Laboratory Simulation of the Formation Process of Surface Geochemical Anomalies Applied to Hydrocarbon Exploration

The formation mechanisms and processes of geochemical anomalies used as proxies in surface geochemistry exploration (SGE) have not been well understood. Previous studies cannot realize 3D measurement of microseeping hydrocarbons from reservoirs to the surface, which made it difficult to understand the features and pathways of deep hydrocarbon microseepages. Understanding the processes of hydrocarbon microseepages will contribute to the acceptance and effectiveness of surface geochemistry. Based on a simplified geological model of hydrocarbon microseepages, including hydrocarbon reservoir, direct caprock, overlying strata and Quaternary sediments, this work established a 3D experimental system to simulate the mechanisms and processes of deep hydrocarbon microseepes extending to the surface. The dispersive halos of microseeping hydrocarbons in the subsurface were adequately described by using this 3D experimental system. Results indicate that different migration patterns of hydrocarbons above the point gas source within the simulated caprock and overlying strata can be reflected by the ratio of i-butane to n-butane (i-C4/n-C4), which follow diffusion and infiltration (buoyancy) mechanisms. This is not the case for vertical measurement lines far from the point gas source. A vertical gas flow in the form of a plume was found during hydrocarbon microseepage. For sampling methods, the high-density grid sampling is favorable for delineating prospecting targets. Hydrocarbon infiltration or buoyancy flow occurs in the zones of infiltration clusters, coupling with a diffusion mechanism at the top of the water table and forming surface geochemical anomalies. These results are significant in understanding hydrocarbon microseepage and interpreting SGE data.     

Magnetic Influences of Cement Dust on Soil in Industrial Area and Its Environmental Implications

To monitor environmental implications of cement dust on soil in industrial area, magnetic parameters and mineral compositions were measured by the samples of the cement dust, cement factory dustfall, cement, coal ash, topsoil of green space in the factory and topsoil outside the factory. Results showed that the major magnetic minerals in the samples were magnetite, the magnetic mineral particle size of cement dust, dustfall, cement and coal ash was coarse Multi-Domian (MD) and Pseudo-Single-Domain (PSD). As topsoil of green space in the factory and topsoil outside the factory were polluted by cement dust, their magnetic properties had been obviously changed; the concentration of magnetic minerals elevated and particle size became coarser. The magnetic parameters (χ_fd,χ_ARM/χ,χ_ARM/SIRM) value can reflect the pollution level of the soil, the lower its value was, the more serious soil was polluted. X-ray diffraction results showed that the mineral compositions of the topsoil of green space in the factory and topsoil outside the factory were quartz and calcite, which were the same as cement dust. Magnetic parameters combination characteristics of topsoil can monitor the soil environmental changes in cement industry area.     

Two-dimensional landslide dynamic simulation based on a velocity-weakening friction law

Surprisingly, hypermobility (high velocity and long run-out) is a remarkable feature of large landslides and is still poorly understood. In this paper, a velocity-weakening friction law is incorporated into a depth-averaged landslide model for explaining the higher mobility mechanism of landslides. In order to improve the precision of the calculation, a coupled numerical method based on the finite volume method is proposed to solve the model equations. Finally, several numerical tests are performed to verify the stability of the algorithm and reliability of the model. The comparison between numerical results and experimental data indicates that the presented model can predict the movement of landslide accurately. Considering the effect of velocity-weakening friction law, the presented model can better reflect the hypermobility of landslide than the conventional Mohr–Coulomb friction model. This work shows that the application of a universal velocity-weakening friction law is effective in describing the hypermobility of landslide and predicting the extent of landslides.     

A public Cloud-based China’s Landslide Inventory Database (CsLID): development,zone, and spatiotemporal analysis for significant historical events, 1949-2011

Landslide inventory plays an important role in recording landslide events and showing their temporal-spatial distribution. This paper describes the development, visualization, and analysis of a China's Landslide Inventory Database (CsLID) by utilizing Google’s public cloud computing platform. Firstly, CsLID (Landslide Inventory Database) compiles a total of 1221 historical landslide events spanning the years 1949-2011 from relevant data sources. Secondly, the CsLID is further broken down into six zones for characterizing landslide cause-effect, spatiotemporal distribution, fatalities, and socioeconomic impacts based on the geological environment and terrain. The results show that among all the six zones, zone V, located in Qinba and Southwest Mountainous Area is the most active landslide hotspot with the highest landslide hazard in China. Additionally, the Google public cloud computing platform enables the CsLID to be easily accessible, visually interactive, and with the capability of allowing new data input to dynamically augment the database. This work developed a cyber-landslide inventory and used it to analyze the landslide temporal-spatial distribution in China.     

Study on biogenic amines in various dry salted fish consumed in China

This study was carried out to investigate the biogenic amines（BAs）, physicochemical property and microorganisms in dry salted fish, a traditional aquatic food consumed in China. Forty three samples of dry salted fish were gathered from retail and wholesale markets and manufacturers, which had been produced in various regions in China. Cadaverine（CAD） and putrescine（PUT） were quantitatively the most common biogenic amines. About 14% of the samples exceeded the histamine content standards established by the FDA and/or EU. The highest histamine content was found in Silver pomfret（Pampus argenteus）(347.79 mg kg^-1). Five of forty three samples exceeded the acceptable content of TYR(100 mg kg^-1), and 23.26% of dried-salted fish contained high contents of biogenic amines(above 600 mg kg^-1). In addition, species, regions, pickling processes and drying methods made the physicochemical property, microorganisms and biogenic amines in dry salted fish to be different to some extents. The total plate count（TPC） was much higher than that of total halophilic bacteria in all samples. The biogenic amines, physicochemical property and microbiological counts exhibited large variations among samples. Furthermore, no significant correlation between biogenic amines and physicochemical property and TPC was observed. This study indicated that dry salted fish may still present healthy risk for BAs, depending on the processing methods, storage conditions among others.