bluuebunny/crossref_metadata_2025 huggingface dataset:
New Material of Pterosaur Sinopterus (Reptilia: Pterosauria) from the Early Cretaceous Jiufotang Formation, Western Liaoning, China
Authors: Junchang LÜ , Jinyuan LIU , Xuri WANG , Chunling GAO , Qingjin MENG , Qiang JI
Published: September 2010

Abstract: Based on a new nearly complete postcranial skeleton of an adult specimen of Sinopterus from the Early Cretaceous Jiufotang Formation of western Liaoning, China, the diagnosis of Sinopterus is amended. The revised diagnosis of Sinopterus includes skull relatively elongate with weakly developed cranial crest; ratio of the length of Ph2d4 to that of Ph1d4 is approximately 0.73; ratio of the length of wing metacarpal to that of metatarsal 3 is 4.5; ratio of the length of mt3 to that of tibia is approximately 0.21, and wing phalanges 1 and 2 are straight. Comparison between the ratios of the limb bones between non‐adult and adult individuals of Sinopterus indicates that during the ontogenetic process, some ratios between bones are constant, such as the first wing phalanx to the second wing phalanx, the wing metacarpal to the metatarsal 3, metatarsal 3 to the tibia, but others are not, such as humerus to wing metacarpal and femur to tibia, in which the former grows faster than the latter.
Geochemistry and Petrogenesis of Neoarchean Metamorphic Mafic Rocks in the Wutai Complex
Authors: Yongjun LÜ , Shuwen LIU , ZHAO Guochun , Qiugen LI , ZHANG Jian , Chaohui LIU , PARK K. H. , SONG Y. S.
Published: September 2010

Abstract: Neoarchean metamorphic mafic rocks in the lower and the middle Wutai Complex mainly comprise metamorphic gabbros, amphibolites and chlorite schists. They can be subdivided into three groups according to chondrite normalized REE patterns. Rocks in Group #1 are characterized by nearly flat REE patterns (Lan/Ybn=0.86‐1.3), the lowest total REEs (29–52 ppm), and weak negative to positive Eu anomalies (Eun/Eun*=0.84‐1.02), nearly flat primitive mantle normalized patterns and strong negative Zr(Hf) anomalies. Their geochemical characteristics in REEs and trace elements are similar to those of ocean plateau tholeiite, which imply that this group of rocks can represent remnants of Archean oceanic crust derived from a mantle plume. Rocks in Group #2 are characterized by moderate total REEs (34–116 ppm), LREE‐enriched (Lan/Ybn=1.76‐4.34) chondrite normalized REE patterns with weak Eu anomalies (Eun/Eun*=0.76‐1.16), and negative Nb, Ta, Zr(Hf), Ti anomalies in the primitive mantle normalized spider diagram. The REE and trace element characteristics indicate that they represent arc magmas originating from a sub‐arc mantle wedge metasomatized by slab‐derived fluids. Rocks in Group #3 are characterized by the highest total REEs (61–192 ppm), the strongest LREEs enrichment (Lan/Ybn=7.12–16) with slightly negative Eu anomalies (Eun/Eun*=0.81‐0.95) in the chondrite normalized diagram. In the primitive mantle normalized diagram, these rocks are characterized by large negative anomalies in Nb, Ta, Ti, negative to no Zr anomalies. They represent arc magmas originating from a sub‐arc mantle wedge enriched in slab‐derived melts. The three groups of rocks imply that the formation of the Neoarchean Wutai Complex is related to mantle plumes and island‐arc interaction.
Petrogenesis of the Paleoproterozoic Guandishan Granitoids in Shanxi Province: Constraints from Geochemistry and Nd Isotopes
Authors: Chaohui LIU , Shuwen LIU , Qiugen LI , Yongjun LÜ , PARK K. H. , SONG Y. S.
Published: September 2010

Abstract: The Guandishan granitoids consist mainly of various granitoid intrusions with different scales, including the Huijiazhuang intrusion, Shizhuang intrusion and Hengjian intrusion, which were formed between 1906 Ma and 1848 Ma. On the basis of geological and petrological characteristics, these granitoids can be classified into two groups: the earlier gneissic granodiorites and monzogranites, and the later massive leuco‐monzogranites. Their geochemical and Nd isotopic features indicate that they could be derived from complicated partial melting of supracrustal rocks with an affinity of continental arc materials, such as sandy shale and pelite, and with garnet, pyroxene, hornblende and plagioclase as residual phases. Biotite, feldspar and other minerals were most likely fractionated during the magma evolution. Their source may have an affinity with continental arcs, and the granitoids could be derived from the main syn‐collisional to late‐orogenic tectonic environment, which may be related to the final amalgamation between the Eastern and Western continental blocks in the North China Craton.
Detrital Zircon of 4100 Ma in Quartzite in Burang, Tibet
Authors: Ji DUO , Chunqi WEN , Xiaoping FAN , Jianci GUO , Zhiyao NI , Xiaowen LI , Yuruo SHI , Quan WEN
Published: September 2010

Abstract: A detrital zircon aged 4.1 Ga is discovered by the SHRIMP U‐Pb method in a quartzite in Burang County, western Tibet. This is presently the oldest single‐grain detrital zircon in China. The Th‐U ratios of the two testing points of the >4.0 Ga zircon are between 0.76 and 0.86, indicating their magmatic origin. This discovery has offered an important age for investigating the geological evolution of the Qinghai‐Tibet Plateau.
Dynamics Analysis of the Baiyun Sag in the Pearl River Mouth Basin, North of the South China Sea
Authors: Zhen SUN , Zhihong ZHONG , Di ZHOU , Xiong PANG , Chunju HUANG , Changmin CHEN , Min HE , Hehua XU
Published: September 2010

Abstract: The Baiyun sag is a deep one developing on the slope of the Pearl River Mouth Basin. It occurs as a composite graben horizontally, and is composed of two sub‐sags versus one low uplift. Vertically, the sedimentary architecture could be divided into three layers, i.e. the faulted layer on the bottom, the faulted‐ductile stretching layer in the middle and the draping layer on the top. The main rifting stage of the sag is supposed to be characterized by ductile extension and thinning of the crust. The special deformation pattern is probably attributed to the fact that the Baiyun sag is located in the transfer zone of the pre‐existing weak zone, which made the sag a strongly deformed area, characterized by the greatly thinned lithosphere and active magmatism. The highly rising mantle under the Baiyun sag should be an important mechanism responsible for the ductile deformation, which caused partial melting of the upper mantle. Upwelling to the upper crust and the sedimentary layers, the partial melting materials accommodated extensional strain and caused non‐faulted vertical subsidence. Magma was collected under the transfer zone after the first stage of rifting, and transferred laterally in a direction perpendicular to the extension to the ENE and WSW parts of the sag and upwelled along the NW‐trending basal faults, where WNW‐trending shear faults developed in swarms. The faulting activity and sedimentation history of the Baiyun sag may have been affected by the ocean ridge jump around 24 Ma and the cessation of sea floor spreading around 16 Ma.
Excess and Radiogenic Argon in High‐Pressure Mylonites of the Tan‐Lu Fault Zone, Eastern China
Authors: Chenglong XIE , Guang ZHU , Yongsheng WANG , Zhaoqi HU
Published: September 2010

Abstract: Bulk separates of porphyroclastic phengite, neoformed phengite and their mixtures from the Tan‐Lu HP mylonites overprinted on the Sulu UHP rocks were analyzed with the 40Ar/39Ar step heating method. Two samples of the neoformed phengite from ultramylonite give 40Ar/39Ar plateau ages of 209.9±1.8 Ma and 214.3±1.8 Ma, which are interpreted as representing cooling times of the Tan‐Lu sinistral faulting, and provide geochronological evidence for the syn‐orogenic faulting of the Tan‐Lu fault zone. The results show that the phengite formed during the retrograde eclogite‐facies mylonitization was not contaminated with excess argon and can be used for dating the deformation. Argon closure in previous K‐bearing minerals with excess argon under a retrograde HP dry condition is considered to be the reason for lack of excess argon incorporation in the neoformed phengite. Five porphyroclastic phengite samples yield 40Ar/39Ar plateau ages ranging from 666±12 Ma to 307.1±3.3 Ma, which are interpreted as being contaminated with excess argon. Two mixture samples with plateau ages of 239.4±2.1 Ma and 239.3±2.0 Ma show upward‐convex age spectra caused by the mixture of older porphyroclastic phengite with excess argon incorporation and younger neoformed phengite without excess argon incorporation. It is demonstrated that excess argon introduced from the previous UHP metamorphism is still preserved in the pre‐existing phengite after the Tan‐Lu eclogite‐facies mylonitization. The intense deformation under HT and HP conditions cannot erase excess argon in the previous phengite totally due to restricted fluid activities. These porphyroclastic phengite previously contaminated with excess argon cannot be used for dating the later HP deformation. This indicates that deformation under a HP dry condition does not play an important role in removing previous 40Are in phengite.
Pb Isotope Mapping in the Tongbai‐Dabie Orogenic Belt, Central China
Authors: Li ZHANG , Zengqiu ZHONG , Linsen WANG , Benren Zhang
Published: September 2010

Abstract: Tongbai‐Dabie orogenic belt in Central China is a part of the collisional belt between the Yangtze and North China cratons. It represents one of the most extensive ultrahigh‐pressure (UHP) and high‐pressure (HP) metamorphic rocks in the world. The Pb isotope mapping in this area is a significant method to constrain the crustal structure and tectonic evolution and to identify the tectonic boundaries within the vertical tectonic stack. Based on the Pb isotope compositions of the Dabie complex (DBC), the Tongbai complex (TBC), UHP and HP metamorphic rocks and associated foliated granites, the lower metamorphosed rocks from North Huaiyang (NHY) tectonic belt, and Cretaceous granites in the Tongbai‐Dabie orogenic belt, we determined the Pb isotope geochemical map of the Tongbai‐Dabie orogenic belt. The Pb isotope map shows that the Pb isotope compositions are similar within each geological body or lithotectonic unit, but the Pb isotope compositions of different lithotectonic units show systematic variations in the Tongbai‐Dabie orogenic belt. The NHY tectonic belt contrasts strongly with the Tongbai‐Dabie UHP‐HP metamorphic belt in Pb isotope compositions. It is suggested that the line along the Xiaotian‐Mozitan fault, the north limit of the Tongbai‐Dabie UHP and HP metamorphic rocks, represents an important tectonic boundary. Within the Tongbai‐Dabie HP‐UHP metamorphic belt, to the south of Xiaotian‐Mozitan fault, the vertical variations of Pb isotope compositions in different lithotectonic units and the spatial relationship among different major lithotectonic units have been constrained.
Kinetic Parameters of Methane Generated from Source Rocks in the Kuqa Depression of Tarim Basin and Their Application
Authors: Xianqing LI , Xianming XIAO , Jingkui MI , Yongchun TANG , Zhongyao XIAO , Dehan LIU , Jiagui SHEN , Yunfeng YANG , Yan WANG , Peng DONG
Published: September 2010

Abstract: In a thermal simulation experiment of gold tubes of closed‐system, calculating with the KINETICS and GOR‐ISOTOPE KINETICS software, kinetic parameters of gas generation and methane carbon isotopic fractionation from Triassic—Jurassic hydrocarbon source rocks in the Kuqa depression of Tarim Basin are obtained. The activation energies of methane generated from Jurassic coal, Jurassic mudstone and Triassic mudstone in the Kuqa Depression are 197–268 kJ/mol, 180–260 kJ/mol and 214–289 kJ/mol, respectively, and their frequency factors are 5.265times1013s−1, 9.761times1011s−1 and 2.270times1014s−1. This reflects their differences of hydrocarbon generation behaviors. The kinetic parameters of methane carbon isotopic fractionation are also different in Jurassic coal, Jurassic mudstone and Triassic mudstone, whose average activation energies are 228 kJ/mol, 205 kJ/mol and 231 kJ/mol, respectively. Combined with the geological background, the origin of natural gas in the Yinan‐2 gas pool is discussed, and an accumulation model of natural gas is thus established. The Yinan‐2 gas is primarily derived from Jurassic coal‐bearing source rocks in the Yangxia Sag. Main gas accumulation time is 5–0 Ma and the corresponding Ro is in the range from 1.25%–1.95%. The loss rate of natural gas is 25%–30%.
Origin of Oils in “Subtle pools” in the Dongying Depression, Bohai Bay Basin, China
Authors: Sumei LI , Zhengxue JIANG , Keyu LIU , Guiqiang QIU , Yongjin GAO
Published: September 2010

Abstract: Subtle traps or oil pools have become an important exploration play in the Dongying Depression, Bohai Bay Basin, east China. Despite recent successes in exploration, the formation mechanisms of subtle traps are still not well understood. The majority of subtle oil pools in the Dongying Depression are developed in the middle interval of the Es3 Member of the Paleogene Shahejie Formation with the subtle traps being primarily of lenticular basin‐floor turbidite sands encompassed in mudstones. Oil in the subtle traps was previously thought to have migrated directly from the surrounding source rocks of the same formation (Es3). Detailed geochemical investigation of 41 oils and 41 rock samples from the depression now indicates that the oils from the subtle traps cannot be correlated well with the surrounding Es3 source rocks, which are characterized by high Pr/Ph (>1), low Gammacerane/C30hopane, representing a freshwater lacustrine setting. In contrast the oils features low Pr/Ph (<1) and relatively high Gammacerane content, showing a genetic affinity with the underlying Es4 source rocks, which also have the same qualities, indicating a brackish lacustrine setting. Oils in the Es3 subtle traps are probably derived from mixed sources with the contribution from the upper Es4 source rocks predominating. Therefore unconventional oil migration and accumulation mechanisms need to be invoked to explain the pooling of oils from the Es4 source rocks, which probably came through a thick low interval of the Es3 source rocks with no apparent structural or stratigraphic pathways. We suggest that the subtle oil migration pathway probably plays an important role here. This finding may have significant implications for future exploration and the remaining resource evaluation in the Dongying Depression.
New Record of Palaeoscolecids from the Early Cambrian of Yunnan, China
Authors: Shixue HU , Yong LI , Huilin LUO , Xiaoping FU , Ting YOU , Jiyuan PANG , Qi LIU , STEINER Michael
Published: September 2010

Abstract:A new palaeoscolecid,Guanduscolex minorHu, Luo et Fu gen. et sp. nov., with preserved soft parts of introvert and intestines comes from the Lower Cambrian Guanshan fauna of Yunnan, South China. Microstructural details of the cuticle revealed by scanning electron microscopy (SEM) show that each annulation bears three rows of plates and each plate bears 9–10 marginal and 4–5 central nodes. This discovery sheds new light on the relationships and evolutionary pathway of the palaeoscolecids and other early priapulids.
A New Female Cone,Araucaria beipoiaoensissp. nov. from the Middle Jurassic Tiaojishan Formation, Beipiao, Western Liaoning, China and Its Evolutionary Significance
Authors: Shaolin ZHENG , Lidong ZHANG , Wu ZHANG , Yajun YANG
Published: September 2010

Abstract:A new species of Araucaria,Araucaria beipiaoensissp. nov., collected from the Middle Jurassic Tiaojishan Formation, southern hill of Shebudai village, near Beipiao city, western Liaoning is based on a permineralized female cone, which is ovate to elliptical in shape, about 11 cm × 7 cm × 4.5 cm in size. The cone bears rhomboid bracts that are spirally attached, texture thicker, with wings on both sides, with a detached lamina‐like apex at the tip. In inner structure the ovuliferous scales are thicker and fused with bracts at the end with a ligular sulcus. There is one wingless ovule/seed per seed‐scale complex embedded in the ovuliferous scale tissue, with the micropyle directed toward the cone axis. The ovules/seeds are long ovate or elliptical in shape, 1 cm long and near the base about 3 mm in diameter; the ovule/seed integuments have begun differentiation into 3 layers: the sarcotesta, sclerotesta, and endotesta. The nucellus is free from the enclosing integuments except in the chalazal region where it is fused to the inner layer (endotesta) of integument. Some ovules show cellularized nucellar tissue. Mature seeds exhibit the papery‐thin wavy nucellus characteristically near to the micropyle. The embryonic tissue appears to be four cotyledons. The morphology and structure of the cone shows a close relationship to the araucarian cones of fossil and living genera but differs from any known species. The new species is distributed in the Middle Jurassic of the northern hemisphere, especially Asia, and has important significance for the evolution of the Family Araucariaceae.
High Pressure Response of Rutile Polymorphs and Its Significance for Indicating the Subduction Depth of Continental Crust
Authors: Dawei MENG , Xiuling WU , Xiaoyu FAN , Zhengjie ZHANG , Hong CHEN , Xin MENG , Jianping ZHENG
Published: September 2010

Abstract: α‐PbO2‐type TiO2 (TiO2‐II) is an important index mineral for ultrahigh‐pressure metamorphism. After the discovery of a natural high‐pressure phase of titanium oxide with α‐PbO2‐structure in omphacite from coesite‐bearing eclogite at Shima in the Dabie Mountains, China, a nano‐scale (<2 nm) α‐PbO2‐type TiO2 has been identified through electron diffraction and high‐resolution transmission electron microscopy in coesite‐bearing jadeite quartzite at Shuanghe in the Dabie Mountains. The crystal structure is orthorhombic with lattice parameters a = 4.58times10−1 nm, b = 5.42times10−1 nm, c = 4.96times10−1 nm and space group Pbcn. The analysis results reveal that rutile {011}R twin interface is a basic structural unit of α‐PbO2‐type TiO2. Nucleation of α‐PbO2‐type TiO2 lamellae is caused by the displacement of one half of the titanium cations within the {011}R twin slab. This displacement reduces the Ti‐O‐Ti distance and is favored by high pressure. The identification of α‐PbO2‐type TiO2 in coesite‐bearing jadeite quartzite from Shuanghe, Dabie Mountains, provides a new and powerful evidence of ultrahigh‐pressure metamorphism at 4–7 GPa, 850°C‐900°C, and implies a burial of continental crustal rocks to 130–200 kilometers depth or deeper. The α‐PbO2‐type TiO2 may be a useful indicator of the pressure and temperature in the diamond stability field.
Exsolutions of Diopside and Magnetite in Olivine from Mantle Dunite, Luobusa Ophiolite, Tibet, China
Authors: Yufeng REN , Fangyuan CHEN , Jingsui YANG , Yuanhong GAO
Published: September 2010

Abstract: The exsolutions of diopside and magnetite occur as intergrowth and orient within olivine from the mantle dunite, Luobusa ophiolite, Tibet. The dunite is very fresh with a mineral assemblage of olivine (>95%) + chromite (1%‐4%) + diopside (<1%). Two types of olivine are found in thin sections: one (Fo=94) is coarse‐grained, elongated with development of kink bands, wavy extinction and irregular margins; and the other (Fo=96) is fine‐grained and poly‐angled. Some of the olivine grains contain minor Ca, Cr and Ni. Besides the exsolutions in olivine, three micron‐size inclusions are also discovered. Analyzed through energy dispersive system (EDS) with unitary analytical method, the average compositions of the inclusions are: Na2O, 3.12%‐3.84%; MgO, 19.51%‐23.79%; Al2O3, 9.33%‐11.31%; SiO2, 44.89%‐46.29%; CaO, 11.46%‐12.90%; Cr2O3, 0.74%‐2.29%; FeO, 4.26%‐5.27%, which is quite similar to those of amphibole. Diopside is anhedral filling between olivines, or as micro‐inclusions oriented in olivines. Chromite appears euhedral distributed between olivines, sometimes with apparent compositional zone. From core to rim of the chromite, Fe content increases and Cr decreases; and Al and Mg drop greatly on the rim. There is always incomplete magnetite zone around the chromite. Compared with the nodular chromite in the same section, the euhedral chromite has higher Fe3O4 and lower MgCr2O4 and MgAl2O4 end member contents, which means it formed under higher oxygen fugacity environment. With a geothermometer estimation, the equilibrium crystalline temperature is 820°C‐960°C for olivine and nodular chromite, 630°C‐770°C for olivine and euhedral chromite, and 350°C‐550°C for olivine and exsoluted magnetite, showing that the exsolutions occurred late at low temperature. Thus we propose that previously depleted mantle harzburgite reacted with the melt containing Na, Al and Ca, and produced an olivine solid solution added with Na+, Al3+, Ca2+, Fe3+, Cr3+. With temperature decreasing, the olivine solid solution decomposed; and Fe3+, Cr3+ diffused into magnetite and Ca2+ and Na+ into clinopyroxene, both of which formed intergrowth textures. A few Fe3+ and Cr3+ entered interstitial chromite. Through later tectonism, the peridotite recrystallized and formed deformational coarse grained olivine, fine grained and poly‐angled olivine, and euhedral grained chromite. Due to the fast cooling rate of the rock or rapid tectonic emplacement, the exsolution textures in olivine and compositional zones of chromite are preserved.
SAED and HRTEM Investigation of Palygorskite
Authors: Tao CHEN , Hejing WANG , Xiaoping ZHANG , Nan ZHENG
Published: September 2010

Abstract: The microstructure of palygorskite from Longwang Mountain of Xuyu County, Jiangsu Province, was studied by energy dispersive X‐ray analysis (EDX), selected‐area electron diffraction (SAED) and high‐resolution transmission electron microscopy (HRTEM). The average composition of the palygorskite studied is (Si7.38Al0.62) (Al0.96Fe3+0.62Mg2.86□0.56)Ca0.03K0.06O20(OH)2(OH2)4, which is rich in Mg. Several SAED patterns from a single crystal of palygorskite were obtained with different zone axes. The polymorphs (monoclinic and orthorhombic) are unequivocally distinguished by distant interplanar angles, even though they possess similar sets of d‐values. High‐resolution images of three principal zones ([010], [100] and [110]) were obtained. The lattice fringes on HRTEM images along [010] have spacings of 0.319 nm. These fringes are interpreted as periodic alterations of two tetrahedral (T) sheets and one octahedral (O) sheet (‐TT‐O‐TT‐O‐). We have directly observed trioctahedral and dioctahedral individual palygorskite particles along [100]. They are all presented as dark lines along [001], but the width of dark lines corresponding to trioctahedral crystals (0.913 nm) is twice that of the dioctahedral ones (0.456 nm). This is because the trans‐sites are occupied by cations in trioctahedral palygorskite. The width of dark lines along [110] is 1.024 nm, a bit thinner than the theoretical spacing (1.044 nm). This is because water molecules quickly leave the structure upon the irradiation by the electron beam.
Petrologic and REE Geochemical Characters of Burnt Rocks
Authors: Lei HUANG , Chiyang LIU , Lei YANG , Junfeng ZHAO , Jianjun FANG
Published: September 2010

Abstract: The study of burnt rocks is beneficial to the discussion on the tectonic movement, paleoclimate and paleogeography that coal seams are subjected to after they were formed. In order to obtain the basic data on the features of the burnt rocks, a systematic study of petrology and REE geochemistry on burnt rocks in Shenmu, Northern Shaanxi Province has been done, using the methods of SEM, EDS, susceptibility measurements and ICP‐MS. The burnt rocks are divided into two series in the section: the melted rocks and the baked rocks. SEM and EDS analyses reveal that all the minerals show burnt and melted traces, and there are no clay minerals except illite found in the burnt rocks. Susceptibility measurements reveal that the burnt rocks have abnormally high susceptibility values, whereas a geochemical analysis shows that the REE distribution pattern of burnt rocks is similar to that of sedimentary rocks (initial rocks). In the longitudinal section, with increasing degree of burning (from baked rocks to melted rocks), the ΣE gradually decreases, and the total REE of melted rocks is obviously lower than that of baked rocks. Besides, the melted rocks show apparent negative Ce anomalies, while the baked rocks show no anomaly of Ce, and sometimes even show positive anomalies.
Precise Dating and Geological Significance of the Caledonian Shangyou Pluton in South Jiangxi Province
Authors: Jianren MAO , Qingtao ZENG , Zilong LI , Qing HU , Xilin ZHAO , Haimin YE
Published: September 2010

Abstract: The zircon SHRIMP dating age for the Shangyou granites is 464±11 Ma. The geological feature of the pluton is consistent with the isotopic age, which shows that it is a product of Caledonian orogenesis. The Shangyou granites are regarded as peraluminous crust‐derived granites to possess the typical geochemical characteristics of calc‐alkaline rocks on the active continental margin with enriched Si, K, Al (A/CNK = 1.11 on average), HREE, Rb, U, Th and heavily depleted V, Cr, Co, Ni, as well as Ti‐Y, Nb‐Ta, Zr, Sr, P and Ba, to be commonly corundum normative (av C = 1.44). The Shangyou granites with higher 87Sr/86Sr ratios (0.707126‐0.712186), εNd(t) values (‐7.29 to −10.22) and (tDM) values (1.52‐1.63 Ga), which are considered to result from partial melting of continental crust metamorphic sedimentary rocks with relatively low of crust maturation degree corresponding to the Middle Proterozoic, to have some possible contributions of mantle‐derived components. The Shangyou granites are regarded as post‐collision granites, which were formed in a transitional tectonic setting from compression to extension in the Middle Ordovician period after the Yangtze plate was subducted beneath the Cathaysian plate. The Ar‐Ar total ages of K‐feldspar and biotite are 292.1 Ma and 295.5 Ma respectively, which have recorded information of a late‐stage thermal alteration event.
SHRIMP U‐Pb Zircon Dating of the Tula Granite Pluton on the South Side of the Altun Fault and Its Geological Implications
Authors: Suoping WU , Cailai WU , Meiying WANG , Qilong CHEN , WOODEN Joseph L.
Published: September 2010

Abstract: The Tula A2‐subtype granite pluton is located between the Altun fault and its branching fault. According to the geological, geochemical, REE and trace elements characteristics, it belongs to the A2 (PA) subtype granite. The SHRIMP U‐Pb zircon dating gives a result of 385.2±8.1 Ma, which is located between the Middle and Late Devonian in the international stratigraphic chart, and can be regarded as the crystallization age of the Tula granite. The study indicates that the Tula area was in a local extensional environment in the end of the Middle Devonian, and that environment was probably related to the synchronized strike‐slip activity of the Altun fault.
North‐south Differentiation of the Hydrocarbon Accumulation Pattern of Carbonate Reservoirs in the Yingmaili Low Uplift, Tarim Basin, Northwest China
Authors: Xiuxiang Lü , Jianjiao LI , Fengyun ZHAO , Ning YANG , Qiucha ZHANG
Published: September 2010

Abstract: By analyzing the characteristics of development, structural evolution and reservoir beds of the residual carbonate strata, this study shows that the residual carbonate strata in the Yingmaili low uplift are favorable oil and gas accumulation series in the Tabei (northern Tarim uplift) uplift. There are different patterns of hydrocarbon accumulation on the northern and southern slopes of the Yingmaili low uplift. The north‐south differentiation of oil reservoirs were caused by different lithologies of the residual carbonate strata and the key constraints on the development of the reservoir beds. The Mesozoic terrestrial organic matter in the Kuqa depression and the Palaeozoic marine organic matter in the Manjiaer sag of the Northern depression are the major hydrocarbon source rocks for the northern slope and southern slope respectively. The hydrocarbon accumulation on the northern and southern slopes is controlled by differences in maturity and thermal evolution history of these two kinds of organic matter. On the southern slope, the oil accumulation formed in the early stage was destroyed completely, and the period from the late Hercynian to the Himalayian is the most important time for hydrocarbon accumulation. However, the time of hydrocarbon accumulation on the northern slope began 5 Ma B.P. Carbonate inner buried anticlines reservoirs are present on the southern slope, while weathered crust and paleo‐buried hill karst carbonate reservoirs are present on the northern slope. The northern and southern slopes had different controlling factors of hydrocarbon accumulation respectively. Fracture growth in the reservoir beds is the most important controlling factor on the southern slope; while hydrocarbon accumulation on the northern slope is controlled by weathered crust and cap rock.
REE Compositions of Lower Ordovician Dolomites in Central and North Tarim Basin, NW China: A Potential REE Proxy for Ancient Seawater
Authors: Xuefeng ZHANG , Wenxuan HU , Zhijun JIN , Juntao ZHANG , Yixiong QIAN , Jingquan ZHU , Dongya ZHU , Xiaolin WANG , Xiaomin XIE
Published: September 2010

Abstract: Rare earth element compositions of Lower Ordovician dolomites in the Central and Northern Tarim Basin are studied. Most dolomite samples are more or less contaminated by clay minerals. Their rare earth element compositions have been consequently changed, showing both seawater‐like and non‐seawater‐like features. The clay contamination should be disposed before the REE data are used. Through ICP‐MS and ICP‐AES analyses, the REE features are well documented. The clay contamination is quantitatively determined by microscopic investigation, trace elements and REE contents. The dolomites, at least in the Tarim Basin, are thought to be pure when their total LREE contents are less than 3times10−6. Through comparison, the pure dolomites show similarities in REE patterns but differences in REE contents with co‐existing pure limestone, which indicates that dolomitization may slightly change the REE compositions. Nevertheless, whatever the change is, the pure dolomites may act as a potential REE proxy for Ordovician seawater, which would be significant for ancient massive dolomite strata that lack limestone.
Research on Potential Fertilization of Coal Gangue in the Weibei Coalfield, China
Authors: Tong WANG , Ying WANG , Jun WANG
Published: September 2010

Abstract: Based on the systematic analysis of the coal gangue in Weibei Coalfield, such as petrologic characteristics, chemical composition, nutrient elements, deleterious elements, and the transformation, and compared with the soil element content background values of Loess Plateau and national harmful materials controlling standards, we conclude that the coal gangue in the Weibei Coalfield has huge potential to be used as clay fertilizer.
Experimental Study on Gold Dissolution from Hosting Minerals of the Hadamengou Gold Deposit and the Implications
Authors: Qiangzhi LI , Fengzeng YAN , Xinhu WANG
Published: September 2010

The Hadamengou gold deposit is located in western part of the northern margin of the North China craton. It is a hydrothermal deposit related to alkaline magmatism. Dissolution of Au, Fe from pyrite and iron oxide (including magnetite and hematite) individual minerals in the three main types of ore shows: in iron oxides (magnetite and hematite), Au and Fe were dissolved simultaneously and their solubilities are positively correlated, which means Au is mainly chemical‐bonded (lattice gold) and/or colloidal‐adsorbed in iron oxides; while in pyrite, on the contrary, Au dissolution obviously lags behind Fe and the solubility of Au shows negative relationship with that of Fe, which indicates Au is mainly hosted as grains of elemental gold (or native gold) within pyrite. Previous studies revealed that the Hadamengou gold deposit is characterized by intensive K‐feldspathization and holds high content of iron oxides occasionally replaced by sulfides, which was caused by oxidizing K‐enriched alkaline fluids under a stretching geodynamic setting. These geological features, together with the high Au‐content in iron oxides, comparable with that of the Olympic Dam deposit in South Australia, suggest that this deposit is the first example of iron oxide‐type gold deposits in China.
Metallogenic Series Related to Permian Mafic Complex in North Xinjiang: Post‐collisional Stage or Mantle Plume Result?
Authors: Yuwang WANG , Jingbin WANG , Lijuan WANG , Lingli LONG
Published: September 2010

There are four deposit types related to a Permian mafic complex in northern Xinjiang, i.e., copper‐nickel sulfide deposit, vanadic titanomagnetite deposit, magnetite (‐cobalt) deposit and Cu‐Ni‐VTiFe composite deposit. The deposits are distributed spanning tectonic units with close and consecutive metallogenic ages. A transitional deposit type can occur among the end‐member deposits. Trace elements of host rocks show that they can derive from similar source area. Hence, they constitute a particular metallogenic series related to a mafic‐ultramafic complex that is also a symbol series of the post‐collisional stage of the Central Asia Metallogenic Province (CAMP). The metallogenic ages of the series are between 260 Ma and 300 Ma throughout the Permian. Unlike mineralization from a mantle plume, the metallogenic period of this series spans at least 40 Ma. Compared with related deposits of the Emeishan mantle plume, the North Xinjiang series has a similar ore‐forming element assemblage but has preferably developed Cu‐Ni sulfide deposits rather than vanadic titanomagnetite deposits. In concomitance with this series, North Xinjiang area has developed a set of syntectonic Au‐Cu‐Mo metallogenic series related to a felsic volcanic‐intrusive complex, which might indicate that there is no direct relationship with mantle plume activity. From early to late, i.e., the sequence of copper‐nickel sulfide to magnetite (‐cobalt) to vanadic titanomagnetite deposit, the host rock series evolves from mafic‐ultramafic and tholeiite series to mafic and alkalic series, the ΣREE content tends to increase with increasing of REE fractionation, and some of the trace elements (particularly LIL) also show an increasing tendency. The above evolutionary regularity possibly reflects a course where the magma source deepens and thermal interface moves down, energy gradually exhausts, and neo‐continental crust forming in the post‐collision stage tends to stabilize.
Distribution Characteristics of Cobalt‐rich Ferromanganese Crust Resources on Submarine Seamounts in the Western Pacific
Authors: Fuyuan ZHANG , Weiyan ZHANG , Kechao ZHU , Shuitu GAO , Haisheng ZHANG , Xiaoyu ZHANG , Benduo ZHU
Published: September 2010

Based on the survey data of five submarine seamount provinces (chains) in the Western Pacific, the distribution characteristics of cobalt‐rich ferromanganese crust resources have been researched in this paper by using the relative reference data and applying the theories of hotspot and seafloor spreading. The main research results obtained are as follows: The Co‐rich crust thickness in the study area is gradually increasing from east to west and from south to north having a negative correlation (r = −0.59) with longitude and a positive correlation (r = 0.48) with latitude. The crust thickness varying along longitude and latitude is influenced by the hotspot and seafloor spreading. The oceanic crusts and seamounts in the northwest part of the study area are older, and the crust resources are superior to those in the southeast part. In the depth of <1500 m, 1500–2000 m, 2000–2500 m in the study area, the cobalt crust thickness is respectively 5.45 cm, 4.34 cm and 3.55 cm, and in the depth of 2500–3000 m and 3000–3500 m, it drops respectively to 2.84 cm and 3.37 cm. The Co‐rich crust resources are mainly concentrated in the seamount summit margins and the upper flanks in the depth of <2500 m. There is a strong negative correlation (r = −0.67) between the cobalt crust abundance and the slope of the seamount, 75 kg/m2 and 50 kg/m2 at the slopes of 0°–20° and 20°–34° respectively. Cobalt crusts are mainly distributed in the parts whose slopes are less than 20°. It is consistent with the fractal result that the slope threshold of cobalt crust distribution is 19°, and slopes over 20° are not conducive to the crust growth. The cobalt crusts of high grade are mainly enriched in the region within 150°E‐140°W and 30°S‐30°N in the Pacific, where there are about 587 seamounts at the depth of 3500–6000 m and over 30 Ma of the oceanic crusts. The perspective area rich in cobalt crust resources is about 41times104 km2 and the resource quantity is approximately 27 billion tons.
Mineralization of a Proterozoic Sulfide Black Smoker Chimney and Thermophilous Microorganisms in Eastern Hebei, China
Authors: Xuehui XIA , Wei LIAN , Congjian YUAN , Fei YAN , Jiazhong YUAN
Published: September 2010

A sulfide black smoker chimney exists in the Gaobanhe seabed exhalation massive sulfide deposit in the Xinglong‐Kuancheng secondary fault basin of the Proterozoic Yanliao rift trough in Hebei Province, taking the shape of mounds, individually about 2–3 cm high. Abundant fossils of thermophilous bacteria and algae in perfect preservation are found in the ore surrounding the black smoker chimney. Scanning electron microscopy (SEM) and molecular biomarker studies on the microorganismal ore fabric show that the microorganism in the sulfide ore is in fact a sedimentary product of probiotic bacteria and algae. In the special food chain based on black smoker chimney at ancient seabed‐ thermophilous bacteria, the thermophilous bacteria and algae reproduce in large quantity. Intermittently erupting of fluid from the chimney creats conditions for formation of sulfide deposit. In the process of exhalation action of hot fluid, thermophilous bacteria and algae grow and reproduce around the sulfide black smoker chimney, absorbing mineralizing substances brought by the fluid. Massive sulfide deposits are formed in this process of absorption of seabed black smoker chimney exhalation‐mineralizing fluid pulsation‐thermophilous microorganism.
Multifractal Analysis of Element Distribution in Skarn‐type Deposits in the Shizishan Orefield, Tongling Area, Anhui Province, China
Authors: Qingfei WANG , Jun DENG , Li WAN , Jie ZHAO , Qingjie GONG , Liqiang YANG , Lei ZHOU , Zhijun ZHANG
Published: September 2010

A series of element concentrations sampled from four drill cores with a length about 1000 m into different skarn‐type deposits were selected from the Shizishan orefield, central Tongling, southeastern part of Anhui Province. Using the multifractal method, the distribution and migration characteristics of the major and trace elements are analyzed. The multifractal spectrum of the major elements is left‐skewed, whereas the spectrum of the trace elements is right‐skewed, which shows that in the process of skarn formation, the trace elements were enriched only locally, and major elements transported within a much larger range. The correlation coefficients of the multifractal parameters Δa (width of the multifractal spectrum) of the four drill cores are relatively low, but the correlation coefficients of the multifractal parameters R (spectrum symmetry parameter) and Δf are relatively higher, indicating that although the non‐homogeneous intensity of the distribution of elements is inconsistent, their spatial accumulation patterns are almost the same during the ore‐forming process. The statistics of the multifractal parameters of various elements in the different locations show that the ore‐forming processes and element migration pattern in the Shizishan orefield are consistent, and that the migrations of trace elements and major elements exhibit some differences.
Anaerobic Biodegradation of Tetrachloroethylene with Acetic Acid as Cometabolism Substrate under Anaerobic Condition
Authors: Ye LI , Fei LIU , Honghan CHEN , Jinhua SHI , Yufan WANG
Published: September 2010

A series of batch‐type experiments with acetate acid as the primary substrate were performed using enrichment cultures developed from the anaerobic sludge to investigate the effect of acetate acid on tetrachloroethylene (PCE) biodegradation. Experimental results indicated that acetate acid was an efficient electron donor in affecting the biotransformability of PCE. Trichloroethylene (TCE) was the primary dehalogenation product, and small amounts of dichloroethylenes (DCEs) were also detected. No significant further DCEs degradation was detected. PCE degradation rate in the experiment was 36.6 times faster than background rate in natural groundwater.
Study on Assessment of Mine Environments
Authors: Qiang WU , Wei LI , Ruijun LI
Published: September 2010

Mine environmental evaluation is the key to mine environmental study. On the basis of the characteristics of the mine environmental problems, they are classified into (1) three wastes problem, (2) ground distortion, (3) contradiction among mine drainage, water supply, ecological environment, (4) desertification, and (5) soil erosion. The evaluation is the basis of mine environmental problem classification and investigation, mine environmental rehabilitation, and the information system constructed can be used for subsequent research of evaluation techniques. A synthetic assessment of the 5 kinds of mine environmental problems can be divided into single‐factor or multi‐factor synthetic assessments; while by the viewpoint of time, the mine environmental assessment can be classified as the historical assessment, the current status assessment and the forecasting assessment.
Selection and Basic Properties of the Buffer Material for High‐Level Radioactive Waste Repository in China
Authors: Zhijian WEN
Published: September 2010

Radioactive wastes arising from a wide range of human activities are in many different physical and chemical forms, contaminated with varying radioactivity. Their common features are the potential hazard associated with their radioactivity and the need to manage them in such a way as to protect the human environment. The geological disposal is regarded as the most reasonable and effective way to safely disposing high‐level radioactive wastes in the world. The conceptual model of geological disposal in China is based on a multi‐barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the main engineered barriers for HLW repository. It is expected to maintain its low water permeability, self‐sealing property, radio nuclides adsorption and retardation properties, thermal conductivity, chemical buffering property, canister supporting property, and stress buffering property over a long period of time. Bentonite is selected as the main content of buffer material that can satisfy the above requirements. The Gaomiaozi deposit is selected as the candidate supplier for China's buffer material of high level radioactive waste repository. This paper presents the geological features of the GMZ deposit and basic properties of the GMZ Na‐bentonite. It is a super‐large deposit with a high content of montmorillonite (about 75%), and GMZ‐1, which is Na‐bentonite produced from GMZ deposit is selected as the reference material for China's buffer material study.
Groundwater Systems and Resources in the Ordos Basin, China
Authors: Guangcai HOU , Yongping LIANG , Xiaosi SU , Zhenghong ZHAO , Zhengping TAO , Lihe YIN , Yuncheng YANG , Xiaoyong WANG
Published: September 2010

The Ordos Basin is a large‐scale sedimentary basin in northwestern China. The hydrostratigraphic units from bottom to top are pre‐Cambrian metamorphic rocks, Lower Paleozoic carbonate rocks, Upper Paleozoic to Mesozoic clastic rocks and Cenozoic deposits. The total thickness is up to 6000 m. Three groundwater systems are present in the Ordos Basin, based on the geological settings, i.e. the karst groundwater system, the Cretaceous clastic groundwater system and the Quaternary groundwater system. This paper describes systematically the groundwater flow patterns of each system and overall assessment of groundwater resources.
A New Diverse Macrofossil Lagerstätte from the Uppermost Ediacaran of Southwestern China
Authors: Feng TANG , Chongyu YIN , Pengju LIU , Linzhi GAO , Wenyan ZHANG
Published: September 2010

Abstract: A new macrofossil Lagerstätte was discovered from the uppermost Ediacaran Jiucheng Member at Jinning and Jiangchuan of the eastern Yunnan, yielding numerous diverse well‐preserved thallophyte macrofossils. These include the previously‐known representatives of vendobionts, Vendotaenia and Tyrasotaenia, and the biggish multicellular benthos such as Chuaria‐like and Tawuia‐like fossils, as well as Longfengshaniaceaens with diverse holdfast structures. There are still some other problematic macrofossils with peculiar configurations as well as uncertain relatives. The distinct dominance of the giant, unbranching thallophytes occasionally with holdfast structures distinguishes this assemblage from the other Ediacaran macrofossil Lagerstättes in the Doushantuo Formation at Miaohe, Wenghui and Lantian, and the contemporary assemblage in the Shibantan Member of Dengying Formation, Yangtze Gorges area. This paper outlines the characteristics of some of the multicellular macrofossils from the Jiucheng Member at Jiangchuan. They include some macrofossils with different types of holdfast structure, larger Chuaria‐like and Tawuia‐like morphology and questionable affinities as well. The discovery of greater diverse macrofossil assemblages from the Jiucheng Member of eastern Yunnan has further indicated that an important diversification and evolutionary radiation of metaphytes took place in the latest Ediacaran time. This radiation of large‐scale, benthic metaphyte along with phytoplankton was likely important contributors to the early Cambrian explosion of metazoans.
A New Species of Cathayornis from the Lower Cretaceous of Inner Mongolia, China and Its Stratigraphic Significance
Authors: Jianjun LI , Zhiheng LI , Yuguang ZHANG , Zhonghe ZHOU , Zhiqiang BAI , Lifu ZHANG , Tuya BA
Published: September 2010

Abstract: An incomplete postcranial avian skeleton is described from the Lower Cretaceous Jingchuan Formation of Otog Banner of western Inner Mongolia and referred to a new species of Cathayornis, C. chabuensis sp. nov. This is the first report of a Cathayornis from outside Liaoning Province. The new discovery indicates that Cathayornis coexisted with Otogornis genghisi, and a more detailed comparison between these two enantiornithine genera shows that Otogornis represents a more primitive genus than Cathayornis. Our analyses further indicate that Cathayornis is an arboreal bird. The discovery of a Cathayornis from this region also confirms that the avian fossil‐bearing Jingchuan Formation is comparable to the Jiufotang Formation of the upper Jehol Group in western Liaoning, and should be referred to the middle‐late Early Cretaceous.
Fossil Association from the Lower Cambrian Yanjiahe Formation in the Yangtze Gorges Area, Hubei, South China
Authors: Junfeng GUO , Yong LI , Jian HAN , Xingliang ZHANG , Zhifei ZHANG , Qiang OU , Jianni LIU , Degan SHU , MARUYAMA Shigenori , KOMIYA Tsuyoshi
Published: September 2010

Abstract: Apart from previously reported Small Shelly Fossils (SSFs), a macroscopic fossil assemblage, comprising abundant algae, cone‐shaped tubular fossil forms, and probable impressions of a megascopic metazoan, comes from the Lower Cambrian Yanjiahe Formation in the Yangtze Gorges area of western Hubei Province, south China. The visible fossils are preserved in thinlaminated siltstone or muddy siltstone intercalated between 8–15 mm‐thick carbonate deposits, probably representing sedimentary settings of a constrained local depression in the shallow water carbonate platform during the Early Cambrian Meishucunian Stage. The macroscopic fossil association provides significant fossil evidence about the evolution of life from the late Precambrian to the ‘Cambrian explosion’ interval.