Entity

Time filter

Source Type


Yang H.,Chinese Academy of Geological Sciences | Yang H.,The International Research Center on Karst under the Auspices of | Lu M.,Chinese Academy of Geological Sciences | Cao J.,Chinese Academy of Geological Sciences | Cao J.,The International Research Center on Karst under the Auspices of
Environmental Earth Sciences | Year: 2015

The transfer processes of trace elements within the soil–plant system is part of the biochemical cycling of chemical elements—representing a flow of elements from nonliving to living compartments in biosphere. Trace elements distribution in soil–plant system is a key issue in assessing their mobility and availability in soils. This study was conducted to assess the transfer mechanism of copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), strontium (Sr) and zinc (Zn) in eleven natural plants and associated rhizosphere soils in subtropical karst and clasolite areas, Southwestern China, using inductively coupled plasma-atomic emission spectroscopy. Trace elements except Sr are rich in the limestone soil of the karst area, whereas they are dispersed in the red soil of the clasolite area. Moreover, their active rates in the limestone soil are greatly reduced, compared with the red soil. Contents of trace elements in plants are both affected by the geochemical and biogeochemical characteristics of trace elements. Distributions of trace elements are related to plants’ physiological characteristics, trace elements’ chemical characteristics, and geological background as well. © 2014, Springer-Verlag Berlin Heidelberg. Source


Jiang G.,Institute of Karst Geology | Jiang G.,The International Research Center on Karst under the Auspices of | Guo F.,Institute of Karst Geology | Guo F.,The International Research Center on Karst under the Auspices of | Polk J.S.,Western Kentucky University
Carbonates and Evaporites | Year: 2015

Salt crystallization in pore spaces will usually cause major damage to natural sandstone. Salt distribution and movement are hard to detect in the field within a small scale. Understanding salt generation and transportation in semi-arid regions can help to protect natural cultural relics and control the salt weathering damage. Salt transportation behavior and deposition processes in Yungang Grotto were studied through a detailed hydrochemistry analysis within the context of the atmosphere–rock–water environmental system. Changes of salt types in different media were analyzed according to the sequence of water and salt transportation, integrating the results of atmospheric dry and wet deposition, soil in the aeration area and sandstone, and salt on the rock surface. The study shows the generation of salt is related to vertical transport in the soil and rock weathering zone. Salt transportation originates from soil cover, passes through the sandstone weathering zone, and finally accumulates in the grottoes. Due to coal burning pollution, acid deposits leading to sulfate bind to the soil. Salt generation in soil is the result of neutralization among sulfate, carbonate, and carbonate minerals, leading to cations of soluble salt that give priority to bonding with Ca2+ and Mg2+, while the anions are mainly HCO3 − and SO4 2−. Salt in sandstone weathered crust is not only impacted by soil, but also carbonate dissolution from CO2-rich water, its inverse process, and feldspar dissolution. Rock surfaces in the inner grottoes suffer intense evaporation, resulting in salt accumulation, and carbonate and sulfate mineral deposition or dissolution, producing the salt type of MgSO4 or NaSO4, while HCO3 − and Ca2+ are heavily consumed. The result can provide a scientific basis for engineering measures that reduce the hazard of salt accumulation. © 2014, Springer-Verlag Berlin Heidelberg. Source


Guo F.,Institute of Karst Geology | Guo F.,The International Research Center on Karst under the Auspices of | Jiang G.,Institute of Karst Geology | Jiang G.,The International Research Center on Karst under the Auspices of
Carbonates and Evaporites | Year: 2014

Yungang Grottoes in north of China are the classical masterpieces of Chinese Buddhists, dating from the Northern Wei Dynasty 1,500 years ago. This rock art is threatened by weathering processes that has been accelerated due to coal mining. The dominant weathering processes occurring on the rock surface are collapse, flaking, and efflorescence. Salt crystal growth plays a major cause of these deteriorations, and it has a close relationship with water movement. The major salt on the rock surface are sulfates, with a primary composition of epsomite, thenardite, and gypsum. In addition, carbonate minerals are found, mostly calcite and nesquehonite. In this paper, three grottoes in the eastern part have been investigated via measuring the rock surface moisture and recording the surface temperature and humidity. These nondestructive techniques are used for the first time in China on cultural relics. The movement of moisture has been calculated and mapped, and then analyzed for its relationship with the weathering process. Three main sources of water transport in the sandstone are adopted to explain the moisture content patterns. The aim of this study is to help rock art conservation in Yungang Grottoes, thus to provide a better understanding regarding the driving processes of internal moisture transport, which results in significant weathering processes. The evidence shows that the natural character of sandstone, water transport mechanism, and continental semi-arid conditions are the major causes of rock deterioration. Meanwhile, air pollution due to coal mining is also an important factor in driving the weathering process. © 2014 Springer-Verlag Berlin Heidelberg. Source


Guo F.,Institute of Karst Geology | Guo F.,The International Research Center on Karst under the Auspices of | Jiang G.,Institute of Karst Geology | Jiang G.,The International Research Center on Karst under the Auspices of | And 3 more authors.
Environmental Earth Sciences | Year: 2013

Karst terrains are generally regarded as a fragile and vulnerable environment. China's karst is mainly developed in pre-Triassic, old-phase, hard, compact carbonate rock. The lack of soil cover in bare karst land can enhance desertification. Its underground drainage system can aggravate both drought and flooding problems; the interconnected surface and subsurface conditions allow for easy contamination by pollutants. Moreover, karst terrains quite often suffer from a series of engineering problems, such as water infiltrating into mines or transportation tunnels, leakage from reservoirs, and failure of building foundations. As resources and energy exploitation intensified in recent years, karst areas in Southwest China faced some severe geo environmental problems. In order to find out how the problems action and evolution in recent years, field and laboratory investigations were conducted in Guangxi autonomous region, Guizhou, Yunnan, Guangdong, Hunan, Hubei provinces, and Chongqing municipality. About 100 experts from the Provincial Geological Survey and graduate students took part in this project. Several symposiums were held during those 3 years. Besides the in situ survey, data were collected from hydrogeological survey results since 2000 when the new round of land resources investigation began. After analyzing these data, rock desertification, drought and flooding, and contamination and engineering geological environmental problems were considered the most prevalent problems in karst areas in Southwestern China. The status of each problem is elaborated upon in this paper and should be considered for future sustainable development. © 2012 Springer-Verlag Berlin Heidelberg. Source


Guo F.,Institute of Karst Geology | Guo F.,The International Research Center on Karst under the Auspices of | Yuan D.,Institute of Karst Geology | Yuan D.,The International Research Center on Karst under the Auspices of | And 2 more authors.
Acta Carsologica | Year: 2010

Approximately 33% of China is karstic. The most extensive karst areas are in southwestern China and cover approximately 540,000 km 2. Southwestern China hosts some of the most typical karst landforms in the world and has important high-quality karst water resources. Due to the rapid development of China, karst waters are threatened by various types of contamination. Detail field and laboratory investigations in five provinces including several cities in southwestern China were conducted in 2008 and 2009. Eighty-three springs and underground rivers were surveyed and water samples collected from each for laboratory analyses for major ions. Four main types of karst aquifer contamination were identified based on contaminant sources: Rural and agricultural pollution, pollution from urban development and industry, pollution from mining, and accidental groundwater pollution. Several representative instances for each type of contamination and their impacts on the environment are discussed in more detail. Contamination countermeasures of karst waters and a framework for overall management of karst water resources in southwestern China are provided. Source

Discover hidden collaborations