|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Timing of the Early Paleozoic Yangtze and Cathysian Convergence: Constraint from U-Pb Geochronology of Hydrothermal Zircons from Mafic Mylonite within the Shoucheng-Piaoli Ductile Shear Zone, Northern Guangxi显示文摘Objective The northern Guangxi region is in the southwestern part of the Southern China continent,which is located at the junction of the southwest section of the Early Paleozoic Yangtze block and Cathaysian block.A series of NNE-trending ductile shear zones are developed in this region,and these ductile shear zones are mostly previously suggested boundary faults of the Early Paleozoic Yangtze block and Cathaysian block,such as the | QIN Ya FENG Zuohai HU Rongguo LI Saisai WANG Chunzeng | 2018 | Acta Geologica Sinica(English Edition)2018，92，5： | 8 |
| 2 | The emplacement mechanisms and growth styles of the GuposhanHuashan batholith in western Nanling Range, South China显示文摘The Guposhan-Huashan batholith was emplaced during transition from Tethysian tectonic regime to Pacific tectonic regime in the Middle-Late Jurassic. The regional EW-striking Yishan-Quannan basement deep fault zone, associated with the Tethysian regime, is thought likely to control the formation of the batholith. The development of the batholith was, however, achieved when the Pacific tectonic extensional regime dominated. The batholith consists of seven individual intrusive units that were emplaced subsequently over a 15 m.y. span. Deformation structures and strain analysis of the intrusive units and their country rocks suggest the existence of active and passive emplacement mechanisms. For example, shape-preferred orientation of dioritic enclaves and megacrystic K-spars within earlier units and the development of rim synforms resulted from active mechanisms. It is estimated that active expansion and structural propagation each contributed approximately 27%, and stoping accounted for 46% of the space for the entire batholith. The active emplacement mechanisms produced earlier units at deeper levels of the crust and followed by passive emplacement mechanism at shallower crustal levels when the tectonic regime changed from compression to extension. Each intrusive unit shows a different growth mode. Niumiao and Yangmeishan intrusions show a polarized lateral growth mode, the main-phase Lisong and Wanggao intrusions show either a central growth mode or an eccentric growth mode, and the youngest Baishuidai and Huamei units have a polarized multi-point central growth mode. Both Guposhan and Huashan plutons show a concentric growth zoning pattern with the former built in an outward growth style and the latter an inward growth style. The well-preserved circular shape of both plutons is indicative of relatively stationary magma feeders, suggesting that any considerable horizontal displacement in the region was unlikely even if the area was in an intracontinental strike-slip tectonic setting during the last emplacement phases of the batholith. | FENG ZuoHai WANG ChunZeng LIANG JinCheng LI JunZhao HUANG YongGao LIAO JiaFei WANG Rui | 2011 | Science China Earth Sciences2011，54，1： | 5 |
| 3 | On the role of buoyancy force in the ore genesis of SEDEX deposits:Example from Northern Australia显示文摘Finite element modeling on a highly conceptualized 2-D model of fluid flow and heat transport is un-dertaken to simulate the paleo-hydrological system as if the Mount Isa deposits were being formed in the Mount Isa basin, Northern Australia, and to evaluate the potential of buoyancy force in driving ba-sin-scale fluid flow for the formation of sedimentary-exhalative (SEDEX) deposits. Our numerical case studies indicate that buoyancy-driven fluid flow is controlled mainly by the fault penetration depth and its spatial relation with the aquifer. Marine water recharges the basin via one fault and flows through the aquifer where it is heated from below. The heated metalliferous fluid discharges to the basin floor via the other fault. The venting fluid temperatures are computed to be in the range of 115 to 160℃, with fluid velocities of 2.6 to 4.1 m/year over a period of 1 Ma. These conditions are suitable for the formation of a Mount Isa-sized zinc deposit, provided a suitable chemical trap environment is present. Buoyancy force is therefore a viable driving mechanism for basin-scale ore-forming hydrothermal fluid migration, and it is strong enough to lead to the genesis of supergiant SEDEX deposits like the Mount Isa deposit, Northern Australia. | YANG JianWen FENG ZuoHai LUO XianRong CHEN YuanRong | 2009 | Science China Earth Sciences2009，52，4： | 3 |
| 4 | Numerically quantifying the relative importance of topography and buoyancy in driving groundwater flow显示文摘Both topography and buoyancy can drive groundwater flow;however,the interactions between them are still poorly understood.In this paper,the authors conduct numerical simulations of variable-density fluid flow and heat transport to quantify their relative importance.The finite element modeling experiments on a 2-D conceptual model reveal that the pattern of groundwater flow depends largely upon the relative magnitude of the flow rate due to topography alone and the flow rate due to buoyancy alone.When fluid velocity due to topography is greater than that due to buoyancy at large water table gradients,topography-driven 'forced convection' overwhelms buoyancy-driven 'free convection'.When flow velocity due to buoyancy is greater than that due to topography at small water table gradients,mixed free and forced convection takes place.In this case,free convection becomes dominant,but topography-driven flow still plays an important role since it pushes the free convection cells to migrate laterally in the downhill direction.Consequently,hydrothermal fluid flow remains changing periodically with time and no steady state can be reached.The presence of a low-permeability layer near the surface helps eliminate the topography effect on the underlying free convection. | YANG JianWen 1,2,FENG ZuoHai 1,LUO XianRong 1 & CHEN YuanRong 1 1 Faculty of Earth Sciences,Guilin University of Technology,Guilin 541004,China 2 Department of Earth and Environmental Sciences,University of Windsor,Windsor,Ontario,N9B 3P4,Canada | 2010 | Science China Earth Sciences2010，53，1： | 2 |
| 5 | The U-Pb Geochronology and Lu-Hf Isotope Compositions of Detrital Zircons from the Nanhua Group of the Longsheng Region,South China and their Implications for Pan-African Events显示文摘It is unclear whether the South China blocks have an affinity with continental Gondwana due to a lack of direct Pan-African magmatic and metamorphic features.In this study,we conducted U-Pb geochronological and Lu-Hf isotopic analyses for detrital zircons from a sandstone of the Chang'an Formation of the Nanhua Group in the Longsheng region of northern Guangxi,with the aim of constraining the timing of sedimentation and information as to its source,as well as seeking evidence for Pan-African events in the South China blocks.The results show that the ages of detrital zircons peaked at 654.7±6.2 Ma,773.2±4.1 Ma and 821.9±6.5 Ma,with some at 920–870 Ma;the youngest age indicates the existence of the Pan-African thermal event.The ε_(Hf)(t)and T_(DM2) values demonstrate that the study area has experienced three stages of crustal growth at 3.0–2.4 Ga,2.1–1.5 Ga and 1.3–0.9 Ga.With intensively distributed Neoproterozoic mafic-ultramafic and granitic plutons emplaced at 830–810 Ma along the southwestern section of the Jiangnan Orogenic Belt and positiveεHf(t)values from a large group of zircon grains,it is proposed that the sediments of the Chang'an Formation(of Nanhua Group)were largely sourced from the southeastern margin of the Yangtze block.Comparison with the zircon age spectra of the Cathaysian block shows that about 79%of the Pan-African aged detrital zircon grains that have TDM2=1352–1031 Ma andεHf(t)=3.68–8.79,were sourced from the recycled Grenvillian crust of the Cathaysian block,suggesting that the Cathaysian block had a close connection with Gondwana. | ZHANG Chenglong QIN Ya YANG Yicheng FENG Zuohai LIU Xijun LI Saisai WAN Lei WANG Chunzeng | 2021 | Acta Geologica Sinica(English Edition)2021，95，3： | 1 |
您所在的机构暂未开通此部分的功能，请联系管理员