• Volume 88,Issue 6,2014 Table of Contents
    Select All
    Display Type: |
    • Comparative Osteology and Phylogenetic Relationship of Edmontosaurus and Shantungosaurus (Dinosauria: Hadrosauridae) from the Upper Cretaceous of North America and East Asia

      2014, 88(6):1623-1652.

      Abstract (3866) HTML (0) PDF 36.10 M (2599) Comment (0) Favorites

      Abstract:Abstract: The close affinity between Edmontosaurus and Shantungosaurus is corroborated on the basis of the following shared features: an occipital condyle deflected strongly posteroventrally; a posterodorsally reflected, lip-shaped oral margin of the premaxilla, with a deep, oval concavity at the anteromedial corner of the bone; a well-demarcated posterodorsal margin of the deeply excavated circumnarial fossa formed by a prominent arched ridge along the entire posterior half of the lateroventral border of the nasal; an anteroposteriorly broad jugal process of the postorbital; a strongly concave dorsal surface of the paired frontals; seven teeth per alveolus in the middle of the dentary tooth row; and a circular distal blade of the pubis that is much more expanded ventrally than dorsally. A revised phylogenetic analysis of Hadrosauroidea recovers a sister taxon relationship between Edmontosaurus and Shantungosaurus. Kerberosaurus is recovered as the sister taxon to the clade formed exclusively by these two genera. The clade Edmontosaurini could be defined as the least inclusive clade containing Kerberosaurus and Edmontosaurus, which is currently composed of the genera Kerberosaurus, Edmontosaurus, and Shantungosaurus. Zhuchengosaurus and Huaxiaosaurus, both from the Upper Cretaceous Wangshi Group in Zhucheng, are interpreted as junior synonyms of Shantungosaurus. Kundurosaurus is likewise considered a junior synonym of Kerberosaurus. The strict consensus tree together with biogeographic information indicates that the clade Edmontosaurini originated in Asia and subsequently dispersed into North America.

    • Braincase Anatomy of the Basal Theropod Sinosaurus from the Early Jurassic of China

      2014, 88(6):1653-1664.

      Abstract (3518) HTML (0) PDF 14.04 M (2669) Comment (0) Favorites

      Abstract:Abstract: The neuroanatomy of the mid-sized theropod Sinosaurus triassicus from the Lower Jurassic Lufeng Formation, Lufeng Basin in Yunnan Province, China was studied using X-ray computed tomography. The braincase is characterized by a large supraoccipital knob that is capped by a posterior projection of the parietal and two external foramina for the caudal middle cerebral vein, which is completely enclosed by the supraoccipital. The basicranium has well defined, short basipterygoid processes that project ventral to the basal tubera. The basisphenoid is expanded, projects posteroventrally, and is pierced by four pneumatic recesses. The endocranial morphology resembles that observed in other basal theropods—in particular some allosauroids—and has a strongly marked pontine flexure and a large dorsal expansion. The inner ear morphology is also similar to that observed in other basal theropods, with slender semicircular canals. The anterior semicircular canal is 20% larger than the posterior semicircular canal, and the angle formed between them is less than 90° when seen in dorsal view.

    • Ichnology and Depositional Environment of the Cambrian Nagaur Sandstone (Nagaur Group) Along the Dulmera Section, Bikaner-Nagaur Basin, Rajasthan

      2014, 88(6):1665-1680.

      Abstract (1416) HTML (0) PDF 15.44 M (2326) Comment (0) Favorites

      Abstract:Abstract: The Lower Cambrian Nagaur Sandstone (Marwar Supergroup) has yielded trace fossils Treptichnus, Cruziana, serially repeated Rusophycus, Diplichnites, Monomorphichnus, Bergaueria, arthropod swimming traces and leap frogging marks of Cruziana ichnofacies. This ichnofossils assemblage is dominantly preserved in fine to medium grained red sandstone beds of the Mohra Member (Nagaur Sandstone). The presence of graded rip-up clasts, current ripples, dune cross-stratification with mud drapes and tidal bundles indicates a subtidal paleoenvironment for the deposition of Nagaur Sandstone Formation, which is corroborated by the Cruziana ichnofacies trace fossil assemblage.

    • Biostratigraphy and Sequence Stratigraphy of the Gurpi Formation at Deh Dasht Area, Zagros Basin, SW Iran

      2014, 88(6):1681-1695.

      Abstract (1210) HTML (0) PDF 14.87 M (1460) Comment (0) Favorites

      Abstract:Abstract: A rich assemblage of planktonic foraminifera has been studied from an outcrop of the Gurpi Formation, the hydrocarbon source rock in the southwest Iran, Deh Dasht area (Kuh-e Siah anticline). Based on the distribution of the planktonic foraminifera, eight biozones have been recognized that included: Dicarinella concavata Interval Zone (Earliest Santonian), Dicarinella asymetrica Total Range Zone (Santonian to Earliest Campanian), Globotruncanita elevata Partial Range Zone (Early Campanian), Globotruncana ventricosa Interval Zone (Middle to Late Campanian), Radotruncana calcarata Total Range Zone (Late Campanian), Globotruncanella havanensis Partial Range Zone (Late Campanian), Globotruncana aegyptiaca Interval Zone (Late to latest Campanian), Gansserina gansseri Interval Zone (Latest Campanian to Early Maastrichtian). These biozones indicates that the Gurpi Formation deposited during the Early Santonian- Early Maastrichtian. These biozones are compared to the most standard biozones defined in Tethysian domain. Based on distribution of morphotype groups of planktonic foraminifera, planktonic to benthic ratio (P/B) and content of carbonate, nine third-order sequences are recognized.

    • Assessing Possibilities and Limitations for Biomarker Analyses on Outcrop Samples: A Case Study on Carbonates of the Shibantan Member (Ediacaran Period, Dengying Formation, South China)

      2014, 88(6):1696-1704.

      Abstract (893) HTML (0) PDF 9.45 M (1152) Comment (0) Favorites

      Abstract:Abstract: The Shibantan Member (Dengying Formation, South China) represents one of only two carbonate settings with Ediacara-type organisms and offers a rare opportunity to study the biogeochemistry of these ecosystems. To evaluate possibilities and limitations for future biomarker studies on fossil-bearing outcrop samples of the Shibantan Member, we analysed the spatial distribution of hydrocarbons in extractable organic matter (i.e. bitumen) on a millimetre scale. Our study demonstrates that the sample and most likely also other rocks from the same setting are contaminated with petroleum-derived compounds that bear the potential for erroneous interpretations in palaeo-reconstructions. The contamination was revealed by distribution patterns and amounts of extractable n-alkanes and acyclic isoprenoids. The contamination is linked to the external weathering surfaces but also to cracks within the rock, and the extent most likely depends on concentration gradients between these contamination sources. Here we show that contamination can successfully be distinguished from syngenetic signals obtained from non-extractable organic matter (i.e. kerogen) using catalytic hydropyrolysis (HyPy). However, we observed that decalcification is necessary to achieve sufficient yields of kerogen-bound hydrocarbons and to avoid artificial alteration of the biomarker signals due to matrix effects.

    • Compositional Variation and Mineral Chemistry of the Jinshajiang and Lancangjiang Serpentinites, Yunnan Province, SW China

      2014, 88(6):1705-1728.

      Abstract (892) HTML (0) PDF 27.23 M (1342) Comment (0) Favorites

      Abstract:Abstract: We present the whole rock and the mineral chemical data for upper mantle peridotites from the San-Jiang region in Yunnan, SW China. These peridotites are a part of a Paleo-Tethyan ophiolite belt occurring along the Jinshajiang and Lancangjiang suture zones. All samples of the Jinshajiang and Lancangjiang ultramafic rocks are completely serpentinized. The Jinshajiang serpentinites are characterized by no relict of olivine and pyroxene, and the Cr# content of spinels is 0.32–0.49. The Lancangjiang serpentinites were collected from two different locations; the northern location which has some relict of Opx (Al2O3 is 0.13–2.2 wt%, TiO2 is 0.004–0.057 wt% and Mg# content is 0.895–0.933) and the Cr# content of spinel is 0.26-0.55; the southern location, which has some relict of Olivine (Fo = 90–92.5 and NiO = 0.12–0.26 wt%), and spinel Cr# ranging from 0.41 to 0.57. The whole rock geochemical and the mineral chemistry data imply that the Jinshajiang and Lancangjiang serpentinites represent abyssal peridotites residues after ~15–20% partial melting for the Jinshajiang and Lancangjiang serpentinites (south location), and ~11–19% partial melting for the Lancangjiang serpentinites (north location). In addition, the compositional trends of the spinel analyses of the Lancangjiang serpentinites imply that the MORB melt-peridotite interaction process played a significant role during their evolution. These processes are evidenced by an increase in Cr# with an increase in TiO2, whereas the spinel analyses of the Jinshajiang serpentinites display an increase in Cr# with a decrease in TiO2, indicating that the Jinshajiang serpentinites were subjected to a simple partial melting process.

    • Mica Inclusions inside Host Mica Grains from the Sutlej Section of the Higher Himalayan Crystallines, India—Morphology and Constrains in Genesis

      2014, 88(6):1729-1741.

      Abstract (818) HTML (0) PDF 15.34 M (1315) Comment (0) Favorites

      Abstract:Abstract: Biotite and muscovite inclusions inside mica host minerals from the Sutlej section of the Higher Himalayan Crystalline were studied under an optical microscope. These inclusions formed possibly by local recrystallization of mica grains during regional prograde metamorphism, with some affected by top-to-SW shear leading to parallelogram shapes. Recrystallization may have been assisted by solution transfer along the cleavage planes of the host grains. The relative competency of deformed phyllosilicate inclusions with the same or different composition to the host depends on the size and orientation of (001) cleavage planes of the inclusions relative to the host. Shearing of mica inclusions led to their parallelogram geometries within the contained mica inclusions. Some of the sheared inclusions deflect cleavage planes in the host minerals and define flanking microstructures. Trapezoid-shaped inclusions are a new finding that deserves more attention for their genesis. These structurally anisotropic inclusions did not originate from sub-grains, secondary infillings or retrogression. These inclusions are also not related to pseudomorphism, isomorphism, folding of the bulk rock etc. Some of the inclusions formed by recrystallization of the host mineral during top-to-SW ductile shear.

    • The Yanshanian Granites and Associated Mo-Polymetallic Mineralization in the Xiangcheng-Luoji Area of the Sanjiang-Yangtze Conjunction Zone in Southwest China

      2014, 88(6):1742-1756.

      Abstract (1272) HTML (0) PDF 15.32 M (1308) Comment (0) Favorites

      Abstract:Abstract: The Xiangcheng-Luoji area is located in the conjunction of the southern part of the “Sanjiang” mineralization belt and the west margin of Yangtze craton. The geological studies were carried out to know the Indosinian large porphyry Cu polymetallic deposits. Recent studies revealed that the area existed in the superposition of Late Yanshanian acidic intrusive rock belt and developed Mo-Cu polymetallic mineralization where promising exploration results have been achieved. Through the systematic study of geochronology, formation age of the Renlin Mo-minieralization monzogranite is 81.7±1.1 Ma. Re-Os dating results concentrate on 82.34±1.2–88.27±1.23 Ma for the model ages of molbdenite of Tongchanggou Mo deposits, average age is 85 ± 2 Ma where seven data points constitute a good isochron which shows that they were the same period products of mineralization. Geochemical features shown that the rocks have a high content of SiO2 (66.59–77.36wt%), alkaline-rich (K2O=2.68–6.08wt%; Na2O=0.50–4.91wt%; K2O/Na2O ratios are 0.71–5.56, where average ratio of 1.89) and have aluminum–rich features (Al2O3 10.38–15.15wt%) with σ values less than 3.3. Which indicate that they belong to the high-K calc-alkali to shoshonite series. Geochemistry of Yanshanian intrusions shows that rocks are enrich in LREE with obvious negative δEu anomalies, enrichment of trace elements like, LILE elements (Rb, Th, Ba) with a relative loss of Ba, and loss of high field strength elements (Nb, Ta, P, Ti) and HREE elements. The granite genetic classification diagram shows that the granites belong to A-type granite and formatted in syn-collision tectonic environment. Meanwhile, the Yanshanian granites also inherited the characteristics of island arc environment which formed in the process of crustal melting caused by upwelling of asthenospheric substances in the extensional tectonic background. The process of partial melting existed substances from the deep (lower crust or upper mantle) which have been added. In the Xiangcheng-Luoji area, monzogranite and granodiorite porphyry bodies are widely developed Mo polymetallic mineralization, the deep porphyry mineralization have great potential for geological prospecting.

    • New Evidence for Genesis of the Zoige Carbonate-Siliceous-Pelitic Rock Type Uranium Deposit in Southern Qinling: Discovery and Significance of the 64 Ma Intrusions

      2014, 88(6):1757-1769.

      Abstract (1357) HTML (0) PDF 13.39 M (1263) Comment (0) Favorites

      Abstract:Abstract: The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts due to its scale, high grade and abundant associated ores. Because of the insufficient reliable dating of intrusive rocks, the relationship between mineralization and the magmatic activities is still unknown. In order to study this key scientific issue and the ore-forming processes of the Zoige uranium ore field, the LA-ICP-MS zircon U-Pb dating of magmatic rocks was obtained: 64.08±0.59 Ma for the granite-prophyry and ~200 Ma for the dolerite. U-Pb dating results of uraninite from the Zoige uranium ore field are mainly concentrated on ~90 Ma and ~60 Ma. According to LA-ICP-MS U-Pb zircon dating, the ages for the dolerite, porphyry granite and granodiorite are 200 Ma, 64.08 Ma approximately and 226.5?200.88 Ma, respectively. This indicates that the mineralization has close relationship with activities of the intermediate-acidic magma. The ages of the granite porphyry are consistent with those uraninite U-Pb dating results achieved by previous studies, which reflects the magmatic and ore-forming event during the later Yanshanian. Based on the data from previous researches, the ore bodies in the Zoige uranium ore field can be divided into two categories: the single uranium type and the uranium with polymetal mineralization type. The former formed at late Cretaceous (about 90 Ma), while the latter, closely related to the granite porphyry, formed at early Paleogene (about 60 Ma). And apart from ore forming elemental uranium, the latter is often associated with polymetallic elements, such as molybdenum, nickel, zinc, etc.

    • Growth Pattern and Its Indication of Spheroidal Nano-Micro Crystal Aggregates of Pyrite in the Baiyunpu Pb-Zn Polymetallic Deposit, Central Hunan

      2014, 88(6):1770-1783.

      Abstract (982) HTML (0) PDF 14.39 M (1726) Comment (0) Favorites

      Abstract:Abstract: The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle Devonian, and its geological occurrence is consistent with the wall rocks. A large number of spheroidal pyrite aggregates are found unevenly distributed in the ores. The spheroidal aggregates are made up of kernels and concentric rings. The kernels are composed of approximately epigranular pyrite nanocrystals, while the rings are composed of accumulated pyrite microcrystals growing along the radial direction. The spheroidal pyrite aggregate and its outer zones can be divided into five areas (A–E). The results of electron probe micro analysis (EPMA) show that from the zone A1 to B, Co/Ni <1, the sum of Co and Ni is 0.08%–0.26%, S/Fe increases from 2.06 to 2.15. While from the zone C to E, Ni cannot be detected and S/Fe decreases from 2.22 to 2.08. Powder X-ray diffraction (XRD) analysis in the micro zone shows obvious crystalline characteristics in the aggregates. Moving from the inside outwards, the maximum diffraction peak intensity of the (111) and (220) crystal planes of pyrite increases, and the crystallinity improves. The degree of change in the (111) plane is the most prominent. Considering the theory of crystal growth along with the geologic features of the depositional environment where the spheroidal pyrite aggregates developed, we confirm that the spheroidal aggregates are the result of nano-micro crystalline gathering and growth occurring by the following sequence of processes: nano-crystalline nucleation and growth, gathering into a ball, oriented growth of microcrystals, continuous accumulation, and adjustment of grain boundaries. The formation of the spheroidal pyrite aggregates in the late Qiziqiao Formation of the Middle Devonian occurred in a neutral to weak alkaline and reductive sedimentary environment in the normal oxygen-rich shallow-water carbonate platform edge. The variations in the S/Fe ratio and crystallisation characteristics indicate that during pyrite crystal growth, the sulphur fugacity was high locally and rose constantly, the degree of supersaturation decreased locally and the growth environment was stable relatively.

    • A Preliminary Study of Holocene Climate Change and Human Adaptation in the Horqin Region

      2014, 88(6):1784-1791.

      Abstract (931) HTML (0) PDF 9.03 M (1117) Comment (0) Favorites

      Abstract:Abstract: Human activity during the Holocene in the Horqin region, northeastern China, has been widely documented. As an important proxy record of human activity, black carbon (BC) in sediments has been linked to climate change and human adaptation. A loess-paleosol section located in south Horqin was chosen for this study. Holocene climate change and human adaptation to the environment were discussed by analyzing BC, organic carbon (OC) and other proxies. The conclusions included: (1) before 3900 cal BP, human activity was closely related to the natural environment and cultural development was dominated by climate change. For example, the rapid decline of the agrarian Hongshan culture was caused by a slight decrease in temperature at ~5000 cal BP; (2) during 3900-3200 cal BP, the heavy dependence of human societies on nature gradually lessened and the ability of those human societies to adapt to the environment was enhanced. However, the farming-dominated Lower Xiajiadian culture was nonetheless replaced by the pastoralist Upper Xiajiadian culture due to an extremely cooling event at ~3200 cal BP; (3) during the late Holocene period, the marked influence of climate change on human activity might have lessened as a result of a clear improvement in human labor skills. After this, human living styles were influenced by cultural developments rather than climate change because humans had mastered more powerful means of productivity.

    • Correction Method of Light Hydrocarbons Losing and Heavy Hydrocarbon Handling for Residual Hydrocarbon (S1) from Shale

      2014, 88(6):1792-1797.

      Abstract (1114) HTML (0) PDF 7.00 M (1033) Comment (0) Favorites

      Abstract:Abstract: In China, hot researches on shale oil were raised by the important breakthrough of shale oil in America. Obviously, the first important issue is the actual shale oil resource potential of China, and the selection of the key appraisement parameter is vital to the shale oil resource amount. Among the appraisement parameters, the oil content parameter (S1) is the key one, but the evaluation result is generally lower because of light hydrocarbon losing and heavy hydrocarbon handling. And the more important thing is that the light hydrocarbon with small molecular weight is more recoverable, and therefore its amount is important to the total shale oil yields. Based on pyrolysis experiments and the kinetic model of hydrocarbon generation, correction factors and a model of light hydrocarbon losing and heavy hydrocarbon handling were established. The results show that the correction factor of heavy hydrocarbon handling is 3.2, and that of light hydrocarbon losing is controlled by kerogen type, maturity and hydrocarbon generation environment (closed or open).

    • Evidence of Oil Sources and Migration in Triassic-Jurassic Reservoirs in the South Tianhuan Depression of the Ordos Basin, China Based on Analysis of Biomarkers and Nitrogen-Bearing Compounds

      2014, 88(6):1798-1810.

      Abstract (1251) HTML (0) PDF 12.57 M (1285) Comment (0) Favorites

      Abstract:Abstract: The Ordos Basin is an important intracontinental sedimentary basin in western China for its abundant Mesozoic crude oil resources. The southern part of the Tianhuan Depression is located in the southwestern marginal area of this Basin, in which the Jurassic and Triassic Chang-3 are the main oil-bearing strata. Currently, no consensus has been reached regarding oil source and oil migration in the area, and an assessment of oil accumulation patterns is thus challenging. In this paper, the oil source, migration direction, charging site and migration pathways are investigated through analysis of pyrrolic nitrogen compounds and hydrocarbon biomarkers. Oil source correlations show that the oils trapped in the Jurassic and Chang-3 reservoirs were derived from the Triassic Chang-7 source rocks. The Jurassic and Chang-3 crude oils both underwent distinct vertical migration from deep to shallow strata, indicating that the oils generated by Chang-7 source rocks may have migrated upward to the shallower Chang-3 and Jurassic strata under abnormally high pressures, to accumulate along the sand bodies of the ancient rivers and the unconformity surface. The charging direction of the Jurassic and Chang-3 crude oils is primarily derived from Mubo, Chenhao, and Shangliyuan, which are located northeast of the southern Tianhuan Depression, with oils moving toward the west, southwest, and south. The results show that an integration of biomarker and nitrogen-bearing compound analyses can provide useful information about oil source, migration, and accumulation.

    • Geological Features and Reservoiring Mode of Shale Gas Reservoirs in Longmaxi Formation of the Jiaoshiba Area

      2014, 88(6):1811-1821.

      Abstract (1453) HTML (0) PDF 10.43 M (1777) Comment (0) Favorites

      Abstract:Abstract: This study is based on the sedimentation conditions, organic geochemistry, storage spaces, physical properties, lithology and gas content of the shale gas reservoirs in Longmaxi Formation of the Jiaoshiba area and the gas accumulation mode is summarized and then compared with that in northern America. The shale gas reservoirs in the Longmaxi Formation in Jiaoshiba have good geological conditions, great thickness of quality shales, high organic content, high gas content, good physical properties, suitable depth, good preservation conditions and good reservoir types. The quality shales at the bottom of the deep shelf are the main target interval for shale gas exploration and development. Shale gas in the Longmaxi Formation has undergone three main reservoiring stages: the early stage of hydrocarbon generation and compaction when shale gas reservoirs were first formed; the middle stage of deep burial and large-scale hydrocarbon generation, which caused the enrichment of reservoirs with shale gas; the late stage of uplift, erosion and fracture development when shale gas reservoirs were finally formed.

    • Composite Sand Bodies Architecture of Deep-Water Turbidite Channels in the Niger Delta Basin

      2014, 88(6):1822-1834.

      Abstract (1071) HTML (0) PDF 13.40 M (1159) Comment (0) Favorites

      Abstract:Abstract: Deep-water turbidite channels have attracted much attention as a focused issue in petroleum exploration and development. Extensive studies have been performed on the architecture of turbidite channels, and most researches have focused on their geometric shapes, sedimentary processes and controlling factors. However, little attention has been paid to the distribution patterns, distribution laws and quantitative studies of composite sand bodies of turbidite channels. Taken one slope area of the Niger Delta Basin as an example, this study conducted a semi-quantitative to quantitative analysis on architecture of composite sand bodies of turbidite channels based on cores, well logging and seismic surveys. It is shown that turbidite channel systems can be classified as confined and unconfined channel systems. For confined channel systems, the vertical evolution process involves four stages. The sinuosity of a channel system is controlled by slope, with a negative power function relationship between them. When slope gradient reaches four degrees, the channel system is nearly straight. Based on the migration direction and migration amount of single channels within channel complexes, channel composite patterns can be divided into four classes (the lateral composite, en-echelon composite, swing composite and vertical composite) and several subclasses. Various channel composite patterns show specific distribution laws spatially. For meandering channel complexes at the middle-late evolution stage of confined channel systems, the lateral migration amongst single channels shows the features of integrity and succession. The sinuosity of single channels in the late period is greater than that in the early period, and cut-offs may occur locally when the sinuosity is larger than five degrees. This study provides a better understanding for the geological theory of deep-water sedimentary, and also improves exploitation benefits of this type of reservoirs.

    • Geochemistry and Origin of Layers in Single Manganese Nodule from the Philippine Sea and Manganese Nodules from Offshore Minami-Torishima, Western Pacific

      2014, 88(6):1835-1845.

      Abstract (970) HTML (0) PDF 10.64 M (868) Comment (0) Favorites

      Abstract:Abstract: Layers from one manganese nodule dredged from the Philippine Sea (16°56'N, 129°48'E; water depth, 5700 m) and 45 bulk nodules from offshore Minami-Torishima Island, Japan (23°3'N, 153°22'E; water depth, 1200 m) were analyzed chemically and their origin is discussed based on geochemical constraints. In general, Cu, Ni, Zn and Mo tend to increase with increasing Mn content, while Co, Pb, Ba, V, Sc, Th, and the rare earth elements (REEs) show less variation with increasing Mn content. Nodule 42H from the Philippine Sea has an average Mn/Fe ratio close to 1 and shows a positive Ce anomaly, suggesting a predominant hydrogenous origin. Profiles of 230Thex and 230Thex/232Th ratios in the outer ~0.3 mm of nodule 42H indicate a steady growth rate of ~1.7 mm/Myr. Nodule E30 from offshore Minami-Torishima is characterized by lower Mn, Fe, Mn/Fe (0.53) and Mo/V (0.2) ratios but higher P and Cu/Ni (0.31) ratio relative to other nodules from that area. The Ce content of E30 is unusually low (82 ppm) when compared with other nodules from the area and it is the only nodule analyzed with a negative Ce anomaly (-0.64). Based on the geochemical data we suggest that most nodules from offshore Minami-Torishima are primarily of hydrogenous origin except E30, which is dominated by hydrothermal input, and E45, which has about a 35% hydrothermal contribution.

    • The Influx of the Tsushima Current into the Central Ulleung Basin of East Sea (Sea of Japan), Korea

      2014, 88(6):1846-1851.

      Abstract (1087) HTML (0) PDF 6.30 M (998) Comment (0) Favorites

      Abstract:Abstract: A total of 85 samples, collected from the UBGH1-9 core taken from the Ulleung Basin, East Sea, Korea, were analyzed using diatom assemblages. 111 diatom species belonging to 46 genera were identified, and three diatom assemblage zones were established on the basis of occurrence and distribution pattern of diatoms. Diatom assemblage zone I (134.10–174 m) is characterized by a relatively high abundance of marine species, while the increased number of the brackish species is recorded in diatom assemblage zone II (75–125 m). The assemblage zones IIIa became drastic drop of valve abundances and brackish planktons, whereas it became increase during the IIIb. High Td values which indicate an influence of warm current are recorded both in diatom assemblage zone I and III, and low Td values in diatom assemblage zone II. Analysis of diatom assemblages indicating that the depositional condition moved from oceanic to littoral-neritic environments and that paleotemperature underwent a shift from warm to cold condition at the middle interval, and from cold to warm condition in the upper interval of the UBGH1-9 core. This suggests that the lower (130–162 m) and upper intervals (0–20 m) of the UBGH1-9 core were deposited in the warm current condition (Tsushima Warm Current).

    • The Origin of Paleokarst in the Huanglong Formation of the Eastern Sichuan Basin: Evidence from δ13C, δ18O and 87Sr/86Sr

      2014, 88(6):1852-1862.

      Abstract (932) HTML (0) PDF 13.21 M (1311) Comment (0) Favorites

      Abstract:Abstract: Karst rocks from the Huanglong Formation exposed at the margin of the Eastern Sichuan Basin can be divided into four types: slightly corroded, moderately corroded porous, intensely corroded brecciated and intensely corroded and replaced secondary calcic karstic rocks. The carbon, oxygen and strontium isotope compositions of the various karst rocks are analyzed systematically and compared to rocks without karst corrosion. The results indicate that (1) the Huanglong Formation?in the eastern Sichuan Basin was a restricted?bay supplied and controlled by freshwater in which mud-micrite and mud-dolomicrite exhibit low δ13C and δ18O values and high 87Sr/86Sr ratios; (2) all types of karstic rocks in the paleokarst reservoirs of the Huanglong Formation in the research area are affected by atmospheric freshwater with the δ13C and δ18O values and 87Sr/86Sr ratios in the original formation approaching those of atmospheric freshwater, which reflects ancient hydrological conditions, fluid properties, isotopic source and the fractionation effect; (3) the intensely corroded and replaced secondary limestone is affected by a variety of diagenetic fluids, often reflected by δ13C and δ18O values, while the 87Sr/86Sr ratios exhibit the strong degree of the corrosion; (4) after comparing the 87Sr/86Sr ratios of each type of karst rock, the diagenetic fluids are determined to be mainly atmospheric freshwater, and depending on the strength of corrosion, and the low 87Sr/86Sr ratio fluids in the layer will participate in the karst process. The carbon, oxygen, and strontium isotopes of different karstic reservoirs can provide meaningful geochemical information for forecasting and evaluating the development and distribution rules of the Huanglong Formation at the margin of the eastern Sichuan Basin in time and space.

    • Last Deglaciation Climatic Fluctuation Record by the Palaeo-Daocheng Ice Cap, Southeastern Qinghai-Tibetan Plateau

      2014, 88(6):1863-1874.

      Abstract (1450) HTML (0) PDF 13.64 M (1035) Comment (0) Favorites

      Abstract:Abstract: The last deglaciation, a key period for understanding present and future climate changes, has long been the hot topic for palaeoclimatological study. The Qinghai-Tibetan Plateau (QTP) is often a target study area for understanding hemispheric, or even global environment changes. The glacial landforms on the QTP provide a unique perspective for its climate change. In order to investigate the onset of the last deglaciation at the QTP and its regional correlation, the terrestrial cosmogenic nuclides (TCN) 10Be and 26Al surface exposure dating was chosen to date the roche moutonnée, the polished surface and the moraine debris located at the palaeo-Daocheng Ice Cap (p-DIC), southeastern QTP. Our results show that the onset of the last deglaciation is at about 19 ka, followed by another warming event occurring around 15 ka in the p-DIC area. These timings agree well with other records, e.g. equivalent with a rapid sea level rise at 19 ka and the onset of B?lling warming event at about 15 ka. Thus, our new data can provide good reveal constraint on the climate evolution at the QTP.

    • Experimental Set-up for Determining Soil Water Retention Curves for Granular Soils During Drying

      2014, 88(6):1875-1883.

      Abstract (1206) HTML (0) PDF 10.15 M (927) Comment (0) Favorites

      Abstract:Abstract: Soil water retention curves (SWRCs) provide an important means of describing the response of unsaturated soils during drying / wetting processes in terms of variations of degree of saturation, water content or void ratio with suction. A key consideration in generating these curves is how to measure the suction. Frequently the filter paper technique is adopted, especially when high suctions are developed, e.g. with plastic clays. As each measurement takes at least a week with this technique, it can take months or years to generate a full SWRC in drying and wetting. Developments in laboratory tensiometers now allow matrix suctions up to about 1.5 MPa to be measured. With such a device it is possible to develop SWRCs for granular soils such as silts and clays in hours or days by continuous measurement. This paper describes an experimental set-up that was developed to measure changes in volume, water content and matrix suction during drying of three granular soils. Limitations of the apparatus and usefulness of the curves are discussed.

    • Low Mantle Perovskite: Solid Solution, Spin State of Iron and Water Solubility

      2014, 88(6):1884-1894.

      Abstract (769) HTML (0) PDF 14.05 M (960) Comment (0) Favorites

      Abstract:Abstract: Silicate perovskites ((Mg, Fe)SiO3 and CaSiO3) are believed to be the major constituent minerals in the lower mantle. The phase relation, solid solution, spin state of iron and water solubility related to the lower mantle perovskite are of great effect on the geodynamics of the Earth’s interior and on ore mineralization. Previous studies indicate that a large amount of iron coupled with aluminum can incorporate into magnesium perovskite, but this is discordant with the disproportionation of (Mg,Fe)SiO3 perovskite into iron-free MgSiO3 perovskite and hexagonal phase (Mg0.6Fe0.4)SiO3 in the Earth's lower mantle. MnSiO3 is the first chemical component confirmed to form wide range solid solution with CaSiO3 perovskite and complete solid solution with MgSiO3 perovskite at the P-T conditions in the lower mantle, and addition of MnSiO3 will strongly affects the mutual solubility between MgSiO3 and CaSiO3. The spin state of iron is deeply depends on the site occupation of the Fe3+or Fe2+, the synthesis and the annealing conditions of the sample. It seems that the spin state of Fe2+ in the lower mantle perovskite can be settled as high spin, however, the existence of intermediate spin or low spin state of Fe2+ in perovskite has not been clarified. Moreover, different results have also been reported for the spin state of Fe3+ in perovskite. The water solubility of the lower mantle perovskite is related with its composition. In pure MgSiO3 perovskite, only less than 500 ppm water was reported. Al–MgSiO3 perovskite or Al–Fe–MgSiO3 perovskite in the lower mantle accommodates water of 1100 to 1800 ppm. Further experiments are necessary to clarify the detailed conditions for perovskite solid solution, to reliably analyze the valence and spin states of iron in the coexisting iron-bearing phases, and to compare the water solubility of different phases at different layers for deeply understanding the geodynamics of the Earth’s interior and ore mineralization.

    • The Major Ore Clusters of Super-Large Iron Deposits in the World, Present Situation of Iron Resources in China, and Prospect

      2014, 88(6):1895-1915.

      Abstract (1411) HTML (0) PDF 26.06 M (1483) Comment (0) Favorites

      Abstract:Abstract: The metamorphosed sedimentary type of iron deposits (BIF) is the most important type of iron deposits in the world, and super-large iron ore clusters of this type include the Quadrilatero Ferrifero district and Carajas in Brazil, Hamersley in Australia, Kursk in Russia, Central Province of India and Anshan-Benxi in China. Subordinated types of iron deposits are magmatic, volcanic-hosted and sedimentary ones. This paper briefly introduces the geological characteristics of major super-large iron ore clusters in the world. The proven reserves of iron ores in China are relatively abundant, but they are mainly low-grade ores. Moreover, a considerate part of iron ores are difficult to utilize for their difficult ore dressing, deep burial or other reasons. Iron ore deposits are relatively concentrated in 11 metallogenic provinces (belts), such as the Anshan-Benxi, eastern Hebei, Xichang-Central Yunnan Province and middle-lower reaches of Yangtze River. The main minerogenetic epoches vary widely from the Archean to Quaternary, and are mainly the Late Archean to Middle Proterozoic, Variscan, and Yanshanian periods. The main 7 genetic types of iron deposits in China are metamorphosed sedimentary type (BIF), magmatic type, volcanic-hosted type, skarn type, hydrothermal type, sedimentary type and weathered leaching type. The iron-rich ores occur predominantly in the skarn and marine volcanic-hosted iron deposits, locally in the metamorphosed sedimentary type (BIF) as hydrothermal reformation products. The theory of minerogenetic series of mineral deposits and minerogenic models has applied in investigation and prospecting of iron ore deposits. A combination of deep analyses of aeromagnetic anomalies and geomagnetic anomalies, with gravity anomalies are an effective method to seeking large and deep-buried iron deposits. China has a relatively great ore-searching potential of iron ores, especially for metamorphosed sedimentary, skarn, and marine volcanic-hosted iron deposits. For the lower guarantee degree of iron and steel industry, China should give a trading and open the foreign mining markets.

    • Successful Extraction of Low-Grade Ni–Co Ores from Ophiolite-Type Serpentinite by Chinese Experts

      2014, 88(6):1916-1916.

      Abstract (710) HTML (0) PDF 15.56 M (884) Comment (0) Favorites

      Abstract:

    • 2015–2020 Geological Survey Program of China Geological Survey Bureau

      2014, 88(6):1917-1919.

      Abstract (1015) HTML (0) PDF 15.56 M (1762) Comment (0) Favorites

      Abstract:

    • Congratulation for Our Deputy Editor-in-Chief Chunmiao Zheng Receiving Two Prestigious International Awards

      2014, 88(6):1920-1921.

      Abstract (745) HTML (0) PDF 15.56 M (926) Comment (0) Favorites

      Abstract:

Chief Editor:HOU Zengqian

Governing Body:China Association for Science and Technology

Organizer:Geological Society of China

start publication :1922

ISSN:ISSN 1000-9515

CN:CN 11-2001/P

  • Most Read
  • Most Cited
  • Most Downloaded
Press search
Search term
From To