矿田构造变形岩相分类与应用效果

    Classification and application effect of structural deformation lithofacies in the orefield

    • 摘要: 矿田相当于Ⅴ级成矿区带的地质找矿勘查对象,需要研究"构造与建造共生"的地质现象,建立相应的概念和野外观测方法,有别于"沉积构造岩相"、"岩浆岩相"、"变质岩相"、"大地构造相"、"构造岩相"、"构造相"等理论观点。在长期矿田构造和深部外围找矿实践基础上,研究提出"构造变形岩相"的地质概念。构造变形岩相被理解为"显示构造变形的那部分岩相",是喻示受构造影响的那部分(沉积、岩浆和变质地质作用的)岩相,是包含构造变形及建造特征的地质实体,或构造建造形迹。构造变形岩相,是岩石形变和相变密切共生的地质体,既能反映成岩地质环境又包含成岩物理化学条件,是一种适用于开展"构造结合建造"观测和分析的构造岩石单元。依据地质作用类型,划分了4种矿田构造变形岩相:沉积构造变形岩相、岩浆构造变形岩相、变质构造变形岩相和复成构造变形岩相。根据地质亚相,划分了矿田尺度的27类构造变形岩相。建立矿田构造变形岩相的观测和分析方法,不仅推动了构造结合建造的地质调查和研究,而且为矿田构造向矿田地质学的发展奠定了基础。构造变形岩相研究,用1:1000~1:50000不同精度,可以调查几十至几百平方千米范围的地质找矿问题,直接服务于已知矿床的深部外围找矿。地表结合中段大比例尺填图,三维刻画矿化岩相带的分布特征,成为圈定靶区的最佳途径。在"就矿找矿"的基础上,探讨了中距离找矿的预测方向——构造变形岩相界面成矿带。

       

      Abstract: The orefield is equivalent to the grade V metallogenic belt of geological exploration object. It is necessary to study the geological phenomenon of "structure and construction association" and establish the corresponding concept and field observation method. It is different from the theoretical viewpoints of "sedimentary tectonic lithofacies", "magmatic lithofacies", "metamorphic lithofacies", "geotectonic facies", "tectonic lithofacies" and "tectonic facies". On the basis of long-term orefield structure and deep peripheral ore prospecting practice, the geological concept of "tectonic deformation lithofacies" is proposed in this paper. Tectonic deformation lithofacies is regarded as "a part of lithofacies showing structural deformation", which indicates the part of lithofacies (sedimentary, magmatic and metamorphic geological processes) affected by structure. It is a geological entity containing structural deformation and formation characteristics or structural formation features. Tectonic deformation lithofacies is a geological body closely associated with rock deformation and phase transformation. It can not only reflect the geological environment of diagenesis but also contain the physical and chemical conditions of diagenesis. It is a kind of structural rock unit suitable for observation and analysis of "structure combined construction". According to the types of geological processes, four types of tectonic deformation lithofacies are recognized:sedimentary structural deformation lithofacies, magmatic tectonic deformation lithofacies, metamorphic structural deformation lithofacies and composite structural deformation lithofacies. According to the geological subfacies, 27 types of tectonic deformation lithofacies at the orefield scale are distinguished. The establishment of observation and analysis methods of structural deformation lithofacies in the orefield not only promotes the geological investigation and study of structural combination construction but also lays a foundation for the development of orefield structure to orefield geology. With different precision from 1:1000~1:50000, tectonic deformation lithofacies can be used to investigate geological prospecting problems in the range of tens to hundreds of km2, directly serving the deep peripheral prospecting of known deposits. The best way to delineate the target area is to depict the distribution characteristics of mineralized lithofacies zones from the surface and large-scale mapping in the middle section. On the basis of "prospecting on the basis of ore", this paper discusses the prediction direction of medium distance ore prospecting, that is, the metallogenic belt of tectonic deformation lithofacies interface.

       

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