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He J.-Q.,China Earthquake Administration | He J.-Q.,China National Offshore Oil Corporation | Ding R.-X.,Sun Yat Sen University | Ding R.-X.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | And 3 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2014

The North Yellow Sea basin is one of the basins with lower exploration degrees in offshore areas of China. As so far, there is no research and report about thermal evolution of this basin. This work studies the thermal evolution history of this area based on apatite fission track analysis, which lays a foundation for further research. The sandstone samples used for analysis we recollected from different wells down to different strata (upper Jurassic, lower Cretaceous and Paleogene). The low-temperature thermal history modeling of fission track indicates that the basin experienced two heating stages and two cooling stages since about 160Ma, and an obvious temperature change might have occurred during 100-80 Ma, which means that North Yellow Sea Basin had undergone a major tectonic-thermal event in that time. This modeling result suggests the thermal history is corresponding to basin prototype evolution in the North Yellow Sea basin, which has some significance to exploration of oil and gas in this region. ©, Science Press. All right reserved.

Zheng Z.,Sun Yat Sen University | Zheng Z.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | Wei J.,Sun Yat Sen University | Huang K.,Sun Yat Sen University | And 15 more authors.
Journal of Biogeography | Year: 2014

Aim: Our aims were to provide new pollen data for establishing a sub-continental surface pollen database (East Asian Pollen Database, EAPD) and to study relationships between vegetation and climate. Location: The sample sites covered most regions of East Asia, including China, Mongolia, the Russian Far East, Vietnam, Cambodia and Thailand. Methods: Data quality control procedures were applied, including taxonomic standardization, removal of duplicates, and adjustment of geographical coordinates. Vegetation types and climate parameters were assigned to each sample. Modern pollen distribution maps were drawn using circle scattergrams. The plots of pollen percentages versus climate variables allowed quantitative estimates of climate values. The modern analogue technique (MAT) was used to predict modern biomes and climate parameters. Results: Pollen assemblages extracted from 2858 sites were used to model the geographical distribution of selected taxa and their relationships with climate. For most taxa, the reconstructed range fitted the observed geographical distribution rather well. Arboreal pollen (AP) and Pinus dominated the transition zone between forest and steppe. Use of the MAT revealed that the predicted and observed biomes matched in 71% of the cases. The warm temperate evergreen broadleaf forest had the best agreement between predictions and observations. Climate values reconstructed using MAT were highly correlated with observed values in January temperature. The correlation coefficient of the temperature variables ranged from 0.799 to 0.930 and was as high as 0.939 for precipitation. Main conclusions: This paper documents a new modern pollen database for East Asia and makes the data readily available. The reconstructed biomes and climate variables are significantly correlated with the observed values, thus demonstrating the utility of the pollen database for future multiscale palaeoenvironmental studies. © 2014 John Wiley & Sons Ltd.

Hu G.,Sun Yat Sen University | Cao J.,Sun Yat Sen University | Cao J.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | Hopke P.K.,Clarkson University | And 2 more authors.
Resource Geology | Year: 2015

Samples of ascending geogas flow particles were collected on to SiN grids directly in the Quaternary sediments overlying the Dongshengmiao polymetallic pyrite deposit, China. Corresponding soil samples were collected in the surface of Dongshengmiao district at the same time. After pretreatment, these SiN grid samples were analyzed by transmission electron microscopy. The tests focused on the characteristics of particles including size, shape, chemical composition, structure and association. The results show that there are numerous carbon-bearing particles in particulate samples of the ascending geogas flow. The particles contain organic matter, carbonate or carbonate mixed with other minerals. These carbon-bearing particles generally contain metallic elements like Fe/Zn/Au/Cu/Pb. However, all of the soil particles do not contain elemental C and only consist of common elements (O, Na, Mg, Al, Si, Ca, Ti) just like the composition of earth crust. Through a comparison between the particles from different sources, the carbon-bearing particles were found to come only from the deep earth and carried useful information about concealed deposits as they pass through the deep-seated orebodies. Given the influences of organic matter on mineralization, the carbon-bearing particle may provide information on the deposit genesis. Combining the use of geogas particle for prospecting with characteristics of large depth, and the carbon-bearing materials' close spatial and genetic relationship with orebodies, we propose a new prospecting method based on the characteristics of carbon-bearing particles, including morphology, size, chemical component and ultra-microstructure. This approach could be applied to the exploration of deposits deep in the earth and abundant in carbon-bearing matter. This approach can provide efficient and effective deposit exploration. Through analyzed the characteristics of carbon-bearing particles in ascending geogas flow samples which collected in the Dongshengmiao polymetallic pyrite deposit and tested by TEM, the particles were found to come from deep earth and carry useful information about concealed deposits. Thus a new efficient prospecting method based on the characteristics of carbon-bearing particles was proposed. © 2014 The Society of Resource Geology.

Wang Y.,Sun Yat Sen University | Wang Y.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | Zhang L.,Sun Yat Sen University | Zhang L.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | And 8 more authors.
Lithos | Year: 2014

Geochemical and isotopic data for metabasic rocks in NW Yunnan constrain the nature of the mantle source beneath the East Himalayan Syntaxis during the Neotethyan subduction and the timing of initial collision between India and Asia. Our results indicate that these mafic rocks crystallized at 50-55Ma and were metamorphosed at ~39Ma, contemporaneous with magmatic flare-ups and high-grade metamorphism in South Tibet. The mafic rocks in NW Yunnan are divisible into three groups. Group 1, from Nabang, shows geochemical affinity to a MORB-like source modified by the recycled component with εNd(t) of +5.1 to +9.5 and εHf(t) of +5.1 to +11.6, and resembles back-arc basin basalt. Group 2 is mainly from Jinzhouzhai and Tongbiguan to the east of Group 1, and is marked by high Al2O3, enrichment in LILEs and depletion in HFSEs, along with negative εNd(t) (-1.1 to -5.6) and εHf(t) (-4.6 to -0.9) values. Group 2 is interpreted to have originated from the lithospheric mantle modified by input from a slab-derived component in a continental arc setting. Group 3, from Nanjingli, is located a considerable distance east from Group 1, and exhibits negative εNd(t) (-6.7 to -7.6) and εHf(t) (-7.1 to -2.2), and is inferred to be derived from the Tengchong lithospheric mantle but with limited involvement of a slab-derived component. Overall Nd-Hf isotopic compositions show a sharp decrease from Group 1 to Group 2 and then a more subdued decrease to Group 3, with the three groups corresponding to an overall spatial distribution from west to east. Our results suggest that early Eocene magmatism in NW Yunnan represents the eastward continuation of the Gangdese magmatic belt and that the Neotethyan subduction continued until ~50Ma followed by the India-Asia collision. It is proposed that at least two eastward-dipping subduction zones are involved in the Neotethyan suprasubduction system prior to 55Ma. The sudden decrease in convergence rate in the early Eocene (55-50Ma), together with the inferred positive buoyancy of the Tengchong lithosphere, stimulated rollback of down-going slab and induced melting of heterogeneous mantle sources to result in a flare-up in magmatic activity. © 2014 Elsevier B.V.

Cai Y.,CAS Guangzhou Institute of Geochemistry | Cai Y.,Sun Yat Sen University | Cai Y.,University of Chinese Academy of Sciences | Wang Y.,Sun Yat Sen University | And 9 more authors.
Precambrian Research | Year: 2014

Lenses of amphibolites occur along the Ailaoshan suture zone at the southwestern margin of the Yangtze Block, South China. Petrological, geochemical and zircon U-Pb geochronological data indicate that they are divisible into two coeval groups. Group 1, represented by the Jinping amphibolite, has mg-number of 71-76 and (La/Yb)cn ratios of 7.2-7.7, and displays a geochemical affinity to island arc volcanic rocks. Group 2 amphibolites occur at Yuanyang and are characterized by high Nb contents (14.3-18.4ppm), resembling Nb-enriched basalts. The eNd(t) values for Group 1 range from -3.45 to -2.04 and for Group 2 from +4.08 to +4.39. A representative sample for Group 1 yields a U-Pb zircon age of 803±7Ma, whereas two samples for Group 2 give U-Pb zircon ages of 813±11Ma and 814±12Ma. Petrogenetic analysis suggests that Group 1 originated from an orthopyroxene-rich source and Group 2 from a mantle wedge modified by slab-derived melt. In combination with other geological observations, these amphibolites are inferred to constitute part of an early Neoproterozoic (~815-800Ma) arc-back-arc basin system. The Neoproterozoic amphibolites and related rocks along the Ailaoshan zone may be the southward extension of the Neoproterozoic supra-subduction zone that developed along the western margin of the Yangtze Block. © 2014 Elsevier B.V.

Ding R.,Sun Yat Sen University | Ding R.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | Wang W.,Tongji University
Journal of Earth Science | Year: 2013

The traditional paleotopographic explanation of mountain belts from low-temperature thermochronology is based on the simulation of low-temperature age data, the main defect of which is that we cannot make comparisons at the same time between the samples. In this article, we intend to make paleotopographic reconstruction on the basis of thermal history modelling. We first digitalize the thermal history curve and take contemporary temperatures for comparison, then reconstruct the paleotopography according to the distribution of the samples' temperatures. The finite difference method is used to solve the diffusion equation for heat in the reconstruction process. Our paleotopography reconstruction method can restore the topography over time. However, due to the nature of thermal history modeling and the noise in the data, the accuracy of this reconstruction is currently limited. © 2013 China University of Geosciences and Springer-Verlag Berlin Heidelberg.

Zhou P.,State Oceanic Administration | Chen C.,State Oceanic Administration | Ye J.,State Oceanic Administration | Shen W.,Sun Yat Sen University | And 6 more authors.
Marine Pollution Bulletin | Year: 2015

Oil fingerprints have been a powerful tool widely used for determining the source of spilled oil. In most cases, this tool works well. However, it is usually difficult to identify the source if the oil spill accident occurs during offshore petroleum exploration due to the highly similar physiochemical characteristics of suspected oils from the same drilling platform. In this report, a case study from the waters of the South China Sea is presented, and multidimensional scaling analysis (MDS) is introduced to demonstrate how oil fingerprints can be combined with mathematical methods to identify the source of spilled oil from highly similar suspected sources. The results suggest that the MDS calculation based on oil fingerprints and subsequently integrated with specific biomarkers in spilled oils is the most effective method with a great potential for determining the source in terms of highly similar suspected oils. © 2015 Elsevier Ltd.

Wu J.,Sun Yat Sen University | Wu J.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | Liu C.,Sun Yat Sen University | Fursich F.T.,Friedrich - Alexander - University, Erlangen - Nuremberg | And 2 more authors.
Journal of Foraminiferal Research | Year: 2015

A total of 117 surface sediment samples from sites across the Pearl River Estuary, southern China, were collected to analyze relationships between foraminiferal distributions and environ-mental parameters such as salinity, depth, substrate, and water energy. A total of 123 species of foraminifera were identified. A Q-mode cluster analysis resulted in five clusters (relative abundance s5%), which each corresponded to a particular species association, reflecting different sub-environments: (A) the Ammonia tepida-Elphidium excavatum association, found in distributary channels and river mouths of the estuary, with low salinity, shallow water, strong currents, and comparatively coarse sediments; (B) the Ammobaculites formosensis-Cavar- otalia annectens association, found in brackish waters near Lantau Island and southeastern Lingding Bay, characterizing turbid brackish-water conditions and sediment consisting of a mixture of sand-clay-silt; (C) the Haplophragmoides canariensis-Ammobaculites agglutinans var. association, found in the artificial harbor near Macao and greatly affected by human activities; (D) the Ammonia beccarii var. -Cavarotalia annectens association, mainly found in the deep channels of two bays and representing euryhaline conditions; and (E) the Ammonia tepida-Elphidium advenum association, mainly found at depths >10 m, higher salinity, low energy, and fine-grained substrate, indicating relatively stable conditions. Agglutinated foraminiferal taxa are better indicators than calcareous taxa of littoral zone environments with a mixture of sand-clay-silt substrate. Benthic foraminiferal distributions in the surface sediments were strongly influenced by salinity. Consequently, a salinity transfer function was developed using weighted-averaging partial least-squares regression. The transfer function was tested on a sediment core collected near the Modaomen distributary, with the goal to reconstruct the palaeosalinity from ~10,100 to ~5960 cal yr BP, an interval with sufficient foraminiferal tests for analysis. At ~10,100 cal yr BP, marine waters flooded the Da'ao plain. Then, a semi- enclosed estuarine environment developed and persisted until ~5960 cal yr BP. Salinity at the core site increased gradually during the early Holocene (from ~10,100 to -8200 cal yr BP), although a short-term decrease can be recognized. The peak salinity occurred between ~8520 and 8200 cal yr BP, when brackish-marine taxa reached their highest abundances. The core site experienced declining salinity from ~8200 cal yr BP onwards as a result of strong river discharge and a decrease of marine water influence at the core site.

Tang L.,Sun Yat Sen University | Tang L.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | Chen H.,Sun Yat Sen University | Sang H.,Sun Yat Sen University | And 2 more authors.
Soil Dynamics and Earthquake Engineering | Year: 2015

The determination of the depth of traffic load influence is significant for pavement and embankment design on soft soil. In this study, a method based on strain-controlled criteria is presented to estimate the depths within which the behavior of a saturated clayey subsoil is affected by cyclic traffic loads. Based on the shakedown concept, the following depths of influence can be defined: (1) the threshold depth, beyond which the dynamic effect of the traffic loads is insignificant; (2) the plastic shakedown limit depth, within which the subsoil experiences noticeable and continuous deformation; and (3) the critical failure depth, within which the soil fails due to the accumulation of strain. This method for determining the depths of influence is advantageous because it is applicable to various soil types. The data required for this method consist of vertical stress responses along the soil profile and three cyclic stress limits of the soil. Based on the development of pore pressure and the dynamic strain behaviors during undrained cyclic triaxial tests, the following cyclic stress limits of the soft clay subsoil are determined: a threshold cyclic stress ratio CSRt of 0.03, a plastic shakedown limit stress ratio CSRp of 0.33 and a critical cyclic stress ratio CSRc of 0.44. These cyclic stress limits are used to determine the corresponding depths of influence, which are then used to implement ground improvements and strengthen the dynamic carrying capacity of the road structures. © 2015 Elsevier Ltd.

Wang Z.,Sun Yat Sen University | Wang Z.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | Cao J.,Sun Yat Sen University | Cao J.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes | And 4 more authors.
Journal of Geochemical Exploration | Year: 2016

In this paper, we used transmission electron microscopy (TEM) to study metal-bearing particles in the Gobi Desert soil of the concealed Xiaohulishan deposit in north-western Inner Mongolia. By analysing the category, size, shape, and chemical composition of metal particles in soil samples, as well as their co-occurrence with soil mineral particles in the surface overburden, we determined the characteristics of the metal particles that are related to mineralization. Along with the geological setting, this information can provide insight into prospecting the concealed ore body based on the surface overburden particles. In addition, studying the association between metal particles and soil mineral particles allows us to summarize the adsorption properties of soil minerals for metal particles, and analysing the metal particles carried by ascending gas helps us determine the mechanism by which metal particles are transported by ascending gas flow in the surface overburden. This paper discusses both the natural metal particles and the soil mineral particles that contain metals. We propose that it is possible to prospect a concealed ore body using the characteristics of surface overburden particles, and we summarize the preferences and behaviour of metal particles (mainly Fe-, Mo-, Cu-, Pb- and Zn-bearing particles) adsorbed by soil minerals such as Ca sulphates, silicates, carbonate minerals, and clay minerals. This knowledge is significant because it can help explain the migration mechanisms of metal particles in the soil-covered areas of the Gobi Desert. These findings will also help to explore concealed deposits by facilitating the use of elemental concentrations, as well as the characteristics of metal particles carried by ascending gas flow. © 2016 Elsevier B.V.

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