2017 Vol. 23, No. 4

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INSAR CO-SEISMIC DEFORMATION OF 2017 Ms 7.0 JIUZHAIGOU EARTHQUAKE AND DISCUSSIONS ON SEISMOGENIC TECTONICS
YAO Xin, ZHANG Zhenkai, LI Lingjing, LIU Xinghong, YAO Jiaming
2017, 23(4): 507-514.
Abstract (222) HTML (153) PDF (3802KB)(25)
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An Ms7.0 earthquake occurred in Jiuzhaigou county on Aug. 8, 2017. Tectonic location is the NE part of Bayan-Har block, with epicenter in the earthquake-free zone surrounded by Minjiang fault, Tazang fault, Huya fault as well as Xueshanliangzi fault, and where is of free earthquake zone. Which is the seismogenic fault? How to define the relationship between this earthquake and the neighbor faults? Does it have the causal association with huge earthquakes in recent years? The answers to those questions are of great significance to understand the current tectonic activity pattern, predict seismic development trend and deploy earthquake geological disaster prevention and control. Using two periods of Sentinel-1 SAR data to carry out InSAR survey, co-seismic deformation (-13~28 cm) and movement direction within 2000 km2 in meizoseismal area were measured, showing passive singe wall strike-slip and thrust ground deformation. Based on analysis of focal mechanism solution, fault distribution, tectonic background and recent seismic migration, conclusions are made as follows. The seismogenic structure is the end structure of an arc rotation system in northeastern boundary of Bayan-Har block, and the seismogenic fault is the southern branch of Tazang fault, with the trend to connect with Huya fault, therefore, the section between them should be paid more attention to in the future. There are certain spatio-temporal genetic relation between Jiuzhaigou earthquake and Wenchuan earthquake: in condition of ruptures existed in north and south boundary of Bayan-Har block, the 2008 Wenchuan earthquake induced new rupture in east edge to accelerate block eastward extrusion, and 2013 Ludian earthquake released tectonic stress in southern section, further exacerbating stress concentration in northeastern angle, which led to the 2017 Jiuzhaigou earthquake.
JURASSIC DEFORMATION AT THE WESTERN MARGIN OF THE EAST ASIA CONTINENT: A CASE STUDY OF DUCTILE DEFORMATION IN THE CENTRAL SEGMENT OF THE BANGONG CO-NUJIANG BELT
SHI Wei, DONG Shuwen, HUANG Xingfu, CHEN Hong, CUI Jianjun
2017, 23(4): 515-525.
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The Bangong Co-Nujiang belt resulted from the convergence and collision between the Chiangtang and Lhasa blocks in late Mesozoic. The key issue in this tectonic study is when and how the belt was formed. With the Ando-Nyainrong block of the central segment of the Bangong Co-Nujiang belt as the study area, the ductile shear belts with approximately E-W strike developed in the internal basement of the block are studied based on ductile shear deformation analysis and syntectonic geochronology. The foliation and lineation measurement and analysis of the shear belts indicate tectonic compression with NE-SW strike. Through the test analysis of 40Ar/39Ar in syntectonic minerals, the age is worked out as 167 Ma. All the evidence shows that the central segment of the Bangong Co-Nujiang belt was caused under the convergence and collision between the Chiangtang and Lhasa blocks in the middle of Middle Jurassic, which provides direct tectonic evidence for the Jurassic deformation at the western margin of the East Asian continent.
REVIEW ON THE RESEARCH PROGRESS OF THE COMPLIANCE OF ROCKS IN IN-SITU STRESS MEASUREMENT METHODS OF ANELASTIC STRAIN RECOVERY (ASR)
MA Xiumin, PENG Hua, BAI Jinpeng, LI Zhen, JIANG Jingjie
2017, 23(4): 526-530.
Abstract (275) HTML (77) PDF (1154KB)(18)
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In this article, through the analysis of the research progress on in-situ stress measurement of Anelastic Strain Recovery (ASR) method at domestic and abroad and the systemic review of the compliance parameters of ASR method, it is believed that ASR method is mature in theory and has broad prospect in application. In the measurement principle, however, few studies on the influence of temperature and stress environment (stress) on the ASR compliance of rocks have been done. To this end, the suggestions on the improvement or supplement of ASR method are proposed, which point out the direction of the improvement of the measurement principles and has great importance to the development of the ASR in-situ stress method.
A STUDY ON THE INFLUENCE RULE OF THE FRACTURE CHARACTERISTICS ON ROCK SEEPAGE CHARACTERISTICS
ZHOU Hanguo, GUO Jianchun, LI Jing, FAN Zuosong, GAO Shuai, WANG Chang, LIU Zhen
2017, 23(4): 531-539.
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Fracture is the main reservoir space and fluid seepage channel in oil and gas reservoirs, which affects hydrocarbon migration directly as an important indicator of oil and gas exploration and development. In this study, the Ren 10 well in Renqiu Oilfield of the Jizhong depression was taken as an example, the influence rule of fracture width and fracture surface roughness on rock seepage characteristics was studied in this work by numerical simulation. The results show as follows: 1) When fracture width is small, fluid pressure in pore distributes as a fan and only in a small range of the entrance; pressure distribution curve in fracture is tangent function type, and fluid and flow velocity are both relatively small in fracture and pore. With the increase of fracture width, fluid pressure in pore increases gradually; pressure distribution curve in fracture gradually changes to linear type. Moreover, the fluid and flow velocity decrease first and then tend to be stable at the entrance while increase first and then tend to be stable in fracture. 2) The influence of fracture surface roughness on rock seepage characteristics varies with fracture width. When fracture width gets bigger, the influence of fracture surface roughness gets greater on the distribution of fluid pressure. With the increase of fracture surface roughness, flow velocity in pore gradually increases while that in fracture decreases. 3) With the increase of fracture width, the main controlling factor affecting fluid flow in fracture changes from fracture width to fracture surface roughness.
FACTORS INFLUENCING GAS PRODUCTION EFFECTIVENESS OF LONGMAXI FORMATION SHALE IN SICHUAN BASIN AND ADJACENT AREAS
WANG Yufang, ZHAI Gangyi, WANG Jinzhu, ZHANG Yunxiao
2017, 23(4): 540-547.
Abstract (152) HTML (101) PDF (1769KB)(16)
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Many important findings and breakthroughs concerning the exploration and development of Lower Silurian Longmaxi shale gas in Sichuan basin and adjacent areas have been made. A series of drilling wells and fracturing reconstructions, such as Well JY1HF, Pengye1Hf, Well DY2HF, Nanye1HF, Well Longcan2 and Well Baoye1, all show a good prospect of Longmaxi shale gas in exploration and development. Correlational analysis were made between relevant parameters and post-fracture production in several shale gas wells in Sichuan Basin and adjacent areas, such as reservoir geological condition, reservoir physical property, in-situ stress, structure preservation, construction scale of fracturing and so on. It is concluded that the main controlling factors affecting the exploration and development of shale gas are thickness of high quality shales, gas-bearing properties, brittle mineral content, porosity, formation pressure coefficient and horizontal stress difference coefficient, which provides important reference and guidance for the efficient exploration and development of marine shale gas in the future.
ACTIVITY STUDY AND DISASTER EFFECT ANALYSIS OF THE NORTH SECTION OF HUANGZHUANG-GAOLIYING FAULT IN BEIJING
ZHANG Lei, ZHANG Xiaoliang, BAI Lingyan, YANG Tianshui, CAI Xiangmin, LIANG Yanan
2017, 23(4): 548-557.
Abstract (301) HTML (96) PDF (3622KB)(34)
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In order to further study the Huangzhuang-Gaoliying hidden active fault in the innovation industrial site, future technology city of Beijing, the structural characteristics of the fault zone, Quaternary activity as well as disaster-causing mechanism were determined by the shallow artificial earthquake, high-density resistivity method and drilling engineering. The results show that the north section of the Huangzhuang-Gaoling fault presents as a tensional normal fault in general and dips 70°—80° SE. Near the bedrock depth the vertical separation is relatively large. The fault extending up to the inside of the Quaternary system has the characteristics of listric fault and its occurrence gradually becomes stepper. Parts of the fault are combined with feature "Y" shape. The north section of Huangzhuang-Gaoliying fault has been active since Quaternary, and the average vertical velocities were respectively 0.07 mm/a, 0.04 mm/a, 0.23 mm/a, and 0.10 mm/a in early Pleistocene, middle Pleistocene, late Pleistocene and Holocene. The change characteristics are consistent with that of the neotectonics of Xishan uplift. There has been a strong creeping deformation in the Huangzhuang-Gaoliying fault since Holocene. As the lower walls of the fault keep moving, the geological disasters, such as ground fissures, ground subsidence, wall cracking and so on, were formed along the fault zone.
A STUDY ON ZIRCON LA-ICP-MS U-PB AND 40AR/39AR AGES OF VOLCANIC ROCKS FROM KENDEKEKE, QIMANTAGE AND THE GEOLOGICAL SIGNIFICANCE
MA Shuai, CHEN Shiyue, SUN Jiaopeng, WANG Feng, SHAN Tengfei
2017, 23(4): 558-566.
Abstract (381) HTML (204) PDF (2712KB)(12)
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Zircon LA-ICP-MS U-Pb dating and 40Ar/39Ar dating were made on the volcanic samples of Qigaisu group from Kendekeke in upper Devonian. Combined with regional geological features, multicyclic tectonic evolution of Qimantag tectonic zone are summarized and analyzed. The results show that, rhyolites in Qigaisu group formed in late Devonian(384.9±6.0 Ma), while Qigaisu group formed no later than late Devonian. The two inherited zircon ages 767±15 Ma and 915±18 Ma certify that the study area responded to supercontinent aggregation-cracking, but evidence from stratum, sedimentation, metamorphism and deformation do not support the existence of the late Paleozoic ocean or aulacogen in Qimantag area, and Qimantag area in late Paleozoic was an epeiric sea located at the southwest margin of Qaidam. The 40Ar/39Ar effective plateau age of the samples is 220.3±1.7 Ma, which shows the latest burial depth is about 8000 m. Large-scale uplift events happened after the late Triassic volcanism, multiphase tectonic events, such as late Indosinian, Yanshanian and Himalayanian, caused the lack of large-scale settlement in Mesozoic and Cenozoic. Intra-continent orogeny lasted to 32 Ma or so. Because of the extension of Kumukuli basin afterwards, Qimantage orogenic belt separated from East Kunlun orogenic belt.
THE GEOCHEMICAL CHARACTERISTICS AND TECTONIC SIGNIFICANCE OF LA-ICP-MS ZIRCON U-PB DATING OF YAMATUO INTRUSIVE ROCKS, QINHAI PROVINCE
SUN Jian, SUN Dongliang
2017, 23(4): 567-576.
Abstract (218) HTML (201) PDF (3503KB)(13)
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Yamatuo intrusive rocks, distributing in the northern margin of Qaidam basin, compose the east part of Tataleng River batholith. The lithology of these rocks is the combination of porphyritic-like syenogranite and porphyritic monzogranite. The phenocryst content in the rocks is 6~25% and its grain size is 1~5 cm, revealing rapakivi texture. The geochemical characteristics show that Eu is with obvious depleted characteristics reflecting the strong fractional crystallization of rocks which is very similar to crustal-derived granite (S). All the facts indicate the intrusive rocks are the partial melting of the crust, belonging to the mixture of crust-derived magmatite in post-collisional tectonic setting. The result analysis of LA-ICP-MS zircon U-Pb dating indicates that the rock mass was formed in early Silurian 429.9±1.4 Ma, being the signature of the end or near the end of the orogenic process in early Paleozoic This finding provides important chronological constraints for further study of the tectonic evolution of the northern margin of Qaidam orogenic belt.
CHARACTERISTICS AND COMPREHENSIVE EVALUATION OF CHANG 31 RESERVOIRS OF YANCHANG GROUP IN SHISHE AREA, ORDOS BASIN
YU Yamin, WEN Zhigang
2017, 23(4): 577-584.
Abstract (332) HTML (154) PDF (4060KB)(11)
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Based on the data of rock thin sections, casting thin sections, physical property analysis and intrusive mercury curves, the characteristics of Chang 31 reservoirs of Yanchang group in Shishe area of Ordos Basin were studied. The results show that the reservoirs of Chang 31 in Shishe area are mainly composed of feldspar lithic sandstone and lithic feldspar sandstone, belonging to low-ultra low porosity and low-ultra low permeability reservoir. The main pore types are intergranular pore and feldspar dissolved pore. The distribution of reservoirs is mainly controlled by sedimentary facies and the diagenesis afterwards also affects the reservoir properties. According to the evaluation criterion, the reservoirs of the study area can be divided into three types. Chang 31 reservoir group in Shishe area mainly are type Ⅰ reservoir and type Ⅱ reservoir.
THE GEOCHEMICAL AND MINERALOGICAL CHARACTERISTICS OF SHALES IN CHAIWOBU DEPRESSION, SOUTHERN MARGIN OF JUNGGAR BASIN
XIONG Jinhong, LIANG Mingliang, CAO Zhanyuan, WANG Zongxiu, ZHENG Jianjing, WANG Zuodong
2017, 23(4): 585-593.
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Using XRD, Rock-eval and GC-MS, kerogen type, organic geochemical characteristics and inorganic mineralogy features of shales in upper Carboniferous, upper Permian, and lower Jurassi from the Chaiwobu depression at southern margin of Junggar Basin were analyzed. The organic geochemical index shows that from Carboniferous to Permian, it has been a long period of fresh-brackish water sedimentary environment in Chaiwobu depression. The sources of organic matter shared the similar source input characteristics, and kerogen type were mainly featured by type Ⅱ. The thermal evolution of organic matter indicates that shales in lower Jurassic were in low mature stage while shales in upper Carboniferous and upper Permian showed the features of high abundance, rich in types and mature-high mature stage in the thermal evolution. The mineralogical characteristics show that the content of brittle minerals feldspar and quartz in upper Permian shales is 73%, followed by clay mineral, indicating a high brittleness index and good property of fracturing and adsorption. Combined with the previous studies, it is predicted that a certain scale of shale gas resources may be contained in shales of this member with a good prospect and potential for exploration.
APPLICATION OF LASER RAMAN SPECTROSCOPY IN THE STUDY OF ORGANIC INCLUSIONS: A CASE STUDY ON OIL AND GAS INCLUSIONS IN THE 8th MEMBER OF THE SHIHEZI FORMATION IN WESTERN SULIGE GASFIELD
DONG Hui, WANG Zhihai, DONG Min, LI Hong, WEI Xiaoyan, LIANG Jiwei
2017, 23(4): 594-601.
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Based on the application of laser raman microprobe analysis in situ technique, the nature of oil and gas inclusions in the 8th member of the Shihezi formation in western Sulige gas field was identified. The composition and relative molar fraction of phaseⅡhydrocarbon-bearing organic inclusions in the healing fracture of the quartz grain surface and in the secondary enlargement margin were determined. The results show that the early-stage inclusions mainly are gas-liquid two-phase organic inclusions containing gaseous hydrocarbon and brine gaseous hydrocarbon, and the late-stage inclusions are gas-liquid two-phase organic inclusions containing gaseous hydrocarbon; The gas phase is dominated by gases such as CO2, CH4 and N2, and the CO, H2S, H2, C2H2, C2H4, C2H6, C4H6, H2O and CO2are dissolved in it; the liquid phase mainly is consist of H2O and CO2, and also contains a very small amount of anion SO42- and CO32-(less than 0.03 mol/L). The research makes clear that the early-stage organic inclusions contain large amounts of CO2, H2O and a small amount of inorganic gas of low carbon alkane. It indicates that the early maturity of organic matter was in immature-low mature stage. Although natural gas is generated, the migration is limited in scale. The organic inclusions are few and far between. It reflects the replacement of formation water by natural gas entering reservoir. The late-stage organic inclusions are the opposite. The content of hydrocarbons and N2 are higher, but the content of CO2, inorganic gas and H2O are lower. It represents the characteristics of the peak of oil and gas formation and large-scale oil and gas accumulation. It provides a scientific basis for the thermal evolution of organic matter, the generation and migration of oil and gas, and the division of oil and gas accumulation stages.
LATER QUATERNARY CLIMATIC AND ENVIRONMENTAL CHANGES IN THE SOUTHEASTERN MARGIN OF INNER MONGOLIA
TIAN Fei, WANG Yong, CHI Zhenqing, LIU Jin, JIANG Nan, TANG Wenkun, YAO Peiyi
2017, 23(4): 602-611.
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A multi-proxy record including grain size, magnetic susceptibility and trace element from the fluvial-lacustrine Linjiadian section in the upper reaches of Xilamulun River, situated in the southeastern margin of Inner Mongolia, has been proposed to reconstruct the environmental and climatic changes since the last 36 ka BP. The results show that, during 35.23 to 25.15 ka BP, the late stage of Marine Isotope Stage 3 (MIS 3), warm and wet climate conditions dominated this region accompanied by the trend of regional drought climate. The following period, approximately 25.25~11.35 ka BP, corresponding to MIS 2, was characterized by frequent fluctuations in climate change. The driest and coldest interval was recognized as the last glacial maximum (LGM), ranging from 22.25 to 18.47 ka BP, and two minor climate optimums occurred in 18.47~16.24 ka BP and 14.72~11.13 ka BP. The Holocene commenced at about 11.13 ka BP with the transition to a relatively humid and warm climate. Regional comparisons suggest a roughly synchronous pattern of climate change and variation in the East Asian summer monsoon (EASM), attributing to the force of the northern hemisphere summer insolation and ice volume. In addition, the millennial-scale EASM fluctuation had some influence on the Heinrich (H), and the Younger Dryas (YD), indicating the relevance to the rapid Atlantic meridional overturning circulation (AMOC) oscillations.
A STUDY ON PARTIAL ANHYSTERETIC REMANENCE IN SEDIMENTS FROM GANHAI LAKE, NINGWU TIANCHI
ZHANG Shuwei, LIU Qingsong, WANG Xisheng, Cioppa Maria, HUO Junjie, LV Yiqing, QIAO Yansong, ZHAO Yue
2017, 23(4): 612-616.
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A study of partial anhysteretic remanent magnetization (pARM) spectra in samples from a sediment profile of Ganhai Lake (38°53'N, 112°11'E) shows variations in effective magnetic grain sizes of the lake sediment magnetite particles, consistent with the hysteresis results. Within the full profile, most magnetite particles are of coarse, multi-domain (MD) size, as shown by the dominant low coercivity (AF < 20 mT) spectra, with a few samples showing finer single domain (SD)-pseudo-single domain (PSD) particles with higher coercivity (AF>20 mT). The uppermost level (~7.3~4.0 ka) contains more coarse MD magnetite grains due to higher pARM peaks than the middle (~12.0~7.3 ka) and the lowermost level (~13.0~12.0 ka) that shows lower peaks. The middle level shows slight more fine SD-PSD magnetite grains than both the uppermost and lowermost level. High-field pARM spectrum can effectively identify fine PSD-SD magnetite grains and reduce effects of MD grains. Therefore, pARM spectrum analysis can be utilized to quickly and effectively determine the relative amount of fine magnetic grains in the samples, which is helpful to the study of the paleo-climate, rock magnetism and paleomagnetism of the lake sediments.
THE PRINCIPLE OF GEOCHEMICAL ANOMALY DELINEATION BASED ON THREE DIMENSIONAL GEOCHEMICAL EXPLORATION DATA METHOD AND ITS SIGNIFICANCE
XU Guozhi, LI Nan, SUN Lu, LI Peng, WU Ting
2017, 23(4): 617-626.
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Two-dimensional geochemical data calculation method, as the traditional method in geochemical exploration anomaly delineation, has been used in the geochemical exploration industry for many years. However, this data processing method has some deficiencies in the prospecting and prospecting area in the premise of sampling and landscape differences. In order to compensate for these shortcomings, three-dimensional data processing and mapping method is proposed, which added elevation elements. It is proved by experiments that this method is better for comprehensive anomaly delineation and the abnormal material flows are clearer. The delineation range of the 3D data processing and mapping method is relatively small with obvious concentration center, which is conducive to the accurate arrangement of surface exploration engineering, saving prospecting cost and improving the accuracy of prospecting.
DEVELOPMENT AND APPLICATION OF THE LOG AUXILIARY SOFTWARE FOR MARINE GEOLOGICAL SURVEY
JIANG Jingjie, PENG Hua, LI Zhen, MA Xiumin
2017, 23(4): 627-630.
Abstract (156) HTML (73) PDF (2049KB)(2)
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Log is an important content for marine geological survey. Automatic technology for data acquisition has been greatly improved while no corresponding improvement to log technology has been made, which led to the increase of labor intensity adverse to the field work of marine geological survey. To solve this problem, a set of log auxiliary system were designed, which provides assistant to traditional paper log, reduces the labor intensity, and improves the quality and efficiency of marine geological survey.
A STUDY ON THE INTEGRATION OF REMOTE SENSING MONITORING AND REGULATION MODEL IN RESTORATION AND TREATMENT OF MINE GEOLOGICAL ENVIRONMENT IN LIAOYUAN
AN Zhihong, CHENG Yushu, WANG Baocun, SUN Xiyong, WANG Yajuan
2017, 23(4): 631-637.
Abstract (244) HTML (145) PDF (3334KB)(25)
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In order to get a clear picture of the progress and results of restoration and treatment of mine geological environment in Liaoyuan city, remote sensing technology was first used in monitoring the mine geological environment of Liaoyuan City in this study. Through the extraction of thematic information about mine geological environment, the typical models of mine geological environment restoration and treatment in Liaoyuan city was summarized and classified. The results show that, progress in mine geological environment restoration and treatment in the Liaoyuan city goes fast, and there are various kinds of models, namely disaster management type, public parks type, improvement of landscape function, Landscape reconstruction type, mine greening type and comprehensive management type, which can provide a typical demonstration for other regions.