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Zhou J.-L.,China University of Geosciences | Shao S.,China University of Geosciences | Shao S.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Luo Z.-H.,China University of Geosciences | Rasoamalala V.,Directorate of Geology
Precambrian Research | Year: 2015

Tectonic setting of the ca. 840-760Ma Imorona-Itsindro Suite throughout central Madagascar is critical to understanding Madagascar-India correlation in pre-Gondwana time and the paleogeography of the rifting Rodinia. Here, we present new geochronological and geochemical data for gabbros of this suite from the Ambatondrazaka area in east-central Madagascar. SIMS U-Pb zircon dating reveals that the gabbros emplaced between ca. 797 and 772Ma. They define a typical tholeiitic trend on the AFM and FeOT/MgO vs. SiO2 plots, which is confirmed by the occurrence of layered Fe-Ti-V oxide mineralization. Owing to the high-K nature, they were previously misinterpreted as a "calc-alkaline" association produced in a mature continental arc. Indeed, it implies in return an intra-plate affinity for tholeiitic rocks. Their high Zr/Y, La/Y and Ti/V ratios differ from those of typical arc and back-arc mafic suites but are compatible with an intra-plate setting. Additionally, they are characterized by low AlZ/TiO2 ratios in clinopyroxene, further supporting an intra-plate environment. The negative e{open}Nd(t) (-8.4 to -5.1) and zircon e{open}Hf(t) (-6.84 to -3.08) values, together with enriched trace element signatures, indicate their derivation from an enriched lithospheric mantle source. Considering the initial 87Sr/86Sr ratios (0.705409-0.706892) and Nd modal ages (~2.1-2.4Ga), we postulate that this mantle reservoir has EM1-type isotopic characteristics and was enriched by a Late Neoarchean "super accretion event". Taken together, our results question the existence of the Betsimisaraka Suture but support the proposal that the Malagasy Shield and the Dharwar Craton of India are parts of the same entity - the Greater Dharwar Craton. Within this framework, the widely cited hypothesis that an extensive Andean-type arc was developed along the northwestern margin of the rifting Rodinia is challenged, at least that the magmatic arc did not extend to the Malagasy Shield. © 2014 Elsevier B.V.

Chen W.,Wuhan University | Chen W.,Key Laboratory of Disaster Reduction | Li X.,Wuhan University | Wang Y.,State Key Laboratory of Biogeology and Environmental Geology | And 2 more authors.
Environmental Earth Sciences | Year: 2013

The objective of this study is to map landslide susceptibility in Zigui segment of the Yangtze Three Gorges area that is known as one of the most landslide-prone areas in China by using data from light detection and ranging (LiDAR) and digital mapping camera (DMC). The likelihood ratio (LR) and logistic regression model (LRM) were used in this study. The work is divided into three phases. The first phase consists of data processing and analysis. In this phase, LiDAR and DMC data and geological maps were processed, and the landslide-controlling factors were derived such as landslide density, digital elevation model (DEM), slope angle, aspect, lithology, land use and distance from drainage. Among these, the landslide inventories, land use and drainage were constructed with both LiDAR and DMC data; DEM, slope angle and aspect were constructed with LiDAR data; lithology was taken from the 1:250,000 scale geological maps. The second phase is the logistic regression analysis. In this phase, the LR was applied to find the correlation between the landslide locations and the landslide-controlling factors, whereas the LRM was used to predict the occurrence of landslides based on six factors. To calculate the coefficients of LRM, 13,290,553 pixels was used, 29.5 % of the total pixels. The logical regression coefficients of landslide-controlling factors were obtained by logical regression analysis with SPSS 17.0 software. The accuracy of the LRM was 88.8 % on the whole. The third phase is landslide susceptibility mapping and verification. The mapping result was verified using the landslide location data, and 64.4 % landslide pixels distributed in "extremely high" zone and "high" zone; in addition, verification was performed using a success rate curve. The verification result show clearly that landslide susceptibility zones were in close agreement with actual landslide areas in the field. It is also shown that the factors that were applied in this study are appropriate; lithology, elevation and distance from drainage are primary factors for the landslide susceptibility mapping in the area, while slope angle, aspect and land use are secondary. © 2012 Springer-Verlag Berlin Heidelberg.

Yan B.,CAS Institute of Remote Sensing | Yan B.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Wang R.,CAS Institute of Remote Sensing | Wang R.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | And 3 more authors.
Icarus | Year: 2010

The distribution of minerals on the lunar surface is information which could contribute to studying lunar origin and evolution. In this paper, the distribution of clinopyroxene, orthopyroxene, olivine, ilmenite, and plagioclase on the lunar surface has been mapped based on Hapke radiative transfer model and linear unmixing of spectra with Clementine UVVIS/NIR data. The results have been validated on the basis of minerals modal abundance data of the Apollo samples, and problems in the minerals abundance mapping have been analyzed. The validation based on analysis data of Apollo samples indicates that plagioclase mapped in this paper represents the total abundance of plagioclase and agglutinitic glass. The minerals mapping results show that the lunar surface is mainly composed of pyroxene, plagioclase, agglutinitic glass, and ilmenite. Basalt in the lunar mare is mainly composed of clinopyroxene and ilmenite, and lunar highland is mainly composed of plagioclase and agglutinitic glass. Orthopyroxene is mainly distributed on the north of Mare Imbrium, on the south of Maria and Aitken Basin. According to our results, there is probably no large area of olivine distribution on the lunar surface which is different from earlier published results. Therefore, emphasis should be put on the olivine distribution in the minerals mapping using hyperspectral data such as M3 of Chandrayaan-1 and IIM of ChangE-1. © 2010 Elsevier Inc.

Song R.,CAS Institute of Remote Sensing | Song R.,University of Chinese Academy of Sciences | Guo H.,CAS Institute of Remote Sensing | Liu G.,CAS Institute of Remote Sensing | And 2 more authors.
IEEE Geoscience and Remote Sensing Letters | Year: 2014

The Goldstein filter is one of the most commonly used synthetic aperture radar (SAR) interferogram filters. This letter proposes a new method to find filter parameters of the Goldestein filter based on noise level derived by the empirical mode decomposition (EMD) method. The filtering parameter determined by this method has a definite physical meaning.We used bidimensional empirical mode decomposition (BEMD) to extract features of an interferometric phase image into multiple scales of spatial frequencies, called intrinsic mode functions (IMF). We constructed a pseudo-SNR (signal-to-noise ratio) with the given IMF component, then the new parameter was applied to the Goldstein filtering method in place of the original fixed value ascertained artificially. The results from simulation and real data show that the performance of the new algorithm outperforms the original Goldstein filter, and its enhanced version, the Baran filter. The quantitative evaluation also shows that modification based on the EMD proposed in our paper minimizes the loss of phase while still reducing the level of noise in an interferogram. © 2013 IEEE.

Zhang W.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Yu L.,Zhejiang University
CCTAE 2010 - 2010 International Conference on Computer and Communication Technologies in Agriculture Engineering | Year: 2010

Multispectral and synthetic aperture radar (SAR) image fusion is one of the most complex tasks to perform integration of multi-source remotely sensed imagery. Fusion of SAR and optical remote sensing image, with highly complementary characteristics, may contribute to a better understanding of the objects with the imaged scene and finally benefit to application such as precision farming/agricultural. In this paper, we adopt a variational model to fuse SAR imagery and multispectral imagery. Experimental results on Cosmo-Skymed SAR and Landsat-7 Enhanced Thematic Mapper Plus (ETM+) satellite images of an urban area, demonstrate accurate spectral preservation, which is indicated by high correlation between original multispectral and fused bands. © 2010 IEEE.

Li L.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources
Proceedings - 2010 2nd WRI World Congress on Software Engineering, WCSE 2010 | Year: 2010

Based on the principle of spectral responses of remote sensing, using multi-phases TM data and measured points as basic data, the main methods are correlation analysis on spectral data, regression analysis and fitting inversion in the study area of Zhabuye salt lake that lies in Tibet autonomous region. This paper had achieved distributions of the salt content in the lake, meanwhile, generated their contour maps reflecting salt content with method of dual inline encryption. By the method of principal component analysis, extracted salt information on the basis of 3-D salt index. Among those components, the first component is the one reflecting salt content. At last, the paper established salt content model for the salt lake, which is proved to be quadratic polynomial fitting. At last, inverse the salt content models by colors slice. Compare between inversion results and measured data on the aspects of salt contour map, it proved that inversion effect meet the distribution of measured date. © 2010 IEEE.

Li W.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Lu W.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Liu Y.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Xu J.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources
Geoscience Frontiers | Year: 2012

The North Yellow Sea Basin is a Mesozoic and Cenozoic basin. Based on basin-margin facies, sedimentary thinning, size and shape of the basin and vitrinite reflectance, North Yellow Sea Basin is not a residual basin. Analysis of the development of the basin's three structural layers, self-contained petroleum systems, boundary fault activity, migration of the Mesozoic-Cenozoic sedimentation centers, different basin structures formed during different periods, and superposition of a two-stage extended basin and one-stage depression basin, the North Yellow Sea Basin is recognized as a superimposed basin. © 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

Zhao H.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Fan J.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Guo X.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources
Applied Mechanics and Materials | Year: 2013

Subsidence has been affecting Tianjin since 1960s. It posed comprehensive detrimental effects on natural environment, the economy and society. Considering the actual monitoring demand for land subsidence in Tianjin area, multi-baseline D-InSAR technique was studied. Using the multi-baseline DInSAR technique more interferograms can be generated, which is useful for retrieving the subsidence velocity accurately. And then regression algorithm and least square method are used to deal with the time series to get deformation result. In this paper, the multi-baseline DInSAR technique is used to measure the subsidence velocity in Tianjin area. It can be concluded that the algorithm is effective and feasible especially in the study area. © (2013) Trans Tech Publications, Switzerland.

Ye P.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Li Q.,Chang'an University
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2013

The linear traveltime interpolation (LTI) method is based on linear assumption so that its precision depends on grid division, and the rays transported from the reverse direction are not considered when we recalculate traveltime row by row or column by column, and the computation is unstable in the complex models. Here, we put forward two improvements for the LTI method. First, calculating the minimum travel-time of all grid nodes by all-round cycle strategy during ray tracing. Secondly, inserting secondary nodes in the original grid boundary. Model tests show that the all-round cycle strategy of LTI considers the races from all direction, so it's more stable for complex models. In the case of same grid division, comparing with the traditional LTI, the LTI method with secondary inserted nodes has higher precision that be improved at least an order of magnitude. At the same time, the calculation speed of our method is faster and time consuming decreases more obviously when the grids become smaller. The calculation speed of our method can be n-10n times than the traditional one's.

Chen J.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources | Du L.,China Aerospace Geophysical Survey and Remote Sensing Center for Land and Resources
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

The airborne LiDAR (Light Detection And Ranging) technology is a new type of aerial earth observation method which can be used to produce high-precision DEM (Digital Elevation Model) quickly and reflect ground surface information directly. Fault structure is one of the key forms of crustal movement, and its quantitative description is the key to the research of crustal movement. The airborne LiDAR point-cloud data is used to detect and extract fault structures automatically based on linear extension, elevation mutation and slope abnormal characteristics. Firstly, the LiDAR point-cloud data is processed to filter out buildings, vegetation and other non-surface information with the TIN (Triangulated Irregular Network) filtering method and Burman model calibration method. TIN and DEM are made from the processed data sequentially. Secondly, linear fault structures are extracted based on dual-threshold method. Finally, high-precision DOM (Digital Orthophoto Map) and other geological knowledge are used to check the accuracy of fault structure extraction. An experiment is carried out in Beiya Village of Yunnan Province, China. With LiDAR technology, results reveal that: the airborne LiDAR point-cloud data can be utilized to extract linear fault structures accurately and automatically, measure information such as height, width and slope of fault structures with high precision, and detect faults in areas with vegetation coverage effectively. © 2015 SPIE.

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