In Zhu 1Depression,there existed 10source depressions,of which 4was proven to be hydrocarbon enriched depressions,the rest of them were potentialized hydrocarbon enriched depressions,their scales and source extent were more than those of the proven ones,but because of the poor quality of the data collected from mid-deep reservoirs,is severely restricted the evaluation and understanding of the hydrocarbon enriched depressions.To implement the understanding of oil exploration and bring the breakthrough of exploration potential and in consideration of the problem existed in seismic data and the characteristics of the buried depth and structural characters of the depressions,the collected data are systematically analyzed and improved,effect which is better than that of the data is obtained,which provides strong evidence for evaluation.Suggestion is given for further improvement based on the effect of data acquisition.
Abstract Eutrophication refers to the nutrient enrichment, leading to blooms of algae. Such blooms in lakes can happen throughout the year because of the changes in nutrient and hydrological cycles. Nutrient export to lakes from rivers is the main cause of eutrophication problems. Seasonal trends in nitrogen (N) export by rivers to lakes are still not well understood. The objective of this study is, therefore, to better understand the seasonal trends in river export of dissolved inorganic N (DIN) to lakes of the Hai He Basin. To this end, we selected Guanting and Baiyangdian as representative lakes, whose drainage areas include various cropping systems. We developed a seasonal version of the Model to Assess River Inputs of Nutrients to lAkes (MARINA‐Lakes) model for Guanting and Baiyangdian while assessing N flows from the land to the lakes. The model accounts for the seasonality in human activities (e.g., cropping systems and fertilizer practices), climate, and hydrology. The effective seasons are winter (December–February), spring (March–May), summer (June–August), and fall (September–November). The model results for the year 2012 indicate that river export of DIN was highest in winter and lowest in summer. Point sources accounted for over 50% of DIN exports to Guanting and Baiyangdian across seasons. Avoiding direct discharges of animal manure (point source) in winter is needed to reduce future lake pollution. We argue that effective lake pollution control requires accounting for seasonal N cycles. Our study can support effective nutrient management and environmental policies.
This paper analyzes the changing characteristics of the temperature and rainfall of Mengzi according to the meteorological information obtained from the weather observatory in Pinbian County of Mengzi from 1951 to 2002.The results indicate that there is urban heat island effect in Mengzi and it is increasing year by year.Through the investigation,we know that the average intensity in Mengzi is 1.56 ℃.It is strongest in spring and weakest in summer.It is strongest at 08:00 and weakest at 14:00 in a day.This article uses gray connection analysis method to analyze the main weather factor which affects this urban heat island in Mengzi.At last,it comes to the conclusion that the velocity of wind is the main weather factor.
Abstract Prevailing mantle plume models reveal that the roles of plume‐lithosphere interactions in shaping surface topography are complex and controversial, and also difficult to test. The exposed and complete strata in the Emeishan large igneous province (LIP) recorded abundant paleoenvironmental information associated with preeruptions and syneruptions, attracting numerous workers to this province to test these models. Despite intensified research these models are still strongly debated. This study represents an extensive field investigation combining new and previously published data from the Emeishan LIP to further seek information on plume‐induced topographic variations. Our results indicate that there are inconspicuous vertical motions of the surface topography during the ascent of mantle plume, and a significant surface subsidence occurred at the early stage of the volcanism that has a significantly positive correlation with the thickness of local lavas, and the topographic uplift emerged in the late stage of the volcanism. Our studies provide key geological and geochemical evidence that the ascent of the Emeishan plume is unable to drive a significant surface uplift, owing to the plume containing numerous entrained bodies of dense recycled oceanic crust (10–20%) that can significantly reduce plume buoyancy. The significant surface subsidence maybe linked to a significant loss of thermal buoyancy due to the release of heat, which, accompanied by rapid loading of numerous dense erupted lava and a strong lithospheric flexure, also lead to a later synchronous and significant surface subsidence in the Emeishan LIP.
This paper discusses the tail of Emeishan mantle plume and suggests that it locates in Miyi—Yongren area, southern Sichuan—northern Yunnan. On the basis of the classic mantle plume theory, the estimated diameter of Emeishan plume tail was 65~105km when it reached the upper mantle. Picrite distributions and sedimentary responses showed that the center zone of the Emeishan plume was ca. 260~300km wide. Eruption and outcropping of flood basalts were constrained by deep-seated faults and paleogeomorphology, which resulted in the concentration of picrite in the west of the Emeishan large igneous province.
Abstract In many continental large igneous provinces, giant radiating dyke swarms are typically interpreted to result from the arrival of a mantle plume at the base of the lithosphere. Mafic dyke swarms in the Emeishan large igneous province ( ELIP ) have not received much attention prior to this study. We show that the geochemical characteristics and geochronological data of the mafic dykes are broadly similar to those of the spatially associated lavas, suggesting they were derived from a common parental magma. Based on the regional geological data and our field observations, we mapped the spatial distribution patterns of mafic dyke swarms in the ELIP , and recognized six dyke sub‐swarms, forming an overall radiating dyke swarm and converging in the Yongren area, Yunnan province. This location coincides with the maximum pre‐eruptive domal uplift, and is close to the locations of high‐temperature picrites. Our study suggests that the Yongren area may represent the mantle plume centre during the peak of Emeishan magmatism.
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