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Review Articles
Study of overthrust nappe structure and its geodynamic mechanism along the southeastern margin of Nansha Trough
Guang-xue Zhang, Zhen Yang, Li Zhang, Wei Yan, Kun-sheng Qiang
2018, 1(4): 459-465. doi: 10.31035/cg2018060
[Abstract](36) [FullText HTML] (30) [PDF 7421KB](12)
Abstract:
On the basis of interpretation of comprehensive geophysical data and foreign data analysis, there existed a lot of overburden detachment shear thrust faults along the southeastern margin of Nansha Trough, which composed imbricated overthrust nappe structure. Thrust-faulted nappe structure pattern is determined in this area, which consists of frontal fault zone, thrust fault-folded zone and root zone structures, and presents regularly zonation on plane. The detail description of the structural geometrical characteristics is given in shallow thrust fault zone, and the kinematical mechanism of thrust fault nappe structure is furtherly discussed. Overthrust nappe structure in this area is resulted from island arc-continent collision and orogenic activities.
Geological resources and environmental carrying capacity evaluation review, theory, and practice in China
Rui-min Li, Zhi-qiang Yin, Yi Wang, Xiao-lei Li, Qiong Liu, Meng-meng Gao
2018, 1(4): 556-565. doi: 10.31035/cg2018050
[Abstract](52) [FullText HTML] (15) [PDF 37844KB](1)
Abstract:
Evaluations of resources and environmental carrying capacities (GRECC) are the premise of land space planning and use control. Resource allocations and environmental capacity are the basic conditions that restrict development in a region. In this paper, based on a systematic review of China's geological environment, groundwater resources, mineral resources, other geological resources and the environmental carrying capacity research status, the relationship between the natural resource environmental system and the socio-economic system is studied. Then a " coordination theory of resources and environmental carrying” is proposed. Next, on the basis of an evaluation experiment performed at different scales and for different types of regions, the technical methods for an evaluation of the geological resources and environmental carrying capacity at the regional (inter-provincial) and provincial scales in China are established for the first time. This paper presents a standardized method based on technical ideas, evaluation methods, and index systems for geological resource and environmental carrying capacity evaluation. Finally, an evaluation of the groundwater resource carrying capacity in China is used as an example for the demonstration of the groundwater resource background and use of state evaluation methods.
Original Articles
Origin of the serpentinites in the Lichi mélange, eastern Taiwan, China: implication from petrology and geochronology
Long Huang, Wei Geng, Zhi-lei Sun
2018, 1(4): 477-484. doi: 10.31035/cg2018070
[Abstract](31) [FullText HTML] (16) [PDF 7051KB](9)
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Lichi mélange, located in the southern coastal range, eastern Taiwan, China, is a typical tectonic mélange of the plate’s boundary zone between the Eurasian Plate and the Philippine Sea Plate. It formed during the collision of the Luzon arc with the Eurasian Continent (arc-continent collision). It is composed of sandstone and/or mudstone matrix and many kinds and sizes of rock fragments, including some sedimentary rocks, volcanic rocks and a few metamorphic rocks. The serpentinite is one of the common fragments in the Lichi mélange. By the petrographic characteristics and the zircon U-Pb chronology analyses, protolith of the serpentinite is peridotite, the age is 17.7 ± 0.5 Ma. Taking the tectonic background into account, it is inferred that the serpentinite (serpentinised peridotite) come from the forearc basin (the North Luzon Trough) and was taken into the mélange by a second thrust westwards. The origin of the serpentinite in Lichi mélange is helpful to understand the formation of the Lichi mélange and can provide reliable detailed information for the study of the arc-continent collision orogenic activity in and offshore Taiwan.
Discussion on “sandwich” structures and preservation conditions of shale gas in the South Yellow Sea Basin
Jian-qiang Wang, Jian-ming Gong, Li Zhang, Hai-yan Cheng, Jing Liao, Jian-wen Chen, Jing Su, Chuan-sheng Yang
2018, 1(4): 485-492. doi: 10.31035/cg2018064
[Abstract](35) [FullText HTML] (21) [PDF 7935KB](3)
Abstract:
In order to make a breakthrough in Mesozoic-Paleozoic shale gas exploration in the South Yellow Sea Basin, a comparison of the preservation conditions was made within the Barnett shale gas reservoirs in the Fortworth Basin, the Jiaoshiba shale gas reservoirs in Sichuan Basin and potential shale gas reservoirs in Guizhou Province. The results show that the " Sandwich” structure is of great importance for shale gas accumulation. Therein to, the " Sandwich” structure is a kind of special reservoir-cap rock assemblage which consist of limestone or dolomite on the top, mudstone or shale layer in the middle and limestone or dolomite at the bottom. In consideration of the Mesozoic-Paleozoic in the Lower Yangtze, and Laoshan Uplift with weak Paleozoic deformation and thrust fault sealing on both flanks of the Laoshan Uplift, a conclusion can be drawn that the preservation conditions of shale gas probably developed " Sandwich” structures in the Lower Cambrian and Permian, which are key layers for the breakthrough of shale gas in the South Yellow Sea. Moreover, the preferred targets for shale gas drilling probably locate at both flanks of the Laoshan Uplift.
Distribution of gas hydrate reservoir in the first production test region of the Shenhu area, South China Sea
Ru-wei Zhang, Jing-an Lu, Pen-fei Wen, Zeng-gui Kuang, Bao-jin Zhang, Hua Xue, Yun-xia Xu, Xi Chen
2018, 1(4): 493-504. doi: 10.31035/cg2018049
[Abstract](55) [FullText HTML] (23) [PDF 7551KB](4)
Abstract:
In May and July of 2017, China Geological Survey (CGS), and Guangzhou Marine Geological Survey (GMGS) carried out a production test of gas hydrate in the Shenhu area of the South China Sea and acquired a breakthrough of two months continuous gas production and nearly 3.1 × 105 m3 of production. The gas hydrate reservoir in the Shenhu area of China, is mainly composed of fine-grained clay silt with low permeability, and very difficult for exploitation, which is very different from those discovered in the USA, and Canada (both are conglomerate), Japan (generally coarse sand) and India (fracture-filled gas hydrate). Based on 3D seismic data preserved-amplitude processing and fine imaging, combined with logging-while-drilling (LWD) and core analysis data, this paper discusses the identification and reservoir characterization of gas hydrate orebodies in the Shenhu production test area. We also describe the distribution characteristics of the gas hydrate deposits and provided reliable data support for the optimization of the production well location. Through BSR feature recognition, seismic attribute analysis, model based seismic inversion and gas hydrate reservoir characterization, this paper describes two relatively independent gas hydrate orebodies in the Shenhu area, which are distributed in the north-south strip and tend to be thicker in the middle and thinner at the edge. The effective thickness of one orebody is bigger but the distribution area is relatively small. The model calculation results show that the distribution area of the gas hydrate orebody controlled by W18/W19 is about 11.24 km2, with an average thickness of 19 m and a maximum thickness of 39 m, and the distribution area of the gas hydrate orebody controlled by W11/W17 is about 6.42 km2, with an average thickness of 26 m and a maximum thickness of 90 m.
Historical records and the sources of polycyclic aromatic hydrocarbons in the East China Sea
Xiao-yong Duan, Yan-xia Li, Xian-guo Li, Ping Yin
2018, 1(4): 505-511. doi: 10.31035/cg2018058
[Abstract](28) [FullText HTML] (15) [PDF 10769KB](2)
Abstract:
The coastal cities are the most advanced regions in China. In the past few decades, the environment changed very significantly due to large scale human activities in the coastal regions. Polycyclic aromatic hydrocarbons (PAHs) in three dated sediment cores from the west coast of the Yellow Sea (core A01), the Yangtze River estuary (YRE; core A02) and the Oujiang River estuary (ORE; core A03) were analyzed to reconstruct the environmental evolutionary process of the east China coastal region over the past century. In the three cores, PAHs concentrations were increased rapidly. Lower concentrations of PAHs were measured in core A02 than in cores A01 and A03. The vertical variation of PAHs in the YRE was dominated by the petrogenic sources. Historical records of PAHs in the ORE were controlled by pyrolytic sources. PAHs on the west coast of the Yellow Sea were contributed by the two sources.
Coastal erosion in Shandong of China: status and protection challenges
Ping Yin, Xiao-yong Duan, Fei Gao, Mei-na Li, Sheng-hua Lü, Jian-dong Qiu, Liang-yong Zhou
2018, 1(4): 512-521. doi: 10.31035/cg2018073
[Abstract](28) [FullText HTML] (17) [PDF 23603KB](2)
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Shandong has more than 70% of natural coasts are under erosion. Coastal erosion started from the 1970’s and became a very serious problem at 1990’s. The dramatic decrease of sediment supplies from rivers caused rapid erosion at the delta and estuary areas, especially in the abandoned Yellow River Delta. Most sandy coasts along the Peninsula were eroded due to lack of sand supply and interruption of alongshore sediment drift, sand dredging from the beach or the offshore area caused serious erosion during short time. Sea-level rise causes slow but constant shoreline retreats and became a more serious threat. Different types of hard solutions for coastal protection against erosion were used in Shandong. Seawalls are most widely used, especially at the Yellow River Delta and city center waterfront. Groynes, jetties and breakwater are used on the north and east sandy coast of the Peninsula. Hard approaches are effective to protect the coast erosion but not change the erosion causes and led secondary impact on the coast. Soft engineering solution or the combined solutions are taken into acts. Beach nourishment is mostly considered as the better soft solution, especially to those tourists attracting sandy beaches along the Shandong coast. Long term monitoring and continuous lessons learning from the coastal erosion management will be adaptive for better coast solution in the future.
Discussion on the dextral movement and its effect in continental China and adjacent areas since Cenozoic
Rui-zhao Qiu, Stephen D. Ludington, Su Zhou, Yong-jie Tan, Guang-sheng Yan, Zhi-gang Liu, Xiu-fa Chen, Quan-long Zhu, Lei Qiu, Xiao-dong Ren, Li-ke Zhao
2018, 1(4): 522-539. doi: 10.31035/cg2018056
[Abstract](35) [FullText HTML] (15) [PDF 7699KB](3)
Abstract:
Continental China has moved dextral Eastward since Cenozoic time, driven by the collision of the Indian with the Eurasian plate. Evidence for this comes from landscape evolution, the distribution of earthquake epicenters, Cenozoic sedimentary and volcanic rocks, and the measurement of GPS velocity vectors, the distribution of crustal stress, paleomagnetic data, and deep mantle structure, among others. This movement commenced around 40 Ma, coupled with thickened lithosphere and widespread stress release along strike-slip faults that bound the continental Chinese block. Because of continued Northward subduction of the Indian plate, manifestation of the dextral movement has intensified since 25 Ma. Far-reaching effects include extensive strike-slip movement on the Tan-Lu fault in Eastern China, formation of the Dabie ultrahigh pressure metamorphic terrane, extensive thrust faults in East China, delamination and thickening of the lithosphere of South China, a possible tectonic doubling of the Middle-Lower Yangtze Valley metallogenic belt, and the formation of the Japan, Huanghai (East China), and South China Sea.
Early-middle Mesoproterozoic tectonic evolutionary history of the southwestern Yangtze Block, China: lithostratigraphic, geochronologic and elemental geochemical constraints
Fu-guang Yin, Zhi-ming Sun, Guang-ming Ren
2018, 1(4): 540-555. doi: 10.31035/cg2018048
[Abstract](62) [FullText HTML] (22) [PDF 7323KB](5)
Abstract:
During the Early-Middle Proterozoic era, three major lithostratigraphic unit associations, namely Hekou-Dahongshan, Dongchuan, and Kunyang-Huili Groups, were established for the metamorphosed volcanic-sedimentary rocks exposed in the southwestern Yangtze Block (SWYB). The integration of petrology, geochemistry and geochronology constrains tectonic framework and evolution of the SWYB, in which four sets of SHRIMP U-Pb zircon ages were obtained from the volcanic rocks interbedded within the Middle Proterozoic successions: 1800–1600 Ma, 1600–1300 Ma, 1300–1100 Ma, and 1100–1000 Ma. Major and trace elemental analysis indicate that four key tectonic evolutionary stages, each coinciding with the above radiometric age set, of the SWYB during the Early-Middle Mesoproterozoic. The SWYB was characterized by an east-westerly trending rift in the Hekou, Dongshan, and Dongchuan areas, and separate basin-forming events during 1800–1600 Ma and 1600–1300 Ma, respectively. In the SWYB, an intracontinental rift basin and a rift basin occurred in the Caiziyuan-Matang and Laowushan areas, respectively in 1300–1100 Ma ago. During 1100–1000 Ma, the SWYB was characterized by the closure of the Caiziyuan-Matang rift-ocean basin, collision between the Huili Blocks and Kunyang Blocks, and presence of volcanic arcs in the Tianbaoshan and Fulingpen areas. Accordingly, the SWYB represents a new basin that records the relatively complete assembly process of the Rodina during the Early-Middle Mesoproterozoic era.
Research Advances
Evidence of the existence of paleo reservoirs in Laoshan Uplift of the South Yellow Sea Basin
Yin-guo Zhang, Jian-wen Chen, Jie Liang, Guangxi Ou, Di Wu
2018, 1(4): 566-567. doi: 10.31035/cg2018067
[Abstract](29) [FullText HTML] (21) [PDF 6480KB](4)
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Thermal recovery method of submarine gas hydrate based on a thermoelectric generator
Cui-ling Xu, Zhi-lei Sun, Wei Geng, Xian-rong Zhang, Hong Cao, Li-ping Liu, Xi-lin Zhang, Bin Zhai
2018, 1(4): 568-569. doi: 10.31035/cg2018068
[Abstract](41) [FullText HTML] (25) [PDF 6592KB](3)
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A three-dimensional environmental monitoring system for the production of marine gas hydrates
Zhi-lei Sun, Hong Cao, Wei Geng, Le Zhang, Xian-rong Zhang, Cui-ling Xu, Xin Li, Jian-wei Guo
2018, 1(4): 570-571. doi: 10.31035/cg2018066
[Abstract](31) [FullText HTML] (28) [PDF 6950KB](3)
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News and Highlights
China has launched a deep gold prospecting demonstration project to evaluate gold resource potential within 3000 m underground in the east of the North China Craton
2018, 1(4): 572-573. doi: 10.31035/cg2018047
[Abstract](22) [FullText HTML] (24) [PDF 6731KB](5)
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Introduction of International Research Center on Karst under the Auspices of UNESCO
2018, 1(4): 574-576. doi: 10.31035/cg2018055
[Abstract](15) [FullText HTML] (15) [PDF 24705KB](0)
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