bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining Pressure with Daughter Minerals in Fluid Inclusion by Raman Spectroscopy: Sphalerite as an Example
Authors: YANG Yuping , ZHENG Haifei , ZHANG Lifei 
Published: August 2010

Abstract:Raman frequency of some materials, including minerals, molecules and ions, shifts systematically with changing pressure and temperature. This property is often used as a pressure gauge in high pressure experiments with the hydrothermal diamond anvil cell (HDAC). Since the system of fluid inclusion is similar to that of HDAC, it can also be used to determine the internal pressure of fluid inclusions. Sphalerite is a common daughter mineral. In this study, the frequency shift of the 350 cm−1 peak of sphalerite has been studied from 296 to 523 K and from 0.07 to 2.00 GPa using the HDAC. The global slope of the isotherms (∂V350/∂p)T is 0.0048 in the studied pressure range. No significant variation of the slopes with temperature has been observed. The correlation between the frequency shift of the 350 cm−1 peak of sphalerite and pressure and temperature is constrained as P=208.33(ΔVp)350+3.13T–943.75. This relationship may be used to estimate the internal pressure of the sphalerite‐bearing fluid inclusions.
Age and Provenance of Loess deposits on the Northern Flank of Tianshan Mountain
Authors: YUAN Qingdong , ZHANG Zhicheng , WU Chaodong , GUO Zhaojie 
Published: August 2010

Abstract:The distribution, optically stimulated luminescence dating and granulometric properties suggest that the loess on the northern flank of Tian Shan should be divided into two types. One which is like mantle and is named type A, is located on the windward slopes and dated to about 54.5±5.73 Ka. The other, called type B, lies flatly on the terraces of the rivers or low hills and penetrated 30.8±2.05 Ka ago. Here we study the origin and the age of two types of loess, and a model of loess formation is proposed. The dust was entrained from the Gobi Desert located to the north of Tian Shan by the monsoon from Mongolia, obstructed by the high mountains and deposited on the windward slopes of the mountains. The rivers and flows then transported the aeolian loess to low terraces and piedmont alluvial plains.
Discovery of a Miocene Mafic Dyke from the Western Hills of Beijing and its Geological Implications
Authors: ZHANG Zhicheng , HAN Baofu , WU Tairan 
Published: August 2010

Abstract:The present study is the first report of a Miocene mafic dyke from the Dahuichang, in the Western Hills of Beijing. The dyke cuts the fossil‐dated Changxindian Formation of Eocene sequences and yields K‐Ar ages of 14–15 Ma. The dyke is fine‐grained diabase and has 49.84%–50.81% SiO2 and 3.56–3.97% Na2O+K2O, high TiO2 (1.65%–1.93%) and MgO (7.36%–9.85%), and low K2O (<1.22%) contents, with Na2O>K2O and slightly varied magnesium numbers (Mg#=55.54–62.74). In trace elements geochemistry, the dyke is very similar to the Miocene basalts from Jining and Hanuoba. The enrichment of light rare earth elements ([La/Yb]N=5.03–6.12) and large ion lithophile elements (LILEs), no negative Eu anomalies, relatively high Cr (265–326 ppm) and Ni (155–262 ppm), and almost constant V concentrations (194–213 ppm) reveal that the composition close to the primary basaltic magma from an enriched‐mantle source, with little crustal contamination and fractional crystallization. The basaltic magma was possibly derived from the upwelling asthenosphere mantle beneath eastern China during the Miocene lithospheric thinning.
A New Perleidiform (Actinopterygii, Osteichthyes) from the Middle Anisian (Middle Triassic) of Yunnan, South China
Authors: SUN Zuoyu , TINTORI Andrea , JIANG Dayong , LOMBARDO Cristina , RUSCONI Marco , HAO Weicheng , SUN Yuanlin 
Published: August 2010

Abstract:Two complete specimens from the Pelsonian (Middle Anisian, Middle Triassic) of Luoping, Yunnan Province, South China are referred to a new actinopterygian genus, Luopingichthys gen. nov., and ascribed to the perleidiform family Polzbergidae based especially on a typical synapomorphy of a peculiar premaxillary‐maxillary complex, i.e., the fusion between premaxillary and maxillary along the antero‐dorsal margin of the maxillary. The new taxon differs from other deep‐bodied representatives of the family, Felberia and Stoppania, in its fusiform or deep fusiform body shape; sickle‐shaped preopercular with short infraorbital process; lack of modified scales at the base of the anal fin; the short‐based dorsal fin; scarcely ornamented scales; and thin anterior teeth. Based on a redescription of the holotype of the taxon Ctenognathichthys hattichi from the Middle Triassic (Ladinian) Prosanto Formation, Canton Graubünden, eastern Switzerland, the only known specimen, which shows the same fusion between premaxillary and maxillary, the systematic position of the species is clarified and the taxon is proposed to be a further representative of the family Polzbergidae, and is transferred to the new genus.
Vestrogothia spinata (Phosphatocopina, Crustacea), Fossils of Orsten‐type Preservation from the Upper Cambrian of Western Hunan, South China
Authors: LIU Zheng , DONG Xiping 
Published: August 2010

Abstract:Fossils of Orsten‐type preservation represented by the crustacean Skaracarida and Phosphatocopida were found in western Hunan, South China in 2005, including the important phosphatocopid species Vestrogothia spinata based on exquisitely preserved soft‐bodied specimens that allow the first growth stage to be reestablished. The taxonomy of Vestrogothia spinata is revised employing the character of a two‐divided limb stem of the mandible. A new foundation for the phytogeny of the Phosphatocopina using mandible characters related to crustacean appendages is postulated. Vestrogothia spinata has only previously been found from Sweden.
Archaeopteris halliana from the Late Devonian (Famennian) of Anhui Province, China
Authors: GUO Yun , WANG Deming 
Published: August 2010

Abstract:New materials from the Upper Devonian (Famennian) Wutong Formation of Chizhou District, Anhui Province, South China, allow description of fertile and sterile characters of Archaeopteris halliana. This plant has penultimate axes attached by sterile leaves and paired ultimate branches in the same ontogenetic spiral. Sterile leaves are narrowly cuneate in shape and bear distal margins dissected deeply. These leaves are spirally arranged on sterile ultimate axes. Non‐laminated sporophylls occur spirally on the ultimate axes and bifurcate once or twice. Elongate sporangia with longitudinal dehiscence are borne adaxially below or above the dividing points of the sporophylls. Despite the leaf shape resembling that of Archaeopteris macilenta, our plant is assigned to A. halliana because of its non‐laminated sporophylls. Fertile characters should be given priority or enough consideration in identifying species of Archaeopteris.
Geochemical Characteristics, Genesis of Concealed Cu‐rich Ore Body in the Jinchuan Deposit, Northwestern China, and Its Prospecting
Authors: Yalin GAO , Zhongli TANG , Mingjie ZHANG , Yulong TIAN , Lizhong XIAO 
Published: August 2010

Abstract:The Jinchuan deposit is hosted by the olivine‐rich ultramafic rock body, which is the third‐largest magmatic sulfide Ni–Cu deposit in the world currently being exploited. Seeking new relaying resources in the deep and the border of the deposit becomes more and more important. The ore body, ore and geochemistry characteristics of the concealed Cu‐rich ore body are researched. Through spatial analysis and comparison with the neighboring II1 main ore body, the mineralization rule of the concealed Cu‐rich ore body is summed up. It is also implied that Cu‐rich magma may exist between Ni‐rich magma and ore pulp during liquation differentiation in deep‐stage chambers, which derives from deep‐mantle Hi–MgO basalt magma. It is concluded that the type of ore body has features of both magmatic liquation and late reconstruction action. It has experienced three stages: deep liquation and pulsatory injection of the Cu‐ and PPGE‐rich magma, concentration of tectonic activation, and the later magma hydrothermal superimposition. In addition, the Pb and S isotopes indicate the magma of 16 concealed Cu‐rich ore body originates predominantly from mantle; however, it is interfused by minute crust material. Finally, it is inferred that the genesis of the Cu–Ni sulfide deposit is complex and diverse, and the prospect of seeking new deep ore bodies within similar deposits is promising, especially Cu‐rich ore bodies.
Petroleum System of the Sufyan Depression at the Eastern Margin of a Huge Strike‐slip Fault Zone in Central Africa
Authors: Yamin ZHANG , Qin GU 
Published: August 2010

Abstract:The present paper mainly studies the petroleum system of the Sufyan Depression in the Muglad Basin of central Africa and analyzes its control of hydrocarbon accumulation. On the basis of comprehensive analysis of effective source rock, reservoir bed types and source–reservoir–seal assemblages, petroleum system theory has been used to classify the petroleum system of the Sufyan Depression. Vertically, the Sufyan Depression consists of two subsystems. One is an Abu Gabra subsystem as a self generating, accumulating and sealing assemblage. The other subsystem is composed of an Abu Gabra source rock, Bentiu channel sandstone reservoir and Darfur group shale seal, which is a prolific assemblage in this area. Laterally, the Sufyan Depression is divided into eastern and western parts with separate hydrocarbon generation centers more than 10 000 m deep. The potential of the petroleum system is tremendous. Recently, there has been a great breakthrough in exploration. The Sufyan C‐1 well drilled in the central structural belt obtained high‐yielding oil flow exceeding 100 tons per day and controlled geologic reserves of tens of millions of tons. The total resource potential of the Sufyan Depression is considerable. The central structural belt is most favorable as an exploration and development prospect.
Character of the Si and Al Phases in Coal Gangue and Its Ash
Authors: Lihua WANG , Pengda ZHAO , Geng LI 
Published: August 2010

Abstract:Analysis of the Si and Al phases in coal gangue fuel and its ash is important for use of coal gangue ashes. A comprehensive study by theoretical and experimental analyses with differential thermal analysis, X‐ray diffraction and Infrared Spectroscopy has been made in the present article to explore the diagram of the Si and Al phases in coal gangue fuel and its ashes. It is found that kaolinite and quartz are the main phases in coal gangue fuel. The ratio of moles Al2O3to SiO2 (i.e., Al2O3 (mole)/ SiO2 (mole)) is usually no more than 0.5 in most coal gangue fuel and its ashes. The kaolinit at about 984°C releases a large quantity of SiO2, which makes calcine coal gangue more active than coal gangue itself. The relationship between the ratio Al2O3 (mole)/SiO2 (mole) and the components of coal gangue ash is analyzed, resulting in a formula to calculate the quantity of each phase. Applying the formula to the testing samples from an electric plant in north China supports the above conclusions.
Active Faulting Pattern, Present‐day Tectonic Stress Field and Block Kinematics in the East Tibetan Plateau
Authors: ZHANG Yueqiao , DONG Shuwen , YANG Nong 
Published: August 2010

Abstract:This paper examines major active faults and the present‐day tectonic stress field in the East Tibetan Plateau by integrating available data from published literature and proposes a block kinematics model of the region. It shows that the East Tibetan Plateau is dominated by strike‐slip and reverse faulting stress regimes and that the maximum horizontal stress is roughly consistent with the contemporary velocity field, except for the west Qinling range where it parallels the striking of the major strike‐slip faults. Active tectonics in the East Tibetan Plateau is characterized by three faulting systems. The left‐slip Kunlun‐Qinling faulting system combines the east Kunlun fault zone, sinistral oblique reverse faults along the Minshan range and two major NEE‐striking faults cutting the west Qinling range, which accommodates eastward motion, at 10–14 mm/a, of the Chuan‐Qing block. The left‐slip Xianshuihe faulting system accommodated clockwise rotation of the Chuan‐Dian block. The Longmenshan thrust faulting system forms the eastern margin of the East Tibetan Plateau and has been propagated to the SW of the Sichuan basin. Crustal shortening across the Longmenshan range seems low (2–4 mm/a) and absorbed only a small part of the eastward motion of the Chuan‐Qing block. Most of this eastward motion has been transmitted to South China, which is moving SEE‐ward at 7–9 mm/a. It is suggested from geophysical data interpretation that the crust and lithosphere of the East Tibetan Plateau is considerably thickened and rheologically layered. The upper crust seems to be decoupled from the lower crust through a décollement zone at a depth of 15–20 km, which involved the Longmenshan fault belt and propagated eastward to the SW of the Sichuan basin. The Wenchuan earthquake was just formed at the bifurcated point of this décollement system. A rheological boundary should exist beneath the Longmenshan fault belt where the lower crust of the East Tibetan Plateau and the lithospheric mantle of the Yangze block are juxtaposed.
Deep Background of Wenchuan Earthquake and the Upper Crust Structure beneath the Longmen Shan and Adjacent Areas
Authors: LI Qiusheng , GAO Rui , WANG Haiyan , ZHANG Jisheng , LU Zhanwu , LI Pengwu , GUAN Ye , HE Rizheng 
Published: August 2010

Abstract:By analyzing the deep seismic sounding profiles across the Longmen Shan, this paper focuses on the study of the relationship between the upper crust structure of the Longmen Shan area and the Wenchuan earthquake. The Longmen Shan thrust belt marks not only the topographical change, but also the lateral velocity variation between the eastern Tibetan Plateau and the Sichuan Basin. A low‐velocity layer has consistently been found in the crust beneath the eastern edge of the Tibetan Plateau, and ends beneath the western Sichuan Basin. The low‐velocity layer at a depth of ∼20 km beneath the eastern edge of the Tibetan Plateau has been considered as the deep condition for favoring energy accumulation that formed the great Wenchuan earthquake.
Vp/Vs Anisotropy and Implications for Crustal Composition Identification and Earthquake Prediction
Authors: WANG Qian , JI Shaocheng , XU Zhiqin 
Published: August 2010

Abstract:The ratio of P‐ to S‐wave velocities (Vp/Vs) is regarded as one of the most diagnostic properties of natural rocks. It has been used as a discriminant of composition for the continental crust and provides valuable constraints on its formation and evolution processes. Furthermore, the spatial and temporal changes in Vp/Vs before and after earthquakes are probably the most promising avenue to understanding the source mechanics and possibly predicting earthquakes. Here we calibrate the variations in Vp/Vs in dry, anisotropic crustal rocks and provide a set of basic information for the interpretation of future seismic data from the Wenchuan earthquake Fault zone Scientific Drilling (WFSD) project and other surveys. Vp/Vs is a constant (Φ0) for an isotropic rock. However, most of crustal rocks are anisotropic due to lattice‐preferred orientations of anisotropic minerals (e.g., mica, amphibole, plagioclase and pyroxene) and cracks as well as thin compositional layering. The Vp/Vs ratio of an anisotropic rock measured along a selected pair of propagation‐vibration directions is an apparent value (Φij) that is significantly different from the value for its isotropic counterpart (Φ0). The usefulness of apparent Vp/Vs ratios as a diagnostic of crustal composition depends largely on rock seismic anisotropy. A 5% of P‐ and S‐wave velocity anisotropy is sufficient to make it impossible to determine the crustal composition using the conventional criteria (Vp/Vs≤1.756 for felsic rocks, 1.756<Vp/Vs≤1.809 for intermediate rocks, 1.809<Vp/Vs≤1.944 for mafic rocks, and Vp/Vs>1.944 fluid‐filled porous/fractured or partially molten rocks) if the information about the wave propagation‐polarization directions with respect to the tectonic framework is unknown. However, the variations in Vp/Vs measured from borehole seismic experiments can be readily interpreted according to the orientations of the ray path and the polarization of the shear waves with respect to the present‐day principal stress directions (i.e., the orientation of cracks) and the frozen fabric (i.e., foliation and lineation).
Risk Assessment and Treatment Countermeasures for the Barrier Lakes of Wenchuan Earthquake on May 12th, 2008
Authors: ZHANG Fawang , ZHANG Zhaoji , HAN Zhantao , SUN Jianping , XIAO Guoqiang 
Published: August 2010

Abstract:This paper introduced the first hand investigation results of the risk and treatment measures for the barrier lakes triggered by the earthquake of Wenchuan. Characteristics of 10 barrier lakes were investigated and analyzed; procedure and methods for barrier lake treatment were brought forward. The dams of the barrier lakes can be classified as two classes: block rock in the south and loose deposit in the north. All the barrier dams were stable at the time of investigation, but water drainage channel needed to be constructed and to be protected from blockage or collapse. After the rain season of 2008, some dams needed to be consolidated, and change the barrier lakes to reservoirs.
Lithostratigraphy, Sedimentology, and Provenance of the Balfour Formation (Beaufort Group) in the Fort Beaufort–Alice Area, Eastern Cape Province, South Africa
Authors: KATEMAUNZANGA David , GUNTER Cornelis Janse 
Published: August 2010

Abstract:The Balfour Formation has a pronounced lithological variation that is characterized by alternating sandstone‐ and mudstone‐dominated members. The sandstone‐dominated Oudeberg and Barberskrans Members are composed of lithofacies that range from intraformational conglomerates to fine‐grained sediments, whereas the mudstone‐dominated members (Daggaboersnek, Elandsberg, and Palingkloof) are dominated by the facies Fm and FI. Petrography, geochemistry, and a paleocurrent analysis indicated that the source rock of the Balfour Formation was to south east and the rocks had a transitional/dissected magmatic arc signature. The sandstones‐rich members were deposited by seasonal and ephemeral high‐energy, low‐sinuous streams, and the fine‐grained‐rich members were formed by ephemeral meandering streams. The paleoclimates have been equated to present temperate climates; they were semiarid becoming arid towards the top of the Balfour Formation. This has been determined by reconstructing the paleolatitude of the Karoo Basin, geochemistry, paleontology, sedimentary structures, and other rock properties, like color.
Palladium, Platinum and Gold Concentrations in Fengshan Porphyry Cu–Mo Deposit, Hubei Province, China
Authors: WANG Minfang , DENG Xiaodong , BI Shijian , LI Zhanke 
Published: August 2010

Abstract:The Fengshan porphyry‐skarn copper–molybdenum (Cu–Mo) deposit is located in the south‐eastern Hubei Province in east China. Cu–Mo mineralization is hosted in the Fengshan granodiorite porphyry stock that intruded the Triassic Daye Formation carbonate rocks in the early Cretaceous (∼140 Ma), as well as the contact zone between granodiorite porphyry stock and carbonate rocks, forming the porphyry‐type and skarn‐type association. The Fengshan granodiorite stock and the immediate country rocks are strongly fractured and intensely altered by hydrothermal fluids. In addition to intense skarn alteration, the prominent alteration types are potassic, phyllic, and propylitic, whereas argillation is less common. Mineralization occurs as veins, stock works, and disseminations, and the main ore minerals are chalcopyrite, pyrite, molybdenite, bornite, and magnetite. The contents of palladium, platinum and gold (Pd, Pt and Au) are determined in nine samples from fresh and mineralized granodiorite and different types of altered rocks. The results show that the Pd content is systematically higher than Pt, which is typical for porphyry ore deposits worldwide. The Pt content ranges from 0.037 to 1.765 ppb, and the Pd content ranges between 0.165 and 17.979 ppb. Pd and Pt are more concentrated in porphyry mineralization than skarn mineralization, and have negative correlations with Au. The reconnaissance study presented here confirms the existence of Pd and Pt in the Fengshan porphyry‐skarn Cu–Mo deposit. When compared with intracontinent and island arc geotectonic settings, the Pd, Pt, and Au contents in the Fengshan porphyry Cu–Mo deposit in the intracontinent is lower than the continental margin types and island are types. A combination of available data indicates that Pd and Pt were derived from oxidized alkaline magmas generated by the partial melting of an enriched mantle source.
FIAs (Foliation Intersection/Inflection Axes) Preserved in Porphyroblasts, the DNA of Deformation: A Solution to the Puzzle of Deformation and Metamorphism in the Colorado, Rocky Mountains, USA
Authors: SHAH Afroz Ahmad 
Published: August 2010

Abstract:FIAs have been used extensively for more than a decade to unravel deformation and metamorphic puzzles. Orogenic processes developing early during the history or orogenesis challenge scientists because compositional layering in rocks always reactivates where multiple deformations have occurred, leaving little evidence of the history of foliation development preserved in the matrix. The foothills of the Rocky Mountains in Colorado, USA contain a succession of four FIA sets (trends) that would not have been distinguishable if porphyroblasts had not grown during the multiple deformation events that affected these rocks or if they had rotated as these events took place. They reveal that both the partitioning of deformation and the location of isograds changed significantly as the deformation proceeded.
Discovery of Radiolaria from the Zongzhuo Formation in Tianba, Kangmar, Tibet and its Age Implication
Authors: LI Guobiao , XIE Dan , WAN Xiaoqiao , HAN Hongdou , CHEN Puli 
Published: August 2010

Abstract:There is a group of variegated marine deposits, including the red beds widespread in the area of Tianba, Kangmar, southern Tibet, which previous works have contributed to Cretaceous Zongzhuo Formation by lithologic associations only, but with poor fossil evidence. Due to the absence of age dating fossils, the red bed age is obscure. Abundant Cretaceous radiolaria were discovered from the Zongzhuo Formation in the present study. In spite of the poor general preservation of some radiolarian specimens as recrystallized quartz infillings, 58 species from 46 genera of radiolaria, extracted from chert and silicous limestone of the Zongzhuo Formation in Kangmar, were identified on the basis of their shape and ornamentation. Based on the radiolaria, the age of the Zongzhuo Formation of this area has been referred to as Late Cretaceous. The new radiolarian data from the Zongzhuo Formation of Tianba area provide a local basis to correlate these deposits with other regions of the Tethyan Himalaya.