阿坝-简阳地学剖面深部温度及热结构   总被引：3，自引：0，他引：3       下载免费PDF全文

徐明  朱传庆  饶松  胡圣标 《地质科学》2011,46(1):203-212

在青藏高原东部到四川盆地这两个构造单元进行了稳态钻孔温度测量和岩石热导率测试,确定了相应钻孔的大地热流数据.应用这些可靠的热流数据,对横穿这两个构造单元的阿坝-简阳地学断面进行了2-D温度场研究,获得其深部热结构的认识.模拟结果显示,松潘-甘孜地块地表为高热流区域,达到80～110 mW/m2,四川盆地地表为中低热流区...  相似文献   

黑河流域生态水文样带调查   总被引：1，自引：0，他引：1  

冯起  苏永红  司建华  常宗强  席海洋  郭瑞  陈丽娟  霍红  秦燕燕 《地球科学进展》2013,28(2):187-196

样带研究是研究全球变化与陆地生态系统关系最有效的途径之一。通过在黑河流域上、中、下游分别确定具有代表性的流域样带和空间网格,系统调查植被、土壤、水文、地貌和气候特征及人类活动和社会经济特征,建立相应的数据库。完善流域整体概念的野外观测试验研究网络,形成以流域为单元、科学问题为导向的生态—水文过程的数据—模拟研究平台,使我国流域生态水文研究进入国际先进行列。  相似文献   

基于CASS的土石方多种计算方法与比较   总被引：1，自引：0，他引：1  

李建飞  秦岩宾  齐中举 《测绘工程》2012,21(3):78-80

对传统常规计算土方量的具体方法、算法原理、应用范围、计算步骤等进行对比分析,对其注意问题进行探讨,研究并总结常规方法的优缺点.  相似文献   

川渝地区气温随地形、经度和纬度的变化(英文)   总被引：4，自引：1，他引：3  

邵景安  李阳兵  倪九派 《地理学报(英文版)》2012,22(2):223-244

Using the daily temperature data of 95 meteorological stations from Si-chuan-Chongqing Region and its surrounding areas, this paper adopted these methods (e.g., linear regression, trend coefficient, geographical statistics, gray relational analysis and spatial analysis functions of GIS) to analyze the relations of temperature variability with topography, latitude and longitude. Moreover, the rank of gray correlation between temperature variability and elevation, longitude, latitude, topographic position and surface roughness also was measured. These results indicated: (1) The elevation affected temperature variability most obviously, followed by latitude, and longitude. The slope of the linear regression between temperature change rate and elevation, latitude and longitude was 0.4142, 0.0293 and -0.3270, respectively. (2) The rank of gray correlation between temperature change rate and geographic factors was elevation > latitude > surface roughness > topographic position > longitude. The gray correla-tion degree between temperature change rate and elevation was 0.865, followed by latitude with 0.796, and longitude with 0.671. (3) The rate of temperature change enhanced with the increase of elevation. Especially, the warming trend was significant in the plateau and mountain areas of western Sichuan, and mountain and valley areas of southwestern Sichuan (with the warming rate of 0.74℃/10a during the 1990s). However, there was a weak warming trend in Sichuan Basin and its surrounding low mountain and hilly areas. (4) The effects of latitude on temperature change rate presented the specific regulation, which the warming rate of low-latitude areas was more significant than that of high-latitude areas. However, they were consistent with the regulation that the increasing of low temperature controlled most of the warming trend, due to the effects of terrain and elevation on annual mean temperature. (5) Ba-sically, temperature variability along longitude direction resulted from the regular change of elevation along longitude. It was suggested that, in Sichuan-Chongqing Region, special features of temperature variability largely depended on the terrain complexity (e.g., undulations, mutations and roughness). The elevation level controlled only high or low annual mean temperature and the range of temperature change rate in the macro sense.  相似文献   

Hydrogeochemical study in the Main Ethiopian Rift: new insights to the source and enrichment mechanism of fluoride   总被引：2，自引：0，他引：2  

Tewodros Rango  Gianluca Bianchini  Luigi Beccaluva  Tenalem Ayenew  Nicolò Colombani 《Environmental Geology》2009,58(1):109-118

The central Main Ethiopian Rift suffers a severe water quality problem, characterized by an anomalously high fluoride (F) content that causes an endemic fluorosis disease. The current study, conducted in the Ziway–Shala lakes basin, indicates that the F content exceeds the permissible limit for drinking prescribed by the World Health Organization (WHO; 1.5 mg/l) in many important wells (up to 20 mg/l), with even more extreme F concentration in hot springs and alkaline lakes (up to 97 and 384 mg/l respectively). The groundwater and surface water from the highlands, typically characterized by low total dissolved solids (TDS) and Ca (Mg)–HCO₃ hydrochemical facies, do not show high F content. The subsequent interaction of these waters with the various rocks of the rift valley induces a general increase of the TDS, and a variation of the chemical signature towards Na–HCO₃ compositions, with a parallel enrichment of F. The interacting matrixes are mainly rhyolites consisting of volcanic glass and only rare F-bearing accessory minerals (such as alkali amphibole). Comparing the abundance and the composition of the glassy groundmass with other mineral phases, it appears that the former stores most of the total F budget. This glassy material is extremely reactive, and its weathering products (i.e. fluvio/volcano-lacustrine sediments) further concentrate the fluoride. The interaction of these “weathered/reworked” volcanic products with water and carbon dioxide at high pH causes the release of fluoride into the interacting water. This mainly occurs by a process of base-exchange softening with the neo-formed clay minerals (i.e. Ca–Mg uptake by the aquifer matrix, with release of Na into the groundwater). This is plausibly the main enrichment mechanism that explains the high F content of the local groundwater, as evidenced by positive correlation between F, pH, and Na, and inverse correlation between F and Ca (Mg). Saturation indices (SI) have been calculated (using PHREEQC-2) for the different water groups, highlighting that the studied waters are undersaturated in fluorite. In these conditions, fluoride cannot precipitate as CaF₂, and so mobilizes freely without forming other complexes. These results have important implications for the development of new exploitation strategies and accurate planning of new drilling sites. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

东海重磁地震综合探测剖面研究   总被引：24，自引：8，他引：16       下载免费PDF全文

高德章  赵金海  薄玉玲  唐建  王舜杰 《地球物理学报》2004,47(5):853-861

依据东海南部一条自东海陆架直至菲律宾海盆的重磁地震综合探测剖面,采用地壳结构重磁地震综合反演解释系统开展岩石圈结构的综合研究,制作了岩石圈结构地学断面图. 结果表明基隆凹陷为一中新生代沉积凹陷,沉积厚度达到14km;冲绳海槽盆地为弧后扩张地堑型盆地,地壳厚度仅为14.5km;菲律宾板块沿北西西方向向欧亚板块俯冲,莫霍面急剧下插,导致冲绳海槽的形成与发展;岩石圈厚度约为80km,但在370km处仅为53km,在450km至540km处岩石圈厚度大于100km.  相似文献   

The Jurassic Coast: Geoscience and education – An overview     

Jonathan Larwood 《Proceedings of the Geologists' Association. Geologists' Association》2019,130(3-4):265-273

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Expression of the Toarcian Oceanic Anoxic Event: New insights from a Swiss transect     

Alicia Fantasia  Karl B. Fllmi  Thierry Adatte  Jorge E. Spangenberg  Emanuela Mattioli 《Sedimentology》2019,66(1):262-284

A sedimentological, biostratigraphical and geochemical (stable isotopes and Rock‐Eval parameters) analysis was performed on four Swiss successions, in order to examine the expression of the Toarcian Oceanic Anoxic Event along a north–south transect, from the Jura through the Alpine Tethys (Sub‐Briançonnais and Lombardian basins). The locations were selected to represent a range of palaeoceanographic positions from an epicontinental sea to a more open marine setting. The Toarcian Oceanic Anoxic Event was recognized by the presence of the characteristic negative carbon‐isotope excursion in carbonate (ca 2 to 4‰) and organic matter (ca 4 to 5‰) at the base of the falciferum ammonite Zone (NJT6 nannofossil Zone). The sedimentary expression of the Toarcian Oceanic Anoxic Event varies along the transect from laminated mudstone rich in total organic carbon (≤11 wt.%) in the Jura, to thin‐bedded marl (≤5 wt.% total organic carbon) in the Sub‐Briançonnais Basin and to hemipelagic reddish marly limestone (total organic carbon <0·05 wt.%) in equivalent levels from the Lombardian Basin. The carbon‐isotope excursion is thus independent of facies and palaeoceanographic position. The low nannofossil abundance and the peak in Calyculaceae in the Jura and the Sub‐Briançonnais Basin indicate low salinity surface waters and stratified water masses in general. Sedimentological observations (for example, obliquely‐bedded laminae and homogeneous mud layers containing rip‐up clasts) indicate the presence of dynamic conditions, suggesting that water mass stratification was episodically disrupted during the Toarcian Oceanic Anoxic Event. The proposed correlation highlights a stratigraphic gap and/or condensed interval between the Pliensbachian–Toarcian boundary and the Toarcian Oceanic Anoxic Event interval (most of the tenuicostatum ammonite Zone is missing), which is also observed in coeval European sections and points to the influence of sea‐level change and current dynamics. This transect shows that the sedimentary expression of the Toarcian Oceanic Anoxic Event is not uniform across the Alpine Tethys, supporting the importance of local conditions in determining how this event is recorded across different palaeoceanographic settings.  相似文献   

中国满洲里－绥芬河地学断面地球化学研究     

李双林  迟效国  尹冰川  戚长谋 《矿物岩石地球化学通报》1996,(2)

中国满洲里－绥芬河地学断面地球化学研究李双林，迟效国，尹冰川，戚长谋（中国科学院地球化学研究所贵阳５５０００２）（长春地质学院．长春１３００６１）关键词地学断面，地球化学分区，地球计学分带，构造演化地学断面的地球化学研究的目的是为了查明断面域地壳一上...  相似文献   

青藏高原“亚东-格尔木地学断面”综合地球物理调查与研究   总被引：53，自引：9，他引：53  

吴功建  高锐 《地球物理学报》1991,34(5):552-562

本文概述亚东-格尔木地学断面的地球物理研究成果.在前人工作基础上,沿断面补做了多方法地球物理调查,对原有资料重新解释,综合新、老资料,给出了断面岩石层构造的地球物理解释模型.研究结果认为,青藏高原是一个拼合的增生大陆,是世界上一种新型的俯冲加逆冲叠覆的复杂类型造山带.  相似文献