Liu X.,CAS Institute of Tibetan Plateau Research |
Wei L.,CAS Institute of Geology and Geophysics |
Huang F.,China Metallurgical Geology Bureau |
Fang A.,China Metallurgical Geology Bureau |
And 3 more authors.
Scientia Geologica Sinica | Year: 2013
The multi-disciplinary study of past ice surface elevations in the Grove Mountains of interior East Antarctica provide direct land based data on the behaviour of the East Antarctic Ice Sheet since the Pliocene. The glacial geology, the ages of cold desert soils, the depositional environment of younger moraine sedimentary boulders and their spore pollen assemblages combine to imply a possible significant shrinkage of the ice sheet before the Middle Pliocene Epoch, with the ice sheet margin retreating south of the Grove Mountains(~400 km south from its present coastal position) . Exposure age measurements of bedrock indicate that the elevation of the ice surface in the Grove Mountains region subsequently rose at about Mid-Pliocene to at least 400 m higher than today's levels. The ice surface then progressively lowered, with some minor fluctuations. Middle to Late Pleistocene exposure ages found on the lowest samples, at the ice/bedrock contact line, indicate a long period with ice surface elevations was kept at current level or complex fluctuation history during the Quaternary Epoch. Such event of Antarctic ice sheet collapse should correspond with some of huge tectonic events in north hemisphere in global scale, such as the Messinian salinity crisis in the Mediterranean region.
Zhang Z.-W.,China University of Geosciences |
Zhang Z.-W.,Bureau of Mineral Resources |
Li H.,Geophysical Exploration Academy of China Metallurgical Geology Bureau |
Yu B.,Geophysical Exploration Academy of China Metallurgical Geology Bureau |
Zhou S.-G.,China Metallurgical Geology Bureau
Applied Mechanics and Materials | Year: 2014
The Dayaoshan, which has nearly 200 gold deposits (or mineralization points), is one of the most important gold deposits distribution areas in Guangxi, and the Gupao gold deposit is an important representative one. Previous researches have carried out numerous works there to guide the gold prospecting work. Due to multiple episodes of gold mineralization and multiple sources materials in ore-forming, there are heated debates on the era of the mine, and the main mineralization age of the Gupao gold deposit is focused on the Caledonian or Early Yanshanian. According to the distribution characteristics of the gold ore body showing in the Zhilong, Gulinao, and Dawangding gold deposit, the discussion of macro-tectonic setting of the area, as well as the comparative study of surrounding gold deposits, we conclude that the main mineralization age of the Dawangding gold deposit is Early Yanshanian, and the main mineralization may be controlled by the nearly east-west trending fold which was caused by the north-south extrusion. © (2014) Trans Tech Publications, Switzerland.
Liu X.,CAS Institute of Tibetan Plateau Research |
Hsu K.J.,CAS Institute of Geology and Geophysics |
Ju Y.,China Metallurgical Geology Bureau |
Li G.,Chinese Academy of Geosciences |
And 4 more authors.
Journal of Asian Earth Sciences | Year: 2012
We present a new interpretation of tectonic evolution in southern Tibet that is drastically different from the existing models. A detailed tectono-sedimentary study crossing the Yarlung Zangpo ophiolite zone shows that many geological features are different from those commonly described in large subduction collision models. For example, no N-S oriented shear zones are found between the ophiolitic sequence and country flysch strata, whereas a conformable contact relationship is recognized between them. A tectonic window exists inside the ophiolite body in the Bailang region. Some intrusion-like mafic-ultramafic bodies occurred in the Renbu region, where the country strata are in sub-concordant contact with these bodies and show contact metamorphic aureole. Toward the west, the ophiolite zone was separated by flysch sequences into sub-parallel branches. In the Lhasa region, the sedimentary facies are similar on both sides of the Zangpo Valley, and have preserved an intact Mesozoic basin system. Instead of ophiolite rocks, volcaniclastic deposits occurred in the corresponding location of the ophiolite in the Zangpo Valley. Consequently, we conclude that the Zangpo ophiolite zone has a tectonic affinity of back-arc basin with its spasmodic growth of juvenile oceanic crust. The real tectonic suture, or the closure zone of the Neotethys, should be represented by the High Himalaya Central Gneiss Unit, which shows a large scale strong shearing in same orientation, high metamorphism and protracted re-mobilization. The oceanic crust subducted northward and split off the Himalaya continental front arc, created the Zangpo back-arc basin since Late Triassic. The collapse of the Zangpo back-arc basin by supra-subduction occurred since the Eocene. The final collision between India and the Himalayan arc took place since Late Eocene with a re-mobilized large shear system. The major mylonitic zones migrated progressively southward with bulk of shear slip absorbing the crust of north India and south Tibet. © 2012 Elsevier Ltd.
Gu Z.,Hohai University |
Li G.,Hohai University |
He G.,Hohai University |
Zhang J.,Guangdong Province Highway Co. |
And 2 more authors.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2015
An anchorage scheme against the imminent failure of slope has been researched using construction monitoring data and 3-D numerical modeling based on an actual engineering slope. The research shows that 3-D numerical modeling is of more pertinence to slope deformation analysis with irregular section as it can consider the influence of changing slope section morphology on slope deformation and the results of numerical modeling agree well with the actual deformation status. According to monitoring data, the slope state parameters and calculation model which satisfies with field conditions can be attained by the 3-D numerical modeling back analysis. Thus the slope anchoring parameters based on above are more scientific. ©, 2015, Editorial Office of China Civil Engineering Journal. All right reserved.
Sun W.Y.,China University of Geosciences |
Sun W.Y.,University of Tasmania |
Li S.R.,China University of Geosciences |
Santosh M.,China University of Geosciences |
Zhang X.Y.,China Metallurgical Geology Bureau
Geological Journal | Year: 2015
The Yanjiagou deposit, located in the central North China Craton (NCC), is a newly found porphyry-type Mo deposit. The Mo mineralization here is spatially associated with the Mapeng batholith. In this study, we identify four stages of ore formation in this deposit: pyrite phyllic stage (I), quartz-pyrite stage (II), quartz-pyrite-molybdenite stage (III), which is the main mineralization stage, and quartz-carbonate stage (IV). We present sulphur and lead isotope data on pyrite, and rhenium and osmium isotopes of molybdenite from the porphyry deposit and evaluate the timing and origin of ore formation. The δ34S values of the pyrite range from -1.1‰ to -0.6‰, with an average of -0.875‰, suggesting origin from a mixture of magmatic/mantle sources and the basement rocks. The Pb isotope compositions of the pyrite show a range of 16.369 to 17.079 for 206Pb/204Pb, 15.201 to 15.355 for 207Pb/204Pb, and 36.696 to 37.380 for 208Pb/204Pb, indicating that the ore-forming materials were derived from a mixture of lower crust (or basement rocks) and mantle. Rhenium contents in molybdenite samples from the main ore stage are between 74.73 to 254.43ppm, with an average of 147.9ppm, indicating a mixed crustal-mantle source for the metal. Eight molybdenite separates yield model ages ranging from 124.17 to 130.80Ma and a mean model age of 128.46Ma. An isochron age of 126.7±1.1Ma (MSWD=2.1, initial 187Os=0.0032±0.0012ppb) is computed, which reveals a close link between the Mo mineralization and the magmatism that generated the Mapeng batholith. The age is close to the zircon U-Pb age of ca. 130Ma from the batholith reported in a recent study. The age is also consistent with the timing of mineralization in the Fuping ore cluster in the central NCC, as well as the peak time of lithosphere thinning and destruction of the NCC. We evaluate the spatio-temporal distribution of the Mo deposits in the NCC and identify three important molybdenum provinces along the northern and southern margins of the craton formed during three distinct episodes: Middle to Late Triassic (240-220Ma), Early Jurassic (190-175Ma), and Late Jurassic to Early Cretaceous (150-125Ma). The third period is considered to mark the most important metallogenic event, coinciding with the peak of lithosphere thinning and craton destruction in the NCC. © 2014 John Wiley & Sons, Ltd.
Li W.-C.,China University of Geosciences |
Liu X.-L.,China University of Geosciences |
Zeng P.-S.,China Metallurgical Geology Bureau |
Yin G.-H.,Yunnan Geological Survey
Geology in China | Year: 2011
The Pulang porphyry copper deposit is a typical Indo-Chinese porphyry copper deposit in Zhongdian area, hosted in southern composite body of the Yidun structural-magmatic belt. The composite rock body is a hypabyssal -ultrahypabyssal intermediate -acid porphyry (porphyrite) body, which can be divided into three invasion stages, i.e., quartz diorite porphyrite, quartz monzonite porphyry, and granodiorite-porphyry. Geochemical characteristics show that the rocks are enriched with Ba, La, Rb, Sr, K, chalcophile elements Cu, Pb, and siderophile elements Mo, Ni, and are depleted in Nb, Zr, Hf and Ti. Porphyry (porphyrite) is the same as the rock series of granite island, belonging to cale-alkaline suite, and their genetic types are also similar to each other, belonging to I-type granite. The ore bodies are controlled by structures. The porphyry copper deposit mainly occurs in the Indo -Chinese intermediate -acid porphyry (porphyrite), and the mineralization was controlled by such factors as magmatic rocks, emplacement formation, uranium migration, hydrothermal alteration and structural space, which joindy constituted a porphyry metallogenic system characterized by the structural-magmatic- hydrothermal coupling in Indo-Chinese period.
Zhang B.,Central South University |
Li X.,Central South University |
Mao X.,Central South University |
Deng H.,Central South University |
Zhou S.,China Metallurgical Geology Bureau
International Conference on Geoinformatics | Year: 2016
On the basis of analysis of manganese metallogenesis conditions in the western Guangxi and southeastern Yunnan area, some geological variables, including sedimentary basins, synsedimentary faults, deposit facies, strata, lithology combinations, digital topographical features, aeromagnetic anomalies, etc., were built by spatial analysis methods of GIS field model. To solve the information asymmetry problem between prediction areas and known areas, this paper brought a method for mineral resources quantitative prediction limited by spatial extent of action, which matched metallogenesis conditions of prediction with prediction models built in known areas to ensure the information symmetry. To avoid subjectivity of evidence designation in the weights of evidence (WofE) method, linear regression analysis method was applied to filter the evidences. A method considering not only manganese deposits' number but also their quantities was taken to lower the information loss in the binary conversion of evidences. © 2015 IEEE.
Mao X.-C.,Central South University |
Mao X.-C.,Key Laboratory of Metallogenic Prediction of Non ferrous Metals |
Hu C.,Central South University |
Zhou S.-G.,China Metallurgical Geology Bureau |
And 4 more authors.
Journal of Central South University of Technology (English Edition) | Year: 2011
Focusing on the issue to deal with inadequate extraction of metallogenic information especially geological information, a new method of extracting metallogenic information based on field model, i.e. the field analysis method of metallogenic information, was proposed. In addition, a case study by using the method of the extraction of metallogenic information from the west Guangxi and southeast Yunnan district as an example was performed. The representation method for the field models of metallogenic information, including the metallogenic influence field model and the metallogenic distance field model, was discussed by introducing the concept of the field theory, based on the characteristic analysis of the distance gradualness and the influence superposition of metallogenic information. According to the field theory superposition principle and the spatial distance analysis method, the mathematical models for the metallogenic influence field and the metallogenic distance field of point, line and area geological bodies were derived out by using parameter equation and calculus. Based on the metallogenic background analysis, the metallogenic information field models of synsedimentary faults and manganese sedimentary basins were built. The relationship between the metallogenic information fields and the manganese mineralization distribution was also investigated by using the method of metallogenic information field analysis. The instance study indicates that the proposed method of metallogenic information field analysis is valid and useful for extracting the ore-controlling information of synsedimentary faults and manganese sedimentary basins in the study area, with which the extraction results are significant both statistically and geologically. © 2011 Central South University Press and Springer-Verlag Berlin Heidelberg.