bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel role for SarX in Staphylococcus epidermidis biofilm regulation
Authors: Rowe Sarah E. , Mahon Vivienne , Smith Stephen G. , O'Gara James P.
Published: February 2011

Biofilm production by staphylococci is an important virulence determinant mediated by the icaADBC-encoded polysaccharide intercellular adhesin (PIA) or by surface and extracellular proteins. Deletion of the Staphylococcus accessory regulator sarX significantly reduced biofilm-forming capacity in Staphylococcus epidermidis CSF41498, whereas multicopy sarX complemented the sarX mutant and increased wild-type biofilm production. In Staphylococcus aureus, SarX negatively regulates the accessory gene regulator (Agr) system, which in turn has strain-specific effects on biofilm regulation. Here we found that purified S. epidermidis SarX protein bound specifically to the agr P3 promoter. However RT-PCR analysis revealed that both mutation of sarX and multicopy sarX activated RNAIII transcription, making it difficult to correlate sarX-mediated biofilm regulation with altered agr activity. In contrast, RT-PCR and immunoblot analysis revealed that icaA transcription and PIA expression were decreased in the sarX mutant, whereas multicopy sarX increased ica and PIA expression. Furthermore, multicopy sarX did not promote biofilms in an icaC mutant. Finally, purified SarX protein bound specifically to the ica operon promoter. Taken together, these data reveal that the S. epidermidis SarX protein regulates the transcriptional activity of the agr and ica loci and controls the biofilm phenotype, primarily by regulating icaADBC transcription and PIA production.
Dioxin receptor and SLUG transcription factors regulate the insulator activity of B1 SINE retrotransposons via an RNA polymerase switch
Authors: Román Angel Carlos , González-Rico Francisco J. , Moltó Eduardo , Hernando Henar , Neto Ana , Vicente-Garcia Cristina , Ballestar Esteban , Gómez-Skarmeta José L. , Vavrova-Anderson Jana , White Robert J. , Montoliu Lluís , Fernández-Salguero Pedro M.
Published: February 2011

Complex genomes utilize insulators and boundary elements to help define spatial and temporal gene expression patterns. We report that a genome-wide B1 SINE (Short Interspersed Nuclear Element) retrotransposon (B1-X35S) has potent intrinsic insulator activity in cultured cells and live animals. This insulation is mediated by binding of the transcription factors dioxin receptor (AHR) and SLUG (SNAI2) to consensus elements present in the SINE. Transcription of B1-X35S is required for insulation. While basal insulator activity is maintained by RNA polymerase (Pol) III transcription, AHR-induced insulation involves release of Pol III and engagement of Pol II transcription on the same strand. B1-X35S insulation is also associated with enrichment of heterochromatin marks H3K9me3 and H3K27me3 downstream of B1-X35S, an effect that varies with cell type. B1-X35S binds parylated CTCF and, consistent with a chromatin barrier activity, its positioning between two adjacent genes correlates with their differential expression in mouse tissues. Hence, B1 SINE retrotransposons represent genome-wide insulators activated by transcription factors that respond to developmental, oncogenic, or toxicological stimuli.
New Material of Sinosauropteryx (Theropoda: Compsognathidae) from Western Liaoning, China
Authors: Shu'an JI , Chunling GAO , Jinyuan LIU , Qingjin MENG , Qiang JI
Published: February 2011

Abstract: An incomplete specimen of Sinosauropteryx prima collected from the Early Cretaceous Yixian Formation of the Dawangzhangzi area in Lingyuan, western Liaoning is depicted. It represents the first systematically described material of this feathered compsognathid outside the Sihetun area in Beipiao. This specimen shows some diagnostic features of Sinosauropteryx prima, such as the very short forelimb in relation to hindlimb with the length ratio of humerus plus radius to femur plus tibia just around 30%, and the long and massive first manual ungual subequal in length to radius. The presence of Sinosauropteryx prima only at Sihetun and Dawangzhangzi supports the suggestion that the fossil‐bearing beds in the Sihetun and Dawangzhangzi areas are equivalent to each other within the Yixian Formation.
High Temperature as a Mechanism for Plant Cytoplasm Preservation in Fossils
Authors: Xin WANG
Published: February 2011

Abstract: Because the cytoplasm of a plant normally degrades after the death of the plant, finding cytoplasm in a plant body after a prolonged period of time, especially in fossil plants, is unexpected. Recent work on several 100‐Myr‐old plant fossils from Kansas, USA indicates, however, that cells and their contents can be preserved. Most of the cells in these fossil plants appear to be in a state of plasmolysis, and these fossil cells bear a strong resemblance to laboratory‐baked cells of extant plant tissues. Based on a comparison with extant material plus biophysical and biochemical analyses of the cytoplasm degrading process, a new hypothesis for cytoplasm preservation in nature is proposed: high temperature, a concomitant of commonly seen wildfires, may preserve cytoplasm in fossil plants. This hypothesis implies that fossilized cytoplasm should be rather common and an appropriate substance for research, unlike previously thought. Research on fossil cytoplasm closely integrates paleobotany with biochemistry, biophysics, as well as fire ecology, and invites inputs from these fields to paleobotany to interpret these provocative findings.
Organic Carbon Isotopic Evolution during the Ediacaran‐Cambrian Transition Interval in Eastern Guizhou, South China: Paleoenvironmental and Stratigraphic Implications
Authors: Xinglian YANG , Maoyan ZHU , Qingjun GUO , Yuanlong ZHAO
Published: February 2011

Abstract: Secular variations of carbon isotopic composition of organic carbon can be used in the study of global environmental variation, the carbon cycle, stratigraphic delimitation, and biological evolution, etc. Organic carbon isotopic analysis of the Nangao and Zhalagou sections in eastern Guizhou reveals a negative excursion near the Precambrian‐Cambrian boundary that correlates with a distinct carbonate carbon isotopic negative excursion at this boundary globally. Our results also demonstrate that several alternating positive and negative shifts occur in the Meishucunian, and an obvious negative anomaly appears at the boundary between the Meishucunian and Qiongzhusian. The isotope values are stable in the middle and lower parts but became more positive in the upper part of the Qiongzhusian. Evolution of organic carbon isotopes from the two sections in the deepwater facies can be well correlated with that of the carbonate carbon isotopes from the section in the shallow water facies. Integrated with other stratigraphic tools, we can precisely establish a lower Cambrian stratigraphic framework from shallow shelf to deep basin of the Yangtze Platform.
Zoned Zircon from Eclogite Lenses in Marbles from the Dabie‐Sulu UHP Terrane, China: A Clear Record of Ultra‐deep Subduction and Fast Exhumation
Authors: Fulai LIU , GERDES A. , ROBINSON P. T. , Huaimin XUE , Jianguo YE
Published: February 2011

Abstract: Eclogite lenses in marbles from the Dabie‐Sulu ultrahigh‐pressure (UHP) terrane are deeply subducted meta‐sedimentary rocks. Zircons in these rocks have been used to constrain the ages of prograde and UHP metamorphism during subduction, and later retrograde metamorphism during exhumation. Inherited (detrital) and metamorphic zircons were distinguished on the basis of transmitted light microscopy, cathodoluminescence (CL) imaging, trace element contents and mineral inclusions. The distribution of mineral inclusions combined with CL imaging of the metamorphic zircon make it possible to relate zircon zones (domains) to different metamorphic stages. Domain 1 consists of rounded, oblong and spindly cores with dark‐luminescent images, and contains quartz eclogite facies mineral inclusion assemblages, indicating formation under high‐pressure (HP) metamorphic conditions of T = 571–668°C and P = 1.7‐2.02 GPa. Domain 2 always surrounds domain 1 or occurs as rounded and spindly cores with white‐luminescent images. It contains coesite eclogite facies mineral inclusion assemblages, indicating formation under UHP metamorphic conditions of T = 782–849°C and P > 5.5 GPa. Domain 3, with gray‐luminescent images, always surrounds domain 2 and occurs as the outermost zircon rim. It is characterized by low‐pressure mineral inclusion assemblages, which are related to regional amphibolite facies retrograde metamorphism of T = 600–710°C and P = 0.7‐1.2 GPa. The three metamorphic zircon domains have distinct ages; sample H1 from the Dabie terrane yielded SHRIMP ages of 245 ± 4 Ma for domain 1, 235 ± 3 Ma for domain 2 and 215 ± 6 Ma for domain 3, whereas sample H2 from the Sulu terrane yielded similar ages of 244 ± 4 Ma, 233 ± 4 Ma and 214 ± 5 Ma for Domains 1, 2 and 3, respectively. The mean ages of these zones suggest that subduction to UHP depths took place over 10–11 Ma and exhumation of the rocks occurred over a period of 19–20 Ma. Thus, subduction from ∼ 55 km to > 160 km deep mantle depth took place at rates of approximately 9.5–10.5 km/Ma and exhumation from depths >160 km to the base of the crust at −30 km occurred at approximately 6.5 km/Ma. We propose a model for these rocks involving deep subduction of continental margin Iithosphere followed by ultrafast exhumation driven by buoyancy forces after break‐off of the UHP slab deep within the mantle.
Fluidization: An Important Process in the Formation of the Qiyugou Au‐bearing Breccia Pipes in Central China
Authors: Yuanhou ZHANG , Shihong ZHANG , PIRAJNO Franco
Published: February 2011

Abstract:Fluidization processes based on experiments are reviewed to gain some useful insights and comparisons with those that occur in hydrothermal systems. Field and petrographic work, and microscope observation were carried out on samples from the Qiyugou Au‐bearing breccia pipes from the East Qinling region, Henan Province. Evidence from macro‐ and micro‐textures suggests that the style of breccias in the Qiyugou area can be grouped into three types: (1) jigsaw fit‐stockwork texture, in which the interval between clasts is marked by fractures or filled with calcite or quartz veins; (2) larger breccias that are supported by smaller breccias, rock flour and alteration materials; in this type clasts moved over short distances, creating open spaces; (3) fluidized texture, where the clasts of different lithologies have rounded shapes. These observations are compared with those resulting from experiments on fluidization processes. The results of this comparison suggest that fluidization is an important geological process in the formation of the Qiyugou Au‐bearing breccia pipes and gold mineralization. In addition, fluidization processes such as expansion, bubbling, slugging, channeling and spouting must have contributed to the formation of the pipes and were conducive to the development of gold mineralization. In the Qiyugou breccia pipes, gold mineralization occurs as disseminations, in stockwork veins, and open space infills. The ore zones form subparallel sheets that are nearly perpendicular to the walls of the pipes.
SHRIMP Zircon U‐Pb Dating of Gabbro and Granite from the Huashan Ophiolite, Qinling Orogenic Belt, China: Neoproterozoic Suture on the Northern Margin of the Yangtze Craton
Authors: Yuruo SHI , Dunyi LIU , Zongqing ZHANG , Laicheng MIAO , Fuqin ZHANG , Hongmei XUE
Published: February 2011

Abstract: The recently identified Huashan ophiolitic mélange was considered as the eastern part of the Mianlüe suture in the Qinling orogenic belt. SHRIMP zircon U‐Pb geochronology on gabbro from the Huashan ophiolite and granite intruding basic volcanic rocks indicates crystallization ages of 947 ± 14 Ma and 876 ± 17 Ma respectively. These ages do not support a recently proposed Hercynian Huashan Ocean, but rather favor that a Neoproterozoic suture assemblage (ophiolite) is incorporated into the younger (Phanerozoic) Qinling orogenic belt.
Evolution of the Mesozoic Granites in the Xiong'ershan‐Waifangshan Region, Western Henan Province, China, and Its Tectonic Implications
Authors: Yigui HAN , Shihong ZHANG , PIRAJNO Franco , Yuanhou ZHANG
Published: February 2011

Abstract: Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan‐Waifangshan region in western Henan Province: high‐Ba‐Sr I‐type granite emplaced in the early stage (∼160 Ma), I‐type granite in the middle stage (∼130 Ma) and anorogenic A‐type granite in the late stage (∼115 Ma). Geochemical characteristics of the high‐Ba‐Sr I‐type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39 Ar plateau ages of the early‐stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle‐stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U‐Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A‐type granite, Taishanmiao pluton, was emplaced at ∼115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post‐collisional to anorogenic between ∼160 Ma and ∼115 Ma. The genesis of the early‐ and middle‐stage I‐type granites could be linked to delamination of subducted lithosphere of the Qinling orogenic belt, while the late‐stage A‐type granites represent the onset of extension and the end of orogenic process. In fact, along the Qinling ‐Dabie‐Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios, which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons.
Chronology and Geochemistry of Volcanic Rocks in the Cretaceous Suifenhe Formation in Eastern Heilongjiang, China
Authors: Weiqiang JI , Wenliang XU , Debin YANG , Fuping PEI , Ke JIN , Xiaoming LIU
Published: February 2011

Abstract: Zircon U‐Pb ages and geochemical data of volcanic rocks in the Suifenhe Formation in eastern Heilongjiang Province are reported, and their petrogenesis is discussed in this paper. The Suifenhe Formation mainly consists of basalt, andesite, and dacite. Zircon from andesite and dacite are euhedral in shape and show typical oscillatory zoning with high Th/U ratios (0.18‐0.57), implying its magmatic origin. Zircon U‐Pb dating results by laser ablation inductively coupled plasma mass spectrometer (LA‐ICP‐MS) indicate that the 206Pb/238U ages of zircons from andesite range within 105–106 Ma, yielding a weighted mean age of 105.5±0.8 Ma (n=14), and that 206Pb/238U ages of zircons from dacite are between 90–96 Ma, yielding a weighted mean age of 93.2±1.3 Ma (n =13). The volcanic rocks from the Suifenhe Formation are subalkaline series and show a calc‐alkaline evolutionary trend with SiO2 content of 47.69%‐65.47%, MgO contents of 1.42%‐6.80% (Mg− = 45–53), and Na2O/K2O ratios of 1.83‐3.63. They are characterized by enrichment in large ion lithophile elements (LILE) and light‐rare‐earth elements (LREE), depletion in heavy rare earth elements (HREE) and high field strength elements (HFSE) (e.g., Nb, Ta, Ti), and low initial 87Sr/86 Sr ratios (0.7041‐0.7057) and positive øNd(t) values (0.39‐4.08), implying that they could be derived from a depleted magma source. Taken together, these results suggest that the primary magma of the volcanic rocks might originate from partial melting of the mantle wedge metasomatized by fluids derived from subducted slab under a tectonic setting of active continental margin.
Composite Metallogenic Systems in the Weihai Area of Shandong and Evolution of Continental Dynamic Regimes
Authors: Zhongshi SUN , Peifu WANG , Jun DENG , Qingfei WANG , Jianping WANG , Taisheng MU , Li SUN , Siqi FAN , Songqing YE , Zhenghong LIU , Shuxue CUI
Published: February 2011

Abstract: Based on 9 sheets of l:50,000‐scale regional geological survey and guided by the theory of metallogenic systems and integrated analyses of the structural and metallogenic features, this paper hereby puts forward the composite metallogenic systems of the Weihai area, Shandong Province, aiming at solving the problems on the origins and ore‐controlling structures of the numerous deposits in the area. Its scientific significance is reflected in the following three aspects: (1) The basic features of the composite metallogenic systems can be recognized, which consist of two types: the Proterozoic metamorphic‐hydrothermal metallogenic system and the Mesozoic magmatic‐hydrothermal metallogenic system (i.e. the Indosinian‐early Yanshanian contact metasomatic metallogenic series and the mid‐late Yanshanian magmatic‐hydrothermal metallogenic series). The two series display arcuate and NW‐right lateral arrangements and a N‐S parallel zonal distribution respectively, with the corresponding mineral assemblages being Au+Ag+Pb+Zn, etc.; and Cu+Mo+Fe, Au+Ag+Cu+Pb‐Zn+Mo+Co‐Ni+suIfides+silicides+K‐feldspar, etc. (2) The composite metallogenic systems may be used to interpret the complicated genetic relations of the deposits. Through analyses of the relations between the three main metallogenic intervals and their corresponding source rock series (the Jingshan and Rongcheng groups; the Wendong super‐unit and the early‐middle Yanshanian Weideshan super‐unit; and the mid‐late Yanshanian Weideshan and Laoshan super‐units) as well as a case study of the Fanjiabu gold deposit, we have distinguished the consanguinity between the contact metasomatic (skarn‐type) metallogenic series and the magmatic‐hydrothermal metallogenic series as well as the noncognate superposition between the two and the metamorphic‐hydrothermal metallogenic system. (3) The composite metallogenic systems are easily related to the evolution of continental dynamic regimes. The formation of the metamorphic‐hydrothermal metallogenic system has undergone transformations of three different types of tectono‐dynamic regimes from extensionŕcompressionŕshearing that of the contact metasomatic (skarn‐type) metallogenic system from compressionŕextensionŕcompression; and that of the magmatic‐hydrothermal metallogenic system from extensionŕsubductive compression of the Pacific Plate. The evolutions of the three types are all attributed to the opening‐closing or divergence‐convergence of the paleocontinent, and all their mineralization corresponds to the interval of transformation from the end of convergence to early integration of the Weihai paleocontinent. All these will benefit our deeper study of the dynamics of continental metallogenic processes.
SHRIMP U‐Pb Zircon Age of the Ka'erjiao Intrusion in the Sawur Region in West Junggar, Xinjiang
Authors: Taofa ZHOU , Lugui TAN , Yu FAN , Feng YUAN , Wenping YANG , Lixin HE , Shucang YUE
Published: February 2011

Abstract: Acid intrusions are widespread in the Sawur region, Xinjiang. The Ka'erjiao intrusion is mainly composed of albite granite porphyry, K‐feldspar granite porphyry, ivernite and granite porphyry. Being a transitional product between magma intrusion and eruption in the Sawur region, the Ka'erjiao intrusion was formed at the telophase of the late Carboniferous to the begining of early Permian as determined by the SHRIMP U‐Pb zircon dating, with an age of 302.6±7.6 Ma (1 γ). The intrusion consists of alkali‐enriched rock, whose REE distribution patterns are of the LREE enrichment type, the δEu value is low and Nd, Sr, Pb isotopes reflect its mantle source characteristics. The δ18O value of intrusion is low as a result of isotope exchange with meteoric water. The geochemical characteristics show that it was formed in a post‐collisional tectonic setting. Taking combined considerations of current studies of A‐type granites and Permian volcanic rocks, we think that in the telophase of the late Carboniferous to the beginning of the early Permian, the Sawur region was within the extension or compressional to extensional period of a post‐collisional stage. The Ka'erjiao intrusion from mantle sources can confirm the vertical continental crust growth in the late Paleozoic. The Sawur region in west Junggar is consistent with east Junggar in post‐collisional tectonic evolution process.
Experimental Study on Treatment of High‐concentrated Sulfur Wastewater by Process of Depositing Natrojarosite and Its Environmental Significance
Authors: Shengfeng MA , Changqiu WANG , Anhuai LU , Yanjun GUO , Hongliao HE
Published: February 2011

Abstract: High‐concentrated sulfur wastewater with sodium and COD (chemical oxygen demand) up to 26000 mg/L from a chemical plant, Jiangsu Province of China has been treated by deposition of natrojarosite in lab. The results indicated that the COD of the wastewater was decreased sharply from 26000 mg/L to 1001 mg/L, with removal rate of COD up to 96% by twice precipitations of natrojarosite and twice oxidation of H2O2. The treated sulfur wastewater reached the requirement of subsequent biochemical treatment to water quality. The optimal operational parameters should be controlled on pH value between 2.50 and 3.20 and 50 g FeCl3˙6H2O solid added in per liter wastewater. The study provided an experimental basis for pretreatment of high‐concentrated sulfur wastewater and proposed a new mineralogical method on treatment of other wastewaters. Depositing process of jarosite and its analogs should be able to be used to treat wastewater from mine and other industries to remove S, Fe and other toxic and harmful elements, such as As, Cr, Hg, Pb, etc. in the water.
Jinfengopteryx Compared to Archaeopteryx, with Comments on the Mosaic Evolution of Long‐tailed Avialan Birds
Authors: Shu'an JI , Qiang JI
Published: February 2011

Abstract: Jinfengopteryx is a newly uncovered Archaeopteryx‐like avialan bird outside Germany, which was found from the Jehol Biota of northern Hebei in northeastern China. It shares many characters only with Archaeopteryx by the possession of three fenestrae in the antorbital cavity, 23 caudal vertebrae and long tail feathers attached to all the caudal vertebrae. But the former differs from the latter in the relatively short and high preorbital region of skull, more and closely packed teeth, much shorter forelimb compared to hindlimb. Such differences indicate Jinfengopteryx is even slightly more primitive than Archaeopteryx, although both birds can be placed at the root position of the avialan tree based on cladistic analysis. Shenzhouraptor is suggested to be slightly more advanced than Jinfengopteryx + Archaeopteryx, supported by some derived features in teeth, shoulder girdles and forelimbs such as the reduction of tooth number, dorsolaterally directed glenoid facet, very long forelimb and comparatively short manus. Meanwhile, the tail of Shenzhouraptor shows more primitive characters than those of Jinfengopteryx and Archaeopteryx, e.g., the strikingly longer tail composed of more caudal vertebrae and the long tail feathers attached only to distal caudal segments. The mixed primitive and advanced characters reveal the evident mosaic evolution among long‐tailed avialan birds.
The First Stegosaur (Dinosauria, Ornithischia) from the Upper Jurassic Shishugou Formation of Xinjiang, China
Authors: Chengkai JIA , FOSTER Catherine A. , Xing XU , CLARK James M.
Published: February 2011

Abstract: A new stegosaur species, Jiangjunosaurus junggarensis, gen. et sp. nov., is erected based on a specimen collected from the Upper Jurassic upper section of the Shishugou Formation in the Junggar Basin, Xinjiang, China. It represents the first stegosaur from the Jurassic of Xinjiang and increases the diversity of the dinosaur fauna in the Shishugou Formation. The new genus is characterized by symmetrical and proportionally wide tooth crowns, a sub‐rectangular axial neural spine seen in lateral view, and large openings on the lateral surfaces of the cervical centra. A preliminary character analysis suggests that this new taxon is more derived than the Middle Jurassic stegosaur Huayangosaurus but more primitive than most other known stegosaur species.
Mesoproterozoic Earthquake Events and Breakup of the Sino‐Korean Plate
Authors: Xiufu QIAO , Linzhi GAO , Yang PENG
Published: February 2011

Abstract: In the Mesoproterozoic time, the northern part of the Sino‐Korean Plate experienced a period of intensive tectonic extension and breakup. 1. An abundance of sedimentary earthquake records is preserved in the Chuanlinggou, Tuanshanzi and Gaoyuzhuang formations in the Mesoproterozoic Changcheng System (1800‐1400 Ma) and in the Mesoproterozoic Wumishan Formation of the Jixian System (1400‐1000 Ma). These earthquake records are characterized by various liquefied sand‐veins, carbonate microspar and coarser spar veins, limestone dikes, liquefied breccia and various forms of liquefied contorted bedding. This deformation is always associated with synsedimentary faults and igneous activity. 2. Three liquefaction models for soft carbonate sediments are recognized, including liquefaction in laminated carbonate rocks, liquefaction in thin‐bedded carbonates and large‐scale liquefaction along huge carbonate dikes. 3. Based on the record of earthquake and volcanic activities, the Sino‐Korean Plate experienced at least twice intraplate breakups. One occurred between 1800‐1400 Ma, and the other occurred at about 1200 Ma. The last breakup resulted in formation of the Yan‐Liao aulacogen, a tectonic zone characterized by deeper material vibrancy, active faults, major igneous activity and frequent earthquakes.
Sedimentology and Chronology of Paleogene Coarse Clastic Rocks in East‐Central Tibet and Their Relationship to Early Tectonic Uplift
Authors: Jiangyu ZHOU , Jianghai WANG , BRIAN K. H. , YIN A. , MATTHEW M. S.
Published: February 2011

Abstract: A systematic sedimentological and chronological study of typical Paleogene basins in east‐central Tibet suggests that the depositional characteristics of extensively developed huge‐bedded, purplish‐red coarse clastic rocks formed in a tectonic setting of regional thrusting and strike‐slipping represent a typical dry and hot subaerial alluvial fan environment formed in a proximal and rapid‐accumulating sediment body in debris flows and a fan‐surface braided river. Combining results from basin‐fill sequences, sequences of coarse clastic rocks, fauna and sporo‐pollen associations and thermochronological data, it is concluded that the coarse clastic rocks formed in the period of 54.2–24.1 Ma, nearly coeval with the formation of Paleogene basins in the northern (Nangqĉn‐Yushu thrust belt), middle (Batang‐Lijiang fault belt), and disintegration of large basins in the southern (Lanping‐Simao fold belt) segments of Tibet. The widespread massive‐bedded coarse clastic rocks, fold thrusting and strike‐slip, thrust shortening, and igneous activities in the Paleogene basins of east‐central Tibet indicate that an early diachronous tectonic uplift might have occurred in the Tibetan Plateau from Middle Eocene to Oligocene, related to the initial stage of collision of the Indian and Asian plates.
Provenance of Precambrian Fe‐ and Al‐rich Metapelites in the Yenisey Ridge and Kuznetsk Alatau, Siberia: Geochemical Signatures
Authors: LIKHANOV Igor I. , REVERDATTO Vladimir V.
Published: February 2011

Abstract: Major, trace and rare earth element contents of Fe‐ and Al‐rich metapelites from the Korda (Yenisey Ridge) and Amar (Kuznetsk Alatau) formations were determined to examine the nature, origin and evolution of their protoliths. Results indicate that these rocks are the redeposited and metamorphosed products of Precambrian kaolinitic weathering crusts, while the geochemical distinctions between the studied metapelites are determined by different weathering conditions in the source area and tectonic settings. The protolith of the Korda Formation metapelites was produced by erosion products of the post‐Archean granitoid rocks, which accumulated under humid climate conditions in shallow‐water basins along the continental margin. The geochemical characteristics of the deeper primary deposits of the Amar Formation suggest that volcanogenic material of mafic composition derived from an island‐arc environment had a major role in supplying the erosion zone. These results agree with lithofacies data and with the geodynamic reconstruction of the evolution of the Yenisey Ridge and Kuznetsk Alatau during the Mesoproterozoic and Neoproterozoic, respectively. It was shown that REEs had limited mobility during contact metamorphism. The coherent mobility of REEs during collisional metamorphism may be attributed both to mineral reactions responsible for modal changes and to local chemical heterogeneity inherited from the initial protolith.
Early Indosinian Weiya Gabbro in Eastern Tianshan, China: Elemental and Sr‐Nd‐O Isotopic Geochemistry, and Its Tectonic Implications
Authors: Zunzhong ZHANG , Lianxing GU , Changzhi WU , Jianping ZHAI , Weiqiang LI , Junhua TANG
Published: February 2011

Abstract: The Weiya gabbro in eastern Tianshan was formed during the early Indosinian. This rock, with low ratios of Ce/Pb (5.74‐10.16), is notably characterized by enrichment in large ion lithophile elements (LILE), such as Rb, K, Ba and Pb, and in high field strength elements (HSFE), such as U and Th, but depletion in Nb and Ta. All samples of the Weiya gabbro display similar chondrite‐normalized patterns with moderate enrichment in LREE (72.58–135.61ppm), moderate depletion in HREE (15.26‐25.31 ppm) and mild fractionation between LREE and HREE (L/H=4.09‐5.98). The average initial Sr value of the rock is 0.7069, and δ18 O values of the rock range from 5.67%‐8.04%. In terms of Nd isotope ratios, the Weiya gabbro is characterized by positive Nd(t) values (0.52‐0.76). All these characteristics indicate that the source region of the Weiya gabbro was metasomatized by fluids released from subducted young continental crust, with limited crustal contamination during magma ascent and emplacement. Continental (A‐type) subduction was induced by northward subduction of the Paleo‐Tethyan oceanic plate during the latest Permian to Triassic. From this point of view, it is supposed that tectonic conversion from the Paleo‐Asian to the Paleo‐Tethys regime occurred during the latest Permian or earliest Triassic.
REE Geochemistry of Sulfides from the Huize Zn‐Pb Ore Field, Yunnan Province: Implication for the Sources of Ore‐forming Metals
Authors: Wenbo LI , Zhilong HUANG , Liang QI
Published: February 2011

Abstract: REE abundances in sulfides from the Huize Zn‐Pb ore field were determined with the ICP‐MS after preconcentration. The REE abundances in 26 sulfide samples (including pyrite, galena and sphalerite) are very low, with the s̀REE ranging from 1.6times10−9 to 166.8times10−9. Their LREE/HREE ratios range from 7.6 to 98, showing LREE enrichment relatively. The δEu values are below 1, indicating that they were deposited from an Eu‐depleted and reducing fluid‐system. Similar to the ore‐hosting carbonate strata, calcite separates from carbonate veinlets filling in the fractures or faults crosscutting the carbonate strata also show clear Eu‐depletion. This indicates that the carbonate veinlets and their parent fluid was possibly sourced from the strata and inherited the REE geochemical features of the strata. Therefore, REE‐geochemical characteristics of both the sulfides and calcites, which were deposited from an ore‐forming hydrothermal system, are similar to those of carbonate strata, and strongly suggest that the ore metals were mainly sourced from carbonate strata.
In, Sn, Pb and Zn Contents and Their Relationships in Ore‐forming Fluids from Some In‐rich and In‐poor Deposits in China
Authors: Qian ZHANG , Xiaoqing ZHU , Yuliang HE , Zhaohui ZHU
Published: February 2011

Abstract: All the indium‐rich deposits with indium contents in ores more than 100times10−6 seems to be of cassiterite‐sulfide deposits or Sn‐bearing Pb‐Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn‐Zn deposit in Yunnan, and the Meng'entaolegal Ag‐Pb‐Zn deposit in Inner Mongolia, the indium contents in ores range from 98times10−6 to 236times10−6 and show a good positive correlation with contents of zinc and tin, and their correlation coefficients are 0,8781 and 0.7430, respectively. The indium contents from such Sn‐poor deposits as the Fozichong Pb‐Zn deposit in Guangxi and the Huanren Pb‐Zn deposit in Liaoning are generally lower than 10times10−6, i.e., whether tin is present or not in a deposit implies the enrichment extent of indium in ores. Whether the In enrichment itself in the ore ‐forming fluids or the ore‐forming conditions has actually caused the enrichment/depletion of indium in the deposits? After studying the fluid inclusions in quartz crystallized at the main stage of mineralization of several In‐rich and In‐poor deposits in China, this paper analyzed the contents and studied the variation trend of In, Sn, Pb and Zn in the ore‐forming fluids. The results show that the contents of lead and zinc in the ore‐forming fluids of In‐rich and ‐poor deposits are at the same level, and the lead contents range from 22times10−6 to 81times10−6 and zinc from 164times10−6 to 309times10−6, while the contents of indium and tin in the ore‐forming fluids of In‐rich deposits are far higher than those of In‐poor deposits, with a difference of 1–2 orders of magnitude. Indium and tin contents in ore‐forming fluid of In‐rich deposits are 1.9times10−6‐4.1times10‐6 and 7times10−6‐55times10−6, and there is a very good positive correlation between the two elements, with a correlation coefficient of 0.9552. Indium and tin contents in ore‐forming fluid of In‐poor deposits are 0.03times10−6‐0.09times10−6 and 0.4times10−6‐2.0times10−6, respectively, and there is no apparent correlation between them. This indicates, on one hand, that In‐rich ore‐forming fluids are the material basis for the formation of In‐rich deposits, and, on the other hand, tin probably played a very important role in the transport and enrichment of indium.
40Ar/39 Ar Dating of the Shaxi Porphyry Cu‐Au Deposit in the Southern Tan‐Lu Fault Zone, Anhui Province
Authors: Xiaoyong YANG , Yongfei ZHENG , Yilin XIAO , Jianguo DU , Weidong SUN
Published: February 2011

Abstract: Four samples of plagioclase and biotite from the Shaxi porphyry in the lower part of the Yangtze metallogenic belt were analyzed for age determination with the 40Ar/39 Ar method. The results yield reproducible ages of 126 Ma to 135 Ma with a high level of confidence according to the agreement between isochron and plateau ages. The four Ar‐Ar ages are relatively consistent within the analytical error. These ages are also consistent with, but more precise than, previous K‐Ar and Rb‐Sr ages and thus provide better constraints on the time of porphyry formation and associated Cu‐Au mineralization along the middle to lower part of the Yangtze metallogenic belt. The ages of 126 to 135 Ma are interpreted to represent the intrusive time of the Shaxi porphyry, so that the Cu‐Au mineralization should have occurred later due to the post‐magmatic hydrothermal event.
Carbonate Sequence Stratigraphy of a Back‐Arc Basin: A Case Study of the Qom Formation in the Kashan Area, Central Iran
Authors: Guoqiang XU , Shaonan ZHANG , Zhongdong LI , Lailiang SONG , Huimin LIU
Published: February 2011

Abstract: The Qom Formation comprises Oligo‐Miocene deposits from a marine succession distributed in the Central Basin of Iran. It is composed of five members designated as A‐F. Little previous work exists on the sequence stratigraphy. Based on an integrated study of sequence stratigraphy with outcrop data, wells and regional seismic profiles, the Qom Formation is interpreted as a carbonate succession deposited in a mid‐Tertiary back‐arc basin. There are two second‐order sequences (designated as SS1 and SS2) and five third‐order sequences (designated as S1‐S5). Five distinct systems tracts including transgressive, highstand, forced regressive, slope margin and lowstand have been recognized. The relationship between the sequences and lithologic sub‐units has been collated and defined (S1 to S5 individually corresponding to A‐C1, C2‐C4, D‐E, the lower and upper portions of F); a relative sea level change curve and the sequence stratigraphic framework have been established and described in detail. The coincidence of relative sea level change between that of the determined back‐arc basin and the world indicates that the sedimentary cycles of the Qom Formation are mainly controlled by eustatic cycles. The variable combination of the systems tracts and special tectonic‐depositional setting causally underpin multiple sequence stratigraphic framework styles seen in the carbonates of the back‐arc basin revealing: (1) a continental margin basin that developed some form of barrier, characterized by the development of multiple cycles of carbonate‐evaporites; (2) a flat carbonate ramp, which occurred on the southern shelf formed by the lack of clastic supply from nearby magmatic islands plus mixed siliciclastics and carbonates that occurred on the northern shelf due to a sufficient clastics supply from the land; and (3) a forced regressive stratigraphic stacking pattern that occured on the southern shelf and in basin lows due to the uplifting of the southern shelf. Thick and widespread aggradational framework limestone usually occurs in the initial sequences (S1 and S3) of the supersequence, which led to preferential oil reservoir deposition but a lack of source and cap rocks, whereas the retrogradational and progradational framework limestone usually occurs in the later sequences (S2 and S4‐S5) of the supersequence, which results in two perfect sets of source, reservoir and cap rock assemblies, so that the limestone in sub‐member C2‐C4 and the F‐Member can be predicted as important objects for oil exploration.
Removal of Cadmium Ions from Aqueous Solution by Silicate‐incorporated Hydroxyapatite
Authors: Hebin SHI , Hong ZHONG , Yu LIU , Jinyang DENG
Published: February 2011

Abstract: This article reports a preliminary research on silicate‐incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate‐incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate‐incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate‐incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite, which were in favor of enhancing the cadmium ion sorption capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions.
Two Species of Zosterophyllum from South China and Dating of the Xujiachong Formation with a Biostratigraphic Method
Authors: Deming WANG
Published: February 2011

Abstract: Zosterophyllum longa sp. nov. is reported from the Lower Devonian Pingyipu Formation, Jiangyou District, northern Sichuan of China. This new plant has vertically elongate sporangia differing from all known species of Zosterophyllum, demonstrating morphological variations in Zosterophyllophytina. New materials of Zosterophyllum yunnanicum from the Lower Devonian Xujiachong Formation, Qujing District, eastern Yunnan of China show that fertile axes of this species are anisotomous or pseudomonopodial or K‐shaped in branching. Sometimes fertile lateral axes are very short and bear an axillary axis at the dividing point. Distinct thickening occurs along the whole margin of a sporangium, with sporangial lobes undeveloped. The evolution of Zosterophyllum is tentatively discussed. A biostratigraphic method of Gerrienne and Streel is introduced and applied to dating of the Lower Devonian Xujiachong Formation, which is considered as of the late Pragian‐early Emsian.
A Large Therizinosauroid (Dinosauria: Theropoda) from the Early Cretaceous of Northwestern China
Authors: Daqing LI , Cuo PENG , Hailu YOU , LAMANNA Matthew C. , HARRIS Jerald D. , LACOVARA Kenneth J. , Jianping ZHANG
Published: February 2011

Abstract: We herein describe an associated partial postcranial skeleton of a theropod dinosaur discovered in the Lower Cretaceous Xinminpu Group of the Yujingzi Basin, in the Jiuquan area of Gansu Province, northwestern China. Features of its humerus, such as strongly expanded proximal and distal ends, a well developed medial tuberosity, distal condyles expressed on the humeral cranial surface, and a hypertrophied entepicondyle, definitively establish the therizinosauroid affinities of the specimen. It differs from other therizinosauroids in having a shallow, poorly demarcated glenoid fossa with a prominent rounded and striated tumescence on the dorsomedial surface of its scapular portion, and a pubis with a strongly concave cranial margin. It represents a new taxon, Suzhousaurus megatherioides gen. et sp. nov. Cladistic analysis recovers Suzhousaurus as the sister taxon of Nothronychus mckinleyi from the mid‐Cretaceous of western North America; together, they are basal members of the Therizinosauroidea, more derived than the Early Cretaceous Falcarius and Beipiaosaurus but less derived than Alxasaurus and the Therizinosauridae. Along with “Nanshiungosaurus” bohlini from possibly coeval beds in the Mazongshan area of northern‐most Gansu, Suzhousaurus represents one of the largest‐known Early Cretaceous therizinosauroids, demonstrating that this clade attained considerable body size early in its evolutionary history.
The First Hadrosaurid Dinosaur from Southern China
Authors: Jinyou MO , Zhongru ZHAO , Wei WANG , Xing XU
Published: February 2011

Abstract: A new hadrosaurid dinosaur, Nanningosaurus dashiensis gen. et sp. nov., is described based on an incomplete skeleton from the Late Cretaceous red beds of the Nalong Basin, Guangxi, southern China. Diagnostic features for the new taxon include the presence of a tall and sharply peaked dorsal process of the maxilla with reduced process of the jugal and a distinct lacrimal facet, gracile humerus with low, rounded deltopectoral crest, mandibular condyle of the quadrate transversly broad with reduced paraquadrate notch, dentary tooth with sinuous median carina and subsidiary ridge, relatively few tooth positions, ischial shaft straight along most of its distance, but to curve dorsally and expand at the distal end before the ischial foot begins. Phylogenetic analysis suggests that Nanningosaurus dashiensis is a basal member of Lambeosaurinae.
A Characteristic Analysis of the Dynamic Evolution of Preseismic‐Coseismic‐Postseismic Interferometric Deformation Fields Associated with the M 7.9 Earthquake of Mani, Tibet in 1997
Authors: Xinjian SHAN , Guohong ZHANG
Published: February 2011

Abstract: By using the D‐InSAR technique, we have acquired the temporal‐spatial evolution images of preseismic‐cosesimci‐postseismic interferometric deformation fields associated with the M 7.9 earthquake of Mani, Tibet on 8 November 1997. The analysis of these images reveals the relationships between the temporal‐spatial evolution features of the interferometric deformation fields and locking, rupturing, and elastic restoring of the source rupture plane, which represent the processes of strain accumulation, strain release, and postseismic restoration. The result shows that 10 months prior to the Mani event, a left‐lateral shear trend appeared in the seismic area, which was in accordance with the earthquake fault in nature. The quantity of local deformation on the north wall was slightly larger than that on the south wall, and the deformation distribution area of the north wall was relatively large. With the event impending, the deformation of the south wall varied increasingly, and the deformation center shifted eastward. Two and half monthd before the event, the west side of the fault was still locked while the east side began to slide, implying that the whole fault would rupture at any moment. These features can be regarded as short‐term precursors to this earthquake. Within the period from 16 April 1996 to two and half months before the earthquake, the most remarkable deformation zones appeared in the north and south walls, which were parallel to and about 40 km apart from the fault, with accumulated local displacements of 344 mm and 251 mm on the north and south walls, respectively. The south wall was the active one with larger displacements. Five months after the earthquake, the distribution feature of interferometric fringes was just opposite to that prior to the event, expressing evident right‐lateral shear. The recovered displacements are ∼179 mm on the north wall and ∼79 mm on the south wall, close to the east side of the fault. However, in the area of the south wall far from the fault there still existed a trend of sinistral motion. The deformation of the north wall was small but recovered fast in a larger area, while the active south wall began to recover from the east section of the fault toward the WSW.
Active Tectonics of the Longmen Shan Region on the Eastern Margin of the Tibetan Plateau
Authors: Rongjun ZHOU , Yong LI , DENSMORE Alexander L. , ELLIS Michael A. , Yulin HE , Yongzhao LI , Xiaogang LI
Published: February 2011

Abstract: There is a massive amount of geomorphic evidence for active tectonics in the Longmen Shan at the eastern margin of the Tibetan plateau. We have surveyed some typical geomorphic markers including the Wenchuan‐Maowen, Beichuan‐Yingxiu and Pengxian‐Guanxian faults, terrace offsets, scarps, fault‐controlled saddles, dextral shutter ridges, dextral channel offsets, graben, shatter belts, and pull‐apart basins. Electron spin resonance (ESR) and thermoluminescence(TL) ages were obtained using silty sand taken from below the surface of the sediments. According to these data, we calculated the rates of thrusting and strike‐slip, and the results indicate that Cenozoic tectonic shortening at the plateau margin is minor with the rate of thrusting less than 1.10 mm/a and the rate of strike‐slipping less than 1.46 mm/a. The Longmen Shan is a zone of NNE‐trending dextral shear with slip‐dip ratio of 6:1‐1.3:1. From NW to SE, the thrust component becomes smaller, whereas the strike‐slip component becomes larger.
Early Pliocene Paleoceanography of the Vityaz Fracture Zone, Central Indian Ridge
Authors: GUPTHA M. V. S. , BANERJEE Ranadip , MERGULHAO Lina P. , BANERJEE Priyanka , PARTHIBAN G. , TEWARI Manish
Published: February 2011

Abstract: Planktic foraminifera from the calcareous substrate of a ferromanganese crust in the Vityaz Fracture Zone (VFZ), Central Indian Ridge were studied to reconstruct the early Pliocene paleoceanography of this region. Eleven species of planktic foraminifera were encountered, among them Globorotalia menardii, Neogloboquadrina dutertrei, Globigerina bulloides and Globigerinoides ruber are prominent. Predominance of N. dutertrei in the top 3 cm of the carbonate substrate is attributed to an influx of fresh water which eventually triggered their productivity by increasing the nutrient level. The presence of G. bulloides and G. menardii in significant proportions in deeper layers suggests the prevalence of open ocean upwelling. The bulk chemical compositions of the substrate at different depth intervals indicates higher enrichment of trace metals in the upper sections which could have been supplied through oceanic water by the chemical weathering of terrestrial matter during the peak of Pliocene Asian monsoon. Thus, it is concluded that during the early Pliocene the biogenic components of the substrate were distinctly contributed by both upwelling and productivity triggered by an influx of fresh water originating from the intensification of the Asian monsoon during the early Pliocene Period.