An integrated linear/non-linear flow model for the conduit-fissure-pore media in the karst triple void aquifer system

Most karstic aquifer media may be characterized as the triple-void media with highly-varied hydraulic properties, including matrix pore, fissure and conduit, in which liner flow may co-exist with non-linear flow. In this paper, an attempt is made to couple linear flow with non-linear flow in a single unified flow governing equations by introducing the concept of equivalent hydraulic conductivity (EHC) and deriving a general Darcys law for various flow. The expression of EHC in the karst conduit and fissure are also derived. The procedures of numerical implementation are demonstrated via an ideal model and a case study of karst aquifer system in the Beishan Ore Formation area, Guangxi Autonomous Region, China.     

Maps and Spaces

Two quite different concepts of space are important in geography and environmental psychology. One is the concept of macro-environment, of space as geographical scale. The other is the concept of form-at-a-timeless-instant: of naive geometry. Confusing these two concepts leads to serious errors. This paper examines some methodological and philosophical sources of this confusion, and points to a number of research problems in geography and psychology that can benefit from an untangling of the two concepts of space. One such problem is the need to understand the development of mapping abilities in very young children. Another is the larger question of building a body of theory to explain the development of macro-environmental cognition and behavior.     

乌鲁木齐城市地域结构问题初探

对乌鲁木齐城市地域结构各种特征的分析,发现此城市地域具有的历史和民族特征及其现代城市特征,并针对乌鲁木齐城市地域结构和发展中出现的问题提出若干解决对策。     

Morphometry and distribution of isolated caves as a guide for phreatic and confined paleohydrological conditions

Isolated caves are a special cave type common in most karst terrains, formed by prolonged slow water flow where aggressivity is locally boosted. The morphometry and distribution of isolated caves are used here to reconstruct the paleohydrology of a karstic mountain range. Within a homogenous karstic rock sequence, two main types of isolated caves are distinguished, and each is associated with a special hydrogeologic setting: maze caves form by rising water in the confined zone of the aquifer, under the Mt. Scopus Group (Israel) confinement, while chamber caves are formed in phreatic conditions, apparently by lateral flow mixing with a vadose input from above.     

乌江磷浓度与通量变化及来源解析

磷(P)是长江流域备受关注的污染物。乌江是长江八大支流之一,位于三峡水库近库尾江段。武隆断面是乌江入长江控制断面。对1998—2019时期武隆断面径流量、悬浮泥沙浓度(SS)与输沙量、磷浓度与通量(包括总磷(TP)、溶解态磷(DP)和颗粒态磷(PP))年际变化及季节特征进行研究,并基于河流基流分割原理对磷的来源进行了解析。结果表明,(1)1998—2019年,乌江武隆断面径流量在一定幅度内上下波动,而悬浮泥沙浓度和输沙量下降剧烈。(2)22年来,乌江TP和DP浓度与通量总体上呈先升高后下降的趋势,2009—2013年为磷污染峰值期,TP和DP浓度与通量远高于其它时期。(3)2007年是一个重要的时间节点,该节点前,TP的赋存形态以颗粒态为主,颗粒态磷在总磷中的占比均值为65%;该节点后,TP的赋存形态转变为以溶解态为主,颗粒态磷占比均值下降为16%,相应地,溶解态磷占比由35%上升为84%。水沙条件改变是磷形态发生显著变化的主要驱动力,磷污染程度亦是磷形态变化的重要影响因素。(4)磷通量在年内的季节分布发生了显著变化,丰水期磷通量减少,枯水期磷通量增加。(5)1998—2012、2009—2013和2014—2019年3个时期点源负荷占比分别为23.5%、36.8%和62.1%,呈增加趋势。(6)建议制定适宜的总磷控制目标,结合目前所存在的磷污染风险点,进一步强化监管,侧重源头治理。     

渤中凹陷CFD18-2油田高岭石胶结作用及其对储层物性的影响

为探究成岩作用过程中所形成的次生黏土矿物对储层物性的影响,借助偏光显微镜及扫描电镜的镜下分析,并结合储层物性等数据,对渤中凹陷附近沙垒田凸起东南部CFD18-2油田东三段高岭石的特征、类型、成因及其对储层物性的影响进行了研究。研究结果表明：1）研究区高岭石为有机酸溶蚀长石形成的自生高岭石,呈现典型的"手风琴状"及"蠕虫状",常充填于粒间孔、长石次生溶孔及碳酸盐胶结物溶孔中并形成良好的晶间孔隙。2）研究区主要发育两期高岭石,第一期主要充填于早期碳酸盐胶结物溶孔中,呈微小"蠕虫状";第二期充填于铁方解石与铁白云石胶结物溶孔中,部分高岭石具碱性溶蚀特征,且第二期高岭石与晚期伊利石共生。3）研究区东三段储层具备一定的渗流能力,使长石溶蚀形成的"副产物"被流体带走;但在破坏性成岩作用下,储层渗流能力会逐渐变差,最终使得"副产物"堆积于孔隙,降低储层物性。4）高岭石及同期硅质胶结物对储层物性的影响是一把"双刃剑",当高岭石及硅质的体积分数低于6.81%时,长石溶蚀有利于改善储层物性;当高岭石及硅质的体积分数高于6.81%时,则不利于储层物性的改善。     

大水金矿床金的迁移形式和沉淀机制探讨

基于大水金矿床地质特征和矿物流体包裹体显微测温研究成果,对金在成矿过程中的迁移形式和沉淀机制进行了探讨。研究认为,金矿床在主成矿作用过程中金主要以AuC12-、Au(HS)2-、AuH3SiO40形式迁移,少量以硫络合物、硫氢络合物、胶体溶液、砷络合物(配合物)及地幔流体等形式迁移。推断水—岩反应(尤其是硅化和硫化作用)和以深部流体为主与古大气水的均一化流体的混合作用以及在此过程中的降温减压作用是金沉淀的重要机制。     

用图形演绎C程序运行的研究

说明了用图形方式展现C程序运行情况的必要性和可行性;介绍了用图形演绎C程序运行的总设计思想;详细介绍了图形界面设计要求和程序模块的功能要求。     

Marine cements in mid-Tertiary cool-water shelf limestones of New Zealand and southern Australia

Large areas of southern Australia and New Zealand are covered by mid‐Tertiary limestones formed in cool‐water, shelf environments. The generally destructive character of sea‐floor diagenesis in such settings precludes ubiquitous inorganic precipitation of carbonates, yet these limestones include occasional units with marine cements: (1) within rare in situ biomounds; (2) within some stacked, cross‐bedded sand bodies; (3) at the top of metre‐scale, subtidal, carbonate cycles; and (4) most commonly, associated with certain unconformities. The marine cements are dominated by isopachous rinds of fibrous to bladed spar, interstitial homogeneous micrite and interstitial micropeloidal micrite, often precipitated sequentially in that order. Internal sedimentation of microbioclastic micrite may occur at any stage. The paradox of marine‐cemented limestone units in an overall destructive cool‐water diagenetic regime may be explained by the precipitation of cement as intermediate Mg‐calcite from marine waters undersaturated with respect to aragonite. In some of the marine‐cemented limestones, aragonite biomoulds may include marine cement/sediment internally, suggesting that dissolution of aragonite can at times be wholly marine and not always involve meteoric influences. We suggest that marine cementation occurred preferentially, but not exclusively, during periods of relatively lowered sea level, probably glacio‐eustatically driven in the mid‐Tertiary. At times of reduced sea level, there was a relative increase in both the temperature and the carbonate saturation state of the shelf waters, and the locus of carbonate sedimentation shifted towards formerly deeper shelf sites, which now experienced increased swell wave and/or tidal energy levels, fostering sediment abrasion and reworking, reduced sedimentation rates and freer exchange of sediment pore‐waters. Energy levels were probably also enhanced by increased upwelling of cold, deep waters onto the Southern Ocean margins of the Australasian carbonate platforms, where water‐mass mixing, warming and loss of CO₂ locally maintained critical levels of carbonate saturation for sea‐floor cement precipitation and promoted the phosphate‐glauconite mineralization associated with some of the marine‐cemented limestone units.     

广州市社会空间景观形态演化初探

相对于形体空间而言 ,社会空间是一个更深层面的城市空间领域 ,在城市形体空间日新月异的嬗变中 ,社会空间内涵的演化显得更为缓慢和深刻。以广州市为例 ,探讨这种景观形态演化的特性及其对现代城市形象建设和个性塑造的意义。