Hydrothermal circulation beneath Mount Pelée inferred by self potential surveying. Structural and tectonic implications     

J. Zlotnicki  G. Boudon  J. P. Viod  J. F. Delarue  A. Mille  F. Brure 《Journal of Volcanology and Geothermal Research》1998,84(1-2)

Self-potential (SP) surveys were made on Mount Pelée volcano (Martinique Island, French West Indies) in 1991 and 1992 in order to recognize its hydrothermal system, the associated groundwater channeling and the main superficial structures of the massif. Almost 70 km of profiles were carried out with an average sample spacing of 50 m. Measurements essentially reveal negative SP anomalies, down to −1700 mV, with high gradients (−1.83 mV/m) due to the infiltration of meteoric water into the massif. Rims of summit calderas Morne Macouba and Etang-Sec present sharp negative SP anomalies on the western, northern, and eastern flanks. Negative SP anomalies indicate no upward water flow beneath Mount Pelée summit. On the southwestern volcano flank, a 3.5×6 km horseshoe-shaped structure corresponding to a southwest flank collapse event, older than 25,000 years BP, is clearly identified by the SP mapping. High gradients border the inner southern rim from Morne Calebasse to St Pierre town and the Caribbean Sea. Along the northern rim of the horseshoe-shaped structure the negative SP anomalies give place to a positive SP anomaly, up to 200 mV, of SW–NE trend. This zone covers the area of two active hot springs (Sources Chaudes and Puits Chaud: 40–65°C). Marine magnetic surveys and bathymetry show that the horseshoe-shaped structure spreads into the Caribbean Sea up to about 10 km from the coast. Buried structural discontinuities are evidenced inside the flank collapse structure. The upper one deviates the groundwater flow coming from the summit toward the south flank where the flow finds an indentation to expand again downwards. This discontinuity is either an old hypothetical caldera rim partly destroyed by the collapse of the south–southwestern flank and covered by recent pyroclastic deposits, or more probably the trace of a bulge landslide. A circulation model of the hydrothermal waters is proposed. Rainfall (5–6 m/year) is partly drained inside the summital calderas and the flank collapse zone through pyroclastic flows down to an impermeable basement. There the groundwater constitutes perched aquifers at the contact of the bulge landslide, or of the hypothetical old caldera rim. Along the inner northern border of the flank collapse structure the phreatic water is reheated. Warm groundwater flows along the northern avalanche structure rim and discharges near the coast in ground and marine outcrops, of medium temperature. Finally, the main part of the meteoric water is channeled along the old caldera rim, or along the bulge landslide towards the south flank of Mount Pelée, where some gaps in the rim exist. There the groundwater finds again a subhorizontal gravitational circulation along Mount Pelée slopes into the Caribbean Sea.  相似文献   

On the volcanology of the Gibeon Kimberlite Field, Namibia     

S. Kurszlaukis  L. Franz  V. Lorenz   《Journal of Volcanology and Geothermal Research》1998,84(3-4)

Kimberlite volcanism in the Upper Cretaceous Gibeon Kimberlite Field, southern Namibia, consisting of at least 42 diatremes and a number of associated dykes, is closely related to carbonatitic and ultrabasic volcanic and intrusive activity which occurred at the margin of the Field. The volcanology of the diatremes and dykes as well as their structural setting is reported here. Because of the paleohydrogeological setting, and since juvenile kimberlite occurring in dykes, intrusive plugs, and spherical lapilli is devoid of vesicles, a phreatomagmatic eruption mechanism is proposed for the genesis of the kimberlite diatremes. Karoo dolerite, basalt and sediment xenoliths in the diatremes provide evidence for the former extent of Karoo strata at the time of eruption.  相似文献   

Seismic study of the Mesozoic carbonate basement around Mt. Somma–Vesuvius, Italy     

Pier Paolo G. Bruno  Giuseppe Cippitelli  Antonio Rapolla 《Journal of Volcanology and Geothermal Research》1998,84(3-4)

Fifteen seismic reflection lines from AGIP surveys, in and around the Campanian Plain and Mt. Somma–Vesuvius (south Italy) have been interpreted. The attention has been focused to the horizon pertinent to the top of the Mesozoic carbonate sequence and the Quaternary faults dissecting it. As a matter of fact, both are very important elements for understanding the origin of the volcanic activity in the area, that often in the past, has been the topic of debates not supported by reliable data. In the study area, referring to the depth of the carbonate basement, comparison between the result achieved by the seismic prospecting and previous gravity studies has been made. It shows coherence in some areas but large discrepancy within others. Near the town of S. Anastasia, the gravity and seismic depth estimates differ as much as 1000 m or more. Furthermore, the seismic data show that the source of the greatest volcanic eruption in the area (the so-called ‘Campanian Ignimbrite') is probably not located in the Acerra depression, as suggested by other authors. A main NE–SW fault directed toward Vesuvius, considered as playing a primary role on volcanogenetic processes and previously recognised only offshore by marine seismic survey, has been now identified also inland using this new seismic information. The results presented here strengthen the hypothesis that Mt. Vesuvius is located at the crossing point of two regional Quaternary sets of fault heading NW–SE and NE–SW.  相似文献   

一次华北暴雨过程中边界层东风活动及作用   总被引：7，自引：0，他引：7       下载免费PDF全文

吴庆梅  刘卓  王国荣  翟亮  丁青兰 《应用气象学报》2015,26(2):160-172

利用常规气象观测资料、NCEP 1°×1°逐6 h分析资料、微波辐射计资料及FY-2E气象卫星及雷达探测资料,针对2013年6月4日发生在北京及周边地区的一次暴雨过程中边界层东风活动及作用进行了天气学诊断分析,结果表明:对流性暴雨过程伴随有源自东北平原的边界层东风活动,东风活动具有尺度小、降温明显和湿度大等特点。暴雨过程是边界层东风和中低空暖式切变线、偏南风急流和500 hPa短波槽共同作用的结果;东风湿冷空气的锋面抬升和地形抬升作用共同加强了中低层暖湿气流的辐合上升运动,同时东风冷垫和地形抬升作用触发了雷暴的再次发生,相应雷暴具有高架对流特点。东风气流起到了边界层水汽输送作用,中低层偏南暖湿气流为暴雨的产生提供了充足的水汽和不稳定层结条件。  相似文献   

中国地源热泵技术应用及进展   总被引：1，自引：0，他引：1       下载免费PDF全文

孙友宏  仲崇梅  王庆华 《探矿工程》2010,37(10):30-34

地源热泵技术在中国应用时间不长,但推广应用速度非常快,几乎以每年20%以上的速度增长,尤其在上海世博场馆中大面积推广,取得了很好的节能效果。随着该技术的推广应用和深入研究,我国已掌握了地源热泵的全套技术,并在浅层地热能勘查评价规范、钻孔热反应测试技术、高效地下热交换井以及太阳能与地源热泵技术的联合应用等方面都取得了一些新进展,这些成果的取得将为实现我国2050年的节能减排目标提供技术保障。  相似文献   

青岛海韵国际大厦第四系大口径水源热泵水井设计与施工          下载免费PDF全文

马连成  宋仕冰  刘世安 《探矿工程》2010,37(10):40-43

水源热泵技术作为供热供冷的重要方法之一,其水井工程的参数需根据具体的水文条件、气候条件、气象条件和地质地层等进行设计。在对第四系大口径水源热泵水井工程设计技术参数、施工工艺流程、成井质量控制、抽水与注水、渗水试验综合成果进行分析的基础上,采用水源热泵供热供冷中央空调技术设计的第四系土层大口径水源热泵水井,作为供冷供热水源达到了各项技术指标,取得了较好的成效,可供类似工程参考。  相似文献   

提水试验在含水层渗透系数求取中的应用——以黄岛地下水封石油洞库为例     

周斌  陈刚 《地下水》2010,32(2):18-19

在利用水文地质试验求取渗透系数的过程中,对于低渗透性含水介质,由于水量小,一般难于实施抽水试验方法,而提水试验能够很好地解决这一问题。以黄岛地下水封石油洞库为例,首先对提水试验的特点、步骤进行了简单介绍,然后根据裘布依稳定潜水井流原理求解渗透系数,并对库区渗透系数平面分布规律进行了分析,将含水层渗透性划分为三个区域。  相似文献   

北京平原区水源热泵应用适宜区划分     

刘立才  张霓  王理许  郑凡东 《地下水》2010,32(6):8-11

北京市水源热泵的应用,宏观上未充分考虑地下水水源地的分布,微观上未注重应用场地的水文地质条件,地下水回灌率低造成了水资源浪费。本文针对北京平原区的水文地质条件,以浅层含水层导水系数、有效导水系数、地下水中的铁和总硬度为评价因子,以水源地保护区及补给区、地面沉降中心区为约束因子,利用叠加分析技术,将平原区分为适宜发展区、较适宜发展区、限制发展区和禁止发展区,为水源热泵的理性推广提供了技术参考。  相似文献   

浅层地热能在合肥地区的应用     

李清  李益湘 《安徽地质》2010,20(4):283-286

根据合肥地区的水文与工程地质条件,研究浅层地热能在合肥地区应用的适宜方式,并结合工程实例,对浅层地热能应用的地源热泵空调系统中的地埋管换热器设计、自动控制与监测、运行控制等关键技术进行了探讨,旨在合肥地区推广应用浅层地热能,实现浅层地热能与地源热泵系统、建筑空调系统相匹配。  相似文献   

Evaluation of suitability area by ground source heat pump system in Baotou plain     

WANG Chunpeng  WANG Qinghua  FENG Lei  FENG Ye  CHENG Sanhuan 《东北亚地学研究》2014,(3)

According to the elements of hydrogeological conditions,lithology,stratigraphic thermal physical parameters,construction technology and economic rational elements,the evaluation system of ground source heat pump( GSHP) were established in Baotou plain. The factor weights were determined by using analytic hierarchy process,and the comprehensive element method was selected to evaluate the region suitability of GSHP system. The results show that the suitable area is 559. 63 km2 for utilizing GSHP in the studied area,accounting for 62. 58% of the total area; while the unsuitable area is 334. 60 km2,accounting for37.42%. The evaluating results can provide not only a scientific basis for development and utilization rationally of shallow geothermal heat in Baotou,but also offer an important reference to the other areas.  相似文献