| 大厂锡矿床成因综合分析及成矿模式 |
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| SYNTHETIC STUDIES ON THE ORIGIN OF THE DACHANG TIN-POLYMETALLIC DEPOSITS AND THEIR METALLOGENETIC MODEL |
| Broad and multi-faceted studies during the past 20 years have shown that all sedimentary exhalative deposits are formed on the seafloor by chemical precipitation from discharged metal-bearing hydrothermal fluids. The fluids are generated within the sub-area floor rock column by reaction between convectively circulated sea water and the rocks themselves. Differing rock columns in various tectonostratigraphic environments give rise to differing fluids and varieties of deposits. However, because of their common genetic process, all sedimentary exhalative deposits share a set of common identifying primary geologic characteristics, and it is of great significance for comparative investigating the origin of certain other deposits.The purpose of this paper is to briefly review the main geological and geochemical characteristics of the Dachang tin-polymetallic deposits, the genetic processes how they are formed, the deformation-metamorphism after ore-formation and its resulting geological characteristics. And then, it is to consider the relationship between the Dachang tin-polymetallic deposits and some strata-bound deposits including massive base metal sulfide deposits, greenstone belt gold lodes and stratiform tin deposits. The facts indicate that many of the geological and geochemical characteristics of the Dachang tin-polymetallic deposits are similar to those of the massive base metal sulfide deposits. These similarities suggest that many of the genetic and me-tamorphic processes involved in massive sulfide formation may have also contributed to formation of the Dachang deposits. So, Dachang deposits belong to the stratabound and stratiform tin deposits of tin-rich type of massive sulfide deposits.The specific tectono-stratigraphic environment formed Dachang tin-rich exhalative deposits is also discussed. The preliminary studies indicate that the following three conditions are necessary for the formation of these deposits (1) A convectively circulated hot brine system has been initiated by rifting; (2) Some involvement of older continental crust pre-enriched in tin in submarine exhalative system is obviously happened 5 (3) At least two or three successive tectono-magmatic stages are involved in the evolutionary metal-logenesis of the Dachang tin deposits. |
| HAN Fa,Richard W.Hutchinson.1991.SYNTHETIC STUDIES ON THE ORIGIN OF THE DACHANG TIN-POLYMETALLIC DEPOSITS AND THEIR METALLOGENETIC MODEL[J].Acta Geoscientica Sinica,12(1):61-80. |
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