牦牛坪矿-(Ce):一种新发现的稀土元素矿物     

沈敢富  杨光明  徐金沙 《沉积与特提斯地质》2005,(Z1)

牦牛坪矿- (Ce)属硅钛铈矿亚族的新成员,发现于四川牦牛坪稀土矿床的碳酸岩、伟晶碳酸岩和碱性岩等矿脉中。与已知的同亚族矿物相比,新矿物要么是chevkinite - (Ce)B位上的Fe3 + 类似物,要么同时是polyakovite- (Ce)B位和C位上的Fe3 + 类似物。牦牛坪矿- (Ce)直接从一类富F、水和REE的岩浆 热液过渡阶段的成矿流体中结晶所成。新矿物得名于产地和稀土元素中Ce居优。牦牛坪矿- (Ce)及其命名,已获国际矿物协会新矿物及矿物命名委员会投票批准。  相似文献   

Continuous reactions between biotite, garnet, staurolite, kyanite-sillimanite-andalusite and P-T-time-deformation path in micaschists from the estuary of the river Vilaine, South Brittany, France     

CLAUDE TRIBOULET  CLAUDE AUDREN 《Journal of Metamorphic Geology》1985,3(1):91-105

Abstract Microprobe analysis of the continuous chemical evolution of coexisting biotite-garnet and biotite-garnet-staurolite has been undertaken from interbedded micaschists of the volcanodetrital group of the Vilaine. A thermobarometric study using pertinent mineralogical equilibria reveals a complex P-T evolution, continuous throughout time, from high pressure, medium temperature (kyanite zone) to medium pressure, high temperature (sillimanite zone), then low pressure, medium temperature (andalusite zone). The T, P, f_H2o and X_H2o variations have been calculated from coexisting biotite-garnet pairs, and from the equilibria: paragonite (in white mica) + quartz ± albite (in plagioclase) + Al silicate + H₂O; and, 3 anorthite ± grossular + 2 Alsilicate + quartz. The P-T evolution is correlated with the continuous change in composition of minerals (using P–X_Mg and T–X_Mg diagrams) and with the evolution of assemblages. This continuous P-T-time evolution, correlated with the successive formation of S₁-S₂ foliations, allows us to propose a P-T-time-deformation path for the micaschists and to relate the growth of its mineral components to tectonic processes.  相似文献   

Geochronology and Geochemistry of the Early Permian A‐type Granite in the Hongol Area,Central Inner Mongolia: Petrogenesis and Tectonic Implications     

ZHANG Xiangxin  GAO Yongfeng  LEI Shihe 《《地质学报》英文版》2018,92(3):988-1007

We performed geochronological and geochemical analyses of the A-type granite in the Hongol area, central Inner Mongolia, to determine its age, petrogenesis and tectonic setting, which are significant for clarifying the Late Paleozoic tectonic evolution of the Xing'an Mongolian Orogenic Belt(XMOB). The rock type of the A-type granite in the Hongol area is alkali-feldspar granite, and it constitutes a western part of the Baiyinwula-Dongujimqin A-type granite belt. Zircon U-Pb geochronology yields ~(206)Pb/~(238)U ages ranging from 293 to 286 Ma for the alkali-feldspar granite, indicating this granitic pluton formed in the Early Permian. The alkali-feldspar granite is high in silica(SiO_2=75.13 wt%-80.17 wt%), aluminum(Al_2 O_3=10.59 wt%-13.17 wt%) and alkali(Na_2 O+K_2 O=7.33 wt%-9.11 wt%), and low in MgO(0.08 wt%-0.39 wt%) and CaO(0.19 wt%-0.70 wt%). It is obviously enriched in LILEs such as Rb, Th and K,depleted in HFSEs such as Nb, Ti, La and Ce, with pronounced negative anomalies of Nb, Ti, P, Eu, Sr and Ba. Its Sr-Nd-Pb isotopic compositions show positive ε_(Nd)(t)(+0.72-+3.08), low T_(DM2)(805-997 Ma),and high radioactive Pb with(~(206)Pb/~(204)Pb)_i of 18.710-19.304,(~(207)Pb/~(204)Pb)_i of 15.557-15.604 and(~(208)Pb/~(204)Pb)_i of 37.887-38.330. Petrological characteristics and geochemical data suggest that the alkalifeldspar granite in the Hongol area belongs to aluminous A-type granite. This A-type granite formed in a post-collisional extensional setting and was generated by the partial melting of felsic rocks in the middlelower crust resulting from post-collisional slab breakoff. It is suggested that the Paleo-Asian Ocean was closed before the Permian in central Inner Mongolia.  相似文献   

江西乐安县咸口花岗岩体的锆石LA-ICP-MS定年及构造意义   总被引：1，自引：0，他引：1  

周佐民  谢财富  孙文良  郭福生  周万蓬  刘林清  刘伟 《地质学报》2015,89(1):83-98

江西乐安县咸口花岗岩体主要由中粗粒巨斑状黑云二长花岗岩、中粗粒少斑黑云二长花岗岩组成,另有较多细粒碱长花岗岩脉,总体呈偏心式环套状分布。锆石LA-ICP-MS U-Pb年龄分别为230±4Ma、235±3Ma和235±3Ma,形成于中三叠世。岩石具有高硅(SiO2=70.35%~76.89%),富碱(Na2O+K2O=6.77%~11.40%),弱过铝-强过铝(A/CNK=1.00~1.18,平均1.07)的特征。主体花岗岩富集稀土元素[∑REE=(121.52~383.33)×10-6]和高场强元素(Y、Zr、Nb等),晚期强分异并受流体作用的细粒碱长花岗岩稀土含量低[∑REE=(25.85~43.75)×10-6]。具有S型-铝质A型过渡型花岗岩的特征。(87Sr/86Sr)i为0.7082~0.7120,εNd(t)值介于-7.07~-8.10之间,平均值为-7.48,t2DM为1585~1669Ma,平均1618Ma,显示其物源以地壳物质为主,混有地幔组份,钾长石Pb同位素组成也显示壳幔混源的特征。提出咸口岩体形成于后造山的构造环境。  相似文献   

中国城市的网络地位及影响因素研究——基于上市公司500强企业网络视角   总被引：1，自引：3，他引：1  

盛科荣  杨雨  孙威 《地理科学》2020,40(5):740-750

利用2016年中国上市公司500强企业网络数据和隶属联系方法构建城市网络,解析了中国城市的网络地位分异格局,并定量测度了城市网络地位的影响因素,在城市网络“行为-结构-绩效”分析框架下解释了地位分异的动力机制。研究发现：正则等价性模型识别的15个正则等价块分化为首位者、经纪人、接收者和孤立者4个地位类型;地位间关系呈现“核心-半边缘-边缘”结构特征,其中首位者地位的正则等价块形成凝聚子群并占据网络权力的核心,经纪人和接收者地位的块位于半边缘位置,孤立者地位的块处于网络权力的边缘;市场潜力、政治资源、知识资本、区位条件和发展基础是中国城市网络地位的关键影响因素;规模偏好、择优选择、地理临近和路径依赖构成了城市网络地位分异的动力机制。城市网络的发展倾向于扩大城市间发展差距,中国城市化政策和城市治理体系需要做出相应调整。  相似文献   

福建太姥山地区和鼓山地区A型花岗岩对比及其地球动力学意义   总被引：1，自引：0，他引：1  

李良林  周汉文  陈植华  王锦荣  陈正华  肖依 《现代地质》2013,27(3)

太姥山和鼓山位于福建东南沿海地带。岩石学和岩相学研究表明太姥山地区和鼓山地区花岗岩分属铝质A型花岗岩和碱性A型花岗岩。锆石LA-ICP-MS U-Pb同位素定年结果表明,两地区花岗岩成岩年龄分别为(96.6±1.6)Ma(MSWD=0.65)和(99.4±2.3)Ma(MSWD=0.49),成岩时代均属晚白垩世早期。结合中国东部沿海两类A型花岗岩,讨论了它们在岩石学、岩相学、地球化学及其判别图解上的区别。总体上认为,碱性A型花岗岩在AKI值、TFeO/MgO比值、104×Ga/Al以及(Zr+Nb+Ce+Y)值上均大于同区域的铝质A型花岗岩,但上述化学指标的数值也存在一定范围的重叠;且传统A型花岗岩判别图解不完全适用于强分异的铝质A型花岗岩。地球化学特征表明,两地区A型花岗岩应具有相似的源区,即岩浆起源于地壳物质熔融,同时成岩过程有一定的地幔物质参与。但鼓山地区碱性A型花岗岩较太姥山地区铝质A型花岗岩有更多地幔物质的加入,导致前者显示出部分幔源岩浆起源的特征。结合地球化学、野外地质、区域背景及年代学综合判定,两地区花岗岩成因与古太平洋板块对欧亚板块的俯冲角度密切相关,均属于弧后拉伸体制之下的构造环境。  相似文献   

Mg–Fe carpholites from aluminous schists in the Diahot region and implications for preservation of high-pressure/low-temperature schists, northern New Caledonia     

P. M. BLACK  P. MAURIZOT  E. D. GHENT  M. Z. STOUT 《Journal of Metamorphic Geology》1993,11(3):455-460

Abstract Mg–Fe carpholite is widespread in the Diahot region of New Caledonia in highly aluminous schists and as veins in what was originally a clay-rich hydrothermal alteration envelope about massive suphide deposits. These carpholites have Fe/(Fe + Mg) ratios of 0.03–0.65 and no significant Mn component. Mg-carpholite + quartz occur in assemblages with chlorite or pyrophyllite, pyrophyllite + kaolinite and pyrophyllite + diaspore. Temperatures of 230–320° C and minimum pressures of 7 kbar are indicated for the Mg–Fe carpholite-bearing rocks. The regional distribution of aragonite and Mg–Fe carpholite parallel to a major zone of dominantly transcurrent movement and oblique to the trend of the subduction complex indicates the high- P /low- T schists owe their rapid uplift and preservation to the vertical component of the transcurrent faulting.  相似文献   

广东南昆山A型花岗岩定年和环带云母研究   总被引：6，自引：1，他引：6       下载免费PDF全文

刘昌实  陈小明  王汝成  张文兰  胡欢 《地质论评》2005,51(2):193-200,i002

广东南昆山 A型花岗岩出露面积约 2 0 0 km2 ,中粒等粒结构、块状构造 ,由铁叶云母、钠长石、微斜条纹长石和石英组成。弱过铝质 ,强亚碱质 ,富氟 (5 5 36× 1 0 - 6 ～ 90 5 4× 1 0 - 6 )贫氯 ,高的锆石饱和温度 (81 0～ 84 7℃ ) ,高 1 0 4 Ga/ Al比值 (4.37～ 7.2 6 )和高 Zr+Nb+Ce+Y含量 (45 0× 1 0 - 6 ～ 5 85× 1 0 - 6 )等 ,均与澳大利亚铝质 A型花岗岩相似。岩石内普遍发育环带云母 ,电子探针分析表明 ,复杂环带云母通常由若干黑云母条带 (铁叶云母 )和白云母条带组成 ,可识别出 3个构成部分 :核部带 ,幔部带和边部带。核部带形成于原岩浆处在深位时结晶的 ,幔部带形成于岩浆自深位快速上升到浅位时结晶的 ,而边部带形成在岩浆冷凝终结时。它们之间不同的边界形态说明了岩浆经历过铁钛氧化物的分离结晶作用、外来岩浆注入作用和去气作用等。环带云母是岩浆结晶历史的极好指纹。花岗岩锆石 U- Pb定年为 1 4 7± 0 .8Ma,应为中侏罗世—晚侏罗世侵入的。  相似文献   

Crust-mantle interaction and its contribution to the Shizhuyuan superlarge tungsten polymetallic mineralization   总被引：4，自引：0，他引：4  

ZHAO Zhenhua  BAO Zhiwei  Zhang Boyou  XIONG Xiaolin 《中国科学D辑(英文版)》2001,44(3):266-276

The Qianlishan granite, which is closely related to the Shizhuyuan tungsten polymetallic mineralization, is aluminous alkali-type granite. The intimate temporal and spatial association among the basaltic, syenite and granitic rocks in the mining area, and their major and trace elements, and Nd, Pb, Sr, O isotopic compositions indicate that the crustal-mantle interaction probably was an important constraint on, and participated in, the formation of the superlarge ore deposit.  相似文献   

Confirmation and Preliminary Study of Aluminous A—Type Granites in the Wuyi Mountain Area,Eastern Jiangxi Province,China     

楼法生  崔学军  黄志忠 《中国地球化学学报》2002,21(4):362-369

Widespread in the Wuyi Mountain area of eastern Jiangxi are petrochemically peraluminous granites and they are characterized as being high in silica (SiO₂ > 75% ) and highly alkaline (ALK=6.9% -7.5%) with K₂O > Na₂O and rather high ratios of FeO^T/MgO (11.3-17.9). The rocks have low contents of CaO, MgO, TiO₂ and P₂ O₅. The granites are enriched in REE (ΣREE =210.3 - 496. 8 μg/g) with remarkable negative Eu anomalies, but depleted in Eu, Ba, Sr, V, Co, and Ni, with 10000 x Ga/Al ratios, varying from 6. 1 to 9. 8. It is clear that these granites are obviously different from the I- and S-type granites, but are quite similar to those typical A-type granites such as aluminous A-type granites in the coastal areas of Fujian Province. State Geological Survey Project: supported by the Regional Geological Survey Project (No: 20001300002091 ) on the basis of the maps (scale 1: 250000) of Jingdezheng City, Nanchang City and Shangrao City.  相似文献