长白山地区幔源捕虏体的硫化物相及其演化

长白山地区新生代玄武岩的一些层位广布地幔岩捕虏体,在其橄榄石、辉石等矿物内发现有较多的硫化物相,按产出特征可鉴别出3种类型,即早期硫化物颗粒、硫化物包裹体和裂隙中硫化物。硫化物包裹体可以单相硫化物、硫化物－硅酸盐熔体、CO2－硫化物－硅酸盐熔体形式存在。早期硫化物颗粒以磁黄铁矿为主,并发现有方黄铜矿;硫化物包裹体以镍黄铁矿为主,并有黄铜矿、硫铜铁矿出现;裂隙中硫化物均为镍黄铁矿,并具有比硫化物包裹体高的Ni/Fe和（Fe Ni)／S值。地幔岩中存在自早期硫化物颗粒、硫化物包裹体至裂隙硫化物,Ni/Fe和（Fe Ni)/S比值逐渐增加的规律。这种演化不仅受温度和压力制约,而且受Ni,Fe,Cu的地球化学特性和硫逸度的控制。     

Mantle metasomatism by P- and F-rich melt/fluids: evidence from phosphate glass in spinel lherzolite xenolith in Keluo, Heilongjiang Province

Spinel lherzolite xenoliths were found in phonolitic alkaline basalt in the Keluo area, Heilongjiang Province. Detailed electron-microprobe study revealed abundant phosphates and associated metasomatic minerals between primary phases in xenolith. The phosphates are considered special residual phases (coagulation) of P- and F-rich mantle melt/fluid, most of which were identified as glass phases based on Raman spectroscopic analyses. Such melt/fluid also further metasomatized primary minerals, thus leading to formation of reaction rims successively composed of Cr-spinel symplectitic zone and olivine diopside zone. Therefore, the P- and F-rich melt/fluid played an important role in the upper-mantle metasomatism in the Keluo area. It is suggested that this kind of metasomstism may occur in some other places of eastern China. The present results may also have significance in study-ing types of metasomatic melt/fluid and its evolution in the lithospheric mantle beneath eastern China.     

Mantle metasomatism by P- and F-rich melt/fluids： evidence from phosphate glass in spinel Iherzolite xenolith in Keluo, Heilonsjiang Province

Spinel Iherzolite xenoliths were found in phonoliUc alkaline basalt in the Keluo area, Heilongjiang Province. Detailed electron-microprobe study revealed abundant phosphates and associated metasomatic minerals between primary phases in xenolith. The phosphates are considered special residual phases （coagulation） of P- and F-rich mantle melt/fluid, most of which were identified as glass phases based on Raman spectroscopic analyses. Such melt/fluid also further metasomatized primary minerals, thus leading to formation of reaction rims successively composed of Cr-spinel symplecUUc zone and olivine ＋ diopside zone. Therefore, the P- and F-rich melt/fluid played an important role in the upper-mantle metasomatism in the Keluo area. It is suggested that this kind of metasomstism may occur in some other places of eastern China. The present results may also have significance in studying types of metasomatic melt/fluid and its evolution in the lithospheric mantle beneath eastern China.     

Mantle xenoliths from Late Cretaceous basalt in eastern Shandong Province： New constraint on the timing of lithospheric thinning in eastern China

Studies of mantle xenoliths hosted in both the Cenozoic alkali basalt and the Early Paleozoic kimberlite suggest that part of the subcontinental lithosphere as thick as more than 100 km has been lost from the Early Paleozoic to Cenozoic[1—8]. Neither the scale and mechanism nor the accurate timing of the lithospheric thinning has been precisely constrained[7-12]. One of the reasons for this is that there are only a few Mesozoic basalts cropped out, especially, few containing mantle-derived …     

Fluid/melt inclusions in Cenozoic mantle xenoliths from Linqu,Shandong Province,eastern China: Implications for asthenosphere-lithosphere interactions

Fluid and melt inclusions in mantle xenoliths are thought as direct samples to study mantle liquids. Here we apply Raman mi- crospectroscopy and microthermometry to fluid/melt inclusions in lherzolite xenoliths in Qiaoshan basalts, a Miocene volcano in Linqu, Shandong Province, eastern China. These inclusions include (1) early CO2 fluid inclusions, (2) early carbonate melt inclu-sions, (3) late CO2 fluid inclusions, and (4) late silicate melt inclusions. Among the early CO2 fluid inclusions, most consist of...     

Patterns of platinum-group elements in mantle peridotite, granulite xenoliths and basalt in Hannuoba

Neutron activation analysis after preconcentration of nickel sulfide fire assay was used in measurement of Ru, Ph, Pd, Os, Ir, Pt (i.e. PGE elements) and Au concentrations for basalt, mantle and granulite xenoliths in Hannuoba. The chondrite- and primitive mantle-normalized PGE patterns generally exhibit flat (for Iherzolite), negative slope (for harzburgite), and positive slope (for basic granulite and basalt). In addition, strong Ir negative anomaly occurs in basalt and granulite xenolith, and little negative anomaly also exists in Iherzolite xenolith in Hannuoba.     

Chondritic osmium isotopic composition of late Archean convecting upper mantle：Evidence from Zunhua podiform chromitites,Hebei, North China

The Os isotopic composition and evolution of con-vecting upper mantle (CUM) are an important and diffi-cult scientific issue related to the distributions of PGEs inearth’s interior and the accretion history of the earth. De-termination of 187Os/188Os of modern CUM has been at-tempted via analyses of abyssal peridotites, mid-oceanridge basalts (MORB), MORB glasses and sulfides. Abyssal peridotites, which are mantle samples re-covered from the ocean ridges, represent the upperm…     

Mantle olivine xenocrysts entrained in Mesozoic basalts from the North China craton：Implication for replacement process of lithospheric mantle

Mesozoic (125 Ma) Fangcheng basalts fromShandong Province contain clearly zoned olivines that arerare in terrestrial samples and provide first evidence for thereplacement of lithospheric mantle from high-Mg peridotitesto Iow-Mg peridotites through peridotite-melt reaction.Zoned olivines have compositions in the core (Mg# = 87.2--90.7) similar to those olivines from the mantle peridotiticxenoliths entrained in Cenozoic basalts from the NorthChina craton and in the rim (Mg# = 76.8--83.9) close to oli-vine phenocrysts of the host basalts (75.7--79.0). Thesecompositional features as well as rounded crystal shapes andsmaller grain sizes (300—800 μm) demonstrate that thesezoned olivines are mantle xenocrysts, i.e. disaggregates ofmantle peridotites. Their core compositions can representthose of olivines of mantle peridotites. The zoned texture ofolivines was formed through rapid reaction between the oli-vine xenocryst and the host basalt. This olivine-basaltic meltreaction could have been ubiquitous in the Mesozoic litho-spheric mantle beneath the North China craton, i.e. an im-portant type of the replacement of lithospheric mantle. Thereaction resulted in the transformation of the Paleozoic re-fractory (high-Mg) peridotites to the late Mesozoic fertile(Iow-Mg) and radiogenic isotope-enriched peridotites, lead-ing to the loss of old lithospheric mantle.     

Noble gas abundances and isotopic compositions in mantle-derived xenoliths, NE China

Following the researches of helium isotopic compositions in mantle-derived xenoliths in eastern China,this study reported noble gas abundances and isotopic compositions of mantle-derived xenoliths from Kuandian of Liaoning Province, Huinan of Jilin Province and Hannuoba of Hebei Province. Compared with the middle ocean ridge basalt (MORB) and other continental areas, mantle-derived xenoliths in NE China are characterized by slightly low noble gas abundances, 3He/4He equivalent to or lower than that of MORB, 40Ar/36Ar lower than that of MORB, 38Ar/36Ar and Ne-Kr-Xe isotopic ratios equivalent to those of atmosphere. These results indicate the heterogeneity of subcontinentai lithospheric mantle beneath northeastern China, that is, a MORB reservoir-like mantle beneath Kuandian and an enriched/metasomatized mantle beneath Huinan. Low 40Ar/36Ar ratios in the three studied areas may imply that a subducted atmospheric component has been preserved in the subcontinental lithospheric mantle.``     

应用锆石研究铀成矿流体的地球化学特征:以粤北棉花坑铀矿床为例

铀矿中锆石富集Li、P、Ti、Nb、Hf、U、Th、Ta、Y、Rare earth elements(REE)等微量元素,Th/U比值较低,在以大陆上地壳为标准化的模式图上呈现明显的重稀土富集、Ce、Y正异常和Eu负异常的特征。根据锆石/热液间微量元素的分配系数估算了成矿流体的微量元素质量分数。铀成矿流体具有富U,低Th/U比值,高稀土元素质量分数,轻、重稀土分异不明显,显著的Ce、Eu负异常和Y正异常,低Ce~(4+)/Ce~(3+)比值等特征。成矿流体主要来源于岩浆期后热液,并得到流体/岩石反应的改造,流体上升减压导致流体沸腾、气体溢出、碱性增高和还原环境,最终导致铀矿物的沉淀和铀矿床的形成。     

Noble gases in corundum megacrysts from the basalts in Changle, Shandong Province, eastern China

This study presents noble gaseous data of the corundum megacrysts from the Cenozoic basalts in Changle, Shandong Province, eastern China. It is known that no noble gaseous data of corundum megacryst have been documented before. The 3He/4He ratios (1.13-7.37 Ra) of the corundums from Changle vary from atmosphere to MORB values; the 20Ne/22Ne (9.67-10.75) and 21Ne/22Ne (0.0280-0.0372) data define two linear trends on Ne three-isotope diagram, respectively, along the MFL and the correlation line between atmosphere and MORB; the 38Ar/36Ar (0.177-0.194) ratios, the 40Ar/36Ar (280.9 -404.2) ratios and the 128-136Xe/132Xe ration with obvious 129Xe excess are generally higher than at-mospheric component, but the 40Ar/36Ar ratios are much closer to atomospheric ratio. The isotopic compositions of noble gases (particularly for He and Ar) of the corundums are similar to those of py-roxene, anorthoclase megacrysts, and mantle-derived xenoliths from this area, and those of man-tle-derived xenoliths from several areas in eastern China. Therefore, the noble gases trapped in the corundums probably are from mantle source, representing a ‘mixed fluid' produced by the interaction between the lithospheric mantle and fluids releasing from the convective plate. Both the noble gas isotopic compositions and the oxygen isotopic compositions of the solid corundums are not the characteristics of crustal source. These suggest that the corundums crystallized from mantle-derived magmas with minimal crustal contamination.     

吉林省沼泽蝗属蝗虫一新种(直翅目:蝗总科)

沼泽蝗属Mecostethus Fieb.是蝗总科、斑翅蝗科中的一个小属，目前全世界已知有9种，主要分布于欧洲、亚洲东北部和非洲北部。栖息的环境多为沼泽地区或湿度大、植被覆盖度较高的地区。我国已知有4种。记述采自吉林省白城市的沼泽蝗属一新种，即白城沼泽蝗Mecostethus baichengensis sp.nov.,并与其近似种做了比较。模式标本保存于东北师范大学生命科学学院动物标本室。     

Glass melt inclusion in clinopyroxene from Linqu Cenozoic basalt, Shandong Province, China

Melt inclusions or glasses usually occur in spinel- facies peridotitic xenoliths entrained in the global ba- salts[1―4], and olivine phenocrysts and/or xenocrysts carried in the intermediate-mafic volcanic rocks (such as basalts, basaltic andesites and h…     

Fe-Ti oxide and Fe-Cu sulfide exsolution in amphibole cumulate xenoliths from granodiorite in Tongling,Anhui Province

Inpastdecades,sulfide(melt)inclusionswithinmineralmegacrystsandmantlerockxenolithsfromCe-nozoicbasaltshavebeenmuchstudied,andtheoriginandevolutionofsulfide(melt)inclusionswerepreliminaryfocused[1—14].Thereportedsulfidephasesareusuallyrichinnickelandtendtooccurwithinolivineandpyroxeneortheirintergranularholes.However,sulfideexsolutionphasesinmegacrysts(especiallyamphibole)andbasicxenolithsoriginatedfromthelowercrustandhostedbyintermediate-acidplutonsarelessreported,exceptforavarietyofexsolvedN…     

U-series dating of Zhangkou Cave in Yiliang,Yunnan Province:Evidence for human activities in China during 40—100 ka

The cultural deposits at pits T1 and T2 in Zhangkou Cave are intercalated with several flowstone layers. U-series dates show that the capping and 2rid flowstone layers are Holocene of age. The 4th and 5th flowstone layers are ca. 55 and 110 ka old respectively. The lithic artifacts bracketed by them provide unequivocal evidence for hominid presence during this time interval. The ““temporal gap““ of hominid fossil, widely quoted as in support of the out-of-Africa hypothesis, is most probably an artifact due to systematic errors of dating techniques. The infillings under 6th flowstone layer date to ＞300 ka, much older than the previous estimate at 15 ka based on classical 14C dating of fossil bones, providing one more example of the limited reliability of this chronometer. With rich relics and favorable conditions for precise dating, this site is promising for further multidisciplinary studies to address issues concerning recent human evolution in China.     

He-Ar isotope geochemistry of the Yaoling-Meiziwo tungsten deposit,North Guangdong Province: Constraints on Yanshanian crust-mantle interaction and metallogenesis in SE China

Isotopic abundances and ratios of He and Ar found in inclusion fluids in pyrites formed in the Yaoling-Meiziwo tungsten miner-alization epoch show that the concentration of 4He varies widely,from 1.54×10-7 cm3 STP/g to 2609×10-7 cm3 STP/g.3He is 0.759×10-12 cm3 STP/g-3.463×10-12 cm3 STP/g.3He/4He is 0.0043-4.362 Ra,varying from crustal to mantle values.The concen-tration of 40Ar ranges from 0.624×10-7 cm3 STP/g to 8.89×10-7 cm3 STP/g.The 40Ar/36Ar varies extensively,from 330 to 2952,between atmospheric and crustal or mantle radiogenic values.Mantle-derived He is present in ore-forming fluids and the calcu-lated average proportion of the mantle He is 22%;the maximum is 67%.Our research results show that mantle-derived fluids play a significant role in tungsten mineralization.The fractionation of He and Ar indicate that there was 4He-enriched air-saturated water(MSAW) in the ore-forming fluid.The ore-forming fluid was a mixture of mantle fluid,crustal magmatic fluid and MSAW.The occurrence of a mantle component in ore-forming fluid indicates the large-scale W and Sn mineralization,including Yaol-ing-Meiziwo,in southeastern China was the result of crust and mantle interaction.The underplating or intrusion of voluminous basaltic magma formed by partial melting of the upper mantle provided the necessary heat to cause partial melting of the crust and the generation of voluminous S-type granitic magmas.Crustal magmatic fluid and mantle fluid with high 3He/4He were released from magma crystallization and fractionation,mixed with the circulating modified air-saturated water,and filled the extensional tectonic fractures,leading to the formation of world-class W and Sn deposits in southeastern China.