Li J.,Chinese Academy of Geological Sciences |
Zhang J.,Chinese Academy of Geological Sciences |
Liu J.,Chinese Academy of Geological Sciences |
Qu J.,Chinese Academy of Geological Sciences |
And 9 more authors.
Earth Science Frontiers | Year: 2014
Structural deformation in the crust is the product of the change of the texture and structure of the rocks and their spatial positions in the crust under the geological stress, and is the main geological phenomenon that geologists can not overlook in the resource exploration, geological environment evaluation and disaster prevention. However, whether the research in the geological structure may provide some constraints on the reconstruction of geological history of an area, as the one in rocks and petro-chemistry does, can not be found out in the available publications. This paper defines the concept of the Deformation System as a assemblage of all the structural deformations with various geometry and kinematics simultaneously formed in the same scale of the region under the same geodynamic setting based on available structural data from global typical geodynamic settings, and 14 kinds of the deformation system are distinguished, which are formed in various geodynamic settings, such as the continental rifting, doming, impacting, mid-ocean-ridge, Andes, Cordilleran, Rocky mountain, East-Asian continental margin, Southwest Pacific, Qinghai-Xizang Plateau, and Alpine types. And then, 11 deformation systems in the mainland of China are briefly described. Structurally, some hot debated issues on the tectonic division and evolution of China are preliminarily discussed. Some new viewpoints are achieved as follows: (1) extensional deformation in East China, a part of the East-Asian continent-marginal type of deformation system, was originated from the northward movement of the Australian plate; (2) an arc-continent collisional zone occurred in the end of the Cretaceous may have been buried under the Cenozoic sediment in the East Sea; (3) Cretaceous geodynamic setting in East China is probably similar to the Cenozoic Cordilleran region of the west American continent; (4) Late Jurassic and early Cretaceous deformation in the south and north sides of the Qinling Mountains may be the far-distance response of the collision between continental margins along the Mongolian-Okhotsck belt in the northmost of Northeast China; (5) Dunhuang-Alashan Block is the fourth biggest ancient continent of China mainland during the early Paleozoic; (6) northern West Tianshan and West Junggar regions of Northwest China were parts of northern accretionary margins of Kazakstan paleoplate, northern part of the East Tianshan, Junggar Block, East Junggar and Altay Mountain were parts of accretionary margin of the Siberian paleoplate; (7) the previously so-called "Heilongjiang Group" exposed along the east foots of Little Xingan Range and Zhangguangcai Range east of Heilongjiang Province, northeast China are relics of the Paleozoic accretionary margins of the Siberian paleoplate, but not the Jurassic accretionary complexes along the east Asian continental margin; and (8) multiple collisional orogeny took place in the northern China and adjacent Phanerozoic orogenic region from the latest Paleozoic to the middle Mesozoic. Our primary study on the deformation system in the mainland of China indicates that the research in the structural deformation may provide some constraints on the tectonic division and evolution, and the reconstruction of geodynamic settings in the geological history of the continent.
Lai Z.,Sun Yat Sen University |
Lai Z.,University of Massachusetts Dartmouth |
Lai Z.,Key Laboratory of Marine Resources |
Chen C.,University of Massachusetts Dartmouth |
And 8 more authors.
Biogeosciences | Year: 2013
The 11 March 2011 tsunami triggered by the M9 and M7.9 earthquakes off the Tōhoku coast destroyed facilities at the Fukushima Dai-ichi Nuclear Power Plant (FNPP) leading to a significant long-term flow of the radionuclide 137Cs into coastal waters. A high-resolution, global-coastal nested ocean model was first constructed to simulate the 11 March tsunami and coastal inundation. Based on the model's success in reproducing the observed tsunami and coastal inundation, model experiments were then conducted with differing grid resolution to assess the initial spread of 137Cs over the eastern shelf of Japan. The 137Cs was tracked as a conservative tracer (without radioactive decay) in the three-dimensional model flow field over the period of 26 March-31 August 2011. The results clearly show that for the same 137Cs discharge, the model-predicted spreading of 137Cs was sensitive not only to model resolution but also the FNPP seawall structure. A coarse-resolution (∼2 km) model simulation led to an overestimation of lateral diffusion and thus faster dispersion of 137Cs from the coast to the deep ocean, while advective processes played a more significant role when the model resolution at and around the FNPP was refined to ∼5 m. By resolving the pathways from the leaking source to the southern and northern discharge canals, the high-resolution model better predicted the 137Cs spreading in the inner shelf where in situ measurements were made at 30 km off the coast. The overestimation of 137Cs concentration near the coast is thought to be due to the omission of sedimentation and biogeochemical processes as well as uncertainties in the amount of 137Cs leaking from the source in the model. As a result, a biogeochemical module should be included in the model for more realistic simulations of the fate and spreading of 137Cs in the ocean. © 2013 Author(s).
Sun G.,Key Laboratory of Marine Resources |
Huang Y.,Key Laboratory of Marine Resources |
Huang W.,Key Laboratory of Marine Resources
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2015
The differences in geophysics characteristics, differences in geology and geochemistry between the north and south of Jiusuo-Lingshui Fault Belt, and the geological structure features of above fault belt were systematically discussed. The results show that the Mesozoic paleo-subduction zone in north margin of South China Sea starts from Jiusuo-Lingshui Fault Belt in the western, first extending in EW direction to the east, cut by the dextro strike-slip fault which strikes in NW direction nearby E112°30′, then extending in NEE direction until to nearby E116°cut by dextro strike-slip fault which strikes in NW direction again, and extending in NEE direction until to nearby E119°30″ cut by dextro strike-slip fault which strikes in NW direction again, and then extending in NEE direction until to Taiwan Island further in east. This paleo-subduction zone displays as strong horizontal gradient peak zones in bouguer gravity anomaly. The north of paleo-subduction zone appears high magnetic anomaly zone which is parallel to this paleo-subduction zone. This high magnetic anomaly zone is explained as the volcanic-arc related to the information of this paleo-subduction zone. The borehole data of the researched area and chronology research on the Jiusuo-Lingshui Fault Belt show that this paleo-subduction zone was formed in late Mesozoic. And the geology and geophysics data such as gravity, magnetic, seismic profiles and drilling wells in north of South China Sea hold up above conclusion about the location of Mesozoic paleo-subduction zone. This Mesozoic paleo-subduction zone in north margin of South China Sea joins the eastern branch fault (No.I fault) of Red River Fault Zone in the Yinggehai Basin in the west, and links Shoufeng Fault in Taiwan Island in the northeast. ©, 2015, Central South University of Technology. All right reserved.