Reconstruction of Physicochemical Environment of Hydrothermal Mineralization at Malanjkhand Copper Deposit,Central India: Constraints from Sulfur Isotope Ratios in Pyrite,Molybdenite and Chalcopyrite     

Mruganka K. Panigrahi  Dinseh Pandit  Rajesh K. Naik  Shunso Ishihara 《Resource Geology》2013,63(1):110-116

δ³⁴S values of pyrite, molybdenite and chalcopyrite were determined from the Malanjkhand copper deposit. These minerals constitute the primary sulfide phases that were deposited after the initial magnetite deposition in the main orebody and host granitoid. Pyrite exhibits a depleted range of values (?2.63 to ?0.56‰), chalcopyrite, a very narrow range of values around zero (?0.039 to 0.201‰) and molybdenite furnishes a range of enriched values (0.68 to 1.98‰). On back calculation of the δ³⁴S values of H₂S in the fluid from which the minerals were likely to have precipitated, using standard expressions for equilibrium fractionation at the temperature range obtained from fluid inclusion and mineral fluid equilibria, it is observed that H₂S in the fluid at pyrite deposition was depleted and gradually became enriched towards molybdenite and chalcopyrite deposition. This trend is best explained as being due to inorganic reduction of SO₄^2? in the fluid and is very much in agreement with the paragenetic sequence indicating increasing activity of H₂S in the fluid. The very restricted range in the δ³⁴S values of sulfide minerals in the fluid does indicate a single, possibly magmatic, source of sulfur that also agrees well with the earlier deduced model of genesis of the deposit as an ancient geothermal system associated with granitic magmatism.  相似文献   

山东商河地区地热井钻效分析   总被引：1，自引：0，他引：1  

范存章  赵岩 《中国煤炭地质》2013,(11):63-65

商河县地热井资源丰富,蕴藏量巨大,其热储含水层主要为新近系馆陶组以及古近系的东营组。通过区内施工的4个地热井的钻效分析,认为：①采用电动机作为动力的4#地热井施工工期明显优于其他3口采用柴油机作动力的;②本区构造较简单,断层稀少,分阶段使用PDC钻头可以将施工工期大大缩短;③泥浆泵的泵量达到或接近钻孔的环空最低上返速度时,可有效携带岩屑,建议泥浆岩屑上返速度不低于0．5m/s;④使用Ф127mm钻杆代替Ф89mm钻杆,可使钻杆的抗扭强度增加,保证施工的安全;⑤地面使用泥浆罐配备除泥器间断性除泥,保证泥浆液面高于泥浆泵阀室,泥浆靠自重流入泥浆泵阀室内,降低了泥浆泵从循环沉淀池抽吸功耗与节省吸人阀磨损。对比结果可为该区进行地热井施工提供借鉴。  相似文献   

上海第四纪地层温度场分布特征与影响因素分析     

瞿成松  陈海洋  曹袁  徐丹 《上海国土资源》2013,(3)

地源热泵是上海开发利用浅层地温能的主要形式。通过对上海地区不同地点、不同埋深范围内第四纪地层地温实测数据,分析了本地区浅层岩土温度场分布的一般规律,并与历史数据比较。40余年来,上海地区第一承压含水层的平均地温有小幅升高,而第二承压含水层则有小幅下降。影响浅层地温场分布的主要因素有太阳辐射的周期变化、城市热岛效应、地表植被、地下水径流、人工回灌等。本文可为本地区地埋管地源热泵系统的勘察设计提供参考。  相似文献   

上海地区浅层地温变化规律特征分析     

王万忠 《上海国土资源》2013,(3)

根据上海地区5处深度均为153m的地温长期监测孔实测数据,地表以下至约19m为变温带;深度约19~36m范围为恒温带,地温平均约18.3℃;36m以下为增温带,增温率为3.08℃/100m。分析了地温随时间与地层岩性的变化特征。成果可为浅层地温能的开发利用提供依据。  相似文献   

火山喷发对辐射传输影响的研究     

周清波 《地理研究》1993,12(3):19-25

本文根据火山灰粒子的辐射光学特性,计算了火山灰粒子和平流层本底的辐射光学参数。另外,采用大气多次散射的辐射传输方程,计算了火山喷发对大气辐射变温的影响效果。结果表明,与平流层本底相比,火山灰粒子具有很强的吸收性。火山喷发使平流层吸收太阳辐射增温,并使到达对流层和地面的太阳辐射减少;同时,对大气长波冷却率的影响甚微。  相似文献   

Geothermal occurrence analysis of Dongying Formation in Tanggu area of Tianjin     

LIU Jiulong  JIN Baozhen  LI Yuanyuan  WANG Jige  YUE Liyan  WANG Xi 《东北亚地学研究》2014,(3)

Based on introducing geological structure of Tanggu area,the authors analyzed the sedimentary environment of Paleogene Dongying Formation,and further analyzed its geothermal occurrence. The studied area spans two grade Ⅳ tectonic units which are Beitang depression and Banqiao depression. The studied area is mainly located in the Tanggu nose-like structure which is the secondary structure of Beitang depression. Its existence affects the sedimentary distribution of the part strata of Paleogene. The depositions of Dongying Ⅲ( SQEd3) and DongyingⅡ( SQEd2) are mainly delta front facies and lake sand bars which are propitious to the geothermal fluid enrichment. The favorable enrichment region of geothermal fluid is located in south HetouTanggu. Most of DongyingⅠ( SQEd1) changes into swamp plain deposition,only the northeast part of this area is the distributary riverway facies with developed sand layers. There is the favorable enrichment region of geothermal fluid. The hydraulic connection is weak among the geothermal reservoirs of Dongying Formation and its overlying Guantao and Minghuazhen formations. The underlying Shahejie Formation geothermal reservoir provides a steady stream of fluid supply and ground pressure protection for Dongying Formation geothermal reservoir.  相似文献   

2008年台风“风神”强迫次级环流的诊断分析     

毕明玉  ;沈新勇  ;袁媛  ;丁治英 《南京气象学院学报》2014,(3):354-365

利用WRF（weather research and forecasting）模式模拟资料对2008年06号台风“风神”进行诊断分析,采用准地转PV-ω方程对台风外围中尺度对流系统较强的6月20日10时（世界时）的资料进行分析.通过PV-ω方程诊断了潜热、摩擦及干动力过程对台风次级环流的作用,结果显示潜热强迫产生的次级环流最强,摩擦强迫主要集中在边界层,而干动力过程则在台风中心附近产生影响.加入摩擦、潜热得到的准平衡流场能够描述70％左右的台风环流.环境垂直切变在台风中心附近强迫产生横向次级环流的垂直切变与环境垂直切变相反,次级环流会使得台风一侧的上升气流减弱而另一侧上升气流增强,从而使得台风不对称增强.同时,发现垂直切变可能在其最大垂直切变方向右侧激发台风外围中尺度系统.通过构造理想的准平衡的台风及叠加在其上的中尺度系统环流,选择不同的切变和环境平均气流,发现增大切变会使得强迫次级环流增强,而增大环境平均气流不一定能够使得强迫次级环流增大,反而可能使得强迫次级环流减弱.通过诊断发现由切变强迫次级环流造成的中尺度对流系统上方扰动可能是中尺度对流系统持续存在的原因.  相似文献   

春末夏初南亚高压的形成过程及其与ENSO事件的联系   总被引：2，自引：1，他引：1  

何金海  刘伯奇  吴国雄 《大气科学》2014,38(4):670-684

利用ERA-Interim再分析资料,分析了春末夏初南亚高压建立过程的气候特征和可能机制,并讨论了ENSO事件冷、暖位相对南亚高压建立过程年际变化的影响。结果表明,第24候,气候平均的南亚高压形成于中南半岛东南部的对流层高层,这与菲律宾群岛南部和中南半岛局地对流的加强有关。一方面,菲律宾群岛南部对流加强能够在其北部产生负涡度源,在高空热带东风急流的作用下,其下游的南海地区出现负涡度,相应地出现闭合的高空反气旋,南亚高压初步形成。另一方面,中南半岛局地对流令南亚高压中心加强发展,并使其最终位于中南半岛上空。春末夏初菲律宾群岛附近对流的经向摆动决定了南亚高压的形成位置,而中南半岛局地对流的强度则控制着南亚高压的加强北抬。由于菲律宾南部和中南半岛的局地对流都受ENSO事件影响,因此在ENSO事件的冷、暖位相下,南亚高压的形态和位置在其建立过程中差异明显。在暖事件发生后,热带对流在加里曼丹岛以东发展,南亚高压形成于苏门答腊群岛北部至泰国湾上空,此时中南半岛对流偏弱,限制了南亚高压的北抬发展;而在冷事件发生后,热带对流在菲律宾群岛中部加强,同时南亚高压形成于中南半岛中部上空,随后中南半岛对流迅速加强,令南亚高压明显西伸北抬。因此,ENSO事件的冷、暖位相对春末夏初南亚高压的形成位置有显著影响。  相似文献   

关中盆地深部地下热水残存沉积水的同位素证据     

何丹  马致远  王疆霞  郑磊 《地球科学与环境学报》2014,(4)

应用环境同位素水文地球化学方法,结合区域沉积演化史,对关中盆地固市凹陷、咸阳-礼泉断阶和西安凹陷深部地下热水成因类型进行了探讨,并就残存沉积水存在的可能性,寻找氢氧同位素关系、硫氧同位素关系、碳氧同位素关系、N(87Sr)/N(86Sr)与古盐度的关系等环境同位素证据,rNa/rCl值、ρ(Cl-)/ρ(Br-)、rBr/rI值与ρ(Cl-)的关系等水文地球化学证据以及沉积演化史证据。结果表明:固市凹陷华阴地下热水的同位素、水文地球化学特征已基本符合沉积水的特征,推测其为混有古入渗水的残存沉积水;固市凹陷华阴之外的其他构造单元、咸阳—礼泉断阶和西安凹陷地下热水的同位素和水文地球化学特征部分接近沉积水的特征,部分介于古入渗水和沉积水之间;咸阳—礼泉断阶东部地下热水可能为古入渗水或残存沉积水与后期入渗水的混合;西安凹陷及咸阳—礼泉断阶西部地下热水属于现代入渗水与古入渗水的混合水。  相似文献   

Geologic remote sensing for geothermal exploration: A review     

《International Journal of Applied Earth Observation and Geoinformation》2014

This paper is a comprehensive review of the potential for remote sensing in exploring for geothermal resources. Temperature gradients in the earth crust are typically 25–30 °C per kilometer depth, however in active volcanic areas situated in subduction or rift zones gradients of up to 150 °C per kilometer depth can be reached. In such volcanic areas, meteoric water in permeable and porous rocks is heated and hot water is trapped to form a geothermal reservoir. At the Earth's surface hot springs and fumaroles are evidence of hot geothermal water. In low enthalpy systems the heat can be used for heating/cooling and drying while in high enthalpy systems energy is generated using hot water or steam. In this paper we review the potential of remote sensing in the exploration for geothermal resources. We embark from the traditional suite of geophysical and geochemical prospecting techniques to arrive at parameters at the Earth surface that can be measured by earth observing satellites. Next, we summarize direct and indirect detection of geothermal potential using alteration mineralogy, temperature anomalies and heat fluxes, geobotanical anomalies and Earth surface deformation. A section of this paper is dedicated to published remote sensing studies illustrating the principles of mapping: surface deformation, gaseous emissions, mineral mapping, heat flux measurements, temperature mapping and geobotany. In a case study from the La Pacana caldera (Chili) geothermal field we illustrate the cross cutting relationships between various surface manifestations of geothermal reservoirs and how remotely sensed indicators can contribute to exploration. We conclude that although remote sensing of geothermal systems has not reached full maturity, there is great potential for integrating these surface measurements in a exploration framework. A number of recommendations for future research result from our analysis of geothermal systems and the present contributions of remote sensing to studying these systems. These are grouped along a number of question lines: ‘how reproducible are remote sensing products’, ‘can long term monitoring of geothermal systems be achieved’ and ‘do surface manifestations link to subsurface features’?  相似文献