江西阳储岭成矿岩体主要造岩矿物标型特征及其地质意义

Typomorphic Characteristics of Major Rock-forming Minerals in the Yangchuling Ore-forming Intrusive Body and Their Geological Significance, Jiangxi Province

无论在成因或空间上,长江中下游铜硫铁成矿带中的阳储岭大型斑岩钨钼矿田均与矿田花岗质岩浆岩有关。矿田花岗质岩浆岩系同源同期多次形成的复合岩体,位于江西省北部九岭隆起带与下扬子凹陷带的交接部位,属燕山早期第三阶段产物(γ2~)。作者对该岩体作了较为系统的研究,本文着重报导对其主要矿物黑云母、斜长石、钾长石标型特征的研究资料。资料表明,矿田成矿岩体形成于浅成—超浅成环境,其物质来源具有深源混溶之混合质特色,为岩体的岩理学研究提供了地质信息。

The Yangchuling large-sized porphyry Lungsten-molybdenum orefield in the copper-sulfur-iron metallogenic belt of middle and lower reaches of the Yangtze River is genetically and spatially related to the granitic rock body in this orefield. This intrusive body, lying at the connection between the Jiuling upwarping zone of northern Jiangxi and the Lower Yangtze downwarping zone; is a complex rock body formed at the same stage by repeated activities of consanguineous magma and seems to be the product of 3rd stage of early Yanshanian(γ_5^(2-3)). The rocks are intermediate-acid-acid and belong to 4th-5th family of 2nd class in Zavaritskii's classification. Researches show that the principal rock-forming mineral biotite in the ore-forming rock body of the orefield belongs to typical biotite of ferromagnesian series whose Mg-coefficient is close to Fe-coefficient, and is characterized by low F, Cl, Li and high Ti as compared with biotite in the Xihuashan rock body; plagioclase is of transitional-ordered texture whose degree of order is 0.55-0.9,and has well-developed girdle band structure with An being 35-42; the degree of order(δ)of potash feldspar varies in the range of 0.19-0.5, belonging to transitional texture, and Or content is 50-80％.Studies on typomorphic characteristics of ore-forming minerals indicate that the ore-forming rock body in the orefield was formed in a hypabyssal-supergene environment with the material sources characterized by anatexis, and this conclusion is supported by stable isotope and REE data of the ore-forming rock body in the orefield. In genetic type, this rock body corresponds basically to the synte tic type granite proposed by professor Xu Keqin.