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Xiong Z.-H.,Peking University | Zhao M.-Z.,South China University of Technology | He J.-G.,Sun Yat Sen University | He J.-G.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | And 3 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2016

Bredigite was synthesized by using the Piston-Cylinder in 1.2 GPa and 1 473 K. With external heating device and diamond anvil cell, high temperature and high pressure Raman spectra of bredigite were collected at temperatures 298, 353, 463, 543, 663, 773 and 873 K and with pressure from 1 atm up to 14.36 GPa (room temperature). The SEM image showed that the sample consisted of one crystalline phase with grain size ranging from 10~20 μm. The EPMA data suggest a chemical formula of Ca7.03(2)Mg0.98(2)Si3.94(2)O16 which was identical to the theoretical component of bredigite. The Raman spectroscopic results indicate there were 29 vibration bands of bredigite at high temperature. Some bands were merging, weakening and disappearing increasingly with the temperature, which was obvious in the range of 800~1 200 cm-1. The vibration bands of 909, 927 and 950 cm-1 disappeared at 873, 773 and 873 K, respectively. The results primarily indicated that the structure of bredigite was stable under experimental condition. In addition, isobaric mode-Grüneisen parameters and isothermal mode-Grüneisen parameters were calculated, yielding 1.47(2) and 0.45(3) as their mean values, respectively. Anharmonic coefficients were estimated based on the high temperature and high pressure Raman experiments, showing that the contributions to anharmonic-effect induced with the Si-O vibration modes were smaller than other modes. © 2016, Peking University Press. All right reserved.

Ma J.,Chinese Research Academy of Environmental Sciences | Zhou Y.,Sun Yat Sen University | Zhou Y.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey
Journal of Environmental Sciences | Year: 2011

Soil samples from Huizhou and Zhanjiang, China were analyzed for 16 priority poly cyclic aromatic hydrocarbons (PAHs) with harmonized sampling, sample extraction and analysis quantification methods. The concentrations and sources of PAHs in soil samples of the two cities were compared. Almost all of the PAH components were detectable in 103 soil samples. The concentrations of {caret insertion point}PAHs ranged from 35.40 to 534.5 μg/kg in soil samples from Huizhou, and ranged from 9.50 to 6618.00 μg/kg in samples from Zhanjiang. Evident differences of concentrations, compositions and sources of PAHs in soils were observed between the two cities. The average concentrations of individual component and the sum of a group of PAHs in soil samples from Zhanjiang were significantly higher than those in Huizhou (P < 0.05). Phe, Flu, Pyr, Bbf and Baa were the dominant PAH components both in soil samples from Huizhou and Zhanjiang. Except for these five components, Bap, Up, Daa and Bgp were also the dominant PAH components in soil samples from Zhanjiang. Coal combustion and liquid fossil fuel combustion were the same sources of PAHs in the two cities with different contributions, and petroleum played a key role in PAHs release in Zhanjiang. © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Liang J.,Sun Yat Sen University | Liang J.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | Zhou Y.,Sun Yat Sen University | Zhou Y.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | And 10 more authors.
Acta Petrologica Sinica | Year: 2012

The Qinzhou Bay-Hangzhou Bay suture zone (QHSZ) is an important porphyry copper deposits (PCD) belt. PCDs are well distributed in the northern, the middle and the south sections of the QHSZ. They are mainly formed in the Yanshanian Period. Porphyries related to copper mineralization are mainly granodiorite porphyry, granite porphyry and sub-dacite porphyry, which belong to the calc-alkaline magma series of acidic rock. The porphyries above have similar trace element geochemical characteristics of the Neoproterozoic island arc igneous rock. They are derived from the partial melting of a mixture of magma in asthenosphere and the lower crustal material, and are related to the lithospheric mantle affected by earlier plate subduction, with evident crust-mantle contamination. The geodynamic setting of the Yanshanian petrogenesis and metallogenesis of the QHSZ is characterized by subduction of the Pacific plate, while the Yanshanian porphyries and copper ore bodies have the trait of island arc magma system, which is related to the geological evolution before the Mesozoic tectonic transition event in South China. It is concluded that such acidic porphyries of the QHSZ resulted from the partial melting of the Proterozoic island arc basaltic rocks during the Mesozoic, and the associated PCDs have the gene of island arc subduction environment.

Li H.-Z.,CAS Institute of Geology and Geophysics | Zhai M.-G.,CAS Institute of Geology and Geophysics | Zhang L.-C.,CAS Institute of Geology and Geophysics | Yang Z.-J.,Sun Yat Sen University | And 7 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2013

The results of Raman, SEM, CL and EDS analysis show that the quartz-type BIF (banded iron formation) in Tieshanmiao formation, from Wuyang area of south North China Craton mainly contains quartz, magnetite and a small quantity of calcite. In comparison, magnetites represent the highest automorphic degree, while calcites contribute to the lowest automorphic degree. In addition, the automorphic degree of the quartz lies between magnetite and calcite. In the results of Raman analysis, the crystallinity and order degree are quite diverse in the vertical direction of the calcite band-like, and this is different from the calcite vein precipitating from the upper hydrothermal fluid. There are obvious plastic flow happening to calcite particles. During the process of plastic flow, the calcites are finally filled in the space between quartz and magnetite. This is the reason why the cross sectional shape and distributional characteristics of calcite aggregate are controlled by the particles of quartz and magnetite, which is also evidenced by the calcite filled into the slight interspace between two particles of quartz. In the Raman analysis, there are apparent differences of microarea component in calcite band-like, and this denotes that it is produced by the plastic flow and concourse process. What's more, the calcite acts as the migration intermedium of tiny magnetite during their concourse and crystallization processes, which is witnessed by the concentrated particles of magnetite in small size in local parts of the calcites. With the help of calcite, the small magnetite particles join together to crystallize with bigger size or form aggregate of minerals.

Tang L.,Sun Yat Sen University | Tang L.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | Chen H.,Sun Yat Sen University | Song J.,Sun Yat Sen University
Geosciences Journal | Year: 2016

Water molecules are adsorbed onto the surface and interlayer of clay minerals and form a film, which causes that pore pressure diffusion in clayey soils differs from that in granular material. In this paper, adsorbed water is classified into strongly adsorbed water and loosely adsorbed water, which provide a better understanding of the physical mechanisms of the adsorbed water. To investigate the impact of adsorbed water on pore pressure diffusion, a series laboratory tests were conducted, including the uplift pressure test, pore pressure diffusion test and adsorbed water content test. The experimental results implies that strongly adsorbed water can neither flow nor participate in pressure diffusion, but loosely adsorbed water shears at pressure gradients and participates in laminar flow. Therefore, as long as the dense clayey soil contains loosely adsorbed water, the pore pressure change at a local site can diffuse throughout the material. A concept called “loosely adsorbed water index (Ilo) is defined to characterize both the content and physical properties of loosely adsorbed water: (1) when Ilo ≥ 1, the peripheral water molecules of loosely adsorbed water layer essentially behave the same as free water; (2) as Ilo → 0, the physical properties of adsorbed water may evolve from a gel-like state to a solid-like state (strongly adsorbed water). According to the density of clay and the content of adsorbed water, the process of pore pressure diffusion can be divided into three modes: flow channels of free fluid, deformations of the adsorbed water layer and shear motions of the peripheral-adsorbed water molecules. Pore pressure response to additional water pressure strongly depends on the permeability, seepage path and boundary conditions. The time-lag effect of pore pressure diffusion should be considered in applications of effective stress in engineering. © 2016 The Association of Korean Geoscience Societies and Springer-Verlag Berlin Heidelberg

Tang Y.-K.,Sun Yat Sen University | Tang Y.-K.,Guangdong Electric Power Design Institute | Chen G.-N.,Sun Yat Sen University | Chen G.-N.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | And 3 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2013

The results on Xilingang pluton, mainly consisting of red beds, granites containing numerous debris of red beds and granites, obtained by X-ray fluorescence spectroscopy, plasma mass spectrometry and Raman spectroscopy show: (1) Xilingang pluton from red beds, granites containing numerous debris of red beds to granites has obvious characteristics of decreasing silicon and alkali content, and rising ignition loss, dark mineral content and oxidation index; (2) Chondrite-normalized REE distribution curves and primitive mantle-normalized spider diagram for trace elements of redbed, granites containing numerous debris of red beds and granites have a good consistency, the distribution characteristics of elements are similar to Nanling transformation-type granite; (3) The value of Raman spectrogram characteristic peak of quartz crystal in Xilingang granite decreased from the center of quartz crystal, and FWHM is steady. According to the above, the authors believe that Xilingang granite formed was related to in-situ melting of red beds and underlying strata and magma consolidation. Volatile components were discharged continuously, and oxidation index decreased gradually in the melting process. In the process of diagenesis, the top of pluton tend to be an ongoing silicon and alkali increase, while TFeO and MgO continue to migrate to bottom, and crystallization environment is a relatively closed and steady system.

Zhang X.,Sun Yat Sen University | Zhang X.,CAS Guangzhou Institute of Geochemistry | Zhang X.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | Cawood P.A.,University of Western Australia | And 7 more authors.
Gondwana Research | Year: 2016

The Kenting Mélange on the Hengchun Peninsula, Taiwan, formed through tectonic shearing of subduction complex lithologies, probably within the plate boundary subduction channel between the Eurasian and Philippine Sea plates, with further deformation and exhumation in the Pliocene-Pleistocene during arc-continent collision. Field relations reveal a structural gradation from normal stratified turbidite sequence (Mutan Formation) through broken formation to highly sheared Kenting Mélange containing allochthonous polygenic blocks. This gradation is consistent with an increase of average vitrinite reflection values from ~. 0.72% in the Mutan Formation through ~. 0.93% in the broken formation to ~. 0.99% in the mélange, suggesting temperatures of at least 140. °C during formation of the Kenting Mélange. Zircons from gabbro in the Kenting Mélange are dated as 25.46. ±. 0.18. Ma, which together with geochemical data constrains the source to South China Sea oceanic lithosphere. In combination with the field relationships, vitrinite reflectance values, microfossil stratigraphy, and offshore geophysical data from S and SE Taiwan, we propose that the Kenting Mélange initially formed at the subduction plate boundary from off-scraped trench deposits. Minor Plio-Pleistocene microfossils (<. 5%) occur within the mélange in proximity to slope basin of equivalent age and were likely sheared into the mélange during out-of-sequence thrusting associated with active arc-continent collision, which in the Hengchun Peninsula commenced after 6.5. Ma. © 2015 International Association for Gondwana Research.

Li H.,CAS Institute of Geology and Geophysics | Li H.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | Zhai M.,CAS Institute of Geology and Geophysics | Zhang L.,CAS Institute of Geology and Geophysics | And 10 more authors.
The Scientific World Journal | Year: 2013

The Qinzhou Bay-Hangzhou Bay joint belt is a significant tectonic zone between the Yangtze and Cathaysian plates, where plentiful hydrothermal siliceous rocks are generated. Here, the authors studied the distribution of the siliceous rocks in the whole tectonic zone, which indicated that the tensional setting was facilitating the development of siliceous rocks of hydrothermal genesis. According to the geochemical characteristics, the Neopalaeozoic siliceous rocks in the north segment of the Qinzhou Bay-Hangzhou Bay joint belt denoted its limited width. In comparison, the Neopalaeozoic Qinzhou Bay-Hangzhou Bay joint belt was diverse for its ocean basin in the different segments and possibly had subduction only in the south segment. The ocean basin of the north and middle segments was limited in its width without subduction and possibly existed as a rift trough that was unable to resist the terrigenous input. In the north segment of the Qinzhou Bay-Hangzhou Bay joint belt, the strata of hydrothermal siliceous rocks in Dongxiang copper-polymetallic ore deposit exhibited alternative cycles with the marine volcanic rocks, volcanic tuff, and metal sulphide. These sedimentary systems were formed in different circumstances, whose alternative cycles indicated the release of internal energy in several cycles gradually from strong to weak. © 2013 Hongzhong Li et al.

Zheng Y.,Sun Yat Sen University | Zheng Y.,CAS Guangzhou Institute of Geochemistry | Zheng Y.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | Li D.,CAS Guangzhou Institute of Geochemistry | And 3 more authors.
Geotectonica et Metallogenia | Year: 2015

The Ashele Cu-Zn deposit is located in the Ashele Devonian volcanic-sedimentary basin to the south of the Altay accretionary orogenic belt. The ore bodies are lens like hosted in the Ashele Formation. Orebodies show deformations concordant with the host rocks. The ore-forming process can be divided into two stages: the first VMS stage represented by banded and massive ores, while the second hydrothermal stage represented by Cu-polymatellic veins. Most of primary ores are preserved, but locally some veins cut across the earlier banded ores accompany with the coarse grains and pressure-solution, crushed, meta-porphyry, replacing textures, indicating metallic remobilization of primary VMS ores. Four types of fluid inclusions are distinguished, which include aqueous water (W-type), pure CO2 (PC-type), CO2-H2O (C-type) and daughter mineral-bearing (S-type). The primary fluid inclusions have homogenization temperatures of 220-280 ℃ and salinities of 4% to 8% NaCl equivalent. Gases in fluid inclusions are CO2, CH4 and N2. The low salinity and high CO2 content indicate the ore-forming fluid may be metamorphic fluid. The hydrostatic-lithostatic pressure of boiling fluid assemblage fluctuates is range of 85-295 MPa, corresponding to the depth of 8.5-10.9 km. Considering the regional tectonic evolution, we conclude that the VMS mineralization was formed in the arc-basin under extensional setting, whereas the late stage hydrothermal remobilization was formed in continental-arc collision setting. Therefore, the Ashele Cu-Zn deposit is a modified VMS deposit. ©, 2015, Science Press. All right reserved.

Zheng Y.,Sun Yat Sen University | Zheng Y.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | Zhou Y.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | Wang Y.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey | And 4 more authors.
Ore Geology Reviews | Year: 2016

The Hetai goldfield is located in the southern section of the Qinzhou Bay-Hangzhou Bay metallogenic belt (QHMB), South China. Gold mineralization is controlled by NE-trending ductile shear zones. Gold grade is higher at the shear zone centers and decreases sharply away from the shear zones, regardless of the host rock type. Fluid inclusions (FIs) preserved in the auriferous quartz veins have been analyzed to constrain their genesis. Three types of gold mineralization-related FIs, including moderate-salinity aqueous (A-type), low-salinity H2O-CO2 (B-type) and CO2-dominated (C-type), have been newly identified. The measured homogenization temperatures (Th) range from 130°C to 310°C, with two peaks of about 245°C and 170°C. The calculated pressures of FIs range from 50MPa to 170MPa. Immiscibility and CO2 effervescence of fluids may have played an important role in gold precipitation during the ascent of the ore-forming fluids. The Hetai goldfield is a typical example of orogenic gold deposits originating from auriferous metamorphic fluids. © 2014 Elsevier B.V.

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