论沉积盆地构造岩相变形史研究方法及应用

On research methodology for deformation history of tectonic lithofacies in sedimentary basin and their application

基于(非)金属矿产-铀-煤-油气资源同盆共存,盆内构造岩相变形史与成藏成矿事件的耦合结构一直是科学难题。在构造岩相学填图和构造岩相变形史研究基础上,将沉积盆地构造岩相变形史划分为前盆地期、成盆期、盆地反转期、盆地构造变形改造期、盆内岩浆叠加期和盆地表生变化期6个演化期。研究发现,采用构造岩相学填图创新方法,可有效圈定沉积盆地内同生构造样式与构造组合。在火山岩区采用次火山岩侵入、火山隐爆-侵出、火山爆发-喷发等12个相系进行构造岩相填图,有助于有效圈定火山机构中心、火山热液成岩成矿中心和火山热水沉积成岩成矿中心的位置。盆-山-原转换构造岩相带是流体大规模运移和储集构造岩相带,也是(非)金属矿-铀-煤-油气资源同盆共存富集成藏成矿的有利构造岩相带;前陆盆地、山间盆地和后陆盆地具有不同的变形构造组合;构造岩相学研究和填图有助于研究沉积盆地变形期内古热储构造、冠羽状垂向热流柱构造、煤系烃(矿)源岩生排烃成藏成矿事件序列等问题。壳源岩浆、幔-壳混源岩浆、幔源岩浆在盆地岩浆叠加期,形成了相应的岩浆叠加构造样式和岩浆叠加成岩相系。在盆内岩浆底拱侵位形成的穹状不对称复式褶皱系统内,发育了强烈的岩浆-构造-岩性-热流体四重耦合结构,形成了与盆内岩浆再造-叠加成岩成矿有关的电气石热流柱构造,以底拱旋转断褶带、电气石和白云母蚀变相系为特征。与盆内岩浆-改造作用有关的富CO_(2)型热流柱构造,表现为热启断裂组和铁锰碳酸盐矿物垂向分带,并与菱铁矿矽卡岩相→矽卡岩化大理岩相→铁锰碳酸盐化大理岩相→大理岩化结晶灰岩垂向分带相共生。

The coupling pattern between the deformation history of tectonic lithofacies and the sequence of ore(reservoir)-forming in the basin remain as an unsettled scientific issue,for(non-)metals,uranium,coal,oil and gas resources being hosted in the same sedimentary basin.On the basis of tectonic lithofacies mapping and tectonic lithofacies deformation history study,the deformation history of tectonic lithofacies can be classified into six stages:pre-basin formation,basin formation,basin inversion,basin deformation,basin-in magmatic superimposition,and basin supergene.The main results are as follows.Firstly,patterns and combination of snygenetic structure in the basin can be delineated by innovative approach of tectonic lithofacies mapping.The tectonic lithofacies mapping of 12 lithofacies series of cryptovolcanic rock intrusion,volcanic cyptoexplosion-intrusion and volcanic explosion-eruption in the volcanic area helps to delineate the central parts of volcanic edifice,diagenesis and mineralization of volcanic hydrothermal fluid,and sedimentation of volcanic hydrothermal vent.Secondly,the transitional tectofacies zone of basin-mountain-plateau is a tectonic lithofacies zone for fluid migration and storage on a large scale,and also a favorable tectonic lithofacies belt for(non-)metals-uranium-coal-oil and gas resources hosted in the same basin.Foreland basin,intermountain basin,and hinterland basin have different styles of deformation tectonics.The study of tectonic lithofacies and mapping contributes to understand the paleo-geothermal reservoir,the series of reservoir-forming and ore-forming events for the hydrocarbon generation and migration derived from the coal-measure metal-bearing source rocks,etc.Thirdly,basin-in crust-source magma,combination of crust-mantle derived magma,and mantle-derived magma had formed their corresponding magmatic superimposing tectonics and magmatic superimposing diagenetic lithofacies system,respectively.Four coupling structures of magma-tectonics-lithology-hydrothermal fluid existed in the asymmetry dome-shaped complex fold formed by magmatic hunch-up.On the one hand,tourmaline-rich plume tectonics produced by the diagenesis and ore-forming of basin-in magmatic reconstruction-superimposing were typified by hunch-up and rotated fault-fold zone,series of tourmaline alteration facies.On the other hand,CO_(2)-rich plume tectonics produced by basin-in magmatic reworking was characterized by thermal-derived faults,vertical zoning of Fe-Mn-carbonate minerals,and they intergrowth with vertical zoning of siderite skarn,skarnized marble,Fe-Mn carbonate minerals hosted in marble,and marbleization crystalline limestone in sequence.