丹霞山陡坡上风化洞穴的基本特征及成因探讨

风化洞穴在全球不同气候区广泛发育,其形成过程和主控因素是地貌学研究的热点问题,但形成机制至今仍存在不少争议,尤其对丹霞地貌区风化洞穴的研究还较少。丹霞山是世界自然遗产地“中国丹霞”的典型代表,陡坡上发育形态和规模各异的风化洞穴,是丹霞地貌的重要景观要素,为认识亚热带湿润气候风化洞穴成因提供了良好的机会。文章以丹霞山砾岩和砂岩陡坡上的5处典型风化洞穴为研究对象,利用野外考察、形态测量、气象监测、样品显微观察及盐化学实验等方法,在已有研究的基础上进一步对湿润气候丹霞地貌区风化洞穴的特征和成因进行探讨。结果表明：1）在砾岩中发育的洞穴一般个体形态较大,洞穴具有较明显的向上和向内生长趋势;砂岩中发育的洞穴大多密集排列,形态较小,常具有蜂巢结构。2）岩石性质是洞穴发育的基本影响因素,在宏观尺度上决定了洞穴的发育位置和排列方式,也决定了不同岩性下发育的风化洞穴的形态特征。在微观尺度上,岩石含有较多长石、钙质胶结物等易溶矿物组分,在酸性雨水渗流过程中发生化学溶解,加上盐结晶作用导致岩石微观结构破坏,诱发洞穴初始形成。3）洞穴尺寸变大后,洞穴内适宜的微气候是洞穴演化的关键因素,为水和盐的聚集及盐风化提...     

下扬子区二叠纪主要岩石类型成因的地球化学信息

作者在全面了解陆相层序地层学研究现状的基础上,认为陆相层序及体系域发育仍受控于湖平面相对变化。构造、气候及沉积物供给的控制作用最终通过湖平面变化表现出来。而湖平面变化可分完整旋回与不完整旋回两种情况,进而提出了所形成的层序及体系域模式：在完整旋回中形成了湖泊充填、湖泊扩张、湖泛和湖泊萎缩四个体系域,对应层序为Ⅰ型层序;在不完整旋回中形成了湖泊充填、湖泊扩张、湖泛三个体系域,或者湖泊扩张、湖泛、湖泊萎缩三个体系域,对应层序为Ⅱ型层序。以松辽盆地西部斜坡实际工作为例,提出了中生代层序及体系域划分方案,较前人研究有新认识。     

陕西省关中及邻区地震的震源参数研究

利用西安数字地震遥测台网记录的宽频带数字地震资料,通过波谱分析的方法,测定了陕西省关中及邻区地震的震源参数,建立并探讨了震源参数与震级ML之间的关系。     

控制网中观测元素作用的分析

本文阐述测量控制网中观测元素作用分析的理论,通过有关的四个数字指标对此进行了多个网例的定量分析,讨论了观测元素的作用与网形、与观测精度匹配等的关系。文中还给出了必要观测分量的几何意义。     

咸潮入侵对长江河口地区地下水质的影响

长江河口咸潮入侵对上海市自来水源水水质带来不良影响,从而殃及水厂产水质量而不利于生产和市民健康,这在上海市宝山区表现尤为显著。然而,宝山区地下承压含水层水质优良,资源丰富,且水质稳定,不受咸潮入侵影响。经研究,在不产生地面沉降危害等前提条件下,宝山区尚可扩采500万米~3/年优质地下水。     

Advances in terrestrial system research in China

Land surface is of spatial-temporal heterogeneity. Terrestrial system (TS) comprehensively studies on land surface and physical regionalization objectively describes geographical zonation of the system. China has a vast area with apparent spatial variations in resources and environmental conditions, which highly influence on socio-economic development. In this paper, progress of the TS studies in China is overviewed and research priorities in the near future are prospected. Since the 1950s, China has paid great attention to the TS study as its socio-economic development, and conducted research on physical geographical regionalization, eco-geographical regionalization and comprehensive regionalization. Along with the deepening of global change research, dynamics of TS have been highly concerned. During the studies, methodology has been developed from qualitative research of integration of experts’ brainpower gradually to quantitative research based on field observation and experiments of the natural processes, including physical, chemical and biological processes, as well as application of information technology and mathematical simulation. In the near future, TS would combine with the ideology, objectives and key researches of Future Earth program, to focus on the mechanism and regional effects of interaction among land surface elements, the response of TS to global change, the quantitative recognition on regional unit boundary, and the application to TS in sustainable socio-economic development.     

Characteristics of Carbonate Reservoir and Its Forming Conditions in Continental Lake Basin of China

For decades of exploration, geologists have made great achievements in the exploration of lacustrine carbonate rocks. By dissecting four typical cases of lacustrine carbonate rocks, such as Lucaogou Formation of Permian in Junggar Basin, Da'anzhai Section of Jurassic in Sichuan Basin, Cretaceous in Yin'e Basin and Oligocene in Qaidam Basin, the reservoir characteristics, hydrocarbon generating capacity and reservoir forming model of source rocks were analyzed. The results show that: \mathrm{①} Lacustrine carbonate reservoirs are generally dense, with nano-micron reservoir space as the main reservoir space, including dolomite intergranular pore, organism cavity and accumulation pore, micro-fracture system and its corrosion expansion pore. Saline environment is beneficial to dolomitization and can improve the reservoir capacity of lacustrine carbonate rocks, but most of the permeability is less than 0.1 mD. \mathrm{②} Lacustrine carbonate rocks have not only reservoir capacity, but also can be used as source rocks. The abundance of organic matter is not high and the maturity is generally low. However, dispersed soluble organic matter in source rocks can generate and expel hydrocarbons in large quantities at low maturity stage, which has high liquid hydrocarbon yield. \mathrm{③} Oil and gas reservoirs are characterized by "high initial production, large reduction of production and long-term low and stable production", and are typical "fracture-pore" reservoirs. Fracture networks provide migration pathways in the process of primary migration and accumulation of oil and gas in geological history and oil and gas exploitation nowadays. \mathrm{④} Oil and gas reservoirs are "continuous" unconventional reservoirs, which often form regional oil and gas field groups together with conventional reservoirs in adjacent areas. The research results lay a theoretical foundation for re-evaluating the exploration potential of lacustrine carbonate rocks.     

Temporal and spatial changes of blue water and green water in the Taihang Mountain Region,China, in the past 60 years

ABSTRACT

Appropriate allocation of limited freshwater resources to humans and ecosystems is an important issue hampering sustainable development in mountainous regions. The Taihang Mountain Region (TMR), including the Yellow and Hai river basins, is an important water source area for the North China Plain. The distributed hydrological model Water and Energy transfer Processes in Large river basins (WEP-L) was used to simulate the water cycle processes and to summarize the temporal and spatial changes in the blue and green water in the TMR from 1956 to 2015. The results show that in the period 2011–2015 the annual average blue water decreased by 7.31 × 10⁹ m³, while the annual average green water increased by 13.60 × 10⁹ m³ compared to 1956–1960. At the inter-annual time scale, the blue water exhibited a downward trend while the green water exhibited an upward trend. The amount of seasonal blue water in the TMR is ranked in descending order: summer, autumn, spring and winter, while for green water, the rank is summer, spring, autumn and winter. The amounts of blue and green water are higher on the windward than on the leeward slopes. The blue water yield is generally higher in forests and grasslands than in farmland, while the green water exhibits the opposite response. A greater emphasis should be placed on the widening gap between blue water and green water due to climate warming, and on soil and water conservation measures.     

‘Qianzhong Uplift’ and evolution of the Late Paleozoic palaeogeography and its control on formation of bauxite in Guizhou Province

The Early Paleozoic regional uplift(e.g.,the Qianzhong Uplift)and sea-level changes had obviously controlled the evolution of the Late Paleozoic palaeogeography and paleogeomorphology in Guizhou Province. However,the formation time and evolution of the Qianzhong Uplift is still in debate,which limits the understanding of the Permo-Carboniferous paleogeographic and paleogeomorphologic evolution that formed bauxite in Guizhou. In this paper,based on field surveys and data collection,we established the palaeogeography of several important geological periods from the Late Cambrian to Permian in Guizhou,and re-recognized the formation time and evolution of the Qianzhong Uplift,and revealed the coupling relationship between the Qianzhong Uplift and Guizhou bauxite formation. During the Cambrian to early-middle Early Silurian,the continent-marine transitional facies were missed in the northern margin of the Qianzhong Uplift,central Guizhou Province,such as Bijie,Jinsha and Zunyi. The large-scale uplift of the central Guizhou Province should begin with the tidal flat deposits of the Hanchiatien Formation in the Early Silurian. Because of the Qianzhong Uplift,the central Guizhou and Zunyi areas experienced long-lasting and intense weathering and erosion,forming karst depressions,funnels,and canyons in the Early Carboniferous. The karst landform provided material conditions and location for the formation of bauxite deposits in the Early Carboniferous. The bauxite ore formed under intense chemical wreathing and leaching induced by the glacio-eustasy and paleoclimate fluctuations. The early long-lasting and intense weathering and erosion occurred in the northern Guizhou along with the Permo-Carboniferous glacio-eustasy,had leaded to the formation of coastal wetland and depressions,which were favorable places for the Early Permian bauxite formation. The Early Permian bauxite ores in Guizhou Province have an obvious coupling relationship with the Late Paleozoic Ice Age.     

上海市近15 a大气稳定度和混合层厚度的研究

利用了上海市1990~2004年逐日4个时次的气象资料,运用修正的Pasquill稳定度分类方法和国家标准GB/T13201-91规定的混合层厚度的计算方法计算得出了逐日四个时次的稳定度等级和混合层的厚度,分析了各类稳定度频率和混合层厚度的逐年、逐月和不同时次的变化规律。结果表明:云量对该地区大气稳定度的影响较大;风速对该地区混合层厚度影响较大。