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煤系石墨属战略性矿产资源,在核石墨、军用飞机轮胎等方面具有独特优势,煤系石墨矿产资源评价对于煤系石墨矿产资源勘查开发、提级增储及战略资源保障至关重要。由于煤系石墨与高变质煤存在连续过渡性质,导致部分煤系石墨被当作无烟煤处理,现有煤系石墨查明资源量可能被大大低估,实际上煤系石墨资源量与高煤级煤的资源量有直接关系。因此,在我国无烟煤等高煤级煤勘查区内,开展煤系石墨资源调查评价工作,将会取得较好效果,预期发现一批新的煤系石墨资源潜力区。通过分析我国目前已知的湖南、福建、吉林等地典型煤系石墨资源分布特征,总结了煤系石墨找矿标志,包括层位、矿化、岩体、构造和围岩蚀变等标志。在高煤级煤勘查区内,基于煤田构造、含煤岩系沉积环境、岩浆活动、煤岩煤质特征、煤类分布与变质情况等资料,结合煤系石墨找矿标志,进行煤系石墨资源调查评价。以科学性、系统性和可操作性为评价原则,依据工作程度、地质条件、矿产条件3类参数,采样点密度、构造变形程度、构造应力、岩体规模与热作用强度、岩体与煤层距离、初步鉴定、精确鉴定7个指标,初步提出了煤系石墨矿产资源评价方法。将实测数据分别与对应指标的预设值比较,利用平面直线拟合方程计算... 相似文献
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《Gondwana Research》2014,25(3):1230-1241
We report here new LA-ICPMS detrital zircon U–Pb ages of a quartzite from the autochthon of Peloponnesus (Feneos locality), southern Greece. The rock classifies as a mature quartz arenite and belongs to an original shale–sandstone succession now metamorphosed into a phyllite–quartzite unit. Zircon age clusters at 0.52–0.75, 0.85, 0.95–1.1, 1.75–2 and 2.4–3 Ga point at the Saharan Metacraton and the Transgondwanan Supermountain as contributing sources; the youngest concordant grain is 522 Ma old. Our data collectively suggest deposition during the Cambro-Ordovician in a collisional setting and are in excellent agreement with those of the virtually intact Cambro-Ordovician sandstone–shale sequences of Libya (Murzuq and Kufrah basins) and the Middle East (Israel and Jordan), interpreted to have been deposited in the Gondwana Super-fan System which draped the northern Gondwanan periphery from ~ 525 to 460 Ma. By contrast, re-evaluating the available zircon age-distribution pattern and depositional setting of an analogous sequence forming the autochthon of north-central Crete (Galinos beds) we demonstrate that it was originally deposited in a completely different setting, i.e. in an accretionary/fore-arc complex outboard of the south Laurussian active margin (Pelagonia) during the Late Carboniferous. Comparing similar Cambro-Ordovician metasiliciclastic rocks from north-eastern Crete (Sfaka paragneiss), north-central continental Greece (Vertiskos terrane), north-western Turkey (central Sakarya terrane) and the Romanian Carpathians we show that their detrital zircon distribution patterns testify to an original depositional setting similar to that of Peloponnesus (Feneos), Libya and the Middle East. Using key time-frames from previously published palaeogeographic reconstruction models we are able to trace in space and time the Palaeozoic–Early Mesozoic wondering paths of the aforementioned sequences. Thus, time- and facies-equivalent rocks presently cropping out in the eastern Mediterranean share a common provenance from the Gondwana Super-fan System which was diachronously dispersed between Early Silurian and Early Triassic. 相似文献
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《Chemie der Erde / Geochemistry》2020,80(1):125535
The Central Pontides (northern Turkey) is one of the key localities to understand the geodynamic evolution of the Palaeo- and Neotethyan oceans. It consists of the pre-Jurassic basement units, the Early Jurassic and the Early Cretaceous accretionary complexes, the widespread Middle Jurassic continental arc magmatics and the Late Jurassic to Tertiary cover units. The Early Cretaceous accretionary complex is represented by the Central Pontide Structural Complex and includes the Middle Jurassic oceanic units, which were metamorphosed during the Early Cretaceous. Apart from these oceanic units, a few metaophiolite and serpentinite fragments have been recognized within the basement units, which may represent the remnants of an older ocean. The pre-Middle Jurassic Devrekani Metaophiolite is the largest oceanic fragment and tectonically intercalated within/between the Devrekani Metamorphics and the Çangaldağ Metamorphic Complex. It is mainly composed of harzburgites, dunites with chromite veins and metagabbros, and cut by metabasaltic andesites and metadacites. Petrographically, the gabbro consists mainly of plagioclase and clinopyroxene, and displays phaneritic/porphyritic texture. In contrast, the metabasaltic andesite includes plagioclase and mica phenocrysts within a fine-grained groundmass. Also, the metadacite is composed predominantly of quartz, plagioclase, and mica minerals. Two different magmatic groups belonging to completely different tectono-magmatic settings have been geochemically determined based on the immobile trace element systematics. The metadacites and metabasaltic andesites are akin to continental arc magmatics and characterized by negative Nb and Ta anomalies and depleted HFSE relative to Th and La contents. However, the metagabbro samples display the geochemical signatures of boninitic rocks and characterized by highly depletion in HFSEs and REEs relative to N-MORB. The Devrekani Metaophiolite in the Central Pontides may represent another remnant of pre-Middle Jurassic oceanic crust generation and can be north-eastward continuation of the Permian-aged Almacık complex and the Boğazköy Metaophiolite fragment in the western Sakarya Composite Terrane. It may have been cut by intrusions of the extensive Middle Jurassic continental arc magmatism after its imbrication within the basement unit. The presence of pre-Middle Jurassic oceanic units may indicate that the Paleozoic ocean may have survived as the Jurassic Intra-Pontide Ocean between the Scythian Platform and Sakarya Composite Terrane during the Mesozoic time. Thus, the Intra-Pontide Suture may normally include the Palaeozoic and Mesozoic remnants of the long-lived northward subducting Tethyan ocean. 相似文献
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The Carboniferous and Permian sedimentary rocks (mainly the Shanxi and Taiyuan formations) in the Linxing region, eastern Ordos Basin, China, host a significant volume of unconventional gas resources (coalbed methane, shale gas and tight sandstone gas). Currently, the in-situ stress state is poorly understood but knowledge of this is extremely important for a range of applications, such as gas exploration and production, fracture stimulation and wellbore stability. The maximum horizontal stress (SHmax), minimum horizontal stress (Shmin) and vertical stress (Sv) magnitudes, and the SHmax orientation in the Linxing region were systematically analyzed for the first time in the present study, which can provide a reference for subsequent numerical simulation and hydraulic fracturing design. Based on borehole breakouts and drilling-induced tensile fractures interpreted from borehole imaging logs, the SHmax orientation rotates from ∼NEE-SWW-trending in the southern part to ∼ NWW-SEE-trending in the northern part of the Linxing region. Both conventional logs and extended leak-off tests were used for stress magnitude determination. The results revealed three types of in-situ stress fields (Sv > SHmax > Shmin, SHmax > Sv > Shmin and SHmax > Sv ≈ Shmin), and a dominant strike-slip stress regime (SHmax > Sv ≥ Shmin) was found for the entire well section in the target Shanxi Formation and Taiyuan Formation in the Linxing region. In addition, differential stress increased with depth in the Linxing region, which indicates that wellbore instability might be a potentially significant problem when drilling wells that are vertical or ∼ N-S-trending. 相似文献
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在对广西河池地区高银铜精矿中铜含量的测定中,由于样品中银含量较高,极大地影响终点判定,常用国标碘量法无法准确对铜含量进行定量.用氨水-碘量法将样品利用盐酸-硝酸-溴体系处理,样品充分溶解后,用盐酸去除高含量银残留的影响,用氨水-乙酸法调节溶液pH值,用硫代硫酸钠标准溶液滴定测定样品中铜的含量,结果满意. 相似文献
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笔者旨在依靠重磁、遥感、GIS信息综合分析等技术手段,从宏观裂缝描述、成因分析、发育规律等方面开展多尺度碳酸盐岩裂缝发育区线性异常的综合研究,寻找不同尺度断裂、裂缝间的空间关系,作出对储层裂缝方位及发育带的预测。提出了运用重磁与遥感多元信息复合技术进行裂缝解释的思路和方法,以哈萨克斯坦阿克纠宾地区扎纳若尔和俄罗斯尤罗伯钦—托霍姆碳酸盐岩油田为例,阐明了地球物理线性异常反映的断裂和宏观裂缝的表征意义,剖析了线性异常数量化分析方法,研究了地球物理场和线性异常的分布特征,建立了研究区宏观裂缝发育模式。 相似文献
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行洛坑超大型钨矿床位于福建省宁化县东部,是武夷山成矿带内最大的钨矿床,具有储量大、品位低、黑钨矿与白钨矿资源量相近的特点。白钨矿作为含钨矿物,其形成年龄可以代表矿床的成矿时代,其地球化学特征反映了成矿作用环境和过程。文章在对行洛坑钨矿床钨矿脉特征、黑钨矿与白钨矿赋存状态开展调查的基础上,挑选白钨矿单矿物进行了Sm-Nd等时线测年和微量元素测试。研究结果显示,白钨矿结晶年龄为（142.6±2.8）Ma,略小于黑钨矿原位U-Pb年龄（150.5±8.1）Ma和石英流体包裹体Rb-Sr等时线年龄（147.5±2.9）Ma,与矿区隐伏岩体成岩年龄143.5~149.5 Ma在误差范围内完全吻合,也与矿物结晶世代关系吻合,都属于晚侏罗世的产物,说明钨成矿与隐伏岩体成岩近于同时或稍晚发生。白钨矿中微量及稀土元素特征显示第一世代成矿流体中Eu3+ < < Eu2+,指示成矿流体为还原性流体;第二世代成矿流体中Eu3+ > > Eu2+,指示成矿流体为氧化性流体。行洛坑钨矿成矿与华南中生代大规模成矿作用及其大地构造背景和动力学环境密切相关。 相似文献
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BAI Wenji Tao Shufeng SHI Rendeng YANG Jingsui FANG Qingsong YAN Binggang ZHANG Zhongming Institute of Geology CAGS Beijing China Beijing General Research Institute of Mining & Metallurgy China 《Continental Dynamics》2001,(2)
1. IntroductionIn order to confirm the presence or absence of diamonds in the Luobusa ophiolitic chromitite in Tibet, about 1500 kg chromitite sample was collected for separating its associated minerals, in which diamond, moissanite, octahedral pseudomorphic serpentine and chlorite, native silicon, native chromium, some alloys and other minerals were found. A wide variety of minerals, including about 70-80 types of mantle minerals from the Luobusa ophiolite, were identified by energy dispersi… 相似文献
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安第斯山中段现今地应力测量及地震相关性分析 总被引：1，自引：0，他引：1
安第斯山位于纳兹卡洋壳板块和南美板块之间,是全球地震频发区域之一,被誉为地震与活动构造学家的天然实验室。本文利用矿山探矿钻孔,采用水压致裂原位地应力测试技术,首次获取安第斯山中段千米深孔原地应力大小及方向随深度变化规律。结果表明测试深度范围内主应力的量值随深度增加而增大,水平最大、最小主应力及垂向应力量值范围分别为12.38~34.47 MPa,7.97~24.15 MPa和6.81~26.10 MPa,主应力之间的关系为σHσv≥σh,σH/σh比值介于1.43~1.66之间。最大水平主应力方向与震源机制解和地表调查结果基本吻合。以实测地应力资料为基础,利用安德森断层理论及库伦摩擦破裂准则,探讨了震源深度(假定30 km)处的应力状态及断层达到临界破坏时的孔隙压力,结果表明除纳兹卡板块持续俯冲外,高孔隙压力可能是该区地震频发的主要原因。研究结果不仅为该区地震机理研究提供了实测资料,而且对世界应力图数据库具有重要补充价值。 相似文献