浙江洋滨黄玉花岗质斑岩的包裹体研究   总被引：1，自引：1，他引：1  

郝艳丽  陈培荣  刘昌实  沈渭洲 《岩石矿物学杂志》1996,15(4):333-338

浙江洋滨黄玉花岗质斑岩的石英斑晶中含有大量原生包裹体，作者对其进行了大量的均一温度、盐度、化学成分等方面的测试工作，在此基础上，将这些包裹体划分为熔融包裹体、羟基化硅酸盐熔体—流体包裹体、不均一捕获多相包裹体、液相包裹体（包括高盐度液相包裹体和低盐度液相包裹体）、气相包裹体等五大类型。并按岩浆阶段、岩浆解聚阶段、岩浆／流体不混溶阶段、热液为主阶段探讨了本区包裹体的形成机制，为本区黄玉花岗质斑岩的岩浆成因解释提供了有力的依据  相似文献   

Dissolved organic carbon, nitrogen and phosphorus in the N-E Atlantic and the N-W Mediterranean with particular reference to non-refractory fractions and degradation     

Alain Aminot  Roger Krouel 《Deep Sea Research Part I: Oceanographic Research Papers》2004,51(12):933

Dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) measured in deep profiles in the N-E Atlantic and in the N-W Mediterranean in the period 1984–2002 are described. After accurate validation, they show close agreement with those previously published.Classic profiles were obtained, with concentrations decreasing in deep waters. In the Mediterranean and in the Atlantic comparable concentrations were found in the 1500–2000 m waters, 44–46 μmol l⁻¹ DOC, 2.6–2.8 μmol l⁻¹ DON and 0.02–0.03 μmol l⁻¹ DOP. In the surface layers, DOC concentrations were higher, but DON and DOP concentrations lower, in the Mediterranean than in the Atlantic, leading to higher element ratios in the Mediterranean. In autumn, values were, respectively, DOC:DON 17 vs. 14, DOC:DOP 950 vs. 500 and DON:DOP 55 vs. 35. The data suggest an increase in DOC and DON in the North Atlantic Central Water over 15 years, which may be linked to the North Atlantic climatic oscillations.Refractory DOM found in the 1500–2000 m layer exhibited C:N:P ratios of 1570:100:1. The labile+semi-labile (=non-refractory) DOM (nrDOM) pool was computed as DOM in excess of the refractory pool. Its contribution to total DOM above the thermocline in the open sea amounted to 25–35% of DOC, 30–35% of DON, and 60–80% of DOP. Element ratios of the nrDOM varied among stations and were lower than those of refractory DOM, except for C:N in the Mediterranean: nrDOC:nrDON 10–19, nrDOC:nrDOP 160–530 and nrDON:nrDOP 15–38. The specific stoichiometry of DOM in the Mediterranean led us to postulate that overconsumption of carbon is probably a main process in that oligotrophic sea.By coupling non-refractory DOM stoichiometry and relationships between the main DOM elements in the water column, the relative mineralization of C, N and P from DOM was studied. Below the thermocline, the preferential removal of phosphorus with regard to carbon from the semi-labile DOM can be confirmed, but not the preferential removal of nitrogen. In the ocean surface layers, processes depend on the oceanic area and can differ from deep waters, so preferential carbon removal seems more frequent. Bacterial growth efficiency data indicate that bacteria are directly responsible for mineralization of a high proportion of DON and DOP in the deep water.  相似文献   

Field geometry, petrography and geochemistry of a dolomitization front (Late Jurassic, central Lebanon)   总被引：1，自引：1，他引：1  

FADI H. NADER  RUDY SWENNEN†  ROB M. ELLAM‡ 《Sedimentology》2007,54(5):1093-1120

This contribution describes the field geometry, petrography and geochemistry of a well-exposed dolomitization front in Upper Jurassic carbonates, and attempts to highlight the sedimentological, structural and relative sea-level controls on multiphase dolomitization and related diagenetic events. The data presented reflect the superposition of various diagenetic phases which have resulted in a single dolostone body, whose dimensions are well defined in the field. Local microbial intraclastic dolomites of Late Tithonian age accumulated in a hypersaline lagoon during relative sea-level fall. These pre-date beige hydrothermal dolostones (51 to 55 mol% CaCO₃; δ ¹⁸O: −9·3 to −4·0‰ V-PDB; δ ¹³C: −1·5 to +2·1‰ V-PDB; ⁸⁷Sr/⁸⁶Sr: 0·70742; matrix porosity: ≈6%; Klinkenberg permeability: ≈0·5 mD), whose dolomitizing fluid circulated along faults and invaded the nearby facies. First, the burrows were dolomitized, then the bulk rocks, resulting in the investigated 'tongue'-shaped dolomite body. Upon Late Jurassic–Early Cretaceous uplift, near-surface water percolated through – and altered – the underlying beige dolostones. This event was followed by a ferroan dolomite cement phase, which occurred during further burial. This contribution, featuring a well-defined geometric pattern of a dolomitization front with a large petrographic and geochemical data set, may also serve as a case study illustrating the complexity of superimposed diagenetic processes which have to be taken into account in modelling exercises of multiphase hydrothermal dolomitization.  相似文献   

CO<Subscript>2</Subscript>-rich fluid inclusions with chalcopyrite daughter mineral from the Fenghuangshan Cu–Fe–Au deposit,China: implications for metal transport in vapor     

Jianqing Lai  Guoxiang Chi 《Mineralium Deposita》2007,42(3):293-299

CO₂-rich fluid inclusions containing opaque mineral crystals were found in the Fenghuangshan skarn-porphyry Cu–Fe–Au deposit in Tongling, Anhui, China. These inclusions show variable CO₂ contents and are accompanied by aqueous inclusions, both occurring as secondary inclusions in quartz and being locally associated with chalcopyrite mineralization. Laser Raman microspectroscopic analyses confirm the predominance of CO₂ in the vapor and the presence of H₂S as high as 8 mol%, and identify the opaque mineral with yellow reflectance color in the inclusions as chalcopyrite. More than half of the CO₂-bearing inclusions contains chalcopyrite, whereas few of the associated aqueous inclusions do so. The chalcopyrite, occupying less than 1% (volume) of the inclusions, is interpreted to be a daughter mineral, and calculated Cu concentrations in the inclusions range from 0.1 to 3.4 wt%. Copper is inferred to have been transported in CO₂-dominated fluids as HS⁻ complexes. The occurrence of chalcopyrite daughter crystals in CO₂-rich fluid inclusions indicates that CO₂-rich vapor has the capacity of transporting large amounts of Cu, and possibly Au. This finding has significant implications for metal transport and mineralization in hydrothermal systems enriched in CO₂, such as orogenic-type and granitic intrusion-related gold deposits.  相似文献   

Lithium isotope composition of ordinary and carbonaceous chondrites, and differentiated planetary bodies: Bulk solar system and solar reservoirs     

Hans-Michael Seitz  Gerhard P. Brey  Jutta Zipfel  Ulrich Ott  Stefan Weyer  Soodabeh Durali  Stephan Weinbruch 《Earth and Planetary Science Letters》2007,260(3-4):582-596

In order to better constrain the Li isotope composition of the bulk solar system and Li isotope fractionation during accretion and parent body processes, Li isotope compositions and concentrations were determined on a number of meteorite falls and finds. This is the first comprehensive study that systematically investigates a representative set of samples from carbonaceous chondrites (CI, CM2, CO3, CV3, CK4 and one ungrouped member), enstatite chondrites (EH, EL), ordinary chondrites (H, L, LL), and achondrites (one eucrite, diogenites, one pallasite, and a silicate inclusion from a IAB iron).

Carbonaceous chondrites have an average isotope composition of δ⁷Li = + 3.2‰ ± 1.9 (2σ) which agrees with the average composition of relatively pristine olivines (representative for the bulk composition) from the Earth primitive upper mantle (PUM). This is lighter than the average δ⁷Li of the basaltic differentiates of the Earth, Moon and Mars and the achondrites. It is an important observation, however, that the lighter end of the isotopic range of the differentiates always coincides with the averages of the mantle olivines and the carbonaceous chondrites. From this we conclude that the bulk of the inner solar system consists mostly of material from carbonaceous chondrites and that the variation seen in the differentiates is due to planetary body processes. Ordinary chondrites are significantly lighter than carbonaceous chondrites. No significant differences in δ⁷Li exist between enstatite chondrites (n = 3) and carbonaceous or ordinary chondrites. The difference between carbonaceous and ordinary chondrites and the variability within the chondrites could indicate the existence of distinct Li isotope reservoirs in the early solar nebula.  相似文献   

江西德兴铜厂斑岩铜矿成矿物质来源的再认识——来自流体包裹体的证据   总被引：10，自引：3，他引：10       下载免费PDF全文

左力艳张德会  李建康张文淮 《地质学报》2007,81(5):684-694,I0004

本文从江西德兴斑岩铜矿铜厂矿床的流体包裹体研究出发,讨论了矿床成矿物质来源与矿床成因。矿床中流体包裹体分为6类,即富液包裹体、富气包裹体、含石盐多相包裹体、含CO2多相包裹体以及熔体包裹体和熔体-流体包裹体。富气包裹体、含石盐多相包裹体和熔体与熔体-流体包裹体代表了成矿早期岩浆热液的特征。在这些包裹体中发现黄铜矿等金属矿物,表明成矿金属主要源自岩浆。含石盐多相包裹体和富气包裹体与矿体关系不甚密切,但其中所含有的金属矿物特别是黄铜矿,暗示早期来自岩浆的热液流体金属含量较高,形成于大气降水与岩浆热液混合之前。成矿中晚期大气降水流体在冷却和稀释岩浆流体方面对于矿床的形成作出了一定贡献,但是来自围岩的大气降水可能并没有向成矿体系提供大量金属。  相似文献   

利用H2O-NaCl-CaCl2体系水盐化合物和冰的融化温度计算NaCl/（NaCl＋CaCl2）比值和盐度的方程   总被引：1，自引：0，他引：1  

Guoxiang Chi Pei Ni 《岩石学报》2007,23(1):33-37

The composition of fluid inclusions in the H_2O-NaCl-CaCl_2 system has been generally graphically estimated using the melting temperatures of hydrohalite(T_(m-HH))and ice(T_(m-ice)).Here we present two equations that can be used to calculate the relative proportion of NaCl(i.e.,NaCl/[NaCl CaCl_2],or X_(NaCl))and the total salinity( i.e.,NaC1 CaC12,wt% )for fluid inclusions with ice as the last melting phase.X_(NaCl)can be calculated from T_(m-HH)using the following equation: y=(a bx)~(-1/c) where y is X_(NaCl),x is T_(m-HH),a=0.33124402,b=-0.031518028,and c=0.22932736.In the cases where only T_(m-ice)is measured and T_(m-HH)is not known,T_(m-ice)can be used as the maximum possible TIn.nil to calculate the maximum value of X_(NaCl)using the above equation.In these cases,the following equation can be used to calculate the maximum total salinity: y=(a bx cx~2)~(-1) where y is salinity,x is T_(m-HH),a=0.057184817,b=0.00078565757,and c=5.7262766E-6.Because the isothems in the field of ice are sub-parallel to the NaCl-CaCl_2 binary side in the H20-NaC1-CaC12 ternary system,the errors in salinity calculation introduced by the above approximation are small(less than 2 wt% ).A Windows program for calculation of X_(NsCl)and salinity is available at: http://uregina.ca/～chiguox.  相似文献   

The origin of medium-K ankaramitic arc magmas from Lombok (Sunda arc, Indonesia): Mineral and melt inclusion evidence   总被引：2，自引：0，他引：2  

Marlina A. Elburg  V.S. Kamenetsky  J.D. Foden  A. Sobolev 《Chemical Geology》2007,240(3-4):260-279

High-calcium, nepheline-normative ankaramitic basalts (MgO > 10 wt.%, CaO/Al₂O₃ > 1) from Rinjani volcano, Lombok (Sunda arc, Indonesia) contain phenocrysts of clinopyroxene and olivine (Fo_85–92) with inclusions of spinel (Cr# 58–77) and crystallised melt. Olivine crystals have variable but on average low NiO (0.10–0.23 wt.%) and high CaO (0.22–0.35 wt.%) contents for their forsterite number. The CaO content of Fo_89–91 olivine is negatively correlated with the Al₂O₃ content of enclosed spinel (9–15 wt.%) and positively correlated with the CaO/Al₂O₃ ratios of melt inclusions (0.9–1.5). Major and trace element patterns of melt inclusions are similar to that of the host rock, indicating that the magma could have formed by accumulation of small batches of melt, with compositions similar to the melt inclusions. The liquidus temperature of the magma was  1275 °C, and its oxygen fugacity ≤ FMQ + 2.5. Correlations between K₂O, Zr, Th and LREE in the melt inclusions are interpreted to reflect variable degrees of melting of the source; correlations between Al₂O₃, Na₂O, Y and HREE are influenced by variations in the mineralogy of the source. The melts probably formed from a water-poor, clinopyroxene-rich mantle source.  相似文献   

Fluid evolution in the nepheline syenites of the Ditrău Alkaline Massif, Transylvania, Romania     

Andrs Fall  Robert J. Bodnar  Csaba Szab  Elemr Pl-Molnr 《Lithos》2007,95(3-4):331-345

The Ditrău Alkaline Massif is an intrusion into the Bucovina nappe system that is part of the Mesozoic crystalline zone located in Transylvania, Romania, in the Eastern Carpathians. Nepheline syenites are the most abundant rocks in the central and eastern part of the Massif, and represent the last major intrusion of the complex. Fluid inclusions in nepheline, aegirine and albite were trapped at magmatic conditions on or below the H₂O-saturated nepheline syenite solidus at about 400–600 °C and 2.5–5 kbars. Early nepheline, and to a lesser extent albite, were altered by highly saline fluids to produce cancrinite, sodalite and analcime, during this process cancrinite also trapped fluid inclusions. The fluids, in most cases, can be modeled by the H₂O–NaCl system with varying salinity; however inclusions with more complex fluid composition (containing K, Ca, CO₃, etc., in addition to NaCl) are common. Raman spectroscopic analyses of daughter minerals confirm the presence of alkali-carbonate fluids in some of the earliest inclusions in nepheline, aegirine and albite.

During crystallization, the melts exsolved a high salinity, carbonate-rich magmatic fluid that evolved to lower salinity as crystallization progressed. Phases that occur early in the paragenesis contain high-salinity inclusions while late phases contain low-salinity inclusions. The salinity trend is consistent with experimental data for the partitioning of chlorine between silicic melt and exsolved aqueous fluid at about 2.0 kbars. The activity of water (a_H2O) in the melt increases during crystallization, resulting in the formation of hydrous phases during late-stage crystallization of the nepheline syenites.  相似文献   

High-density early CO₂ fluids in the ultrahigh-temperature granulites of Ihouhaouene (In Ouzzal, Algeria)     

Michel Cuney  Yacouba Coulibaly  Marie-Christine Boiron 《Lithos》2007,96(3-4):402-414

Fluid inclusion studies in rocks from the Lower Proterozoic granulites from western Hoggar (Algeria) provide new evidence for the hypothesis that a CO₂-rich, H₂O-poor fluid was present during the high-grade metamorphism. CO₂ inclusions represent the main fluid trapped in the Ihouhaouene ultrahigh-temperature (over 1000 °C) and high-pressure (10 to 14 kbar) granulites. The microthermometric and Raman microspectrometric measurements indicate that the carbonic fluid is mainly composed of CO₂ with minor amounts of CH₄ and N₂ detected in some inclusions (< 4 mol% CH₄). Carbonic fluid densities range from 1.18 to 0.57 g/cm³. The highest densities are recorded in superdense carbonic inclusions presenting evidence of the earliest trapping and they correspond to the fluid densities expected for the P–T conditions of the peak of metamorphism in the area previously determined from mineral geothermobarometers. Lower densities of carbonic fluids mainly result from the reequilibration of earlier trapped fluid inclusions during retrograde metamorphism and final uplift of the metamorphic terrane, but a new influx of carbonic fluids during the retrograde event remains possible. Carbonic fluids can be produced in situ from decarbonation reactions in interlayered impure marbles during the prograde event or derived from CO₂ flushing from underlying basic intrusions. The aqueous fluids present large variations of composition (0.5 to 30 wt.% NaCl equivalent) and densities (1.16 to 0.57 g/cm³). They clearly correspond to post-metamorphic fluids because they mainly occur along microfractures, they do not show any evidence of immiscibility with the carbonic fluids and mixed aquo-carbonic inclusions have not been observed. The percolation of aqueous fluids is related to the Pan-African tectonometamorphic event.  相似文献