复合成因矿床分布广泛,把它们单独划分出来进行研究,对于深入认识成矿过程、发展成矿理论和指导找矿勘探,均有重要意义.鉴于中国大陆东部中生代岩浆作用强烈,对前期成矿作用的影响也很明显,因此本文以长江中下游成矿带为例,评介了复合成矿作用的几种主要机理,认同前人提出的叠加和改造是其基本类型,但预富集作用也应重视,同时也不能忽视继承成矿和再生成矿,特别是继承和预富集联合多次出现时,可以形成区域性成矿元素大规模富集.同时,本文还将它们放在区域构造体制和机制转化演化过程中加以考察,进一步明确它们在中生代构造体制转换以前主要以沉积(含热水沉积)成因的含矿建造、矿源层或矿(胚)层产出,而矿床的最终形成与就位则主要与新构造体制下由挤压向引张转化的过渡环境中构造-岩浆活动有关,呈现出“成矿大爆发”的现象.其中早期( 145～136Ma)构造机制是以走滑挤压作用为主,形成与高钾钙碱性岩系有关的铜金矿化.晚期(135 ～ 127Ma)以走滑引张作用为主,形成了与橄榄安粗岩系有关的铁硫矿化.但这两期都有广泛发育的以叠加改造为主的复合成因铜、金、铁、硫及铅锌矿床,从而在典型的岩浆热液矿床和沉积矿床之间形成了一套过渡性矿床序列(层控矽卡岩型→沉积热液叠加型→层控叠改型→迁移式改造型→原地式改造型),构建了一个矿床“家族”.末期( 126 ～ 123Ma)以引张作用为主,出现碱性火山岩和A型花岗岩类,伴随铁、金、钼、铀等矿化,成矿带的成矿活动随之进入尾声.%The polygenetic compound ore deposits are widely distributed in the world. In order to understand the mineralization process, develop the metallogenic theory and guide ore prospecting and exploration; it is significant to make special research on this kind of deposits. As the intense Mesozoic magmatism rebuild the pre-mineralization in the eastern China, this study take the Middle-Lower Yangtze River Valley metallogenic belt as an example of the eastern China to investigate the mineralization mechanisms of this kind of deposits. To the major mechanisms of the polygenetic mineralization, the authors agree that the superposition and transformation are the basic types of the mineralization enrichment, while the pre-enrichment, inheritance and regeneration of mineralization should be paid more attentions. Generally, there is large-scale mineral enrichment after repetitious inherited and pre-enrichment process. The final formation and adscription of polygenetic compound ore deposits the Middle-Lower Yangtze River Valley metallogenic belt were related with the Mesozoic tectono-magmatic activities during the change of tectonic regime from compression to extension, which exhibited as " metallogenic explosion" . During this process, ore bearing formations ( including hydrothermal sediment) and mineralized sedimentary source bed are altered to ore bodies. The mineralization process can be generally divided into two stages: At the early stage (145 to 136Ma) , high-K calc-alkaline series intrusion and copper and gold mineralization formed in a strike-slip compression tectonic setting, and at the later stage (135 to 127Ma) , shoshonitic series volcanic rocks with iron and sulfur mineralization formed in a strike-slip extensional environment. Both the early and late stages of mineralization widely developed the polygenetic copper, gold, iron, sulfur and Pb-Zn deposit, which are mainly effected by the superimposed reformation. They can be further identified as a typical transitional series of polygenetic compound ore deposits between the magmatic hydrothermal ore deposits and the sedimentary deposits such as the strata-bound skarn type, the sediment-hydrothermal superimposed type, the layered superimposed reformed type, the migrated reformed type and the in situ reformation type) , which compose a deposit "family". At the last stage (126 to 123Ma) , it formed alkaline volcanic rocks and A-type granitoids with iron, gold, molybdenum and uranium mineralization in the extension environment, which indicated the end of mineralization in the metallogenic belt.
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