【作者】 师淑娟；

【导师】 王学求；

【作者基本信息】 中国地质科学院 ， 地球化学， 2011， 博士

【摘要】 大型矿床和矿集区的经济价值和战略意义巨大,对全省乃至全国的矿产资源都具有重大意义。对大型、巨型矿床的勘查和研究工作是许多国家的地球化学家和矿床学家们正在研究的重大前沿课题。以成矿物质量为基础,研究大规模地球化学异常与大型矿床或矿集区的关系,成为指导地球化学方法评价大型矿床的理论基础。河北省地处华北地台北缘,是我国前寒武纪陆块成矿域、古亚洲成矿域、滨西太平洋成矿域三大成矿域的一部分,全省在地质历史上经历了太古代、古元古代、中元古代、早古生代、晚古生代、中生代六个成矿集中期,形成了储量可观,资源潜力很大的铁、有色金属和贵金属矿床。由于在以往的地球化学勘查评价过程中,主要集中于利用局部异常评价单个矿点,没有从全省或区域的角度深入挖掘地球化学所蕴含的更多找矿信息,特别是对找寻大型矿床的研究更少。本论文针对上述问题利用河北省已有的1：20万区域化探资料,结合区域岩石和地质矿产资料,从五个层面开展了研究工作,并取得如下成果：(1)地球化学省与矿集区存在密切相关关系：圈定面积大于1000km2的金地球化学省3处,铅地球化学省7处,锌地球化学省4处。分析了三元素地球化学省的分布特征、地质地球化学特征及其所包含的矿集区内的典型矿床(田)的地质地球化学特征。通过金、铅锌的地球化学省与已知矿集区的对比研究发现,河北省现已发现的2个大型金矿集区和1个铅锌矿集区都位于地球化学省范围内。地球化学省与矿集区存在密切的相关关系,地球化学省是矿集区形成的物质基础,地球化学省可以作为潜在矿集区的评价标志。(2)区域地球化学异常与大型矿床存在密切对应关系：进一步的研究了提高异常下限后地球化学省分解的区域异常与大型矿床的关系,研究发现地球化学省内区域异常与大型矿床存在十分密切的关系,河北省的4个大型金矿床均位于金地球化学省所包含的区域异常内,而全省范围产出的4个大型铅锌矿床中的3个也均位于铅锌地球化学省所包含的区域异常内。(3)形成大规模地球化学异常的物质来源有3类：矿床的点源分散、矿源层风化搬运、高背景岩石。高背景岩石提供了成矿元素的高背景,异常比较平坦,不会形成明显的浓集中心；矿源层提供元素的初始富集；矿床风化的点源分散进一步形成叠加异常,异常具有明显的浓集中心。因此,具有多层套合地球化学异常,即地球化学省包含区域异常,区域异常又包含局部异常,才是对找矿最有意义的异常。(4)马兰峪和金厂峪金成矿物质来源的稀土示踪表明稀土元素配分曲线变化趋势与变质岩更为接近,推断遵化岩群和迁西岩群是金矿的主要物质来源。金的表生迁移研究发现矿体剖面金含量的变化特征是从矿体—近矿围岩—远矿围岩—围岩,金的含量渐次降低。水系沉积物中的金含量从矿区到下游水系不断降低。(5)对河北省的3个金地球化学省和地球化学省范围内21处区域异常进行了资源量定量预测,预测方法是面金属量法和成矿可利用金属量法,选择勘探程度高的地球化学省或区域异常作为参考区。预测结果显示分布于冀东的兴隆-遵化-宽城-青龙金地球化学省具大的资源潜力。区域异常中,位于冀东的兴隆-遵化-宽城-青龙金地球化学省内的兴隆陡子峪、遵化马兰峪、青龙安子岭区域异常金的潜在资源量很大,尤其是遵化马兰峪是大型金矿床的重点产出区域。更多还原

【Abstract】 Hebei Province is geologically located in the northern margin of North China Platform, which hosts three metallogenic megaprovinces:the Precambrian, the Paleoasian and the Circum Pacific. Iron, nonferrous and precious metals deposits are rich in the province formed in six main metallogenic periods of Archean, paleoproterozoic, mesoprozerozoic, early paleozoic, late paleozoic and mesozoic. In recent years, most of surface outcropping ore deposits have been explored and evaluated in Hebei, therefore it is more and more difficult to find large or giant ore deposits. The activities in past exploration and assessment process are concentrated on local geochemical anomalies to find single ore deposit. How to use a amount of geochemical data to delineate regional and provincial anomalies for potential large-size ore deposits is a chanllenge. The author tries to reveal the relationship of large-scale geochemical anomalies with large ore deposits or ore districts in order to predict new large ore deposits by using geochemical anomalies..Based on the 1:200000 stream sediments geochemical data in Hebei province, combined with regional rock survey and mineral data, the following results are achieved (1) Good correlation between geochemical provinces and the ore districts:3 gold,7 lead and 4 zinc geochemical provinces, each of them covering an area more than 1000km2, are delineated in whole territory of Hebei province. Two large gold districts and one lead-zinc districts are located within the geochemical provinces. Geochemical provinces are indicates to potential large ore districts. (2) Close relationship of regional anomalies with large deposits:all large gold, lead and zinc deposits are hosted within regional gold, lead and zinc geochemical anomalies (each regional anomalous area more than 20 km2) respectively. (3) Genesis of large-scale geochemical anomalies. Three sources for large-scale geochemical anomalies (regional and provincial):deposits, mineralization beds and high background rocks. High background rocks can provide high background of elements without significant concentration centers; mineralization beds can supply initial concentration of elements; weathering of deposits as point sources can further can be despersed to form superimposed contents, which have obvious concentration centers. Therefore, a multi-nested geochemical anomalies can be formed and delineated that a geochemical province contains regional anomalies, and further regional anomalies contains local anomalies around a mineral district or a large ore deposit. (4) Statistics for distribution of rare earth elements are used to identify the mineralization source of gold in Malanyu and Jinchangyu area. The fact of REE distribution model closer to that of metamorphic rocks show that Qianxi and Zunhua rock group possibly is the main mineralization source of gold. The results of surface transportation of gold in Jinchangyu deposit show that gold contents decrease gradually from ore bodies to wall rocks near mine to wall rocks far from mine to background rocks. The gold contents in stream sediments continue to reduce from ore deposit area to lower reaches of streams. (5) Quantitative resource predictions are conducted for 3 gold geochemical provinces and 21 regional anomalies within gold geochemical provinces. Areal productivity and available metals methods are used for mineral resource predictions. Geochemical province or regional anomalies containing the known gold deposits with explored reserves are chosen as reference areas. Prediction results show that Xinglong-Zunhua-Kuancheng-Qinglong gold geochemical province is potential for large gold deposits in the eastern Hebei. In regional anomalies located at Douziyu in Xinglong County, Malanyu in Zunhua County, Anziling in Qinglong County within Xinglong-Zunhua-Kuancheng-Qinglong gold geochemical province have large potential resources, particularly, Malanyu is a main prediction area of large gold deposits.更多还原