出大地构造背景与成矿作用形式的内在联系。作者还对元古界矿源层的形成给予了概略论述。作者指出,“元古界矿源层”概念将会开拓通过区域基底地球化学背景的研究,进行了有效成矿预测的新途径。
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| 关 键 词： | 元古界 矿源层 显主宙成矿 铅同位素 大陆地壳 区域成矿预测 |
ON THE SOURCE-BED OF THE PROTEROZOIC GROUP |
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| Li Ying.ON THE SOURCE-BED OF THE PROTEROZOIC GROUP[J].Journal of Earth Sciences and Environment,1989(4). |
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| Authors: | Li Ying |
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| Institution: | Xi'an College of Geology |
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| Abstract: | In terms of the research achievements in China and in the world, this paper tried to illustrate a main thought that the Proterozoic Group not only is an important metallogenic epoch, but also some source-beds of the phanerozoic mineralization were formed during this time.In the Proterozoic Erathem the ore deposits not only have a large number of reserves and many metallogenic types, but also they occupy a remarkable proportion in the whole international reserves.In addition, a lot of ore-beds were formed during the Phanerozoic eon. Their source-beds all occurred in the Proterozoic Erathem, but their ore-bodies took place mainly in the Palaeozoic group, in the Proterozoic group, in the Mesozoic group, even in the Cenozoic group.Therefore it is necessary to point out the term "Proterozoic Source-bed." This conception integrates the metallogenic evolution with the continental crust evolution and shows the internal relations between the geotectonic setting and the metallogenic pattern.Thus a new path for the mineralization prediction is opened up through the studies of the regional foundational geochemistry.
In this paper the author first discussed the metallogenic history of the tungsten deposits and their ore-source in China.Early mineralization took place about 2.3-1 billion years ago ( Proterozoic eon) .At that time the "initial source-bed" , the mineralized and geochemistry grade concentrated bed, was formed.The period(0.6-0.5 billion years ago ) was the first mineralization period in the southern China, and the time,that is 1-0.8 billion years ago, was the early metallogenic epoch in the southern margin of the Huabei platform.So during that time a large stratbound tungsten ore cluster was born.Besides several volcanic original W-riching beds, some secondary concentrated beds were mainly formed during the Phanerozoic time.Following the magmatic intrusion during the Into-Chinese-Yenshan epoch, the magm-atogene tungsten ore-series and the more complicated stratbound W-deposits came into being.
Studying plenty of the sediment-hosted exhalative ore deposits, including many well-known deposits in the eastern Australia, Europe,and North America.These two-stage lead or the mixing lead produced by the two normal leads during different periods of time showed that there were two limits of the time-1.8-1.2 billion years and the later period of 0.6 billion years. In particularly, the ore radiogenic lead comtents were decreasing with the increase of the distance from an ancient source region,This kind of deposit included the W-Sb-Hg ( Au ) and Hg-Sb ore deposits.This view is confirmed by two recent research achievements, the porphyry molybdenun and the lead-zinc mineralization in the southern margin of the Huabei platform and the Devonian exhalative lead-zinc ore deposits in the Qinlin mountains.
In a broad sense,the formation of "the Proterozoic source-bed" depended on the crustal evolution and the metallogenic characteristics at that time. That was expounded in details by S.R.Taylor ( 1985 ) , A.Kroner(l983-1985), and A.W.Hutchinson ( 1986 ) , It is obvious that this knowledge is also the result of the recent study of nydrothermal fluid flow and the exhalative hypothesis. |
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| Keywords: | Proterozoic source-bed phanerozoic mineralization lead isotope continental crust regional minerogenic valuation |
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