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排序方式: 共有803条查询结果,搜索用时 562 毫秒
101.
长江水下三角洲层序地层学研究有助于全面了解长江三角洲地层特征和沉积环境演化模式。通过对长江水下三角洲下切河谷区YD0901和YD0903孔岩心的详细沉积物粒度、特征元素比值(Cl/Ti和Zr/Rb)、沉积相对比分析,恢复了冰后期以来长江水下三角洲层序地层格架。研究区冰后期以来自下而上依次出现河流相、潮汐河流相、河口湾相、浅海相和三角洲相的沉积相序。末次冰期海平面下降,古长江形成下切河谷,古河间地发育硬黏土层,构成五级Ⅰ型层序界面。之后海平面回升,分别于15 cal ka BP和8.0 cal ka BP形成最大海退和最大海侵界面,水下三角洲区域最大海侵发生时间略滞后于平原区,约为7.5 cal ka BP。据此3个层序界面将冰后期地层划分为低位体系域、海侵体系域和高位体系域。钻孔岩心记录揭示了14.8 cal ka BP海侵到达研究区;14.8~13 cal ka BP期间,受MWP-1A冰融水事件影响海平面快速上升,海岸线向陆推进速率可达71.9,km/ka;海退期间各钻孔沉积速率较低,直至2 cal ka BP开始,沉积速率明显增加。 相似文献
102.
作为近年来新兴的实验技术,二元同位素(D47)测温技术已被应用于碳酸盐岩成岩环境的研究中。简要介绍了二元同位素测温技术的原理及应用方法,并以塔里木盆地中下寒武统白云岩为例,优选11块样品,测试其D47值和白云石的碳氧同位素,并计算出样品的成岩温度和古流体的δ~(18)O值。综合分析认为:样品中,颗粒白云岩形成于低温准同生—浅埋藏环境,成岩流体为海水;细晶白云岩为深埋藏成岩环境中原岩受到了高温重结晶作用的改造,成岩流体为地下热卤水;孔缝中的白云石胶结物是深埋藏成岩环境富镁热卤水沉淀作用的产物。研究证明二元同位素测温技术可以较好地恢复白云岩的成岩温度,减少储层成因的多解性,它为今后储层成因研究提供了一种新的手段和依据。 相似文献
103.
Huaizhan Li Guangli Guo Jianfeng Zha Yan He Zhiyong Wang Shuangyu Qin 《Environmental Earth Sciences》2017,76(20):704
We studied an underground coal gasification technique using strip mining-face mining gasifier controlled retraction injection technology (SMFM). This green mining approach offers several advantages over conventional strip mining but the stress distribution and stability of SMFM operations remain largely untested. In particular, hyperbolic coking pillars are used in SMFM compared with rectangular pillars used in traditional strip mining, which can influence the ultimate bearing capacity and stability. We use numerical simulations to investigate the influence of different factors (arch height, pillar height and width, mechanical characteristics), under the coupling effect of high temperature, on the ultimate bearing capacity of hyperbolic pillars. Our results indicate that arch height has a strong influence on pillar stress, while changes in pillar width and height are less significant. A stability evaluation method is proposed and tested on a case study in Inner Mongolia. Our theoretical results have practical significance for the promotion and application of SMFM. 相似文献
104.
北京市服务业碳排放增长的分解分析 总被引:1,自引:0,他引:1
The output as well as carbon dioxide emissions of tertiary industry have increased continuously in Beijing. Therefore, the tertiary industry has become a new field that needs to be explored for energy saving and emission reduction. This paper calculates the direct and indirect carbon dioxide emissions of tertiary industry in Beijing from 2005 to 2012 using the input-output analysis method. The results indicate that both the direct and indirect carbon dioxide emissions increased continuously and the latter grew more quickly than the former. The growth of the direct and indirect carbon dioxide emissions of tertiary industry was decomposed, which showed that four factors influence the growth of carbon emission of the tertiary industry, including the changes of industrial scale, industrial structure, energy consumption intensity and carbon coefficient. The results show that the industrial scale advancement and the direct energy carbon coefficient change promote the increase of direct carbon dioxide emissions, while the shift of industrial structure and the change of direct energy consumption intensity have the restrain on it. The industrial scale enlargement, industrial structure shift and the indirect energy carbon emission coefficient change promote the growth of indirect carbon dioxide emissions, while the indirect energy consumption intensity change has a restrain. 相似文献
105.
根据跨山西断陷带的水准剖面观测资料,计算其垂直形变量和垂直形变速率,研究其现今垂直活动性。2006年以来的垂直形变揭示,山西断陷带东北段延怀盆地和蔚县盆地呈掀斜上升活动,北段阳原盆地和大同盆地以下降活动为主,晋中盆地为上下波动,临汾盆地呈现上升活动。2013年山西断陷带活动出现转折性变化,蔚县盆地大幅度下降,大同盆地、代县-定襄盆地、晋中盆地和临汾盆地均呈现不同程度的上升。 相似文献
106.
107.
孔隙衬里绿泥石的成因及对储层性能的影响 总被引:1,自引:0,他引:1
孔隙衬里绿泥石发育的砂岩大多属于优质储层,前人将其归功于绿泥石对孔隙的保护作用。按照孔隙衬里绿泥石形成的铁质来源,可划分为同沉积黏土膜转化型、富铁镁物质溶蚀再结晶型和转化与直接结晶混合型3种类型。通过国内外富孔隙衬里绿泥石砂岩实例的对比研究表明,孔隙衬里绿泥石可以通过抑制自生石英生长、提高抗压实能力、指示早期碱性溶蚀发育程度和堵塞孔喉等4种方式影响储层性能,且不同成因的孔隙衬里绿泥石对储层性能影响方式不同,同一成因绿泥石在不同成岩阶段的影响方式也不同。中成岩A期以前,转化型孔隙衬里绿泥石通过占据孔喉和提高抗压能力影响储层,而溶蚀结晶型孔隙衬里绿泥石主要指示火山物质发生碱性溶蚀的程度;只有砂岩成岩阶段达到中成岩B期以后,孔隙衬里绿泥石对石英生长的抑制作用才得到充分体现。 相似文献
108.
西藏安多剖面沉积物粒度特征及环境意义 总被引:3,自引:1,他引:2
对西藏安多剖面的3个层位沉积物与两个现代流动沙丘表层沉积物粒度组成、传统粒度参数及体积分维值进行了对比分析,探讨其粒度特征以及环境指示意义。结果表明:安多剖面的3层代表了3个不同的气候阶段,第一层(0~172 cm)沉积动力为风,其中在0.44~1.08 m深度处是一次风力加强的阶段,第二层(172~224 cm)、第三层(224~232 cm)均在6 Φ附近出现次峰,悬浮组分明显增加,推断为远距离输送的粉砂级颗粒沉降,表明这两个阶段风力有所减弱;安多剖面颗粒比研究区现代流动沙丘颗粒细,表明剖面可能为固定或半固定沙丘沉积;本研究区样品的体积分维值在0.215~1.77,虽然没有实际的物理意义,但作为粒度参数指标,在指示环境变化上是有效的,并且与粘粒、粉砂含量呈现明显的正相关关系,与细砂呈现明显的负相关关系。 相似文献
109.
Phylogenetic diversity of planktonic bacteria in the Chukchi Borderland region in summer 总被引:1,自引:1,他引:0
Planktonic bacteria are abundant in the Chukchi Borderland region. However, little is known about their diversity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S and K4S where sea ice was melting obviously. The analysis of water samples with fluorescence in situ hybridization (FISH) showed that DMSP-degrading bacteria accounted for 13% of the total bacteria at the station K2S. No aerobic anoxygenic phototrophic (AAP) bacteria were detected in both samples. The bacterial communities were characterized by two 16S rRNA gene clone libraries. Sequences fell into four major lineages of the domain Bacteria, including Proteobacteria (Alpha, Beta and Gamma subclasses), Bacteroidetes, Actinobacteria and Firmicutes. No significant difference was found between the two clone libraries. SAR11 and Rhodobacteraceae clades of Alphaproteobacteria and Pseudoalteromonas of Gammapro-teobacteria constituted three dominant fractions in the clone libraries. A total of 191 heterotrophic bacterial strains were isolated and 76% showed extracellular proteolytic activity. Phylogenetic analysis reveals that the isolates fell into Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. The most common genus in both the bacterial isolates and protease-producing bacteria was Pseudoalteromonas. UniFrac data showed suggestive differences in bacterial communities between the Chukchi Borderland and the northern Bering Sea. 相似文献
110.