浅层测温在夏县南山底地热研究中的应用   总被引：3，自引：0，他引：3  

左海风 《华北地质矿产杂志》1998,13(2):170-177

地热是一种宝贵的矿产资源,具有极高的开发利用价值。地温是地热场的直接量度。它可以查明地热场的空间分布,圈定热异常范围、指导地热勘探并对地温异常作出评价。本文借助前人研究成果,汉夏县南山底地温场为例,探讨浅层测层方法的应用,剖析地热田开发利用前景。实践法若水文地球化学和其它物探方法配合使用,为提供深层热储信息,效果更好。  相似文献   

Thermal perturbation during charnockitization and granulite facies metamorphism in southern India   总被引：1，自引：0，他引：1  

J. GANGULY  R. N. SINGH  D. V. RAMANA 《Journal of Metamorphic Geology》1995,13(3):419-430

Abstract We have deduced the steady-state lithospheric geotherm at c. 1 Ga in the south Indian shield area using the available data on the concentration of radioactive elements, and the P-T conditions of Proterozoic mantle xenoliths in the south Indian kimberlites as constraints. The geotherm was adjusted back to 2.5 Ga by keeping the surface temperature constant and calculating the temperature change at the top of convecting upper mantle. The reduced or mantle heat flux, which was treated as an adjustable parameter, was 20.9–21.3 mW/m² at 1–2.5 Ga. Comparison of the calculated steady-state geotherm with the available P-T data of the Archaean (c. 2.5 Ga) charnockites and granulites from southern India suggests that the granulite facies metamorphism in this region had resulted from a major thermal perturbation, which was c. 400° C at 25 km. Seismic tomographic and gravity data essentially preclude any significant magma underplating of the granulitic crust in southern India. Previous workers have suggested that the formation of charnockites in this region was associated with copious CO₂ influx from a deep-seated source, possibly the mantle. In this work, we have evaluated both the transient and steady-state thermal effects of the heat convected by CO₂ outgassing from upper mantle. It is shown that the thermobarometric array of charnockites and granulites can be produced by the convective perturbation of the steady-state geotherm, and that a flux of CO₂ of ±90 mol/m² yr (corresponding to Darcy velocity of ±0.30 cm/yr) for a period of ±30 Ma was needed to produce the required perturbation. This is c. 150 times the average CO₂ flux through the tectonically active area of the Earth's crust at the present time. There is, however, an uncertainty of a factor of 3 in this value. Seismic tomographic and gravity data independently suggest thickening of the crust beneath the granulite terrane compared with the adjacent Dharwar craton. This suggests thermal perturbation due to overthrusting as a major potential cause for the granulite facies metamorphism in south India. Overthrusting of a 30–35-km-thick thrust block was needed to produce the required thermal effect. The estimated thickness of the original crust from geobarometric and seismic tomographic data south of the orthopyroxene isograd or ‘transition zone’is compatible with the emplacement of a thrust block of this magnitude. However, the latter fails to match the estimated pre-uplift crustal thickness at the transition zone, if it is assumed that the crust has not thinned by non-erosional processes since the Archaean. Thus, we propose a combination of overthrusting and CO₂ fluxing from a deep-seated source as the cause for the formation of charnockites in this zone. The required focusing of CO₂ in this case is c. 40% of that estimated in the model where CO₂ fluxing was considered to be the sole reason for thermal perturbation. This combined thrusting—CO₂ fluxing model also helps explain the development of patchy charnockites in the transition zone from amphibolite facies rocks.  相似文献   

三维电阻率视图揭示南田地热田构造形态     

杨兴沐  刘川宁  杨忠政 《物探与化探》2004,28(1):62-64

南田地热田物探工作布置面积性电测深,采集三维视电阻率数据,制作视电阻率三维视图,揭示了测区断层构造分布形态,布置的地热勘探兼开采孔获得成功,取得良好的地质效果。  相似文献   

冀东陆壳热结构─—由岩石学模型推导     

吴宗絮 《现代地质》1994,8(2):133-138

本文根据变质岩矿物对的平衡热力学研究结果，提出冀东地区早前寒武纪陆壳平均地温分布曲线，并讨论现代陆亮地温曲线的两种可能形态．早前寒武纪在相当于中、下地壳的部分，地温的平均梯度约为７．３℃／ｋｍ，它预示了对流热传输占有重要地位（约占６５％）．基于传导热传输的假设，现代地温分布是一条平滑的曲线，而基于中地壳是一个含水的低速层以及对流热传输的假设，现代地温分布则可能是一条折线．退变质作用引起的放热与扩容可能是诱发地震的能量来源之一．  相似文献   

冀东陆壳热结构─—由岩石学模型推导     

吴宗絮 《现代地质》1994,(2)

本文根据变质岩矿物对的平衡热力学研究结果，提出冀东地区早前寒武纪陆壳平均地温分布曲线，并讨论现代陆亮地温曲线的两种可能形态．早前寒武纪在相当于中、下地壳的部分，地温的平均梯度约为７．３℃／ｋｍ，它预示了对流热传输占有重要地位（约占６５％）．基于传导热传输的假设，现代地温分布是一条平滑的曲线，而基于中地壳是一个含水的低速层以及对流热传输的假设，现代地温分布则可能是一条折线．退变质作用引起的放热与扩容可能是诱发地震的能量来源之一．  相似文献   

大气降水量对成矿流体热场的影响——以锡矿山锑矿床成矿流体为例     

杨瑞琰  马东升  潘家永 《地球科学》2005,30(3):366-370

成矿流体热场直接影响矿床的成矿作用.依据湘中盆地的水文地质特征, 以锡矿山锑矿床成矿流体为例, 利用热-重力驱动型流体运移模型, 选择具有代表性的龙山岳坪峰-锡矿山(AB)剖面, 研究大气年降水量的大小对成矿流体热场的影响.首先选取一个对比降水量1200 mm/a, 计算出区域的温度场分布, 然后分别取年平均大气降水量为600、1800和2400 mm/a与对比降水量的温度场进行对比, 得出2种温度场的差值图.模拟结果表明: 大气降水的水量大小对区域流场影响较大, 而对区域温度场的影响不大, 在不同降水量条件下, 其对温度的影响在5%~20%之间.研究结论认为, 大气降水量对成矿流体的热场影响不大.   相似文献   

低温浅成热液金矿若干问题讨论     

毋瑞身 《地质与资源》1993,2(1):47-53

本文根据29th IGC所交流的金矿地质内容,讨论了关于低温浅成热液金矿的若干问题,包括本类矿床的研究范畴、成矿时代、类型划分、形成的构造环境和主要的标志。本类金矿床是指火山岩地区地热系统所形成的金矿床。其形成时代主要是中新生代,并可早推至晚古生代;除形成于岛弧和其后的张裂构造环境之外,还见于陆核和中间地块的中生代上叠火山盆地;按照成矿地球化学条件及矿物共生组合可以分出冰长石-绢云母型和酸性硫酸盐型两类,按着成矿方式可以分出热液充填型、热液交代型和热液沉积型;主要标志表现在地热系统、赋矿围岩系统、成矿动力系统和矿床组合、矿物组成及热液蚀变系统等。  相似文献   

山东菏泽地区地热田地质特征   总被引：2，自引：0，他引：2       下载免费PDF全文

王福花  侯欣英  孙鹏  柳耀君 《山东国土资源》2008,24(4):40-43

菏泽地热田内蕴藏着丰富的地热资源,地质构造条件、热储地质条件都比较有利,是开发地热资源的有利地段。区域地质构造主要为聊考断裂和曹县断裂,热储层分2大类呈双层结构,上部为新近系孔隙-裂隙热储,下部为奥陶系碳酸盐岩裂隙岩溶热储。该区地下热水是50年前形成的,水中氟、偏硅酸达到矿水命名浓度,为氟水、硅水;锶已接近锶水;偏硼酸已接近矿水浓度,还含有F^-,H2SiO3,HBO2,Li等多种对人体有益的矿物元素,可作为采暖,洗浴等用水。  相似文献   

MT法在河北献县地区地热勘查中的应用     

宋洪伟  夏凡  尚铭森 《地质与资源》2018,27(3):284-287

河北献县地热资源埋藏浅、温度高、储量大、开发潜力大,合理选择物探方法可以很好地确定靶区,圈定储热构造,减少因钻探位置不当带来的额外开发成本.本次勘查工作利用EH4连续电导率成像系统,采取单点进行大地电磁测深（MT）的数据采集方式,能够极大地降低地形因素的影响,由此保证了测量的精度.由于MT法探测深度的优势,其反演电阻率电性特征图能够很清晰地反映出地热田导水导热断裂构造的分布、产状.MT法在本次地下热源勘查工作中取得了很好的测量结果,成功圈定了地下热源的范围,为下一步的钻探工作提供了有力的技术支持.  相似文献   

Geothermal gradient of the upper mantle beneath Jeju Island, Korea: Evidence from mantle xenoliths   总被引：2，自引：0，他引：2  

Seong Hee Choi  Yong-Joo Jwa  Han Yeang Lee 《Island Arc》2001,10(2):175-193

Abstract Ultramafic xenoliths found in alkali basalts from Jeju Island, Korea are mostly spinel lherzolites accompanied by subordinate amount of spinel harzburgites and pyroxenites. The combination of results from a two-pyroxene geothermometer and Ca-in-olivine geobarometer yields temperature–pressure (T–P) estimates for spinel peridotites that fall in experimentally determined spinel lherzolite field in CaO-Fe-MgO-Al₂O₃-SiO₂-Cr₂O₃ (CFMASCr) system. These T–P data sets have been used to construct the Quaternary Jeju Island geotherm, which defines a locus from about 13 kbar at 880°C to 26 kbar at 1040°C. The geothermal gradient of Jeju Island is greater than that of the conventional conductive models, and may be as a result of a thermal perturbation by the heat input into the lithospheric mantle via the passage and emplacement of magma. Spinel–lherzolite is the main constituent rock-type of the lithospheric mantle beneath Jeju Island. Pyroxenites may be intercalated in peridotites at similar depth and temperature as re-equilibrated veins or lenses.  相似文献