Dong Z.-Y.,Chinese Academy of Sciences |
Dong Z.-Y.,University of Chinese Academy of Sciences |
Liu D.-W.,Chinese Academy of Sciences |
Wang Z.-M.,Chinese Academy of Sciences |
And 6 more authors.
Chinese Journal of Applied Ecology | Year: 2013
By using GIS/RS technology, and from the aspects of landscape structure, river- and road densities, wetness index, geomorphology, and cultivated land productivity, a spatial analysis was made on the potentiality of wetland restoration in Northeast China, with the regions of priority and secondary priority restoration wetlands determined. Then, by using the coordinated development index of crop production and wetland as well as the landscape indices, the wetland restoration effect was verified. In Northeast China, the wetland area of priority restoration was 1.78×106 hm2, among which, farmland and grassland were the main types for restoration, accounting for 96.7% of the total, and mainly located in the Sanjiang Plain in the northeastern part and the Songnen Plain in the central part of Northeast China. The wetland area of secondary priority restoration was 1.03×106 hm2. After the restoration of the wetlands, the wetland area in Northeast China would be increased by 37.4%, compared with the present wetland area, and the value of the coordinated development index of crop production and wetland would increase from 0.539 before restoration to 0.733 after restoration. The landscape pattern would be more benefit to the performance of the ecological functions of the wetlands. This study revealed that the restoration scheme of the wetlands in Northeast China based on spatial analysis was practicable, which could provide data support for the implement of wetland restoration and the improvement of ecological environment in Northeast China.
Chen Y.-T.,Northwest University, China |
Zhang G.-W.,Northwest University, China |
Lu R.-K.,Northwest University, China |
Lu R.-K.,Anhui Institute of Geological Survey |
Zhang Y.-Q.,Lizi Goldmine Company Ltd of China National Gold Group Corporation
Geological Bulletin of China | Year: 2010
The samples of mylonite were collected from the Guozhacuo fault, situated in the southwestern end of Altyn Tagh fault zone, which extends from Guozhacuo to Longmuco and then to Kongkashankou. The plateau ages of the syntectonic biotite contained in the samples by means of 40Ar/40Ar isotopic dating are listed as follows: 105.9 ± 0.5 Ma, 121.5 ± 0.6 Ma, 150.4 ± 0.9 Ma, which indicated that the ductile deformation of early stage occurred in the Late Jurassic and Early Cretaceous in Guozhacuo fault, and they were consistent with main stages of activities of Altyn Tagh fault zone. Consequendy new evidence has been provided for the extension of Altyn Tagh fault zone towards west. That is to say, Guozhacuo fault has the consistent characteristics of deformation geochronology and tectonic attribute with Altyn Tagh fault zone, and the former is the western extension of the latter, both of them are of the same tectonic belt and are also the results of impulsive tectonic activity caused by northward movement of Lhasa block.
Yu X.,China University of Geosciences |
Wang D.,Bureau of Mineral Resources |
Jiang D.,University of London |
Jiang L.,Anhui Institute of Geological Survey |
And 2 more authors.
Acta Geologica Sinica | Year: 2011
The major tectonic zone that passes through the border regions of the Anhui, Zhejiang, and Jiangxi Provinces in southeast China has been commonly referred to as the Wan-Zhe-Gan fault zone. Geologically, this zone consists ofseveral regional fault belts of various ages and orientations. We have categorized the faults into four age groups based on field investigations. The Neoproterozoic faults are northeast striking. They start from the northeast Jiangxi Province and extend northeastward to Fuchuan in Anhui Province, the same location of the northeast Jiangxi-Fuchuan ophiolite belt. The faults probably acted during the Neoproterozoic as a boundary fauIt zone of a plate or a block suture with mélange along the faults. The nearly east-west- or east-northeast-striking faults are of Silurian ages (40Ar/39Ar age 429 Ma). This group includes the Qimen-Shexian fault and the Jiangwang-Jiekou ductile shear belt. They represent a major tectonic boundary in the basement because the two sides of the fault have clear dissimilarities. The third group of faults is north-northeast striking, having formed since the early-middle Triassic with 40Ar/39Ar ages of 230-254 Ma. They form a fault beIt starting from Yiyang in northern Jiangxi and connect with the Wucheng as well as the Ningguo-Jixi faults. This fault belt is a key fault-magmatic belt controing the formation of Jurassic-Cretaceous red basins, ore distribution, magmatic activity, and mineralization. When it reactivated during the late Cretaceous, the belt behaved as a series of reverse faults from southeast to northwest and composed the fourth fault group. Therefore, classifying the Wan-Zhe-Gan fault zone into four fault groups wil1 help in the analysis of the tectonic evolution of the eastern segment of the Jiangnan orogen since the Neoproterozoic era.
Qian J.,Hefei University of Technology |
Chen Z.,Hefei University of Technology |
Zhan H.,Texas A&M University |
Zhan H.,Wuhan University |
Guan H.,Anhui Institute of Geological Survey
Hydrological Processes | Year: 2011
Local cubic law (LCL) is one of the most commonly applied physical laws for flow in single fractures (SF) and fractured media. The foundation of LCL is Darcian flow. This experimental study examines if LCL is valid for flow in a single rough fracture and how the fracture roughness and Reynolds number (Re) affect flow. Similar to the Moody diagram for flow in pipes, a diagram for flow in a single rough fracture has been generated to relate the friction coefficient with Re and the roughness. Under the experimental condition of this study, flow appears to be substantially different from Darcian flow. The flow law of q ∝ enJm appears to be valid for describing the flow scheme where q, e, and J are the unit width flux, the average aperture, and the hydraulic gradient. The value of the power index m is found to be around 0·83 ~ 0·98, less than what has been used in Darcian flow (m = 1). The power index n is around 11·2 and 13·0, much greater than the n value used in the LCL (n = 3), and it increases with the average velocity. The Moody type of diagram shows that the friction factor for flow in SFs is influenced by Re and the roughness. It decreases with Re when Re is small, and becomes less sensitive to Re when Re is large enough. It also increases with the roughness. Copyright © 2010 John Wiley & Sons, Ltd.
Wan Q.,Anhui Institute of Geological Survey |
Du J.,Anhui Institute of Geological Survey
Northwestern Geology | Year: 2015
According to metallogenic geological conditions and characteristics of Tongling area, and results of previous studies, deep mineralization and its process were discussed in this paper. Structural analysis shows that the Tongling area covers more than one deformation system with multiple stages. The deformation is dominant by fold and fault, and the deformation properties of strata below Silurian may have already changed; magmatic process showsthat ore-bearing rock are mainly syntectic granitoid; magma tite has obvious mineralization-exclusive characteristics. Copper-gold related rocks are mainly high-K calc-alkaline rocks, while iron-bearing and sulfur-bearing volcanic intrusionsare basically kohalaite rock series. Spatial distribution of magmatic rocks is mainly controlled by tectonic structure; magmatic hydrothermal migration in deep percolation is of middle scale, intruding upward in shallow as dykes. There is certain coupling relationship between ore-forming rock and surrounding rock. The ore mineralization takes place in Yanshanian. The summary of deposit distribution, types and mineralization law, combined with the mineralization prediction theory, the mineralization area, type and location were predicted. The study can provide reference forthe deep exploration in the Tongling area.