热液石英中微量元素特征及应用:认识与进展   总被引：7，自引：0，他引：7  

陈小丹  陈振宇  程彦博  叶会寿  汪欢 《地质论评》2011,57(5):707-717

文章以热液石英为研究对象,基于石英的晶体结构特征和化学性质,以及近年来国内外在此领域取得的认识和成果,论述了石英中微量元素的赋存状态和应用.研究表明,微量元素主要以3种方式进入到石英晶体中:单原子替代、原子团替代和补偿电价替代.石英在SEM-CL图像中的亮度和石英中微量元素的分布具有一定的相关性,根据石英的微量元素组成...  相似文献   

U-Pb SHRIMP Dating of Zircon from Quartz Veins of the Yangshan Gold Deposit in Gansu Province and Its Geological Significance   总被引：7，自引：0，他引：7  

QI Jinzhong  YUAN Shisong  LIU Zhijie  LIU Dunyi  WANG Yanbin  LI Zhihong  GUO Junhua  SUN Bin Gold Geological Institute of China Armed Police Force  Langfang  Hebei  Institute of Geology  Chinese Academy of Geological Sciences  Beijing The th Detachment of Gold Headquarters of China Armed Police Force  Chengdu  Sichuan 《《地质学报》英文版》2004,78(2):443-451

The Yangshan gold deposit is a super-large fine-grained disseminated gold deposit located in southern Gansu Province. Its metallogenic age has been determined by using the cathodoluminescence image and ion probe U-Pb dating techniques. It is found that zircons from quartz veinlet of the fine-grained disseminated gold ore show characters of magmatic origin with prism idiomorphism, oscillatory zoning and dominant Th/U ratios of 0.5-1.5. Three main populations of zircons are obtained, giving average 206Pb/238U ages of 197.6±1.7 Ma, 126.9±3.2 Ma and 51.2±1.3 Ma respectively. The first age corresponds to the K-Ar age of the plagiogranite dike, while the latter two ages indicate that buried Cretaceous and Tertiary intrusives exist in the orefield, suggesting that the Yangshan gold deposit was genetically related to the three magmatic hydrothermal activities. By contrast, zircons from coarse gold-bearing quartz vein in the mining area are much older than the host rock, indicating that the vein was formed ear  相似文献   

Evolution diagénétique dans la craie pélagique dolomitisée du crétacé supérieur du bassin de Paris (région de Provins, France)     

Jean-Pierre Gély  Philippe Blanc 《Eclogae Geologicae Helvetiae》2004,97(3):393-409

Two deep scientific boreholes, named Poigny 701 and Sainte-Colombe 702, located in the Paris Basin near Provins (Seine-et-Marne, France), recovered a complete Upper Cretaceous chalk succession. A correlation between the boreholes lithostratigraphy, reflexion seismic profiles and diagenetic patterns shows that major velocity variations measured in the seismic reflection profiles correspond to dolomitized chalk intervals. Dolomitisations occurred during early and burial diagenesis. The understanding of these complex diagenetic events has an important economic consequence on the static correction of the chalk formation in the Paris Basin. Optimisation of petroleum prospecting below chalk cover is thus possible. The chalk series of the 701 and 702 boreholes range from the Cenomanian to the upper Campanian. In this succession, micrite has a primarily biogenic origin; it consists of pelagic organisms, indicative of warm seawater with values around 25°C. Several hiatuses occur in the 701 borehole. These hiatuses indicate the existence of particular hydrodynamic conditions. Deep-water channels were locally recognised in the Paris Basin as in Normandy and Picardy. In the 702 borehole, massive dolomitisation affected the upper meters of sediment below the sea floor. This early phase of massive dolomitisation was induced by slow circulation of a magnesium-rich seawater mass, along the seawater/sediment interface. Thus, this area was a zone of intense marine circulation between the North-West infralittoral and the South-West bathyal domains, across the London-Paris Basin. Magnesium-rich seawater had as origin the recrystallisation of the biogenic peri-plateform carbonates. During both dolomitisation and dissolution of the calcite matrix of the massive dolomite, the calcite had cemented chalk around the massive dolomite body. After deposition, the chalk series was progressively compacted and lithified by burial calcite cement. During the late Campanian-Maastrichtian, the burial compaction of the chalk and thermal gradient reached their maximum, as compressive stresses from the Pyrenean orogenesis affected the Paris Basin. At this time, compaction of the massive dolomite induced the expulsion of magnesian-rich fluids into the underlying already compacted chalk series. In 702 borehole, a diffuse dolomitisation then affected strongly underlying the chalk series. In 701 borehole, this diffuse dolomitisation affected slightly the lower half of the chalk series. Laterally, dolomitisation decreases gradually and affected a only smaller thickness of the chalk series, disappearing laterally. During the progressive emergence of the Paris Basin, from the Paleogene to the Quaternary, the chalk series were partially invaded by continental fresh water. Thus partial dedolomitisation affected the massive dolomite, whereas total dedolomitisation affected only the upper first meters of it.Manuscrit reçu le 20 juin 2003 Révision acceptée le 9 septembre 2004  相似文献   

甘肃省阳山金矿床石英脉中锆石SHRIMP U-Pb年代学研究   总被引：30，自引：6，他引：30  

齐金忠  李莉  袁士松  刘志杰  刘敦一  王彦斌  李志宏 《矿床地质》2005,24(2):141-150

为研究阳山特大微细浸染型金矿床的成矿时代,文章结合阴极发光对矿区不同类型石英(细)脉中锆石进行了SHRIMPU_Pb年龄的精确测定。结果表明,微细浸染型矿石中锆石呈自形柱状,韵律性环带结构发育,Th/U比值集中于0 .5～1.5之间,具岩浆岩锆石特征,锆石2 0 6Pb/2 3 8U年龄有3组,分别为(197.6±1.7)Ma、(12 6 .9±3.2 )Ma和(5 1.2±1.3)Ma ,其中前一组年龄与矿区斜长花岗斑岩脉的形成时代一致,而后两组年龄指示矿区存在白垩纪及第三纪隐伏岩浆岩体,表明阳山微细浸染型金矿床的形成与中、新生代3次岩浆热液活动有关。矿区含明金石英脉型矿石中所测得的锆石年龄均老于围岩时代。不同时代多期次热液活动在空间上的耦合是形成阳山金矿床的重要因素。  相似文献   

碳酸盐岩常用主微量元素、同位素分析测试结果差异性探讨: 基于川中下寒武统龙王庙组实例研究^*          下载免费PDF全文

刘大卫  蔡春芳  扈永杰  姜磊  李睿  何宏  王石  彭燕燕  魏天媛  柳其源 《古地理学报》1999,24(3):524-539

碳酸盐岩研究中存在多种微量元素、同位素测试方法,为进一步探究各测试手段实际获取地化信息之间是否存在差异?能否进行比对?以川中下寒武统龙王庙组碳酸盐岩样品为例,通过对比研究中常用的主微量元素测试(电子探针[EPMA]、激光剥蚀—等离子质谱[LA-ICP-MS]、溶液法微量[ICP-OES])、氧同位素测定(原位离子探针[in-situ SIMS]、酸溶粉末)结果,揭示讨论各测试结果的差异性,旨在为降低地化信息的多解性提供经验依据。研究发现: (1)各测试手段(EPMA、LA-ICP-MS、ICP-OES)之间的差异性客观存在,但测试结果偏差整体随着所测元素实际浓度的增高而降低。对于主量元素(>10%)各测试结果偏差小于2%;富集元素(>1000 μg/g)各测试结果处于测试误差之内,结果偏差小于6%;微量元素浓度区间(100~1000 μg/g)各测试结果偏差显著增大,并且LA-ICP-MS与ICP-OES结果偏差要小于LA-ICP-MS与EPMA结果偏差,前者偏差幅度由6%增至45%,后者偏差幅度由9.1%增至151%;在低于100 μg/g元素浓度区间,受矿物内非均质性影响LA-ICP-MS与ICP-OES的测试结果可相差几倍。(2)微区原位限定下,EPMA测试结果在邻近检测线区间(100~300 μg/g)与LA-ICP-MS结果偏差逐渐加大,推测此偏差变化是由EPMA结果矫正过程中对低含量元素的矫正补偿机制所造成。(3)in-situ SIMS氧同位素值揭示了矿物微区尺度上的 δ¹⁸O 值差异,但其整体测试结果与传统酸溶法测试的结果存在0.5‰~2.5‰ V-PDB的负偏偏差,推测此偏差可能来自于标样矫正转换误差。(4)实例样品中可见阴极发光特征与Fe、Mn含量无关的现象,故成岩流体判定更需结合岩石学、地化证据探讨。  相似文献   

Allende碳质球粒陨石中某些斜长石的阴极发光现象及其产生的机理     

华欣  杨勇 《矿物学报》1992,12(2):111-119

对Allende陨石的富钙铝包裹体中的斜长石,用电子探针和扫描电镜进行阴极发光的研究。作者对三颗生长在富钙铝包裹体中无尖晶石区域内的斜长石晶体进行了详细的研究。在电子束的轰击下它们都显示出深、浅蓝色的阴极发光带。电子探针定量分析表明,在深蓝色发光带中,杂质元素Na和Mg的含量较高(约为500～1000ppm),而在浅蓝色发光带中,Na、Mg含量相对较低(约为100～500ppm),同时Na的含量与Mg的含量呈正相关。 矿物中微量杂质的存在与矿物的阴极发光之间存在着某些规律性的联系,因此矿物的阴极发光可以作为研究矿物的一种特殊标志。此外,不同微量元素的存在也可以给出某些成因信息。 本文对引起阴极发光的物理机制也进行了讨论。  相似文献   

山东文登金矿成矿条件及成矿过程─—阴极发光技术在包裹体研究中的应用     

赖勇 《矿床地质》1995,(3)

使用阴极发光技术可取得一般岩石显微镜无法得到的地质信息，并可将包裹体的研究从原来的“群分析”统计规律研究水平提高到“单包体分析”水平，获得更小时间单位成矿流体的演化特征，因而能更准确地模拟和恢复地质作用过程。运用阴极发光对石英等矿物的研究，发现蚀变带中的石英按不同的形态特征和发光性可以分为三期，和成矿关系密切为第一、二期石英。根据阴极发光下显示的生长微形态，系统地测试三期石英不同生长时期的包裹体物相，从而获取了整个成矿过程流体的ｐ—ｔ—υ—ｘ参数，确定构造作用加热大气降水形成成矿流体，体系开放流体两次减压沸腾导致金矿沉淀的矿体定位机理和成矿动力学机制。  相似文献   

皖南石耳山新元古代花岗岩锆石U—Pb定年以及元素和氧同位素地球化学研究   总被引：20，自引：2，他引：18  

吴荣新  郑永飞  吴元保 《高校地质学报》2005,11(3):364-382

对皖南新元古代石耳山花岗岩样品进行了锆石微区u—Ph定年、全岩主微量元素分析和Sr—Nd同位素分析以及矿物氧同位素分析。结果表明,石耳山花岗岩中存在两个时代的岩浆锆石,对应的u—Ph年龄分别为777±9Ma和827±15Ma。总体上石耳山花岗岩的特征为：高SiO2（74．7％-78．5％）、高K2O（3．99％～5．64％）和高K2O／Na20比值（1．5—3．0）,以及很低的基性组分含量（YTiO2＋FeO＋MgO=1．2％-3．0％）,显示出高度演化的地壳物质。并具有LREE富集的右倾模式和强烈的Eu负异常（Eu／Eu^＋=0．2—0．4）。全岩εNd（t）值（-0．53—＋0．72）,指示其岩浆源区含有显著的亏损地幔组分。样品的锆石δ^18O值为2．4‰-7．1‰,显示石耳山花岗岩为低δ^18O值岩浆岩;相对较大的δ^18O值变化范围,说明其成因与高温超固相热液蚀变作用有关。其余矿物与锆石相比,大多数表现出很大的δ^18O值变化范围,表明经历了不同程度的高温热液蚀变。根据这些岩石的同位素年代学和地球化学特征,认为U—Ph年龄为827±15Ma的锆石应为继承来源,而年龄为777±9Ma的锆石可解释为同时代岩浆成因。因此在1000—880Ma中,皖南出现过大规模的幔源岩浆活动,沿着大陆边缘形成初生地壳。约827±15Ma热事件（地幔超柱活动？）使岩石圈地幔及其上覆地壳加热,导致拉伸加厚地壳内部的初生地壳重熔形成岩浆岩。随着裂谷的快速打开,约780Ma幔源岩浆沿裂谷带上涌,启动了中上地壳裂谷带高温热液蚀变,同期喷发了大量的火山岩。裂谷带内的岩浆围岩经受了不同程度的水一岩交换,形成各种低δ^18O值的蚀变围岩。在约805℃时,蚀变围岩开始部分熔融并且同期侵位冷却固结,形成花岗岩。较老的继承锆石大多被熔融,大量形成的是约777±9Ma结晶的岩浆锆石。由于处于熔体状态的时间很短,使得岩浆未能均一化,而生成具有不同低δ^18O值的花岗岩。石耳山花岗岩初生地壳的形成至少经历了2个阶段部分熔融成岩过程,因而具有高硅、高钾和低基性组分等高度演化的地壳物质特征。  相似文献   

Quartz and zircon decoupling in sandstone: Petrography and quartz cathodoluminescence of the Early Triassic continental Buntsandstein Group in Germany     

Carita Augustsson  Michaela Aehnelt  Thomas Voigt  Cindy Kunkel  Marcus Meyer  Florian Schellhorn 《Sedimentology》2019,66(7):2874-2893

This study illustrates how decoupling of quartz and zircon can be used advantageously in provenance research. Thirty‐eight fine‐grained to coarse‐grained arkose samples of the Early Triassic intracontinental Buntsandstein Group from the Central European Basin in Germany were analysed for their petrography and 1200 grains in 23 of these for their detrital quartz cathodoluminescence characteristics. The samples represent the Hessian and Thuringian sub‐basins and the Eichsfeld–Altmark Swell separating them. The Hessian Sub‐basin includes more metamorphic lithoclasts with a larger content of plutonic grains than are found further east in the Thuringian Sub‐basin. More than 90% of the detrital quartz from the eastern Thuringian Sub‐basin produce medium to bright blue cathodoluminescence colours and corresponding spectra that are typical for igneous or high‐temperature metamorphic origin. Differently, the quartz from the Hessian Sub‐basin mostly luminesces brown and dark to medium blue, typical for a low‐temperature metamorphic origin. Quartz from the Eichsfeld–Altmark Swell and the western Thuringian Sub‐basin is a mixture between these origins. The quartz indicates different catchments for the sub‐basins, possibly the Bohemian Massif and the Massif Central, with converging transport routes on and close to the eastern fringe of the swell. Taking published zircon data from the same samples into account, light mineral‐zircon grain‐size shifts are up to 2 Φ units. That can be explained by mineral decoupling due to different transport modes for quartz and zircon and different zircon‐size availability in the source areas, exaggerated by combined aqueous–aeolian transport, as well as sample preparation‐induced sorting. This study concludes that submerged highs significantly can influence continental sediment transport. Hence, vast, flat continental areas with submerged morphological highs and a seemingly straightforward transportation pattern may be more complex than expected. The results also illustrate that analysis of detritus that has been affected by different dominating transport modes, and further sorting during sampling and preparation can reveal additional source information.  相似文献   

Provenance analysis of the Cretaceous Laiyang Group on Lingshan Island (western Yellow Sea,China) and its tectono-sedimentary implications     

A. P. Fan  S. N. Sun  Z. Zhang  S. De  J. D. N. Nenzhelele 《Australian Journal of Earth Sciences》2020,67(3):361-377

Abstract

Longstanding debates on the tectonic setting and provenance of the Lower Cretaceous Lingshandao Formation have hindered basin analysis and tectonic studies of the collision of the Yangtze Craton and the North China Craton, and thus the evolution of the Sulu Orogen. Thin-section analysis, identification of rock particles, cathodoluminescence, heavy minerals and trace-element analysis have, in addition to field investigations, been applied to reconstruct the source area and transport pathways of the sediments that build the Lower Cretaceous Laiyang Group on the Lingshan Island, western Yellow Sea. These analyses indicate that the Laiyang Group consists mainly of material derived from a recycled orogen and from transitional continental sediments. The Laiyang Group on Lingshan Island has been sourced from igneous and metamorphic rocks. Comparing analyses of detrital minerals with rocks from surrounding areas leads to the conclusion that the main source area is the Sulu Orogen that supplied sediment to rift basin rather than a residual basin between the Yangtze Craton and the North China Craton.

1. A recycled orogenic belt is the source area for the Laiyang Group on Linshan Island.

2. Felsic metamorphic and igneous rocks form the most probable sources.

3. The rift basin was filled by sediments supplied from the Sulu Orogen on both sides.

  相似文献