首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   133篇
  免费   35篇
  国内免费   30篇
测绘学   2篇
大气科学   10篇
地球物理   41篇
地质学   98篇
海洋学   8篇
天文学   9篇
综合类   12篇
自然地理   18篇
  2023年   2篇
  2022年   5篇
  2021年   11篇
  2020年   6篇
  2019年   4篇
  2018年   8篇
  2017年   4篇
  2016年   9篇
  2015年   3篇
  2014年   7篇
  2013年   15篇
  2012年   7篇
  2011年   14篇
  2010年   6篇
  2009年   10篇
  2008年   7篇
  2007年   1篇
  2006年   6篇
  2005年   7篇
  2004年   3篇
  2003年   2篇
  2002年   2篇
  2001年   3篇
  2000年   7篇
  1999年   5篇
  1998年   1篇
  1997年   7篇
  1996年   7篇
  1995年   3篇
  1994年   7篇
  1993年   2篇
  1992年   1篇
  1991年   4篇
  1990年   4篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1978年   4篇
排序方式: 共有198条查询结果,搜索用时 15 毫秒
1.
临沂市地处鲁西隆起南部,地热资源丰富。该文介绍了临沂市的地层、岩浆岩、构造、地热背景、主要控热断裂及20余眼温泉(井)的情况和分布。通过分析汤头温泉、白塔地热井、汤坊崖地热井、铜井地热井、松山地热井、新村地热井、西高都地热井等主要温泉(井)的控热断裂、成热机制,认为该区地热主要分布在沂沭断裂带与NW向深大断裂交会处,地下水补给多沿NW—SE断裂,热源以深大断裂沟通深部热源,水温、水量较好地热井均处在沂沭断裂带沂水-汤头断裂以西的、控热断裂为张性断裂或的张扭性断裂凹陷区内。结合临沂市区域地质构造特点,认为蒙山断裂与鄌郚-葛沟断裂深部交会处,尼山断裂、峄城断裂与鄌郚-葛沟断裂交会处为地热勘探靶区。  相似文献   
2.
《China Geology》2018,1(3):331-345
The Gonghe Basin, a Cenozoic down-warped basin, is located in the northeastern part of the Qinghai-Xizang (Tibetan) Plateau, and spread over important nodes of the transfer of multiple blocks in the central orogenic belt in the NWW direction. It is also called “Qin Kun Fork” and “Gonghe Gap”. The basin has a high heat flow value and obvious thermal anomaly. The geothermal resources are mainly hot dry rock and underground hot water. In recent years, the mechanism of geothermal formation within the basin has been controversial. On the basis of understanding the knowledge of predecessors, this paper proposes the geothermal formation mechanism of the “heat source–heat transfer–heat reservoir and caprock–thermal system” of the Gonghe Basin from the perspective of a geological background through data integration-integrated research-expert, discussion-graph, compilation-field verification and other processes: (1) Heat source: geophysical exploration and radioisotope calculations show that the heat source of heat in the basin has both the contribution of mantle and the participation of the earth’s crust, but mainly the contribution of the deep mantle. (2) Heat transfer: The petrological properties of the basin and the exposed structure position of the surface hot springs show that one transfer mode is the material of the mantle source upwells and invades from the bottom, directly injecting heat; the other is that the deep fault conducts the deep heat of the basin to the middle and lower parts of the earth’s crust, then the secondary fracture transfers the heat to the shallow part. (3) Heat reservoir and caprock: First, the convective strip-shaped heat reservoir exposed by the hot springs on the peripheral fault zone of the basin; second, the underlying hot dry rock layered heat reservoir and the upper new generation heat reservoir and caprock in the basin revealed by drilling data. (4) Thermal system: Based on the characteristics of the “heat source-heat transfer-heat reservoir and caprock”, it is preliminarily believed that the Gonghe Basin belongs to the non-magmatic heat source hydrothermal geothermal system (type II21) and the dry heat geothermal system (type II22). Its favorable structural position and special geological evolutionary history have given birth to a unique environment for the formation of the geothermal system. There may be a cumulative effect of heat accumulation in the eastern part of the basin, which is expected to become a favorable exploration area for hot dry rocks.  相似文献   
3.
利用离子色谱法对水中常见的7种阴离子进行定性和定量的分析,在既定的条件下,分别建立校正曲线法(外标法)及单点校正法模板,并对温泉水样校正分析。结果显示,外标法测得离子数据较为平稳,相对偏差均小于5%,适用于观测温泉水中其含量的变化。  相似文献   
4.
The Central Asian Orogenic Belt (CAOB) was produced as a consequence of the successive closure of the Paleoasian Ocean and the accretion of structures formed within it (island arcs, oceanic islands, and backarc basins) to the Siberian continent. The belt started developing in the latest Late Neoproterozoic, and this process terminated in the latest Permian in response to the collision of the Siberian and North China continents that resulted in closure of the Paleoasian ocean (Metcalfe, 2006; Li et al., 2014; Liu et al., 2009; Xiao et al., 2010; Didenko et al., 2010). Throughout the whole evolutionary history of this Orogenic Belt, a leading role in its evolution was played by convergent processes. Along with these processes, an important contribution to the evolution of the composition and structure of the crust in the belt was made by deep geodynamic processes related to the activity of mantle plumes.Indicator complexes of the activity of mantle plumes are identified, and their major distribution patterns in CAOB structures are determined. A number of epochs and areas of intraplate magmatism are distinguished, including the Neoproterozoic one (Rodinia breakup and the origin of alkaline rock belt in the marginal part of the Siberian craton); Neoproterozoic–Early Cambrian (origin of oceanic islands in the Paleoasian Ocean); Late Cambrian–Early Ordovician (origin of LIP within the region of Early Caledonian structures in CAOB); Middle Paleozoic (origin of LIP in the Altai–Sayan rift system); Late Paleozoic–Early Mesozoic (origin of the Tarim flood-basalt province, Central Asian rift system, and a number of related zonal magmatic areas); Late Mesozoic–Cenozoic (origin of continental volcanic areas in Central Asia).Geochemical and isotopic characteristics are determined for magmatic complexes that are indicator complexes for areas of intraplate magmatism of various age, and their major evolutionary trends are discussed. Available data indicate that mantle plumes practically did not cease to affect crustal growth and transformations in CAOB in relation to the migration of the Siberian continent throughout the whole time span when the belt was formed above a cluster of hotspots, which is compared with the African superplume.  相似文献   
5.
内蒙古巴彦浩特盆地广泛发育上石炭统太原组煤系烃源岩.在野外地质勘查、典型剖面实测、样品采集及实验分析基础上,开展了有机质丰度、有机质类型、有机质成熟度等有机地球化学特征分析与研究,初步对其生烃潜力进行评价.结果表明:太原组烃源岩有机质丰度高,热演化程度属于成熟—高成熟演化阶段,具备较好的页岩气气源条件.通过多因素叠加分析的方法,圈定了页岩气成藏有利区3处,分别是北部的查干布拉格有利区、通古勒格淖尔嘎查-伊克尔嘎查苏木有利区和南部的下河沿-营盘水有利区.  相似文献   
6.
青海共和盆地位于青藏高原东北缘,以往有关共和盆地及邻区早-中三叠世岩浆岩成因机制的认识分歧较大,且研究主要集中在露头岩石方面。本文以共和盆地干热岩GR1井深部花岗岩岩芯样品作为研究对象,对其进行岩石学、长石电子探针、主微量元素地球化学、锆石U-Pb年代学及Lu-Hf同位素研究。矿物组成及长石电子探针测试结果显示花岗岩主要为奥长花岗岩、英云闪长岩及花岗闪长岩。锆石U-Pb测年结果表明,奥长花岗岩的结晶年龄为236.5±1.7Ma,英云闪长岩的岩浆结晶年龄为241.6±3.0Ma。主、微量元素地球化学显示这些花岗岩主要为准铝质,属于高钾钙碱性系列。全岩Ta-Nb-Hf等不相容元素图解及锆石Hf同位素数据表明共和盆地的236.5~241.6Ma花岗岩显示火山弧及同碰撞花岗岩成分特征,说明中三叠世共和地区发生俯冲-碰撞转换。结合本文数据与区域背景资料,作者认为:共和盆地早-中三叠世花岗岩组合的形成与印支期宗务隆洋的南向俯冲作用密切相关,此时,在宗务隆-青海南山-西秦岭北缘存在统一的大陆边缘弧环境;在236~241Ma时发生俯冲-碰撞转换;晚三叠世时宗务隆-青海南山-西秦岭北缘已处于碰撞期和后碰撞期。  相似文献   
7.
本文利用1961~2014年哈密国家基准气象观测站5~9月逐日最高气温、极端最高气温和NCEP1°×1°再分析资料,统计分析哈密市高温天气的气候特征及其环流特征。结果表明:(1)哈密市高温天气具有明显的时间变化特点,1961~1993年是偏少期,1994年以后明显偏多,而近14a是呈直线上升的趋势,这与全球气候变暖趋势一致。(2)哈密市近54a年平均高温日数是35d,主要集中在6~8月,7月最多。(3)高温日数具有明显的年际变化,最多为2002年出现60d,最少为1993年仅出现了11d。(4)新疆脊、伊朗副热带高压与西太平洋副热带高压的强弱和位置与高温天气有很好的对应关系;哈密出现持续性高温天气过程在500hPa高度场主要表现为三类环流类型:西太副高西伸发展型、伊朗副高东伸发展型、西太副高西伸发展与伊朗副高东伸发展共同作用型。  相似文献   
8.
Field, hand specimen, and microscopic investigations alongside X-ray diffraction analyses revealed four types of hydrothermal alteration (Type-A, -B, -C, and -D) based on the mode of occurrence of altered rocks and alteration mineral assemblage at Hakusui-kyo and Horai-kyo along the Arima-Takatsuki Tectonic Line (ATTL) in western Japan. Type-A alteration locally occurred as gray alteration halos with sulfide minerals. Type-B and -C alterations were confined to fault gouge veins and occurred as greenish-gray veins and brown veins, respectively. Type-C alteration crosscut Type-B alteration. These alterations were associated with a number of granitic fragments including cohesive breccia and micrographic facies. Type-D alteration occurred locally in brown sediments. Different mineralogical features in the four alterations are summarized as (Type-A) illite; (Type-B) chlorite; (Type-C) limonite (Fe3+ hydroxides and goethite) and calcite; and (Type-D) limonite. We propose that the alterations can be broadly divided into Paleocene hydrothermal alteration (Type-A) and post-Late Miocene hydrothermal alteration (Type-B, -C, and -D): Type-A alteration occurred at approximately 200 °C during hydrothermal activity after a granitic intrusion in Late Cretaceous; Type-B, -C and -D alterations occurred under hydrothermal activity accompanying deep fluids with repeated ascents invoked by the seismicity of the ATTL after the Late Miocene. The fluids may have been the “Arima-type thermal waters” (i.e., mixtures of convective groundwater and Na-Ca-Cl-HCO3-type fluids). Type-B alteration occurred in fractures at depths where the temperature was ≥150 °C. Type-C alteration overprinted Type-B alteration as a result of mixing of new deep fluids and descending oxidized meteoric water near the surface. Fe3+ hydroxides and calcite precipitated from the fluids due to the oxidation of Fe2+ and the degassing of CO2, respectively, at ambient to near-boiling temperatures. When the ascending fluids gushed out from the fractures, they generated Type-D alteration at the surface under similar temperature conditions due to the oxidation of Fe2+.  相似文献   
9.
根据河套盆地周缘断裂带泉水的氢、氧同位素组成和水化学组分,讨论了该区地下水的化学类型、成因及其与地震活动的关系。于2014年9月下旬和2015年4月15日MS5.8阿左旗地震震后在河套盆地周缘的乌拉山断裂带、色尔腾断裂带、狼山断裂带以及桌子山断裂带采集了17个泉水和井水样品,测得水样的TDS分布在143.8~42 553.0mg/L范围内,δD和δ18O值分别在-83.6‰~66.56‰和-11.16‰~8.2‰的范围内,来源为大气降水。根据舒卡列夫分类法,震前水样可划分为13种水化学类型,震后西山咀、圐圙朴隆等5个点采样点泉水的水化学类型发生变化。其中,乌拉山断裂带的水样以HCO3-Ca型低矿化度地表水为主;色尔腾断裂带、狼山断裂带泉水受白垩系含水层影响,矿化度较高,富含HCO-3及SO2-4;桌子山一带受煤矿开采影响,水样以富SO2-4和Cl-的高矿化度水为特征。地震前后TDS、阴、阳离子以及γNa/γCl、γ(SO4+Cl)/γHCO3、γHCO3/γCl等毫克当量比值能够较好地反映地震。2015年4月15日阿左旗MS5.8地震后,呼鲁斯太、迪延阿贵庙及八一井的水化学组成变化较大,对地震响应较为敏感。呼鲁斯太地区泉水的TDS稍有降低,但HCO-3在阴离子中所占比例有所增加,表明震后该地区含水层的泉水与较低矿化度的含碳酸盐岩含水层水发生了混合;八一井的TDS值有所增加,γNa/γCl比值有所降低,表明深部高矿化度水的混入;迪延阿贵庙水样的TDS稍有下降,但NaCl的相对含量较震前有所升高,表明有低矿化度NaCl水的混入。本工作不仅确定了该区水文地球化学背景,而且对地震监测和预测具有一定参考价值。  相似文献   
10.
腾冲新生代火山区温泉CO2气体排放通量研究   总被引:6,自引:6,他引:0  
近期研究表明,不仅火山喷发期会向当时的大气圈输送大量的温室气体,火山间歇期同样会释放大量的温室气体。在火山活动间歇期,火山区主要以喷气孔、温(热)泉以及土壤微渗漏等形式向大气圈释放温室气体。腾冲是我国重要的新生代火山区,同时也是重要的水热活动区,那里出露大量的温泉,然而目前未见腾冲火山区温泉气体排放通量的研究报道。本文利用数字皂膜通量仪测量了腾冲新生代火山区温泉中CO2的排放通量。研究结果表明,腾冲新生代火山区温泉向当今大气圈输送的CO2通量达3.58×103 t·a-1,相当于意大利锡耶纳Bassoleto地热区温泉中CO2的排放规模。腾冲火山区温泉的CO2释放通量主要受深部岩浆囊、断裂分布、地下水循环、围岩成分等多方面因素的影响。本文根据温泉中CO2的排放特征,将腾冲温泉分为南北两区,南区温泉CO2通量远高于北区的温泉,热海地热区的通量为腾冲CO2通量的最大值。在北温泉区,CO2通量主要受控于断裂的分布;而在南温泉区,除受到断裂控制外,热海地热区底部的岩浆囊及其与围岩的相互作用成为CO2气体的重要物质来源,同时高温的岩浆囊为温泉及CO2的形成提供了重要热源。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号