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| 1 | Subduction zone geochemistry显示文摘Crustal recycling at convergent plate boundaries is essential to mantle heterogeneity.However,crustal signatures in the mantle source of basaltic rocks above subduction zones were primarily incorporated in the form of liquid rather than solid phases.The physicochemical property of liquid phases is determined by the dehydration behavior of crustal rocks at the slab-mantle interface in subduction channels.Because of the significant fractionation in incompatible trace elements but the full inheritance in radiogenic isotopes relative to their crustal sources,the production of liquid phases is crucial to the geochemical transfer from the subducting crust into the mantle.In this process,the stability of specific minerals in subducting crustal rocks exerts a primary control on the enrichment of given trace elements in the liquid phases.For this reason,geochemically enriched oceanic basalts can be categorized into two types in terms of their trace element distribution patterns in the primitive mantle-normalized diagram.One is island arc basalts(IAB),showing enrichment in LILE,Pb and LREE but depletion in HFSE such as Nb and Ta relative to HREE,The other is ocean island basalts(OIB),exhibiting enrichment in LILE and LREE,enrichment or non-depletion in HFSE but depletion in Pb relative to HREE.In either types,these basalts show the enhanced enrichment of LILE and LREE with increasing their incompatibility relative to normal mid-ocean ridge basalts(MORB).The thermal regime of subduction zones can be categorized into two stages in both time and space,The first stage is characterized by compressional tectonism at low thermal gradients.As a consequence,metamorphic dehydration of the subducting crust prevails at forearc to subarc depths due to the breakdown of hydrous minerals such as mica and amphibole in the stability field of garnet and rutile,resulting in the liberation of aqueous solutions with the trace element composition that is considerably enriched in LILE,Pb and LREE but depleted in HFSE and HREE relative to normal MORB.This provides the crustal signature for the mantle sources of IAB.The second stage is indicated by extensional tectonism at high thermal gradients,leading to the partial melting of metamorphically dehydrated crustal rocks at subarc to postarc depths.This involves not only the breakdown of hydrous minerals such as amphibole,phengite and allanite in the stability field of garnet but also the dissolution of rutile into hydrous melts.As such,the hydrous melts can acquire the trace element composition that is significantly enriched in LILE,HFSE and LREE but depleted in Pb and HREE relative to normal MORB,providing the crustal signature for the mantle sources of OIB.In either case,these liquid phases would metasomatize the overlying mantle wedge peridotite at different depths,generating ultramafic metasomatites such as serpentinized and chloritized peridotites,and olivine-poor pyroxenites and hornblendites.As a consequence,the crustal signatures are transferred by the liquid phases from the subducting slab into the mantle. | Yong-Fei Zheng | 2019 | Geoscience Frontiers2019，10，4： | 47 |
| 2 | Ages and Compositions of the Precambrian High-grade Basement of the Qilian Terrane and Its Adjacent Areas显示文摘Based on geological, chronological, geochemical and Nd isotopicstudies of the high-grade basement of the Qilian terrane, the authors have drawn the following main conclusions: (1) the high-grade basement of the Qilian terrane consists mainly of meta-argillo-arenaceous rocks and granites and its bulk part was formed in the period of 0.8-1.0 Ga (the Jinningian period); (2) most of the meta-argillo-arenaceous rocks and granitic rocks have strong negative Eu and Ba anomalies (Eu/Eu*= 0.47-0.71 and Ba/Ba*= 0.16-0.64), with tDM and εNd (1.0 Ga) ranging from 1.87 to 2.26 Ga and from -8.54 to -4.06 respectively, showing relatively high maturity; and (3) the Jinningian granitic rocks are a typical product of continent-continent collision, being probably related to the formation of the supercontinent Rodinia. These studies, com bined with the study of high-grade basement rocks near the Qilian terrane, suggest that before the Jinningian period, the Qilian-Qaidam northern-margin terrane and Dunhuang-Alxa terrane were separated from each other, belonging to differ ent plate systems of the North China craton and Yangtze platform respectively. The Qilian orogenic belt was the same as or similar to the Qiling orogenic belt in terms of the geological evolution history at least before the Jinningian period. | WAN Yusheng, XU Zhiqin, YANG Jingsui and ZHANG Jianxin Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037 | 2001 | Acta Geologica Sinica(English Edition)2001，75，4： | 40 |
| 3 | Geochemical and Pb-Sr-Nd isotopic compositions of Indosinian granitoids from the Bikou block,northwest of the Yangtze plate:Constraints on petrogenesis,nature of deep crust and geodynamics显示文摘This paper reports geochemical and Pb-Sr-Nd isotopic compositions of the Indosinian Yangba (215 Ma),Nanyili (225 Ma) and Mopi granitoids from the Bikou block of the northwestern margin of the Yangtze plate. These granitoids are enriched in Al (Al2O3:14.56%―16.48%) and Sr (352 μg/g―1047 μg/g),and depleted in Y (<16 μg/g) and HREE (e.g. Yb<1.61 μg/g),resulting in high Sr/Y (36.3―150) and (La/Yb)N (7.8―36.3) ratios and strongly fractionationed REE patterns. The Indosinian granotoids show initial Sr isotopic ratios (ISr) from 0.70419 to 70752,εNd(t) values from-3.1 to -8.5,and initial Pb isotopic ratios 206Pb/204Pb=17.891-18.250,207Pb/204Pb=15.494-15.575,and 208Pb/204Pb=37.788-38.335. Their geochemi-cal signatures indicate that the granitoids are adakitic. However,they are distinct from some adakites,generated by partial melting of subducted oceanic slab and/or underplated basaltic lower crust,be-cause they have high K (K2O: 1.49%―3.84%) and evolved Nd isotopic compositions,with older Nd iso-topic model ages (TDM=1.06―1.83 Ga). Geochemical and Sr-Nd isotopic compositions suggest that the magmas of the Insoninian adakitic rocks in the Bikou block were derived from partial melting of thick-ened basaltic lower crust. Combined with regional analyses,a lithospheric delamination model after collision between the North China and South China plates can account for the Indosinian adakitic magma generation. On the other hand,based on the Pb-Sr-Nd isotopic probing to the magma sources of the adakitic rocks,it is suggested that there is an unexposed continent-type basement under the exposed Bikou Group volcanic rocks. This can constrain on the Bikou Group volcanic rocks not to be MORB-or OIB-type. | ZHANG HongFei XIAO Long ZHANG Li YUAN HongLin JIN LanLan | 2007 | Science China Earth Sciences2007，50，7： | 38 |
| 4 | Geochemical and Pb-Sr-Nd isotopic compositions of granitoids from western Qinling belt: Constraints on basement nature and tectonic affinity显示文摘Geochemical and Pb-Sr-Nd isotopic compositions of five Indosinian granitoid intrusions from the western Qinling belt provide insights into basement nature and tectonic affinity. The results show that the western Qinling granitoids incline towards basic in their bulk chemical composition. The granitoids belong to high-K to shoshonitic series with K2O/Na2O=1.04-1.86 and are dominantly metaluminous with A/CNK=0.90-1.05 (most samples have A/CNK of <1.0). They have similar trace elemental compo- sitional patterns. In Sr-Nd isotopic compositions, they display some extent heterogeneity with Isr=0.70682-0.70845, εNd(t)=?4.85 to ?9.17 and TDM=1.26-1.66 Ga. They are characterized by high ra- diogenic Pb isotopic compositions. Their initial Pb isotopic ratios are 206Pb/204Pb=17.996-18.468, 207Pb/204Pb=15.565-15.677 and 208Pb/204Pb=38.082-38.587. Geochemical and Sr-Nd isotopic composi- tions reveal that magma for the granitoids was derived from partial melting of high-K (Rb) basaltic rocks, which might be formed in 900-1400 Ma. It is suggested that a large amount of the Proterozoic high-K (Rb) basaltic rocks, which underlie the Phanerozoic sedimentary cover, constitute the crustal basement of the western Qinling belt. Pb-Sr-Nd isotopic compositional comparison between the east- ern Qinling and the western Qinling Indosinian granitoids indicates that the crustal basement of the western Qinling is distinct from that of the eastern Qinling. The Baoji-Chengdu railway close to south-north orientation can be taken as an approximate boundary between both basements. The Pb-Nd isotopic compositional characteristics of the western Qinling granitoids suggest that the basement of the western Qinling belt has an affinity with the Yangtze block. | Nigel HARRIS | 2007 | Science China Earth Sciences2007，50，2： | 33 |
| 5 | Shoshonitic intrusive suite in SE Guangxi: Petrology and geochemistry显示文摘A NE-direction Mesozoic shoshonitic intrusive s黫te in SE Guangxi has been identified in terms of geological, petrological and geochemical investigations. The shoshonitic intrusives are characterized by enrichment of LILE, HFSE and LREE and no obvious Nb-Ta depletion, similar to those potassic rocks formed in within-plate and rifting environments. Unlike most shoshonitic rocks forming in arc settings, the SE Guangxi shoshonitic intrusives were likely generated during regional lithosphere extension induced by upwelling of asthenosphere mantle. | LI Xianhua ZHOU Hanwen LIU Ying LEE Chi-yu SUN Min CHEN Chenhong | 2000 | Chinese Science Bulletin2000，45，7： | 32 |
| 6 | Possible early Neoproterozoic magmatism associated with slab window in the Pingshui segment of the Jiangshan-Shaoxing suture zone: Evidence from zircon LA-ICP-MS U-Pb geochronology and geochemistry显示文摘We report here geochemical data, U-Pb zircon ages, and Hf isotopes for the high-Mg diorites (HMDs), Nb-enriched basaltic porphyrys (NEBPs) and plagiogranites (PLAGs) in the Pingshui segment of the Jiangshan-Shaoxing suture zone. The HMDs are characterized by high Mg# (>60), high Na and LREE contents, depletion of HREE and HFSE, and pronounced positive εNd(t) values of 7.0 to 7.7, similar to some adakitic high-Mg andesites. The NEBPs are relatively Na-rich (Na2O/K2O>6) and display high abundances of P2O5 (~1.00%), TiO2 (~3.08%) and HFSE (e.g., Nb=9.53-10.27 ppm). Their Nd isotopic compositions (εNd(t)=6.8-8.0) are comparable to those of the HMDs. The PLAGs are metaluminous (A/CNK=0.84-0.89) and sodic (Na2O/K2O>10). Their depletion in HFSE (e.g., Nb, Ta) is consistent with 'SSZ-type' plagiogranite. Zircon LA-ICP-MS U-Pb dating yields an age of 932±7 Ma for the HMD, 916±6 Ma for the NEBP, and 902±5 Ma for the PLAG, respectively, indicating that they were products of early Neoproterozoic magmatism. The PLAGs exhibit relatively high zircon Hf isotopes and positive εHf(t) values of 11.0 to 16.2, consistent with their Nd isotopic data (εNd(t)=7.5-8.4). Such features are similar to those of oceanic plagiogranites in ophiolites and distinct from those of crust-derived granites. The PLAGs were most likely derived from partial melting of subducted oceanic crust in an active continental margin. Considering these results in the context of the regional geology, we suggest that a slab window in the subducting oceanic crust between the Yangtze Block and Cathaysia Block was possibly the principal cause for the unique arc magmatism in the area. The upwelling asthenosphere below the slab window may have provided significant thermodynamic conditions. | CHEN ZhiHong GUO KunYi DONG YongGuan CHEN Rong LI LongMing LIANG YiHong LI ChunHai YU XiMing ZHAO Ling XING GuangFu | 2009 | Science China Earth Sciences2009，52，7： | 26 |
| 7 | Petrogenesis of Shangyu gabbro-diorites in western Shandong:Geochronological and geochemical evidence显示文摘Chronology and geochemistry of the Shangyu gabbro-diorite in western Shandong were studied to understand their petrogenesis and the nature of the Mesozoic lithospheric mantle. The Shangyu intru-sion is mainly composed of a suite of gabbro-diorite. Zircons from the intrusion display eu-hedral-subhedral in shape and have high Th/U ratios (1.23―2.87), implying their magmatic origin. LA-ICP-MS zircon U-Pb dating results for two samples indicate that they were formed in the Early Cre-taceous, yielding weighted mean 206Pb/238U ages of 129±1Ma and 134±2Ma, respectively. Except for early cumulate such as sample QT-19, their SiO2 and MgO contents range from 50.12% to 56.37% and from 3.52% to 6.37%, respectively. Moreover, the gabbro-diorites are characterized by high Mg# (0.54―0.63), enrichment in Na (Na2O/K2O ratios more than 1), Cr (73×10-6―217×10-6) and Ni (34×10-6―241×10-6), and intensive enrichments in light rare earth elements (LREEs) and large ion lithophile elements (LILEs) and depletion in high field strength elements (HFSEs). Their initial 87Sr/86Sr ratios and ε Nd(t) values range from 0.70962 to 0.71081 and from-16.60 to-13.04, respectively. Taken together with the Early Creta-ceous high-Mg diorites and the mantle xenoliths from the Tietonggou and Jinling as well as basalts from the Fangcheng and Feixian, it is suggested that the primary magma for the Shangyu gab-bro-diorites should be derived from the enriched lithospheric mantle intensively modified by conti-nental crust. The Sr-Nd-Pb isotopic compositions for the Early Cretaceous high-Mg diorites in western Shandong display a trend of spatial variations, i.e., initial 87Sr/86Sr, 207Pb/204Pb and 208Pb/204Pb ratios de-creasing and ε Nd(t) values increasing from southeast to northwest in western Shandong, which is con-sistent with the tectonic model that the Yangtze Craton subducted beneath the North China Craton oriented in north-west direction in the Early Mesozoic. | YANG ChengHai XU WenLiang YANG DeBin WANG Wei WANG WeiDe LIU JinMin | 2008 | Science China Earth Sciences2008，51，4： | 24 |
| 8 | Geochemical studies on the intensity of chemical weathering in Luochuan loess-paleosol sequence, China显示文摘Major and trace element analyses of the Luochuan loess paleosol sequence in China were performed in order to understand the chemical weathering processes occurring on the Loess Plateau during the last 600 ka. Results reveal that most elements in the loess remain immobile during chemical weathering. The typical stable elements are Al, K, Ti, Rb and REE, while the main mobile elements are Ca, Sr, P, Mg and Na. Loess and paleosol experience the incipient stage of chemical weathering characterized by acid leaching and carbonate dissolution. Alteration of silicates in the sequence seems to be limited. Features of less chemical weathering of the loess and paleosol could be indicators for the dry cold climate dominated on the Loess Plateau during the Quaternary. | 陈骏 季峻峰 仇纲 鹿化煜 | 1998 | Science China Earth Sciences1998，41，3： | 22 |
| 9 | Geochemical Features of Ophiolite in Mianxian Lueyang Suture Zone,Qinling Orogenic Belt显示文摘GeochemicalFeaturesofOphioliteinMianxianLueyangSutureZone,QinlingOrogenicBeltLaiShaocong;ZhangGuowei(DepartmentofGeology,Nort... | Lai Shaocong Zhang Guowei(Department of Geology, Northwest University, Xi’an 710069) | 1996 | Journal of Earth Science1996，15，2： | 22 |
| 10 | Chronology and geochemistry of the volcanic rocks in Woruo Mountain region,Northern Qiangtang depression:Implications to the Late Triassic volcanic-sedimentary events显示文摘A suite of sedimentary-volcaniclastic rocks intercalated with the volcanic rocks unconformably overlies the Triassic Xiaochaka Formation in the Woruo Mountain region, Qiangtang Basin, northern Tibet. The vitric tuff from the base of these strata gives a SHRIMP zircon U-Pb age of 216 ± 4.5 Ma, which represents the age of the Late Triassic volcanic-sedimentary events in the Woruo Mountain region, and is consistent with that of the formation of the volcanic rocks from the Nadi Kangri Formation in the Nadigangri-Shishui River zone. There is a striking similarity in geochemical signatures of the volcanic rocks from the Woruo Mountain region and its adjacent Nadigangri-Shishui River zone, indicating that all the volcanic rocks from the Qiangtang region might have the same magmatic source and similar tectonic setting during the Late Triassic. The proper recognition of the Late Triassic large-scale volcanic eruption and volcanic-sedimentary events has important implications for the interpretation of the Late Triassic biotic extinction, climatic changes and regressive events in the eastern Tethyan domain, as well as the understanding of the initiation and nature, and sedimentary features of the Qiangtang Basin during the Late Triassic-Jurassic. | WANG Jian FU XiuGen CHEN WenXi WANG ZhengJiang TAN FuWen CHEN Ming ZHUO JieWen | 2008 | Science China Earth Sciences2008，51，2： | 21 |
| 11 | Geochemical characteristics and formation process of natural gas in Kela 2 gas field显示文摘On the basis of a large amount of natural gascomponents and the carbon isotope as well as some otheranalysis data in Kela 2 gas field, the geochemical character-istics, source, origin, and formation process of natural gashave been discussed. The components of gas in the field tendto be 'dry', and the drying coefficient is close to 1.0. Thecarbon isotope tends to be heavier, for instance, the averageof δ13C1 is -27.36‰ and that ofδ13C2 is -18.5‰. Compre-hensive analysis shows that humic natural gas in the Kuqapetroleum system comes mainly from Triassic and Jurassicsource rocks, and the contribution of Jurassic source rocks tothe pool maybe is more than that of Triassic rocks. The maincause that the gas tends to be dry and bears heavier isotopecomposition lies in the fact that Kela 2 natural gas is the ac-cumulation of late production of humic source rocks, and itis affected by the abnormal high pressure as well. Consider-ing the hydrocarbon generating and structural history, wecan regard the gas pool formation processes as twice fillingand twice adjusting (destroying), that is, the filling anddestroying process in the early Himalayan movement and thefilling and adjusting in the late Himalayan movement. | ZHAO Mengjun LU Shuangfang WANG Tingdong LI Jian | 2002 | Chinese Science Bulletin2002，47，S1： | 20 |
| 12 | High-resolution geochemistry records of climate changes since late-glacial from Dajiuhu peat in Shennongjia Mountains,Central China显示文摘A peat core with depths of 297 cm was obtained from the Dajiuhu Basin(31°29′27″N,109°59′45″E,1760 m)in Hubei Province,Central China.10 AMS ages provide a time control and reveal that this core spans the past about 16.0 kaBP(calibrated age)(1 4C age:13.3 kaBP).Multi-proxy indexes analysis of geochemistry shows the following character of climate and environmental changes since about 16 kaBP:(1) The climate during the late-glacial period was cold and wet as a whole,but fluctuated continually.11.4- 12.6 cal.kaBP,12.6-15.2 cal.kaBP and 15.2-16 kaBP were corresponding respectively to the Younger Drays,Bφlling-Allerφd Warm Period and the Oldest Drays.(2)Inheriting the some climate characteristics of the late-glacial,the climate during the early-Holocene was wet and temperature increased gradually,during which an obvious dry event around 10.6 cal.kaB appeared.(3)The climate during the mid-Holocene was genarally warm and wet.During 9.2-7.5 kaBP,temperature increased gradually, precipitation was less comparatively and the 8.2 kaBP cold event which might be representative in the globe was reflected markedly.Then,multi-proxy records were relatively stable during 6.7-4.2 kaBP, which shows the best water and thermal condition in the Holocene Optimum.(4)Around 4.2 kaBP,the climate and environment transform from warm and wet to cool and dry,which may result in the collapse of the Neolithic Culture and midwifery the civilization of Xia Dynasty in this region.After 0.9 kaBP,the climate turned cool and wet.Climate and environmental changes archived in Dajiuhu peat respond to the global changes since the late-glacial period and can be contrasted to the changes recorded in other high-resolution archives from the East Asia Monsoon region,which take on the variety model that the monsoon strengthened abruptly after the late-glacial,was strong during the early Holocene,subse- quently declined and became weak after the middle Holocene with dry climate.According to our analysis,the driving mechanism should be the response of solar radiation changes in the East Asia Monsoon region at middle latitudes. | MA ChunMei ZHU Cheng ZHENG ChaoGui WU ChunLin GUAN Yong ZHAO ZhiPing HUANG LinYan HUANG Run | 2008 | Chinese Science Bulletin2008，53，S1： | 19 |
| 13 | Petrogenesis and its significance to continental dynamics of the Neogene high-potassium calc-alkaline volcanic rock association from north Qiangtang,Tibetan Plateau显示文摘Detailed studies indicate that the main rock type of the Neogene high-potassium calc-alkaline volcanic rock association from north Qiangtang is andesite, dacite and rhyolite. They belong to typical crust-generation magmatic system and originate from the special thickened crust of the Tibetan Plateau by dehydration melting. This group of rocks exhibits LREE enrichment but no remarkable Eu anomaly that shows their source region should be a thickened deep crust consisting of eclogitic mass group, implying that the crust had been thickened and an eclogitic deep crust had been formed during the Neogene period in Qiangtang area. This understanding is important and significant to making further discussion on the uplift mechanism and continental dynamics of the Tibetan Plateau. | 赖绍聪 刘池阳 S.Y.O’Reilly | 2001 | Science China Earth Sciences2001，44，S1： | 18 |
| 14 | Characteristics of paleoflood deposits archived in unit T0403 of Yuxi Site in the Three Gorges reservoir areas,China显示文摘Based on the detailed analyses,multi-proxies such as AMS 14 C dating,grain size,component and morphology of heavy minerals,micromorphology of zircon,magnetic susceptibility,Rb/Sr and Hg content are used to research the paleoflood sediments archived in the Yuxi Site.The research indicates that, since 7.6 kaBP,at least 16 times of paleoflood with water level above Wusong Elevation 147.024 m(a.s.l.) left deposits in the Neolithic layers of unit T0403 from the Yuxi Site.The results are induced from the following aspects:(1)The plaeoflood sediments take on great similarities with modern flood sediments in the Yuxi Site and Zhongba Site in probability cumulative curves which mainly show a pattern of 3 segments in fluvial pattern.(2)There is some resemblance between the heavy mineral components and the zircon shape characteristics of paleoflood deposits and those of modern flood deposits.(3) Magnetic susceptibility values(40.44―70.10SI)are lower than those of sediments from cultural layers (59.59―188.68SI).(4)Hg values(290.71―742.51 ng/g)are lower than those of sediments from cultural layers(344.16―10518.17 ng/g).(5)Rb/Sr values are higher than those of sediments from cultural layers, while those of the 4th,5th,6th,7th,8th cultural layers are high,which shows that they are inundated by paleoflood.The reason for many flood deposits existing is related to the site situated on the first terrace where the Yuxi River joins with the Yangtze River.As there are some similarities between the plaeoflood sediments and those of the Zhongba Site,it is feasible to confirm the existence of paleoflood sediments based on the above points. | ZHU Cheng MA ChunMei XU WeiFeng BAI JiuJiang ZHENG ChaoGui ZHU GuangYao WANG HuiLin CHEN Ye LU XueFeng | 2008 | Chinese Science Bulletin2008，53，S1： | 16 |
| 15 | LITHOSPHERE-ASTHENOSPHERE INTERACTION: A COMPARATIVE STUDY ON CENOZOIC AND MESOZOIC BASALTS AROUND BOHAI AREA | Yigang Xu Weiming Fan and Ge Lin( Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou , P. R, China)(Department of Gedegy, Royal Holoway Univoersity of London, Egham, Surrey, TW20OEX , UK)(Changsha Institute of Geotectonics,Chin | 1995 | Geotectonica et Metallogenia1995，19，4： | 16 |
| 16 | Sedimentary Characteristics and Paleoenvironment of Shale in the Wufeng-Longmaxi Formation, North Guizhou Province, and Its Shale Gas Potential显示文摘The Paleozoic Wufeng-Longmaxi shale is one of the main horizons for shale gas exploration in Sichuan Basin. Outcrop, core and thin section observations, X-ray diffraction analysis, trace element geochemistry and other methods have been used to understand the sedimentary characteristics and identify hydrocarbon source rocks in suitable sedimentary paleoenvironments in the Wufeng-Longmaxi shale in northern Guizhou Province. The thickness of the Wufeng-Longmaxi Formation ranges from 20 to 200 m and it was mainly deposited on a deep-water shelf. The TOC content is high, up to 5.75%. The main non-organic minerals are detrital quartz and clay minerals, with a little plagioclase feldspar, potassium feldspar, calcite, dolomite and pyrite. There is also biogenic microcrystalline quartz. Six lithofacies have been identified: siliceous shale, clay shale, calcareous shale, silty shale, carbonaceous shale, and muddy siltstone. Using biological Ba, V/(V+Ni), TOC, V/Cr, B, Sr/Ba and other indicators, we estimate primary productivity, redox conditions and paleosalinity and show that the early stage of Wufeng-Longmaxi deposition occurred under strong anoxic conditions, high paleosalinity and yielded a high TOC content and an excellent potential shale gas source. The anoxic environment was destroyed at the late stages of Wufeng-Longmaxi deposition, the TOC content decreased, so that it is likely to be a high quality source rock. Organic pores acted as the key reservoir space in the shales, and the pores are mainly mesopose, with most pore diameters less than 20 nm. The siliceous shale has high TOC content and brittle mineral(quartz) content making it an important exploration target for shale oil and gas exploration. | Chao Liang Zaixing Jiang Yingchang Cao Jinchuan Zhang Ling Guo | 2017 | Journal of Earth Science2017，28，6： | 16 |
| 17 | Geochemistry of Alkali-rich Igneous Rocks of Northern Xinjiang and Its Implications for Geodynamics显示文摘Five nearly E-W-trending alkali-rich igneous rock belts are distributed from north to south in northern Xinjiang, and they are composed mainly of riebeckite, K-feldspar granite and high-K and medium-K calc-alkaline volcanic rocks and shoshonite. They were mainly emplaced or erupted between the Carboniferous and Permian. The compositions of Sr, Nd, Pb, and O isotopes imply that their principal resource materials are derived from the upper mantle or juvenile crust, indicating obvious continental growth in the Phanerozoic. The trace element association implies that their tectonic settings are within plate and volcanic arc for alkali-rich granites, and post-collisional arc, late oceanic arc and continental arc for alkali-rich volcanic rocks. An archipelago model was suggested for the tectonic evolution in northern Xinjiang. It can be named the central-Asia-type orogeny, which is different from the so called circum-Pacific ocean-continent-type tectonics or the Alpine-Himalayan | ZHAO Zhenhua BAI Zhenghua XIONG Xiaolin MEI Houjun WANG Yixian | 2000 | Acta Geologica Sinica(English Edition)2000，74，2： | 16 |
| 18 | Petrological, geochemical and chronological constraints for the tectonic setting of the Dongco ophiolite in Tibet显示文摘The Dongco ophiolite occurred in the middle-western segment of the Bangong-Nujiang suture zone. The thickness of the ophiolite suite is more than 5 km, which is composed, from bottom to top, of the mantle peridotite, mafic-ultramafic cumulates, basic sills (dykes) and basic lava and tectoni- cally emplaced in Jurassic strata (Mugagongru Group). The Dongco cumulates consist of dunite- troctolite-olivine-gabbro, being a part of DTG series of mafic-ultramafic cumulates. The basic lavas are characterized by being rich in alkali (Na2O+ K2O), TiO2, P2O5 and a LREE-rich type pattern dip- ping right with [La/Yb]=6.94―16.6 as well as a trace elements spider-diagram with normal anomaly of Th, Nb, Ta, Hf. Therefore, the Dongco basic lavas belong to ocean-island basalt (OIB) and dis- tinctly differ from mid-ocean ridge basalt (MORB) and island-arc basalt (IAB) formed in the plate convergence margin. The basic lavas have higher 87Sr/86Sr (0.704363―0.705007), lower 143Nd/144Nd (0.512708―0.512887) and εNd(t ) from +2.7―+5.8, indicating that they derive from a two-components mixing mantle source of depleted mantle (DM) and enriched mantle (EMI). From above it is ready to see that the Dongco ophiolite forms in oceanic island (OIB) where the mantle source is replaced by a large amount of enriched material, therefore it distinctly differs from these ophiolites formed in island-arc and mid-oecan ridge. Newly obtained SHRIMP U-Pb dating for zircon of the cumulate troctolite is 132 ± 3 Ma and whole-rock dating of ^(39)Ar/^(40)Ar for the basalt is 173.4 ± 2.7 Ma and 140.9 ± 2.8 Ma, indicating that the Dongco ophiolite formed at Early Cretaceous and the middle-western segment of the Bangong-Nujiang oceanic basin was still in the developing and evolving period at Early Cretaceous. | BAO PeiSheng XIAO XuChang SU Li WANG Jun | 2007 | Science China Earth Sciences2007，50，5： | 16 |
| 19 | Identification of the island-arc magmatic zone in the Lianghe-Raofeng-Wuliba area, south Qinling and its tectonic significance显示文摘Detailed studies indicate that a typical island-arc magmatic zone exists in the Lianghe-Raofeng-Wuliba area of south Qinling. This is characterized by continental marginal andesite and bimodal volcanic rock association which was formed in a rift environment within an oceanic island-arc. The island-arc magmatic zone is the product of Devonian-Carboniferous oceanic crust sub-duction and rifting of Mianlue ancient oceanic basin. The presence of the island-arc magmatic zone suggests that the Mianxian-Lueyang suture zone had extended to the Bashan arcuate area. The Sunjiahe volcanic rock association of the Xixiang Group formed in a volcanic-arc setting which should have a close relationship with Mianlue suture zone. | 赖绍聪 张国伟 杨瑞瑛 | 2000 | Science China Earth Sciences2000，43，S1： | 15 |
| 20 | 湖南芙蓉锡多金属矿床成矿流体地球化学显示文摘湖南芙蓉锡多金属矿床是我国最近发现的与A型花岗岩具有成因联系的超大型锡多金属矿床。本文对该矿床主要的四种矿化类型(矽卡岩型、云英岩型、蚀变花岗岩型、锡石硫化物型)进行了系统的流体包裹体地球化学和稳定同位素地球化学研究。研究结果表明:该矿床中流体包裹体类型复杂,包括富含CO_2包裹体、气液包裹体、含子晶包裹体和气相包裹体。矽卡岩型矿石中流体包裹体均一温度主要集中在400~450℃,云英岩和蚀变花岗岩型矿石的均一温度相对下降,主要分布于250~350℃之间,锡石硫化物型矿石中包裹体温度进一步下降。成矿流体主要由高盐度CaCl_2-NaCl-KCI-HO_O流体(盐度多集中在32.2 wt%~50.6 wt%NaCl.eqv)和富含CO_2的CO_2-CH_4-NaCl-H_2O低盐度流体(盐度多集中在32.2 wt%~50.6wt%NaCl.eqv)组成。芙蓉锡矿云英岩型矿石成矿流体中的水主要以岩浆水为主,锡石硫化物型矿石成矿流体中的水具有岩浆水和大气降水混合的特征,成矿流体中的碳为岩浆碳与沉积碳酸盐不同比例混合的结果。芙蓉锡多金属矿床的成矿流体应主要来源于骑田岭黑云母二长花岗岩岩浆结晶期后分异出的岩浆热流体。岩浆热流体沿岩体周围裂隙对围岩和原生矽卡岩进行热液交代,在造成绢云母化、白云母化、绿泥石化等热液蚀变现象的同时,导致了大规模的锡矿化。减压沸腾和低温流体与高温流体混合造成的沸腾作用是导致芙蓉锡矿锡沉淀的主要机制。 | 双燕 毕献武 胡瑞忠 彭建堂 苏文超 朱长生 | 2009 | 岩石学报2009，25，10： | 15 |
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