A cordierite-bearing granite suite from the New England Batholith,N.S.W., Australia

A suite of cordierite-bearing biotite-muscovite intrusive granites in the New England Batholith, New South Wales, outcrops over 3400 sq km and is the largest reported occurrence of granites of this type. Compositionally the granites are close to the low temperature minimum and display only limited chemical variation. The corundum-normative nature of the granites suggests a pelitic sedimentary parentage. Cordierite with an average 100 Mg/ Mg + Fe of 55 occurs as large tabular crystals and is considered to be a refractory phase brought up from the zone of partial melting. The presence of cordierite and the absence of garnet in these granites suggests a partial melting at a pressure maximum of 6 kb, equivalent to 22 km depth.     

Granitoids from the Moonbi district,New England Batholith,Eastern Australia

The late Palaeozoic granitoids of the Moonbi district are derived both from igneous (I‐type) and sedimentary (S‐type) sources. Field and petrographic observations and chemical data on the I‐type granitoids show that they are derived from four separate and distinct source‐rock compositions and that, consequently, these granitoids may be grouped into four suites. Mafic xenoliths and microxenoliths are relatively more abundant in more mafic I‐type granitoids. Such xenoliths are interpreted as restite, or material residual from partial melting of the source rocks. Variation within the granitoids is ascribed to varying degrees of separation of restite from the melt produced during each fusion event. The source material of the I‐type granitoids is considered to have been material underplated beneath the crust during an earlier subduction event. Two suites of S‐type granitoids can be recognized. These are derivatives of pelitic materials that have undergone only a small amount of chemical weathering.     

Two “S-type” granite suites with low initial 87Sr/86Sr ratios from the New England Batholith,Australia

Two “S-type” (pelitic) granite suites from the New England Batholith, N.S.W., have Upper Carboniferous ages, indicating that they predate by 40 m.y. the intrusion of hornblende biotite granites, and are the oldest plutons of the batholith. Mineralogically and geochemically both suites have “pelitic” characteristics, one suite containing an Al-rich biotite, muscovite and cordierite, the other an Al-rich biotite and rare pyrope-almandine garnet. Low initial ⁸⁷Sr/⁸⁶Sr ratios of 0.706 for both suites probably reflect the volcanoclastic nature and young age of the sedimentary source of these granites at the time of melting. The age of the suites coincides with the last stages of (Andean type?) volcanism along an andesite/dacite volcanic chain to the west, suggesting an origin for the “S-type” granitic magma by partial melting of deformed sediments marginal to a continental region.     

Oxygen and hydrogen isotope ratios in freshwater chert as indicators of ancient climate and hydrologic regime

The oxygen and hydrogen isotopic composition of Eocene and Miocene freshwater cherts in the western United States records regional climatic variation in the Cenozoic. Here, we present isotopic measurements of 47 freshwater cherts of Eocene and Miocene age from the Great Basin of the western United States at two different sites and interpret them in light of regional climatic and tectonic history. The large range of δ¹⁸O of terrestrial cherts measured in this study, from 11.2‰ to 31.2‰ (SMOW: Standard Mean Ocean), is shown to be primarily the result of variations in δ¹⁸O of surface water. The following trends and patterns are recognized within this range of δ¹⁸O values. First, in Cenozoic rocks of northern Nevada, chert δ¹⁸O records the same shift observed in authigenic calcite between the Eocene and Miocene that has been attributed to regional surface uplift. The consistent covariation of proxies suggests that chert reliably records and retains a signal of ancient meteoric water isotopic composition, even though our analyses show that chert formed from warmer waters (40°C) than coexisting calcite (20°C). Second, there is a strong positive correlation between δ¹⁸O and δD in Eocene age chert from Elko, Nevada and Salina, Utah that suggests large changes in lake water isotopic composition due to evaporation. Evaporative effects on lake water isotopic composition, rather than surface temperature, exert the primary control on the isotopic composition of chert, accounting for 10‰ of the 16‰ range in δ¹⁸O measured in Eocene cherts. From authigenic mineral data, we calculate a range in isotopic composition of Eocene precipitation in the north-central Great Basin of −10 to −14‰ for δ¹⁸O and −70 to −100‰ for δD, which is in agreement with previous estimates for Eocene basins of the western United States. Due to its resistance to alteration and record of variations in both δ¹⁸O and δD of water, chert has the potential to corroborate and constrain the cause of variations in isotope stratigraphies.     

Oxygen isotope study of the Suzhou granite

Oxygen isotope studies of the Suzhou granite have been made based on drill-hole samples. In the inner part, the δ¹⁸O values are less variable either in the whole-rock, quartz or in feldspar. Oxygen isotopic compositions are in equilibrium between coexisting quartz and feldspar. Data points from the inner part are plotted in a small area in the δ¹⁸O_Q-δ¹⁸O_f diagram, indicating that this part has not been affected by meteoric hydrothermal fluids. But the whole-rock δ¹⁸O values of the marginal part vary greatly. Oxygen isotopic compositions are in extreme disequilibrium between quartz and feldspar. Data points from the marginal part are displayed with a nearly vertical slope in the δ¹⁸O_Q-δ¹⁸O_f diagram, implying that rocks of this part are affected by the meteoric hydrothermal fluids. Extreme water-rock interactions lead to mineralizations of rare-elements (Nb, Ta, as well as Zr, Hf, Th) in the marginal part. Source materials of the Suzhou granite are also discussed in this paper.     

Oxygen isotope compositions of chondrules in CR chondrites

We report in situ ion microprobe analyses of oxygen isotopic compositions of olivine, low-Ca pyroxene, high-Ca pyroxene, anorthitic plagioclase, glassy mesostasis, and spinel in five aluminum-rich chondrules and nine ferromagnesian chondrules from the CR carbonaceous chondrites EET92042, GRA95229, and MAC87320. Ferromagnesian chondrules are isotopically homogeneous within ±2‰ in Δ¹⁷O; the interchondrule variations in Δ¹⁷O range from 0 to −5‰. Small oxygen isotopic heterogeneities found in two ferromagnesian chondrules are due to the presence of relict olivine grains. In contrast, two out of five aluminum-rich chondrules are isotopically heterogeneous with Δ¹⁷O values ranging from −6 to −15‰ and from −2 to −11‰, respectively. This isotopic heterogeneity is due to the presence of ¹⁶O-enriched spinel and anorthite (Δ¹⁷O = −10 to −15‰), which are relict phases of Ca,Al-rich inclusions (CAIs) incorporated into chondrule precursors and incompletely melted during chondrule formation. These observations and the high abundance of relict CAIs in the aluminum-rich chondrules suggest a close genetic relationship between these objects: aluminum-rich chondrules formed by melting of spinel-anorthite-pyroxene CAIs mixed with ferromagnesian precursors compositionally similar to magnesium-rich (Type I) chondrules. The aluminum-rich chondrules without relict CAIs have oxygen isotopic compositions (Δ¹⁷O = −2 to −8‰) similar to those of ferromagnesian chondrules. In contrast to the aluminum-rich chondrules from ordinary chondrites, those from CRs plot on a three-oxygen isotope diagram along the carbonaceous chondrite anhydrous mineral line and form a continuum with amoeboid olivine aggregates and CAIs from CRs. We conclude that oxygen isotope compositions of chondrules resulted from two processes: homogenization of isotopically heterogeneous materials during chondrule melting and oxygen isotopic exchange between chondrule melt and ¹⁶O-poor nebular gas.     

团结沟金矿氧氢同位素组成特征与成矿关系的研究

氢氧同位素研究表明团结沟金矿成矿热液水主要为大气降水来源，成矿W／R值较小(0.05～0.15)。通过对东露采区蚀变岩石的系统采样和氧同位素分析，获得氧同位素平面等值线趋势图，指示出矿体与高18O蚀变花岗斑岩有密切关系。利用大气降水二阶段理想演化定性解释了高18O蚀变岩石成因。一个浅钻岩心的氧同位素组成向深部具明显升高趋势，指示金矿主矿体还在深部。     

Oxygen and hydrogen isotope compositions of eclogites and associated rocks from the Eastern Sesia zone (Western Alps,Italy)

Oxygen and hydrogen isotope analyses have been made of mineral separates from eclogites, glaucophanites and glaucophane schists from the eastern Sesia zone (Italian Western Alps). Regularities in (1) hydrogen isotope compositions, (2) order of ¹⁸O enrichment among coexisting minerals, and (3) ¹⁸O (quartz-rutile) and ¹⁸O (quartz-phengite) imply attainment of a high degree of isotopic equilibrium. However, some scattering of ¹⁸O values of individual minerals indicates that the eclogitic assemblage did not form in the presence of a thoroughly pervasive fluid. Minerals from an eclogitic lens enclosed in marble have ¹⁸O values distinctly different from those measured in the other rocks. The ¹⁸O values are high in comparison with other type C eclogites of the world, and it is proposed that the fluid present during the high pressure metamorphism has to a large extent been inherited from the precursor rocks of amphibolite facies.An average formation temperature of 540 ° C is inferred from the oxygen isotope fractionations between quartz and rutile and between quartz and white mica. This temperature is in accordance with petrologic considerations and implies subduction of the precursor rocks into the upper mantle to achieve the high pressures required.     

Oxygen isotope studies of granite and migmatite,Grenville province of Ontario,Canada

O¹⁸/O¹⁶ ratios have been obtained for rocks and minerals along a 200 mile traverse from near the Grenville front north of Lake Nipissing to the Paleozoic contact to the east of Georgian Bay. Two types of oxygen isotopic relationships correlated with metamorphic grade and style of plutonic emplacement are observed: (A) from the Grenville fron to the Haliburton Highlands, upper amphibolite to granulite facies paragneisses, migmatites and concordantly emplaced granites all show relatively low and uniform δO¹⁸-values, e.g. δ (whole rock) range from 5·0 to 8·9 per mil (SMOW) and 80 per cent of the 44 samples analyzed lie between 6·5 and 8·4. We attribute this to extensive syn-anatectic oxygen isotope homogenization and exchange with a deep-seated mafic or ultramafic reservoir through a water-rich pore fluid. (B) To the southeast of the Harvey-Cardiff Arch, in the Chandos Lake-Silent Lake area, where metasediments of lower metamorphic grade are abundant and granites intrude at higher crustal level are common, we observed higher O¹⁸/O¹⁶ ratios in the granites (δ = 9?14) and paragneisses (δ = 12?17). The granites apparently have undergone various degrees of oxygen isotope exchange with the intruded metasediments. It thus appears that the granite-paragneiss assemblege as a whole has not been extensively open to some extraneous oxygen reservoir as in case (A).     

Oxygen and hydrogen isotope studies on the basal complexes of the Canary Islands: implications on the conditions of their genesis

¹⁸O/¹⁶O and D/H ratios have been measured in rocks and mineral separates from the basal complexes of Fuerteventura, Gomera and La Palma. These complexes comprise alkali plutonic rocks ranging from olivine gabbros to syenites and dikes of various mineralogy cutting them, all metamorphosed under greenschist conditions. K-Ar determinations gave ages from 48 to 17 My. The ¹⁸O's and D's of these rocks range from –1,4 to +11 and –113 to –45 respectively, with a majority of rocks depleted in heavy isotopes relative to normal, deep seated values. These values do not correspond to those found in ophiolitic sequences, which, for a comparable temperature range, give minimum ¹⁸O's>3. These values are explained in terms of water-rock interactions involving limited amounts of meteoric waters from high elevations. This implies the existence of a very important volcanic edifice over Fuerteventura in the Miocene Oligocene period with elevations between 2,500 and a maximum of more than 4,000 m.     

Cobalt,nickel and selenium in sulphides as indicators of ore genesis

Trace element studies of sulphides have been used to estimate temperatures of mineral formation, to identify metallogenic provinces, and to investigate the environment of mineral deposition. In the investigation of depositional environments, the Co:Ni and S:Se ratios are potentially useful as discriminators between magmatic-hydrothermal and sedimentary environments. A wide range of ore-types occurs in the Lower Palaeozoic rocks of West Tasmania (Australia) which lies in the southern part of the Tasman Geosyncline. The cobalt and nickel contents of pyrites from a number of these ores have been determined by atomic absorption spectrophotometry. Preliminary results show that the pyrites may be grouped as follows: a) those of sedimentary or diagenetic origin in shales (high cobalt and nickel and Co:Ni<1), b) those of probable volcanic origin without accompanying lead and zinc minerals (Co:Ni>1), and c) those of probable volcanic origin associated with lead and zinc minerals, and those with cassiterite or argentiferous galena related to granitic intrusions (low cobalt and nickel and Co:Ni<1). In some areas there is evidence that relatively high cobalt and selenium contents in pyrite may be related to volcanic processes.

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Zusammenfassung Mit Hilfe von Untersuchungen des Spurenelement-Gehaltes von Sulfiden wurden die Temperaturen der Mineralbildung abgeschätzt. Ziel war es, metallogene Zonen zu indentifizieren und das Milieu von Mineralablagerungen zu erforschen. Bei den Untersuchungen der Ablagerungsbedingungen können die Co:Ni- und S:Se-Verhältnisse unter Umständen zur Unterscheidung zwischen magma-hydrothermalem und sedimentärem Milieu dienen. Eine beachtliche Vielfalt von Erzarten ist in den Unter-Paläozoischen Gesteinen von West-Tasmanien (Australien) vorhanden, welches im südlichen Teil der Tasman-Geosynklinale liegt. Die Kobalt- und Nickelgehalte von Pyriten und einer Reihe entsprechender Erze wurden durch Atom-Absorptions-Spektrophotometrie bestimmt. Vorläufige Ergebnisse zeigen, daß die Pyrite in folgender Weise klassifiziert werden können: a) Pyrite sedimentärer oder diagenetischer Herkunft in Schiefern, mit hohem Kobalt- und Nickelgehalt und Co:Ni<1; b) Pyrite wahrscheinlich vulkanischen Ursprungs, frei von Blei und Zinkmineralien (Co:Ni>1); c) Pyrite wahrscheinlich vulkanischen Ursprungs verbunden mit Blei- und Zinkmineralien, und solche mit Kassiterit oder silberhaltigem Bleiglanz, verbunden mit Granit-Eindringungen (mit einem niedrigen Kobalt- und Nickelgehalt und Co:Ni<1). In manchen Gegenden sind Anzeichen dafür vorhanden, daß verhältnismäßig hohe Kobalt- und Selengehalte in Pyriten mit vulkanischen Prozessen zusammenhängen.

     

苏州A型花岗岩氢氧同位素地球化学研究

对苏州Ａ型花岗岩氢氧同位素组成进行了系统深入的研究,其全岩δ１８Ｏ值为＋３．５‰～＋９．２‰,全岩δＤ值在－８１‰～－５９‰之间变化。主要造岩矿物对保持氧同位素平衡分馏的样品,其Ｄ亏损主要受单阶段岩浆去气机理的制约。部分全岩样品表现出不同程度Ｄ－１８Ｏ同步亏损,这种亏损要受岩浆期后固相线下与外来渗透大气降水之间进行同位素交换机理的制约。石英δ１８Ｏ值基本正常,石英与碱性长石之间氧同位素不平衡分馏特征表明,苏州Ａ型花岗岩整体上起源于亏损１８Ｏ源区物质通过地球动力学再循环产生低δ１８Ｏ岩浆的可能性不大。根据氢氧同位素实测值和理论模型计算结果,推测苏州Ａ型花岗岩浆δＤ和δ１８Ｏ初始值分别为－５０±５‰和７．５±１．０‰,这排除了岩浆起源于曾经历过化学风化循环的地壳上部岩石的可能性。     

Renewable energy strategies in England, Australia and New Zealand

The development of renewable energy sources is of prime interest to many countries seeking to pursue greenhouse gas emission reduction obligations. The increased use of renewables offers the possibility of not only contributing to emission reduction, but at the same time improving energy supply diversity and security, and developing employment and business in related supply industries. Two main mechanisms are in common use, one a quota (quantity) instrument often associated with tradable certificates, and the other a prescribed pricing mechanism. This paper considers the renewable energy development strategies of three countries (the UK, Australia, and New Zealand) all using a variant of the quota/certificate approach as the central instrument in their programs. The regulatory frameworks defining the application of the certificate systems differ notably, and the likely differing outcomes suggest that these regulatory settings may be at least as important as the selection of the basic policy instrument, in determining the overall success of programs of this nature.     

Oxygen isotope compositions and magmatic epidote from two contrasting metaluminous granitoids,NE Brazil

Oxygen isotope compositions of mineral separates were determined from two metaluminous granitoids (Emas and São Rafael plutons) from northeastern Brazil. The I-type Emas pluton has high δ¹⁸O (WR) values (11.5–11.8‰), whereas the São Rafael pluton has low δ¹⁸O (WR) values (7.5–8.1‰), but Sr and Nd are characteristics of S-type granitoids. Measured mineral–mineral fractionations suggest continuous sub-solidus inter-mineral isotope exchange among all minerals except zircon. There is a large and consistent quartz–epidote fractionation that gives apparent temperatures that are much lower than anticipated closure temperatures for epidote. Oxygen isotope fractionation between natural zircon and magmatic epidote is opposite to that predicted from theoretical determinations, as δ¹⁸O (epidote) <δ¹⁸O (zircon). An empirical calibration based on these results would suggests a closure T for oxygen in epidote of ~500 °C and Δ(qtz–epi) ~5.19 at 500 °C.     

Formation of weathering-derived magnesite deposits in the New England Orogen, New South Wales, Australia: Implications from mineralogy, geochemistry and genesis of the Attunga magnesite deposit

Nodular, cryptocrystalline, weathering-derived magnesite deposits in the New England Orogen, Australia, provide a significant source of high-purity magnesite. Common textural features and related isotopic fingerprints indicate a close genetic relationship between weathering-derived magnesite deposits hosted by ultramafic rocks at Attunga and by sediments at Kunwarara while silica-carbonate rock alteration and rare hydrothermal magnesite vein deposits reflect contrasting conditions of formation. Localised weathering of carbonates in a soil environment shifts stable isotopic composition towards low δ ¹³C and high δ ¹⁸O typical for weathering-derived magnesites while intrusion-related fluids do not significantly change the isotopic composition of affected carbonates. At Attunga, magnesite consists of irregular, nodular veins and masses filling faults and cracks in the weathered serpentinite host rock as well as soft powdery magnesite in pervasive serpentinite alteration zones. The high-grade magnesite at Attunga can be contaminated by amorphous silica and serpentine relicts but does not contain dolomite or ferroan magnesite as observed for its hydrothermal equivalent, the Piedmont magnesite deposit, or other widespread deposits of silica-carbonate rock in the Great Serpentinite Belt. Heavy δ ¹⁸O values are compatible with a supergene formation from meteoric waters while low δ ¹³C suggests C3-photosynthetic plants as the predominant source of carbon for the Attunga magnesites. We infer that weathering-derived, nodular magnesite deposits hosted in ultramafic rocks like the Attunga magnesite deposit have formed in a two-step process involving the hypogene formation of a pre-cursor magnesite deposit and complete supergene overprinting by meteoric waters that acquired carbon from percolation through soil.     

阿尔金南缘塔特勒克布拉克花岗岩的地球化学特征、锆石U-Pb定年及Hf同位素组成

地球化学研究显示,阿尔金造山带南缘瓦石峡河附近塔特勒克布拉克二长花岗岩具有高硅(SiO2=63.62%～72.06%)、高碱(ALK=6.39～7.83)、过铝质(ASI=1.27～1.43)的特征,其稀土元素含量中等,Eu负异常较明显,轻稀土相对富集;在原始地幔标准化蛛网图上,大部分样品相对富集LREE、Rb、Th、U等大离子亲石元素,亏损Nb、Ta、Sr、P、Ti等高场强元素,指示其为壳源型高钾钙碱性系列的强过铝质S型花岗岩。锆石Hf同位素研究结果表明,其εHf(t)=-9.1～-10.5,两阶段Hf同位素模式年龄tDMC为1457～1553Ma,反映该花岗岩的源岩主要来自于地壳物质的重熔,其来源也相对单一。岩石中Nb/Ta、Zr/Hf、Th/U比值及高的CaO/Na2O比值(0.3),高的Al2O3、CaO和FeOT+MgO+TiO2总量,暗示该花岗岩是由中下地壳的杂砂岩经过黑云母脱水熔融形成的。较低的Al2O3/TiO2比值以及高的Y和Yb含量表明,该花岗岩的源岩是在较高的温度及较低的压力条件下部分熔融产生的,熔融的残留相可能为斜长角闪岩。阴极发光图像显示,该岩石中的锆石呈自形的长柱状,具有明显的岩浆环带结构,LA-ICP-MS微区原位U-Pb定年获得462±2Ma一组年龄,结合阴极发光图像和锆石微量元素特征(Th/U0.1),推断该年龄值为花岗岩的形成年龄。根据CaO/Na2O-Al2O3/TiO2图解和R1-R2构造判别图解,确定该花岗岩可能形成于碰撞造山后抬升初期。对比花岗岩形成年龄(462Ma)与阿尔金造山带南缘已获得的高压-超高压岩石变质年龄(～500Ma),可推断阿尔金瓦石峡南二长花岗岩形成于阿尔金造山带俯冲碰撞造山后应力释放的初级阶段,在该阶段地壳物质由于压力的降低从而发生部分熔融。     

Oxygen,hydrogen and carbon isotope studies of the franciscan formation,Coast Ranges,California

Analyses of 230 Franciscan rock and mineral samples, including the San Luis Obispo ophiolite, show that metamorphism produces no change in the δ¹⁸O of the graywackes (+11 to +14), but that igneous rocks become enriched in ¹⁸O by 2–6% and the cherts depleted by 5–10%. The shales are of two types, a high-¹⁸O type (+16 to +20) associated with chert and a low-¹⁸O type isotopically and mineralogically similar to the graywackes. The vein quartz (δ = + 15 to + 20) is invariably richer in ¹⁸O than the host rock quartz and in most of the rocks the δ¹⁸O of the clastic quartz is similar to the δ¹⁸O of the whole rock. Mineral assemblages are typically not in isotopic equilibrium. Although the δ¹⁸O values are very uniform (+13 to +16). the δ¹³C of vein aragonite and calcite is widely variable (0 to ? 14), implying that a major source of the carbon is oxidized organic material. The δD values of 83 igneous and sedimentary rocks are -45 to -80, exceptions are the Fe-rich minerals howieite and deerite, which have δD = ?100. All of these samples could have equilibrated with H₂O having δD ≈ +10 to ?20 and δ¹⁸O ≈ ?3 to +8. assuming temperatures of 100–300°C. However, the serpentines (δD ≈ ?85 to ?110) and the vein minerals (δD = ?23 to ?55) are exceptions. The vein minerals are 10–20%, richer in deuterium than the adjacent wall rocks; they formed from a relatively D-rich metamorphic water, typically at lower temperatures than did their host rocks. The isotopic compositions of the other Franciscan rocks were affected by three distinct events: (1) hydrothermal alteration of the ophiolite complexes and volcanic rocks as a result of submarine igneous activity at a spreading center or in an island-arc environment; (2) low-temperature, high-pressure regional metamorphism and diagenesis; and (3) a late-stage, very low temperature (<100°C) alteration of the ultramafic bodies by meteoric ground waters, producing lizardite-chrysotile serpentine. In the first two cases, the pore fluid involved in the alteration of the Franciscan rocks was sea water. However, this water became somewhat depleted in D and enriched in ¹⁸O during blueschist metamorphism, evolving to values of δD ≈ ? 20 and δ¹⁸O ≈ + 6 to + 8 at the highest grades. Except for one graywacke sample, the meteoric waters that affected the serpentinites did not significantly change the $\text{D}\text{H}$ ratios of the OH-bearing minerals in any other Franciscan rock.The δ¹⁸O values of orogenic andesites are too low for such magmas to have formed by direct partial melting of Franciscan-type materials in a subduction zone. Andesites either form in some other fashion, or the melts must undergo thorough isotopic exchange with the upper mantle. The great Cordilleran granodiorite-tonalite batholiths, however, are much richer in ¹⁸O and may well have formed by large-scale melting or assimilation of Franciscan-type rocks. The range of δD values of Franciscantype rocks is identical to the ?50 to ?80 range shown by most igneous rocks. This suggests that ‘primary magmatic H₂O’ throughout the world may be derived mainly by partial melting of Franciscantype materials, or by dehydration of such rocks in the deeper parts of a Benioff zone.     

江苏盘石山玄武岩中橄榄岩包体的氧同位素和微量元素地球化学

本文研究了8个来自江苏盘石山新生代碱性玄武岩中的橄榄岩包体，利用ICP—MS技术测定了橄榄岩中单斜辉石的微量元素组成；利用激光氟化技术系统地分析了橄榄石、单斜辉石和斜方辉石的氧同位素比值。结果显示，盘石山橄榄岩包体矿物的氧同位素比值落在“正常”地幔矿物的氧同位素变化范围之内，而且矿物之间达到了氧同位素平衡。部分单斜辉石不相容元素富集的特征表明，有些样品经历了隐性地幔交代作用（cryptical metasomatism），配合氧同位素的数据来看，影响盘石山上地幔的交代介质为来自地幔内部的熔体，不合有地壳组分。从盘石山和安徽女山（盘石山以北约100km）的对比看来，影响女山上地幔的洋壳流体可能来自于华南一华北陆陆碰撞之前的海洋板块俯冲，因此华南一华北的深部缝合带可能就在女山和盘石山之间。     

脉状黝铜矿型铜矿床的稳定同位素组成及其成因意义

脉状黝铜矿型铜矿床是产于兰坪-思茅盆地中的一种新的铜矿床类型。碳酸盐及CO₂包裹体的δ¹³C值大多在-4‰～-7‰之间变化,显示碳来自地幔。矿石中铅同位素组成与盆地中喜马拉雅期碱性岩长石中铅的同位素组成一致,方解石和铁白云石的⁸⁷Sr/⁸⁶Sr比值接近或稍高于碱性岩的⁸⁷Sr/⁸⁶Sr的比值,显示矿石锶、铅与碱性岩锶、铅是同源的,均来自于上地幔。硫化物中硫的δ³⁴S值大多集中在0～-4‰之间,显示其硫主要是深部来源并有少量的地壳硫参与。包裹体水的δ¹⁸O和δD值显示成矿流体的水为大气降水、岩浆水和变质水的混合物。结合其它质、地球化学特征,笔者认为这类矿床的成因类型为壳-幔混合热液成因型。     

Sulfur isotopes and the origin of stibnite mineralisation in New England,Australia

Stibnite mineralisation in the antimony province of New England can be divided into Central type ores (veins of stibnite + quartz ± berthierite) and Peripheral type ores of stibnite + quartz + native antimony ± berthierite. The Central stibnites have ³⁴S_CDT values of –5±2 (1) which may represent equilibrium precipitation from mantle sulfur at about 200°C. Peripheral stibnites have ³⁴S values between 0 and –25, with a large group at 0±2. They represent precipitation from a limited supply of mantle sulfur and the acquisition of sedimentary sulfur. We consider that the different ore types were produced from distinct ore solutions derived from two immiscible melts. These originated in the deep mantle, were mobilised by tectonic activity and supplied the antimony and most of the sulfur to the ores.