He J.-Q.,China Earthquake Administration |
He J.-Q.,China National Offshore Oil Corporation |
Ding R.-X.,Sun Yat Sen University |
Ding R.-X.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes |
And 3 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica)
The North Yellow Sea basin is one of the basins with lower exploration degrees in offshore areas of China. As so far, there is no research and report about thermal evolution of this basin. This work studies the thermal evolution history of this area based on apatite fission track analysis, which lays a foundation for further research. The sandstone samples used for analysis we recollected from different wells down to different strata (upper Jurassic, lower Cretaceous and Paleogene). The low-temperature thermal history modeling of fission track indicates that the basin experienced two heating stages and two cooling stages since about 160Ma, and an obvious temperature change might have occurred during 100-80 Ma, which means that North Yellow Sea Basin had undergone a major tectonic-thermal event in that time. This modeling result suggests the thermal history is corresponding to basin prototype evolution in the North Yellow Sea basin, which has some significance to exploration of oil and gas in this region. ©, Science Press. All right reserved. Source
Ding R.,Sun Yat Sen University |
Ding R.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes |
Wang W.,Tongji University
Journal of Earth Science
The traditional paleotopographic explanation of mountain belts from low-temperature thermochronology is based on the simulation of low-temperature age data, the main defect of which is that we cannot make comparisons at the same time between the samples. In this article, we intend to make paleotopographic reconstruction on the basis of thermal history modelling. We first digitalize the thermal history curve and take contemporary temperatures for comparison, then reconstruct the paleotopography according to the distribution of the samples' temperatures. The finite difference method is used to solve the diffusion equation for heat in the reconstruction process. Our paleotopography reconstruction method can restore the topography over time. However, due to the nature of thermal history modeling and the noise in the data, the accuracy of this reconstruction is currently limited. © 2013 China University of Geosciences and Springer-Verlag Berlin Heidelberg. Source
Zhou P.,State Oceanic Administration |
Chen C.,State Oceanic Administration |
Ye J.,State Oceanic Administration |
Shen W.,Sun Yat Sen University |
And 6 more authors.
Marine Pollution Bulletin
Oil fingerprints have been a powerful tool widely used for determining the source of spilled oil. In most cases, this tool works well. However, it is usually difficult to identify the source if the oil spill accident occurs during offshore petroleum exploration due to the highly similar physiochemical characteristics of suspected oils from the same drilling platform. In this report, a case study from the waters of the South China Sea is presented, and multidimensional scaling analysis (MDS) is introduced to demonstrate how oil fingerprints can be combined with mathematical methods to identify the source of spilled oil from highly similar suspected sources. The results suggest that the MDS calculation based on oil fingerprints and subsequently integrated with specific biomarkers in spilled oils is the most effective method with a great potential for determining the source in terms of highly similar suspected oils. © 2015 Elsevier Ltd. Source
Cai Y.,CAS Guangzhou Institute of Geochemistry |
Cai Y.,Sun Yat Sen University |
Cai Y.,University of Chinese Academy of Sciences |
Wang Y.,Sun Yat Sen University |
And 9 more authors.
Lenses of amphibolites occur along the Ailaoshan suture zone at the southwestern margin of the Yangtze Block, South China. Petrological, geochemical and zircon U-Pb geochronological data indicate that they are divisible into two coeval groups. Group 1, represented by the Jinping amphibolite, has mg-number of 71-76 and (La/Yb)cn ratios of 7.2-7.7, and displays a geochemical affinity to island arc volcanic rocks. Group 2 amphibolites occur at Yuanyang and are characterized by high Nb contents (14.3-18.4ppm), resembling Nb-enriched basalts. The eNd(t) values for Group 1 range from -3.45 to -2.04 and for Group 2 from +4.08 to +4.39. A representative sample for Group 1 yields a U-Pb zircon age of 803±7Ma, whereas two samples for Group 2 give U-Pb zircon ages of 813±11Ma and 814±12Ma. Petrogenetic analysis suggests that Group 1 originated from an orthopyroxene-rich source and Group 2 from a mantle wedge modified by slab-derived melt. In combination with other geological observations, these amphibolites are inferred to constitute part of an early Neoproterozoic (~815-800Ma) arc-back-arc basin system. The Neoproterozoic amphibolites and related rocks along the Ailaoshan zone may be the southward extension of the Neoproterozoic supra-subduction zone that developed along the western margin of the Yangtze Block. © 2014 Elsevier B.V. Source
Tang L.,Sun Yat Sen University |
Tang L.,Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes |
Chen H.,Sun Yat Sen University |
Sang H.,Sun Yat Sen University |
And 2 more authors.
Soil Dynamics and Earthquake Engineering
The determination of the depth of traffic load influence is significant for pavement and embankment design on soft soil. In this study, a method based on strain-controlled criteria is presented to estimate the depths within which the behavior of a saturated clayey subsoil is affected by cyclic traffic loads. Based on the shakedown concept, the following depths of influence can be defined: (1) the threshold depth, beyond which the dynamic effect of the traffic loads is insignificant; (2) the plastic shakedown limit depth, within which the subsoil experiences noticeable and continuous deformation; and (3) the critical failure depth, within which the soil fails due to the accumulation of strain. This method for determining the depths of influence is advantageous because it is applicable to various soil types. The data required for this method consist of vertical stress responses along the soil profile and three cyclic stress limits of the soil. Based on the development of pore pressure and the dynamic strain behaviors during undrained cyclic triaxial tests, the following cyclic stress limits of the soft clay subsoil are determined: a threshold cyclic stress ratio CSRt of 0.03, a plastic shakedown limit stress ratio CSRp of 0.33 and a critical cyclic stress ratio CSRc of 0.44. These cyclic stress limits are used to determine the corresponding depths of influence, which are then used to implement ground improvements and strengthen the dynamic carrying capacity of the road structures. © 2015 Elsevier Ltd. Source