According to incomplete statistics, there are about 52 rare and endangered species in Chongqing, comparing to China, the proportion is 13%. According to different principles, there are 3 pteridophyte species and 14 gymnosperm species and 35 angiosperm species; 5 first-protection species and 23 second-protection species and 24 third-protection species; 5 endangered species and 22 rare species and 25 threatened species among 52 species. Comparing to China, there proportion are 23.1%, 19.7%, 11.5%, 62.5%, 14.5%, 10.8%; 4.1%, 20.0%, 15.9%, respectively. Chongqing also owns 28 rare and endangered species that will be published in a short time.
According to the identification mark of the short-term base-level cylce interface and under the guidance of the theory and technology of the high-resolution sequence stratigraphy, the authors divide the short-term base-level cycle of Nadu Formation in Baise Basin into three basic structure types which are up-deepening non-symmetry, up-shallowing non-symmetry and symmetry from up-deepening to up-shallowing. Furtherly in the light of the high or low accommodation, and the thickness of the uprising periods and subsiding periods of the short-term base-level cycle, seven subtypes of structure are distinguished and they are up-deepening non-symmetry of low accommodation (Type A 1) or high accommodation(Type A 2)?up-shallowening non-symmetry of low accommodation (Type B 1) or high accommodation (Type B 2)?complete～nearly complete symmetry (Type C 1)? in complete symmetry with the majority of uprising semi-cycle(Type C 2) or subsiding semi-cycle(Type C 3).In this paper the sedimentary environment,stacking patterns,lithlolgic association and sedimentary dynamic processes of each basic type and subtype of structure is discussed in detail. And the development position of the advantage reservoir sand body in each structure type are pointed out. On the basis of these studies, the change rule and distribution pattern of the short-term base-level cycle sequence are summarized. From the terrigenous to lacustrine environment, the short-term base level cycle sequence types have the change rule that is in succession from Type A1 to Type A 2, then to Type C 2, to Type C 1?Type C 3?Type B 1 and at last to Type B 2.In the structure types of short-term base-level cycle sequence, the advantage reservoir sand body mainly develops in Type A 1, secondly in Type A 2?Type B1 and Type C 1. In this paper, the authors also briefly discuss the application of the short-term base-level cycle sequence in oil and gas exploration and development stage.
The Upper Sinian bedded chert is widely distributed on the southeast continental margin of the Yangtze plate. Its thickness ranges from 20 m to 150 m. The chemical compositions of the chert are very pure, and the contents of siliceous minerals exceed 90 percent with those of any other minerals very low. The total content of the trace elements change to much degree. The contents of a large part of the trace elements are low compared with crust clarke values of these elements. But the chert is very rich in the trace elements Ba, As, Sb, Ag and U coupled with relatively high contents of Fe, Mn and low contents of Al, Ti, Mg. It can be identified as hydrothermal chert by the values of Fe/Ti, (Fe+Mn)/Ti, Al/(Al+Fe+Mn) and U/Th. In the Al Fe Mn, Fe Mn (Cu+Ni+Co)×10 triangle diagrams and lg[U] lg[Th], Cr Zr diagrams, all samples in the study area fall in the hydrothermal sediment field. All these characteristics show the cherts are mainly the prodocts of hydrothermal processes. That δ 30 Si values of the chert range from 0.0‰ to 0.7‰ with δ 18 O from 20.1‰ to 23.6‰ clearly manifests that the submarine hydrothermal water is the main source of silica.
Studies on the purification efficiency of eutrophicated water body by Vetiveria Zizanioids on floating-beds showed that V. zizanioids had a great ability to remove TN, NH4(+)-N, TP, PO4(3-), COD, and BOD, and had a significant effect on improving water quality. It was proved that V. zizanioids could be used to purify the eutrophicated water body.
Late Precambrian bedded cherts are widely distributed on the southeast continentel margin of the Yangtze Plate. Its thickness ranges from 20m to 150m and chemical composition of them are very pure. A majorarity of them are composed of micritic quartz. The contents of siliceous mineral range from 93.85 percect to 97.08 percent. The average values of siliceous mineral contents exceed 95 percent coupled with relatively high contents of Fe、Mn and low contents of Al、Ti and Mg. The total contents of the trace elements change greatly. The contents of a large part of the trace elements are low compared with crust clarke values of these elements. The cherts are very rich in the trace elements Ba、As、Sb、Ag and U. In order the average contents of these trace elements are differently as 17,5,47,18,3.6 times as these elements corresponding crust clarke values. All these geochemical characteristices state that the siliceous mineral forming the cherts was derived from hot water. The cherts can also be identified as hydrothermal chert by the values of Fe/Ti、(Fe+Mn)/Ti、Al/(Al+Fe+Mn) and U/Th. In sequence these values differently range from 46.1 to 96.4,50.4 to 104,0.24 to 0.32,1.8 to 33.8, with average values distinctly 70.1,75.7,0.29,5.1. In the Al-Fe-Mn,Fe-Mn-(Cu+Ni+Co)×10 triangle diagrams, all samples in the study area fall in the hydrothermal sediment field. The cherts are characterized by low total REE abundance, varying from 5.46×10\+\{-6\} to 52.79×10\+\{-6\}, the average content 19.19×10\+\{-6\}, the content of LREE being higher that of HREE, clearly negative Ce anomaly and positive Eu anomaly. All these characteristics show these cherts were mainly the products of hydrothermal processes. δ\+\{30\}Si values of the cherts are 0.0‰—0.7‰ and δ\+\{18\}O 20.2‰—23.6‰. δ\+\{30\}Si values of the cherts belong to the range of δ\+\{30\}Si values of hydrothermal quartz and are near to δ\+\{30\}Si values of the dissolved silicon from hot springs at Yellowstone, Wyoming and Mammoth, California. δ\+\{18\}O values of the cherts also belong to the range of δ\+\{18\}O values of quartz from hot sinters. Calculation with the oxygen isotope equilibrium fractionation equation of chert-seawater shows formation temperature 66.0℃—89.7℃. All these temperaturs are clearly above to the temperature of plaeoocean when the cherts were formed. According to the values of silicon and oxygen isotopes and formation temperature of the cherts, it is believed that the silica forming quartz was derived from hot water.
Through the comprehensive analysis of outcrops, rock cores,well logs, seismic interpretation and ESR data,and under the guidance of the theory and technology of the high-resolution sequence stratigraphy, this paper has dealt with different grades of sequence interfaces in Baigang Formation of Baise basin. According to the identification symptoms of the sequence interfaces and lake flood sedimentation, four-grade base-level cycle sequences, namely short-term, middle-term,long-term,super-long-term cycle sequences,are distinguished,and one super-long-term,eight long-term,twenty-one middle-term base-level cyclic sequences are recognized.On the basis of the above studies,the vertical sequences,facies associations,lithologic components, structural types and stacking patterns are discussed in detail.Among these sequences, the short-term cycle sequence may be divided into three basic types of structures, i.e., upward deepening non-symmetry, upward thinning non-symmetry and symmetry from upward deepening to upward thinning, and further divided into seven subtypes of low or high accommodation and non-complete or nearly complete symmetry. These basic sequence types and subtypes are of various stacking and distribution patterns. The structural type and stacking pattern of the middle-term cycle sequence are identical with those of the short-term cycle sequence. The long-term cycle sequence is of symmetric structure which develops complete depositional sequence of lacustrine transgressive-regressive cycle, and may be divided into three types of cycle structure in the light of the lacustrine transgressive-regressive rate, viz.,the fast rate type,middle rate type and fast rate transgressive-slow rate regressive type. In this paper the application of these different-grade base-level cycle sequences to the stratigraphic division and oil bed correlation, the foundation of sequence stratigraphic framework and the sand body distribution regularity are probed into in the light of these sequence characteristics.
The concentration of suspended sediments at the estuarine surface (SSC) is a crucial indicator for monitoring water bodies. Given the current situation in which SSC remote sensing inversion is primarily based on low-resolution satellites, this study first discusses remote sensing and GIS technologies before employing the Sentinel-2 satellite, whose resolution can exceed 10 m after resampling. Inversion and comparison of SSC content during wet and dry periods. In addition, based on the neural network’s ability to compensate for the inherent errors of traditional empirical techniques, this study designs and develops an artificial neural network-based neural network corrector to perform secondary correction on the empirical inversion results. In this study, the B2, B3, B4, and B8 inversion models are used to generate the sensitive bands, and the ratio of these bands is used to generate the inversion model. The results indicate that the model has a high level of precision, which can aid in reducing the model’s inherent error and ensuring inversion precision.
Through the comprehensive analysis of out crop, rock cores, well loggings and seismic data, one super-long-term, five long-term and sixteen middle-term base-level cycle sequences are distinguished in Nadu Formation of Baise basin. In this paper, the relationship between the source-reservoir-cap associations and the base-level cycle sequences of Nadu Formation are discussed in detail, and some knowledge is acquired as follows: (1) long-term base-level cycles bear close relation to source-reservoir-cap rock associtations,the main reservoir sand bodies develop in the early-middle stage of the uprising periods and middle-late stage of subsiding periods of the long-term base-level cycle, and the main hydrocarbon source rocks and favourable regional cap rocks develop at the turning position from uprising to subsiding of the long-term base-level cylce; (2) the characteristics of source-reservoir-cap rock associations developed in each long-term base-level cycle are distinctly different and controlled by the frequency, amplitude of the rising and falling of the base-level, facies association, accommodation and A/S ratio; (3) according to the spatial relationship of source rocks, reservoir rocks and cap rocks in the vertical or horizontal section of the formation, three types of basic associations can be divided. The first associations is usually of the type with source rocks in the upper and reservoirs below, the second one with source rocks below and reservoirs in the upper, and the third one with source rocks in other district.
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