辽西中侏罗世高Sr低Y型火山岩的成因及其地质意义   总被引：13，自引：8，他引：13  

李伍平  李献华  路凤香 《岩石学报》2001,17(4):523-532

通过对辽西阜新地区中侏罗世蓝旗组火山岩的岩石地球化学研究,燕山地区存在着中侏罗世高Sr低Y型火山岩。这些高Sr低Y型火山岩为高铝高钠低镁(Al2O3>15％,Na2O≥3.37％,MgO≤1.33％,Mg＃≤0.35)的安山岩-英安岩,高Sr(≥541μg/g)低Y、Yb(Y≤19μg/g,Yb≤1.35μg/g)含量及高Sr/Y(≥40)比值,强烈的稀土元素分馏((La/Yb)N>17,(No/Yb)N>1.2)),Eu异常不明显(0.82～0.96),高场强元素(如Nb、Ta)相对亏损。这些特征与太古代英云闪长岩-奥长花岗岩-花岗闪长岩(TTG)岩套相似。我们认为这些火山岩起源于古老的下地壳玄武质岩石的部分熔融,其形成可能与玄武质岩浆的底侵作用有关。辽西中侏罗世蓝旗组高Sr低Y型火山岩对探讨燕山造山带岩浆起源及地球动力学具有重要意义。  相似文献   

分子有机地球化学与古气候、古环境研究   总被引：30，自引：5，他引：30  

傅家谟  盛国英 《第四纪研究》1992,12(4):306-320

分子有机地球化学可以从分子级水平研究地质体中有机分子化合物的演化规律。本文报道了应用生物标志化合物指标探讨古气候和古环境,例如探讨古生物(含古植物)的输入,淡水、半咸水和高盐度水古环境的判识以及大气飘尘的来源和成因等。  相似文献   

Sm—Nd and Zircon U—Pb Isotopic Constraints on the Age of Formation of the Precambrian Crust in Southeast China   总被引：1，自引：0，他引：1  

李献华  赵振华等 《中国地球化学学报》1992,11(2):111-120

Nd model ages(TDM) of the Pre-Mesozoic crustal rock samples from Southeast China range from 1.2 to 3.5Ga.Two age peaks of 1.4Ga and 1.8 Ga are observed in the histogram of TDM model ages.Available U-Pb zircon inheritance ages are concentrated around 1.2-1.4Ga,1.8Ga and 2.5Ga,respectively.The combined use of Sm-Nd and U-Pb zircon inheritance ages suggests that the formation of the Precambrian curst is of episodic character.The oldest crustal nucleus may have been formed during the Late Archean(2.5Ga or older?).A rapid production of the crust took place 1.8 Ga ago,consistent with the global crust formation event at 1.7-1.9Ga.Another important episode of the addition of juvenile crustal material from the mantle in Southeast China took place 1.2-1.4Ga ago,during which the pre-existing crust was strongly reworked and/or remelted.  相似文献   

Characteristics and Applications of Fluid Inclusions in the Eogene System of the Biyang Depression—I.A Fluid Inclusion Study     

麦碧娴  汪本善 《中国地球化学学报》1992,11(4):370-383

Presented in this paper are the rypes,salinities,homogenization temperatures and organic components of fluid inclusions formed at the four stages of diagenetic authigenesis in the Eogene of the Biyang Depression.The results of cooling experiments on fluid inclusions were used to determine the fluid system and composition of saline aqueous solution in each of the stages .The homogenization temperatures of saline aqueous solution inclusions and hydrocarbon organic inclu-sions have been corrected by two approaches ,and the trapping temperatures and pressures of fluid inclusions at each of the stages have been obtained.This strdy has shed light on the physicochemistry and evolution of diagenetic fluids.The diagentic fluid system is a system which was transformed from a chloride-bearing to a carbonate-bearing system along with the diagenic evolu-tion.The decrease of diagenetic temperature at Stage III of diagenetic authigenesis suggests that the depression would have experiences uplifting at that time.The fluorescent characteristics of fluid inclusions indicate the varieties of organic components in fluid inclusions both in time and in space.  相似文献   

中国黄土¹⁰Be研究进展   总被引：1，自引：0，他引：1  

沈承德  刘东生 《地球科学进展》1995,10(6):590-596

８０年代中期，中国和瑞士科技工作者开始联合进行黄土＾１０Ｂｅ研究。建立了黄土＾１０ＢｅＡＭＳ测量的理想流程，发现了＾１０Ｂｅ在黄土地层良好保存性等重要地球化学行为特征，确认了黄土＾１０Ｂｅ研究具有重要意义。对洛川黄土部面０．４－１３８ｍ段６００多个样品进行了＾１０Ｂｅ测定，建立了２．５Ｍａ以来大陆堆积物同位素记录曲线。  相似文献   

A loess-paleosol dating method     

Zhaoyu Zhu 《GeoJournal》1995,36(2-3):243-249

Based on the non-diachronic nature of loess- paleosol sequences, a paleosol dating method is suggested. Based on this method, the extant drainage system of the Yellow River was found to be 1.67-1.45 Ma old. During its existence, six fluvial terraces and two alluvial plains were formed. In the deposits of this time interval, studied in 400 sections, 33 cycles were identified in the sequence built of aquatic sediments and paleosol. Correlation of loess, paleosol, and aquatic sediment sequences of China and other regions points to a 0.4 Ma periodicity in the hydrologic regime and in the denudational processes. This periodicity might be related to global climatic changes due to changes of orbital parameters of the Earth.  相似文献   

沉积成岩作用对桂西北中三叠统板纳组中金丰度的影响     

刘金钟  范德廉 《沉积学报》1993,11(2):51-57

桂西北中三叠统板纳组浊积岩系是该区微细浸染型金矿床的主要赋矿层位。浊积岩中金丰度受到沉积物来源、沉积速率、岩石类型、碎屑物组份、碳酸盐化、绿泥石化等沉积、成岩作用的影响。  相似文献   

苯并噻吩系列化合物的成因模拟及其地球化学意义   总被引：4，自引：1，他引：3  

夏燕青  孟仟祥  王红勇  杜丽  王春江 《沉积学报》1999,17(1):127-129

在硫和β胡萝卜素反应产物中有丰富的苯并噻吩系列化合物,在硫与饱和链状化合物反应产物中既有噻吩系列化合物也有苯并噻吩系列化合物。所以推断苯并噻吩系列是硫作用于噻吩系列或含侧链的苯而形成的。噻吩系列和苯并噻吩系列的相对含量可以指示成熟度:在沉积条件相同的前提下,前者多后者少指示成熟度低,反之则指示成熟度高。  相似文献   

广西丹池成矿带芒场矿田岩浆岩源区特征及锆石U-Pb年龄分析   总被引：1，自引：0，他引：1  

伍静  苑宏伟  甘能俭  韦绍成  廖娟  张健  梁华英 《岩石学报》2020,36(5):1586-1596

丹池成矿带是我国重要锡多金属成矿带,过去对丹池成矿带成岩成矿研究主要集中在大厂矿田及五圩矿田,而对丹池成矿带北部的芒场矿田岩浆作用时代、源区特征及其成矿性缺少分析。芒场矿田岩浆活动强烈,发育隐伏斑状花岗岩及有关的花岗斑岩脉和隐伏细粒花岗斑岩及有关的白云母花岗斑岩脉。本文分析花岗斑岩脉U-Pb年龄及花岗斑岩脉和白云母花岗斑岩脉主、微量元素组成,以探讨岩浆活动时代、岩浆源区特征及其成矿潜力。芒场矿田花岗斑岩脉锆石U-Pb年龄为89.1±0.9Ma (MSWD=0.9),和丹池成矿带内大厂矿田岩浆活动时代相近,表明丹池成矿带岩浆活动时代都发生于90Ma左右。白云母花岗斑岩脉具高A/CNK比值(2.69～2.88),含高铝硅酸盐矿物白云母及在Th-Rb图上沿S型花岗岩趋势线分布,和大厂矿田S型黑云母花岗岩的特征基本一致,表明其主要为S型花岗岩。花岗斑岩脉形成时代晚于白云母花岗斑岩脉,但其具有更低的SiO_2含量和更高的MgO、Fe_2O_3~T、CaO和TiO_2含量,且在SiO_2与TiO_2、Fe_2O_3~T、Al_2O_3和P_2O_5关系图中分布于不同区域,没有线性变化关系,显示两者不是同一岩浆结晶分异演化形成的,而为不同沉积变质岩部分熔融形成的。白云母花岗斑岩脉富Al_2O_3、K_2O、Rb、Cs、Sn、W、Nb和Ta,在Rb/Ba-Rb/Sr图上位于富粘土源区,为强风化作用形成的富粘土质富稀有金属源区部分熔融形成的产物。华南西部基底发育经强风化作用形成的富粘土质富稀有金属元素沉积变质源区,为华南西南缘大规模锡矿床的形成提供了物质基础。  相似文献   

Cosmic-ray exposure histories of two Antarctic meteorites from Chinese collections and the Guangmingshan and Zhuanghe chondrites   总被引：5，自引：0，他引：5  

王道德  林杨挺  刘小汉  琚宜太 《中国科学D辑(英文版)》2003,46(12):1236-1240

In this paper, we report cosmic-ray exposure ages (3He, 21Ne, 38Ar) and gas retention ages (4He, 40Ar) of two Antarctic meteorites, and the Guangmingshan and Zhuanghe ordinary chondrites. The Antarctic meteorites (GRV98002 and GRV98004) were collected on …  相似文献