Key Laboratory of Western Chinas Mineral Resources and Geological Engineering

Fengcheng, China

Key Laboratory of Western Chinas Mineral Resources and Geological Engineering

Fengcheng, China
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Zhao C.,Chang'an University | Zhao C.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Lu Z.,U.S. Geological Survey | Zhang Q.,Chang'an University | And 2 more authors.
Remote Sensing of Environment | Year: 2012

Multi-temporal ALOS/PALSAR images are used to automatically investigate landslide activity over an area of ~200km by ~350km in northern California and southern Oregon. Interferometric synthetic aperture radar (InSAR) deformation images, InSAR coherence maps, SAR backscattering intensity images, and a DEM gradient map are combined to detect active landslides by setting individual thresholds. More than 50 active landslides covering a total of about 40km 2 area are detected. Then the short baseline subsets (SBAS) InSAR method is applied to retrieve time-series deformation patterns of individual detected landslides. Down-slope landslide motions observed from adjacent satellite tracks with slightly different radar look angles are used to verify InSAR results and measurement accuracy. Comparison of the landslide motion with the precipitation record suggests that the landslide deformation correlates with the rainfall rate, with a lag time of around 1-2months between the precipitation peak and the maximum landslide displacement. The results will provide new insights into landslide mechanisms in the Pacific Northwest, and facilitate development of early warning systems for landslides under abnormal rainfall conditions. Additionally, this method will allow identification of active landslides in broad areas of the Pacific Northwest in an efficient and systematic manner, including remote and heavily vegetated areas difficult to inventory by traditional methods. © 2012.


Zhao C.,Chang'an University | Zhao C.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Lu Z.,U.S. Geological Survey | Zhang Q.,Chang'an University | Zhang Q.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering
Remote Sensing Letters | Year: 2013

Underground mining can induce large vertical displacements that often lead to the loss of coherence in repeat-pass interferometric synthetic aperture radar (SAR) images. Using SAR intensity images, this paper employs the image offset tracking method to map SAR slant range changes due to ground deformation over areas of mining. The rationale of slant range offset measurement with respect to the vertical deformation is analysed and the prerequisite of applying the slant range offset method to monitor vertical deformation is discussed. Results from the slant range offset method are used to produce time-series of cumulative ground displacements via least square estimate. We use six Advanced Land Observation Satellite (ALOS)-Phased Array L-band SAR (PALSAR) images over two coalfields in Inner Mogolia, China, to illustrate the proposed method and its effectiveness.We achieve deformation measurements with a precision of ∼0.2 m, with the maximum vertical displacement over the mining sites reaching ∼4.5 m. Finally, we use time-series results to outline common features identified in mining-induced deformation. Our results are supported by in situ investigations. © 2012 Taylor & Francis.


Bai C.-Y.,Chang'an University | Bai C.-Y.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Huang G.-J.,Chang'an University | Zhao R.,Chang'an University | Zhao R.,China Earthquake Administration
Geophysical Journal International | Year: 2010

The purpose of this study is to introduce a multistage irregular shortest-path method (ISPM) for tracking multiple seismic arrivals including any combinations of transmissions, reflections (or refractions) and mode conversions in complex 2-D/3-D layered media, incorporating irregular interfaces (or subsurface in 3-D) and velocity discontinuities. The basic principle is to first divide the model into several different layers (using irregular cells near each interface, discontinuity and the Earth's undulating surface topography) and then to apply the multistage technique to trace the multiple arrivals. It is possible to realize the multiple arrival tracking with the multistage scheme because the multiple arrivals are just different combinations or conjugations of the simple incident, transmitted, reflected (or refracted) and mode converted waves via the velocity discontinuities and the interfaces. Benchmark tests against the popular multistage fast marching method (FMM) and the multistage MSPM (modified shortest path method) are undertaken to assess the solution accuracy and the computational efficiency. The results show that the multistage ISPM is advantageous over both the multistage FMM and the multistage MSPM in both solution accuracy and CPU time. Several examples (including the Marmousi model) are used to demonstrate the viability and versatility of the multistage ISPM in heterogeneous media, even in the presence of high-velocity contrasts involving interfaces of relatively high curvature. Applications to the seismological problems, such as traveltime tomography and earthquake location, indicate that it is possible to improve the spatial resolution in traveltime tomography and solution accuracy in earthquake location if later arrival information is combined with the first arrivals. © 2010 The Authors Geophysical Journal International © 2010 RAS.


Yang G.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Yang G.,Chang'an University | Li Y.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Li Y.,Chang'an University | And 7 more authors.
Gondwana Research | Year: 2012

The Darbut Ophiolitic Complex consists of ultramafic rocks, cumulates, pillow lavas and abyssal radiolarian cherts, and occurs in the Sartuohai-Suluqiaoke area which is situated in the eastern part of the West Junggar (NW China), Southern Altaids. In the present study, we report new geochronological and geochemical data obtained for gabbro and basalt blocks embedded in the Darbut Ophiolitic Complex. Zircon U-Pb analyses from one representative gabbro sample by LA-ICP-MS yielded a weighted mean age of 391±6Ma, showing that it was emplaced in the Middle Devonian. The samples bear N-MORB, E-MORB, and arc-like geochemical signatures. They are tholeiitic in composition with low concentrations of Na 2O+K 2O varying from 1.36 to 4.09wt.%, Mg and Ti depleted, large ion lithophile elements (LILEs) enriched, with insignificant negative Eu. They also show negative Nb-Ta anomalies and high positive ε Nd(t) values, with relative high La/Nb, Ba/Nb, Ba/La, Ba/Th and Zr/Nb ratios. We interpret that these volcanic rocks were derived from a slightly metasomatized depleted mantle source in a back-arc basin setting, which corresponds to 10-30% partial melting of a depleted spinel lherzolite mantle. The data presented here in combination with previously published data suggest a northwestward subduction model for the West Junggar. During the period of the Early Devonian to Early Carboniferous, the West Junggar was dominated by normal northwestward subduction, and the ridge subduction commenced in the Late Carboniferous. © 2011 International Association for Gondwana Research.


Yang G.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Yang G.,Chang'an University | Li Y.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Li Y.,Chang'an University | And 12 more authors.
Lithos | Year: 2012

The Mayile ophiolitic mélange (MOM) is located in the southwestern part of the West Junggar (NW China) and forms part of the Southern Altaids. The MOM comprises ultramafic rocks, gabbro, pillow and massive lavas, abyssal radiolarian cherts and volcaniclastic rocks. Zircons with magmatic crystallization features including oscillatory zoning and high Th/U values from the isotropic gabbro within the MOM yield LA-ICP-MS U-Pb age of 572. ±. 9. Ma (MSWD. =. 1.0) marking the timing of crystallization of these rocks as late Neoproterozoic. Geochemically, the basalts of the corresponding gabbros from MOM display OIB-type alkali basalt and E-MORB-type tholeiitic basalt features. Both of these groups are characterized by LILE and LREE enrichment and HREE depletion, very weak or no Eu anomalies (Eu/Eu*. =. 0.9-1), and no obvious Nb, Ta and Ti negative anomalies, suggesting a typical OIB affinity. We propose that these volcanic rocks were derived from a mantle plume-related magmatism associated with the evolution of the Paleoasian Oceanic system, with the mantle source containing 2%-5% garnet, ~. 2% spinel and ~. 2% amphibole. The basalts show within-plate affinity marked geochemical similarities with those from Hawaii and Xigaze seamount, suggestive of their intra-oceanic setting. Subduction of the oceanic lithosphere commenced during late Cambrian to early Ordovician, with the eventual accretion of the seamounts in the fore-arc together with oceanic fragments forming the Mayile ophiolitic mélange. © 2012 Elsevier B.V..


Zhang Y.,Chang'an University | Zhang Y.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Gu Q.,Sinopec
Journal of Earth Science | Year: 2011

Petroleum system theory has been used to study characteristics of the Fula depression in the Central African fault zone. In this system, deep lacustrine facies mudstone in the Abu Gabra Formation of the Lower Cretaceous is a very good source rock, thick deltaic facies sandstone of the Abu Gabra Formation and fluvial facies sandstone of the Bentiu Formation are good reservoir beds, and the mudstone in the Upper Cretaceous Darfur Group is the regional cap rock. The oil search mode and fault block trap seal-off conditions are considered here for passive rift basins. Particularly with respect to oil source rock distribution, successive development of reverse fault block and faulted anticlinal traps on low relief structures could have accumulated hydrocarbons because of lateral sealing by downthrown mudstone along the up-dipping reservoir beds. At present, discoveries in this system are all large-duty oil fields. In 2009, proved reserves exceeded 2×108 t, and about 3×106 t annual throughput of crude oil was obtained. Risk exploration of the Fula depression is of short cycle and high benefit, which will be of great help for exploration in the Muglad basin. © 2011 China University of Geosciences and Springer-Verlag Berlin Heidelberg.


Lin G.-C.,Chang'an University | Lin G.-C.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2010

Neoproterozoic magmatic rocks are widespread in western margin of the Yangtze block, and their genesis and tectonic setting have been an issue in hot debate at the present time. SHRIMP U-Pb zircon age, petrology, geochemical and Nd isotopic data are reported for the Neoproterozoic Shimian granite in the Kangdian rift of western Sichuan. This pluton is of metaluminous high-K calc-alkalic I-type granite and emplaced at 818±7 Ma. Petrology, geochemical and Nd isotopic characters suggest that the pluton was generated by partial melting of pre-existing, young (Late Mesoproterozoic to Early Neoproterozoic) island arc crust, with contamination of old crust materials during magma ascending and emplacement. The Shimian granite is the product of the tectonic transition from compression to introplate extension in western margin of the Yangtze block. Their arc-like geochemical features (such as Nb-Ta depletion) should have been inherited from the protoliths, rather than reflection of their tectonic setting when the pluton formed.


Yang G.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Yang G.,Chang'an University | Li Y.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Li Y.,Chang'an University | And 6 more authors.
Bulletin of the Geological Society of America | Year: 2013

New laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon ages and geochemical data are reported for the Karamay ophiolitic mélange in the West Junggar area at the southwestern margin of the Altaids (or Central Asian orogenic belt), northwestern China. The data were used to identify the petrogenesis of the mélange, and to evaluate its tectonic significance. In addition, this study aimed to assess the possible presence of Devonian mantle plume in the region. The Karamay ophiolitic mélange crops out at the boundary of the Junggar Basin but is partly hidden by Meso zoic sediments, with an exposure area of ~40 km2. The site contains ultramafic rocks, cumulates, gabbros, pillow lavas, abyssal radio larian cherts, turbidites, and tuffs, which show typical block-in-matrix structures. Zircon U-Pb analyses from the basalt and gabbro by LA-ICP-MS yielded weighted mean ages of 395 ± 3 Ma and 387 ± 8 Ma, respectively. These ages suggest a Middle Devo nian emplacement. All basalts bear the signature of ocean-island basalt (OIB) and are characterized by alkaline compositions with high concentrations of Na2O + K2O (3.7-8.5 wt%) and TiO2 (1.5-3.1 wt%); large ion lithophile element and light rare earth element enrichment and heavy rare earth element depletion; very weak or no Eu anomalies (Eu/Eu* = 0.9-1.0); and no obvious Nb, Ta, or Ti negative anomalies. We propose that these basaltic rocks were derived from mantle plume-related magmatism associated with the evolution of the Paleoasian oceanic system. The enriched mantle source could have contained 2%-5% garnet and ~3% spinel. The rocks also display strong geochemical similarities with the Xigaze seamount basalts , which formed in intra-oceanic settings. Compared to the basalts, the gabbros display midocean-ridge-basalt-type tholeiitic basalt features, derived from a depleted mantle source with the addition of fluids from a subducted slab within a suprasubduction-zone environment. These observations are supported by previous work, and they indicate Devonian mantle plume-related magmatism within the Paleoasian Ocean. However, as these rocks are mainly parts of accretionary complexes, whether the Karamay and Darbut ophiolitic mélange formed in a single belt remains equivocal, and further work is required to resolve this issue. Thus, there was a complex evolution by subduction-accretion processes from the Devonian to the Carboniferous before final amalgamation and docking to the northern Siberian block. © 2013 Geological Society of America.


Zhao R.,Chang'an University | Bai C.,Chang'an University | Bai C.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering
Acta Seismologica Sinica | Year: 2010

This study introduces the multistage scheme incorporating with an irregular shortest path method (ISPM) for tracking multiple arrivals composed of any kind of combinations of transmissions, conversions and reflections in complex 2D/3D layered media. The principle is first to divide the layered model into several different computational domains using irregular cells at the interface and the Earth's undulated surface, and then to apply the multistage technique to trace the multiple arrivals. It is possible to realize the multiple arrival tracking with the multistage technique, because the multiple arrivals are different combinations or conjugations of the simple incident, transmitted and reflected waves via the velocity discontinuities. Benchmark tests against the multistage fast marching method (FMM) are undertaken to assess the solution accuracy and the computational efficiency. The results show that the multistage ISPM method is advantageous over FMM method in both solution accuracy and CPU times.


Zhao C.-Y.,Chang'an University | Zhao C.-Y.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | Zhang Q.,Chang'an University | Zhang Q.,Key Laboratory of Western Chinas Mineral Resources and Geological Engineering | And 2 more authors.
Journal of Geodynamics | Year: 2011

Datong is located in the north of Shanxi Province, which is famous for its old-fashioned coal-mining preservation in China. Some serious issues such as land subsidence, ground fissures, mining collapse, and earthquake hazards have occurred over this area for a long time resulting in significant damages to buildings and roads. In order to monitor and mitigate these natural man-made hazards, Short Baseline Subsets (SBAS) InSAR technique with ten Envisat ASAR data is applied to detect the surface deformation over an area of thousands of square kilometers. Then, five MODIS data are used to check the atmospheric effects on InSAR interferograms. Finally, nine nonlinear land subsidence cumulative results during September 2004 and February 2008 are obtained. Based on the deformation data, three kinds of land subsidence are clearly detected, caused by mine extraction, underground water withdrawal and construction of new economic zones, respectively. The annual mean velocity of subsidence can reach 1 to 4. cm/year in different subsidence areas. A newly designed high-speed railway (HSR) with speeds of 350. km/h will cross through the Datong hi-tech zone. Special measures should be taken for the long run of this project. In addition, another two subsidence regions need further investigation to mitigate such hazards. © 2010 Elsevier Ltd.

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