By means of thin section,SEM,quartz cathodoluminescence and X-RD analysis,the authors studied the mineral composition and texture of the Upper Tertiary Xujiahe Formation sandstone in the middle part of West Sichuan depression,analyzed the composition maturity and texture maturity and,according to the scheme of genesis-composition,classified the sandstone.Based on an analysis of characteristics of sandstone and clastic components as well as the regional tectonic setting,the authors also investigated the direction of the sources.The results show that there exist multi-provenances of upper Triassic Xujiahe Formation in the middle part of west Sichuan depression,as evidenced by the Dickinson discriminating diagrams of modal composition.Mineral assemblages and cathodoluminescence colors of quartz suggest that the mother rock of xu-2 and xu-3 period was acidic rock and that of xu-4 period is sedimentary rock in Dayi,the mother rock of Xujiahe period is mainly composed of sedimentary rock and metamorphic rock..The results show that the provenance of xu-2 period might have come from northern Longmenshan uplift,the south island chain of Longmenshan and Kangdian old land.The provenance of xu-3 period might be not different from that of xu-2 period.The provenance of xu-4 period and the following periods might have come from Longmenshan old land.Generally speaking,the provenance of the area was controlled by the evolution of Longmenshan.
[Objective] The research aimed to investigate the status and pollution situation of livestock and poultry breeding industry in Chaohu river basin,and put forward the corresponding measures.[Method] Based on investigating the statistical data of Chaohu Animal Husbandry Bureau and pollution status of part breeding districts,the pollution status of large-scale livestock and poultry breeding industry in Chaohu river basin was analyzed and the corresponding environmental management and control measures were proposed.[Result] Currently the quantity of various pollutants produced by large-scale livestock and poultry breeding industry in Chaohu river basin was large.When the feces of all kinds of livestock and poultry investigated in Chaohu river basin were converted to the equated pig excrement,according to the day excretion of livestock and poultry,it was calculated that the annual quantity of total feces from livestock and poultry in Chaohu river basin was 25.153 5 million t,BOD was 1.024 6 million t,COD was 856.4 thousand t,the produced ammonia nitrogen was up to 117 000 t.The number of large-scale breeding farms of Chaohu river basin was comparatively larger(Juchao area was 133),many breeding species,too scattered,quite small in scale(taking pigs for example,the average number was 176).[Conclusion] Aiming at the pollution problems in livestock and poultry breeding farms in this river basin,some measures of environmental management suitable to large-scale livestock and poultry breeding industry in Chaohu river basin were proposed.
The paper is aimed at making clear the distribution of the favorable reservoirs in the area.Based on core description,cast section,popular section,scanning election microscope,x-ray diffraction etc,it is believed that the main diagenesis types are pressure solution,cementation and dissolution.The primary porosity of the reservoir rocks is 37.17%,which is reduced by 18.78% by compaction and pressure solution and 9.16% by cementation,and 5.12% by asphalt-filling.The secondary pores are produced by organic acids' dissolving organic matter at maturing stages,resulting in an increase of porosity by 5.38%.The preserved average porosity is 9.49% at present.
Chlorophyll-a is an important parameter that is used to measure the water quality, and its concentrations indicate the degree of eutrophication. Taking the waters of Chaohu Lake as the research area, four remote sensing inversion models of the chlorophyll-a concentrations were constructed based on GF-1 WFV images using empirical and semiempirical/semianalytical methods. The optimal model was selected by evaluating the model validation accuracies, and this model was used to invert the spatial distributions of the chlorophyll-a concentrations in the waters of Chaohu Lake from May to July 2017. The results show that the NDCI model is the most suitable for inverting chlorophyll-a concentrations in the waters of Chaohu Lake based on GF-1 WFV images. This model has the highest validation accuracy, with a determination coefficient of 0.933, a Root mean square error of 2.85 μg/L and a mean absolute percentage error of 19.69%. The spatial distributions of the chlorophyll-a concentrations in the waters of Chaohu Lake from May to July 2017 all showed decreasing trends from Western Half Lake to Eastern Half Lake, the areas of higher chlorophyll-a concentrations in May and June were mainly concentrated in the northern waters of Western Half Lake, and the area with the highest chlorophyll-a concentrations in July was located in the northwestern waters of Middle Half Lake. The mean chlorophyll-a concentration in the waters of Chaohu Lake from May to July 2017 was 12.5 μg/L, which indicated slight eutrophication.
Finely classifying and contrasting strata,analyzing sequence structure and establishing sequence strata framework are the research purpose of this research.By analyzing information of outcrop profile,drilling core and well logging,3 kinds of different sequence interfaces are distinguished in 2nd and 3rd member of YangYi Formation,which can be divided into 9 middle-term,31 short-term and 66 super-short-term base level cyclical sequences.Then,this research analyzes the characteristic of vertical sequence,lithofacies combination,structure type and stacking patterns of various tapered basal level cyclical sequence,and discusses two kinds of super-short-term base level cyclical sequences,which are upward-darken unsymmetrical and symmetric form developed in research interval.Further,the research discusses the application of high-resolution sequence stratigraphy in strata classification and correlation and sequence strata framework establishment in the fan-delta lacustrine facies depositional systems.
Terrigenous sediment rock develops with a great thickness in the foreland basin of the south part of Longmenshan Mountain, but the sandstone of which distributes most widely and its content ranks first. On the basis of observing and describing the macro characteristics of the sandstone in detail, the mineral composition and texture of the sandstone of Mesozoic and Cenozoic are studied by means of thin section and grain size analysis, the results show that both the composition maturity and texture maturity range from middle to low. The sandstone is classified, according to the scheme of genesis composition. In the light of the characteristics of sandstone as well as sedimentary features of deposited strata in the foreland basin, it is concluded that the provenance of the sandstone is Longmenshan orogenic belt, and the sedimentary model is established finally.
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