内蒙额尔古纳在矿带中生代火山岩浆活动与金属成矿的关系

在岩石学和微量元素地球化学研究的基础上,通过对不同类型矿床的成矿岩体及围岩条件的分析,探讨了中生代火山岩浆活动与金属成矿的关系。认为晚侏罗世火山岩浆活动为成矿提供了有利的围岩的构造空间;早白垩世岩浆活动提供了成矿岩体及热力学条件,该期次火山岩浆的侵入并作用于不同的围岩、形成了由斑岩型Ｃｕ、Ｍｏ矿,浅成熟液型Ａｇ、Ｐｂ、Ｚｎ矿等组成的一系列矿床组合。     

湘南中生代玄武岩浆成因与岩石圈—软流圈相互作用

湘南中生代玄武岩浆成因与岩石圈—软流圈相互作用＠郭锋＠范蔚茗＠林舸￥中国科学院长沙大地构造研究所玄武岩浆,成因,岩石圈—软流圈相互作用,中生代,湘南湘南中生代玄武岩浆成因与岩石圈—软流圈相互作用郭锋范蔚茗林舸（中国科学院长沙大地构造研究所,长沙４１００１...     

Mesozoic Granitoid Types and Metallogeny of the East China Circum-Pacific Continental Margin

Abstract: This paper synthesizes the geotectonic background, genetic types and metallogenetic relations of the Mesozoic granitoids in the East China continental margin. By the Mesozoic, the Siberia Plate, North China Plate and South China Plate amalgamated together, resulting in formation of a unified Eurasia super–continent. Since the late Triassic to early Jurassic period, the territory of East China gradually became a Cordilleran style active continental margin. During the Jurassic to early Cretaceous (early to middle episodes of Yanshanian orogeny), the Paleo-Pacific plate strongly collided with and subducted under the Eurasia continent, reactivated the consolidated East China continental margin. The granitoids of both transformation series and syntexis series were generated. Many granitoid-related large and giant metal deposits were formed. Furthermore, the W, Sn, Be, Nb, Ta and U mineralizations are mostly associated with the transformation series; while the Fe, Cu, Mo and Au mineralizations are mostly associated with the syntexis series. The late Yanshanian orogeny (late Cretaceous) began a transition to the western Pacific style continental margin. A tensional environment resulted in development of alkaline granitoids and formation of continental red basins. The Cenozoic orogeny was characterized by a backarc spreading and rifting regime in this region.     

江苏下扬子区中—古生界的成藏条件及勘探思路

江苏下扬子区的海相中－古生界构造演化经历了前扬子板块、稳定地台和西太平洋活动陆缘等三大阶段。油气地质条件具有多套烃源岩、两类主要储层、四套区域盖层、多种成藏类型和多期成烃等特征。原始生烃量以下古生界为主,下寒武统和下志留统的生烃量约占总生烃量的６０％￣８０％。该领域的勘探应本着“整体评价、区域展开、重点突破”的原则,做到“六个结合”和“五个转变”,加快勘探节奏,重在发现,坚持以下古生界为主,大中型     

岩石圈流变性与沉积盆地以辽西-辽北-松辽盆地区为例

岩石圈流变性取决于岩石圈的地热状态、物质组成和结构,并量化为岩石圈总强度。沉积盆地的沉降和抬升是地球最上层流变带形变的响应,岩石圈板块对构造应力的响应在很大程度上取决于岩石圈流变性在横向和纵向上的不均一性。辽西、辽北、松辽盆地区岩石圈流变性存在明显差异,因而岩石圈总强度明显不同,在晚中生代伸展过程中,变形方式、变形幅度不同,分别形成了断陷盆地、多断少坳型盆地和断坳型盆地。     

鲁西茌平背斜构造带的演化及其古生界原生油气勘探前景

鲁西茌平背斜构造带被夹持在东侧寿张凹降和西侧监清坳陷的莘县凹陷之间,处于“凹中之隆”的有利勘探位置。该构造带的演化受西侧兰聊断裂活动的严格控制,晚三叠世,该断裂的产生接开背斜带演化的序幕。兰聊断裂的燕山期具右旋平移性质,使区内北北东向次级正断层发育,构造带基本定型。该带是相邻两凹限油气运移的主要指向地区,两凹陷内含下古生界开阔（局限）海相烃源岩和上古生界煤系源岩;带内下古生介顶部风化壳为良好储层;     

Extensional Tectonic System of Erlian Fault Basin Group and Its Deep Background

ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｈｉｇｈｌｙｅｘｔｅｎｄｅｄｒｅｇｉｏｎｓ（β＞１．５－２）ｓｕｃｈａｓｔｈｅＢａｓｉｎａｎｄＲａｎｇｅＰｒｏｖｉｎｃｅａｎｄｐａｓｉｖｅｍａｒｇｉｎｓ,ｅｘｔｅｎｓｉｏｎａｌｔｅｃｔｏｎｉｃｓｙｓｔｅｍｉｓｃｈａｒａｃｔ...     

Unpairing metamorphic belts: P–T paths and a tectonic model for the Ryoke Belt, southwest Japan

Southwest Japan is divided into Outer and Inner Zones by the Median Tectonic Line (MTL), a major transcurrent fault. The Outer Zone is composed of the Sambagawa (high-pressure intermediate or high P/T type metamorphism), Chichibu and Shimanto Belts. In the Inner Zone, the Ryoke Belt (andalusite– sillimanite or low P/T type metamorphism) was developed mainly within a Jurassic accretionary complex. This spatial relationship between high P/T type and low P/T type metamorphic belts led Miyashiro to the idea that metamorphic belts were developed as ‘paired’ systems. Textural relationships and petrogenetically significant mineral assemblages in pelites from the Ryoke Belt imply peak P–T conditions of ≈5 kbar and up to 850 °C in migmatitic garnet–cordierite rocks from the highest-grade metamorphic zone. It is likely that the thermal anomaly responsible for metamorphism of the Ryoke Belt was related to a segment of the Farallon–Izanagi Ridge as it subducted under the eastern margin of the Asian continent during the Cretaceous. The sequence of mineral assemblages developed in pelites implies a metamorphic field gradient with shallow dP/dT slope, inferred to have been generated by a nested set of hairpin-like ‘clockwise’P–T paths. These P–T paths are characterized by limited prograde thickening, minor decompression at peak-T , and near-isobaric cooling, features that may be typical of P–T paths in low P/T type metamorphic belts caused by ridge subduction. A ridge subduction model for the Ryoke Belt implies that juxtaposition of the high-P/T metamorphic rocks of the Sambagawa Belt against it was a result of terrane amalgamation. Belt-parallel ductile stretching, recorded as syn-metamorphic, predominantly constrictional strain in both Ryoke and Sambagawa Belt rocks, and substantial sinistral displacement on the MTL are consistent with left-lateral oblique convergence. Diachroneity in fast cooling of the Ryoke Belt is implied by extant thermochronological data, and is inferred to relate to progressive SW to NE docking of the Sambagawa Belt. Thus, an alternative interpretation of ‘paired’ metamorphic belts in Japan is that they represent laterally contemporaneous terranes, rather than outboard and inboard components of a trench/arc ‘paired’ system. Amalgamation of laterally contemporaneous terranes during large translations of forearcs along continental margins may explain other examples of ‘paired’ metamorphic belts in the geological record.     

Zircon U-Pb geochronology of Early Jurassic-Late cretaceous volcanic rocks in North Yellow Sea BasinEI北大核心CSCD

The X-drilling cores of the North Yellow Sea basin reveal two sets of Mesozoic clastic rocks, which are the dark rocks in lower part and the red rocks in upper part, respectively. There are two layers of volcanic rocks at the bottom and the upper part of the dark rock unit. The volcanic rocks at the bottom part are trachytic dacite while rocks at the upper part are clastic dacite. The zircon grains from the upper and lower units of volcanic rocks are euhedral-subhedral columnar crystals and show oscillatory zoning on cathodoluminescence images. 22 tests of zircons in the trachytic dacite from the bottom part yield an age of 141-151 Ma, with weighted mean 206Pb/238U age of 145±2 Ma. Whereas 18 tests of zircons from the sample at the upper part give 206Pb/238U ages around 139-149 Ma with weighted mean 206Pb/238U age of 141±2 Ma, which implies that the X well volcanic rocks belong to Late Jurassic-Early Cretaceous. Comparing with the age and geochemical characteristics of the Mesozoic igneous rocks in Shandong peninsula, we suggest that the igneous rocks from both the North Yellow Sea basin and Jiaolai basin were formed under same dynamic setting, i.e., the subduction related volcano arc and back-arc extension. ©, 2015, Science Press. All right reserved.     

东昆仑地区中生代熔融、同化、存储和均一(MASH)过程及壳幔岩浆混合

哈西亚图石英闪长岩是东昆仑地区中生代具幔源组分贡献的花岗岩类典型代表,岩体出露于东昆仑中构造带,广泛发育暗色微粒包体。包体为闪长质岩石,并含有一系列岩浆混合成因的证据,如水滴状、长条状塑性流变外形,淬冷边、反向脉等高—中温混合迹象,以及低Mg/(Fe+Mg)、Na/(Ca+Na)值等混合成因特征。包体A/CNK值介于0.77~0.87,属准铝质,富Al2O3、Fe2O3、MgO,贫K2O、Na2O,富集大离子亲石元素(Rb、Ba、K等),同时又具有Ta、Nb、Ti的"TNT"负异常,具有俯冲带幔源岩石的成分特点。依据岩石学、地球化学特征并结合同时期大地构造背景,东昆仑晚古生代—早中生代含暗色微粒包体花岗质岩石是幔源岩浆经历多次熔融、同化、存储和均一(MASH)过程后与壳源岩浆混合的产物。在混合岩浆中,富镁铁质端元是由辉长质岩浆进化而来的闪长质岩浆。