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在长江中下游的若干断陷盆地中,发育着一套中、基性到中、酸性而含碱较高的、并以安山质为主的火山-侵人杂岩,与这一套有关的岩浆的演化过程相联系,形成一组从岩浆晚期到伟晶、高温气液、高温接触交代、中、低温热液及可能的矿浆充填、火山喷发沉积成因的铁矿床。这一组铁矿床在时间上基本代表成矿作用各个阶段由高温到低温的转变过程,在分布上主要受它们和辉长闪长玢岩次火山岩体的空间关系所控制。矿石以透辉石(阳起石)-磷灰石-磁铁矿为基本矿物组合,含一定数量的钒、钛,具有特殊的围岩蚀变及矿床构造。在以往报导中,此类产于安山质火山岩分布区的透辉石(阳起石)-磷灰石-磁铁矿矿床常被不同作者归入不同成因类型,这组矿床的多样性可能是产生这种情况的主要原因。长江中下游若干盆地中的这组铁矿发育较好,也可作为一个有代表性的例子。由于它们和辉长闪长玢岩的成因联系以及矿床本身的次火山成因特点,本文特称之为“玢岩铁矿”。
A number of volcanic-intrusive complexes of intermediate-basic to intermediate-acidic and high-alkali-containing andesite are developed in a number of fault-depressed basins in the middle and lower reaches of the Yangtze River and are related to this set of Of the magmatic evolution process, forming a group from the Late Magma to Pei Jing, high temperature gas and liquid, high temperature contact account, medium and low temperature hydrothermal and possible ore filling, volcanic eruption deposits of iron deposits. This group of iron deposits basically represent the transition from high temperature to low temperature at various stages of mineralization in time, and are mainly controlled by the spatial relationship between them and the gabbro-diorite volcanic rocks. The ore is composed of diopside (actinolite) - apatite - magnetite as the basic mineral assemblage, containing a certain amount of vanadium and titanium with special wall rock alteration and ore deposit structure. In previous reports, such diopside (Yangdashi) -apatite-magnetite deposits produced in the An-Shan volcanic rock distribution area are often classified into different genetic types by different authors. The diversity of these deposits may be This is the main reason for this situation. This group of iron deposits in several basins in the middle and lower reaches of the Yangtze River developed well and could also serve as a representative example. Due to their genetic relationship with the gabbro diorite porphyrite and the genesis of the secondary volcano in the deposit itself, this paper calls it “the pluton”.