湖南省煤系石墨成矿规律与找矿方向探讨

湖南省侵入岩多,构造较复杂,为系统研究煤系石墨资源成矿规律,在收集现有地质资料的基础上,借鉴国内外煤系石墨矿床的赋存特点,结合湖南省石墨资源的分布特点和开发现状,采用地质调查、生产井调查、采样化验等手段,研究骑田岭岩体和天龙山岩体2个花岗岩体周边现有矿区的矿体地质特征,探讨石墨矿的成因类型和控矿因素。结果表明,研究区石墨矿成因类型为接触变质型,主要控矿因素为岩体的侵位机制、构造作用方式、矿体的形态及变质程度。进而提出了3种石墨赋存模式：兜底式、向斜式、背斜式。提出研究区寻找煤系石墨的突破方向：煤系走向与主压应力方向大致垂直并在岩体附近1.0~1.5 km范围内。     

锅盔山石墨矿床变质特征与碳质来源

黑龙江省锅盔山石墨矿床为近年新发现的超大沉积变质型石墨矿床,对该矿床变质作用特征与过程以及碳质来源的研究仍属空白.通过岩石学、岩石化学、碳同位素组成等研究,对矿区赋矿变质岩进行了原岩恢复,并探讨了岩石变质特征和矿床成因.研究认为:该区变质岩变质程度达高角闪岩相,并经历了等温降压退变质作用,矽线石形成于熔体结晶;原岩为一套具孔达岩系特征的浅海—滨海相碳硅泥岩建造,具太古宙古大陆与元古宙稳定沉积物的双重信息;成矿物质来源为有机碳,属有机成因.研究成果对在该地区寻找同类型矿床具有一定的指导意义.     

大东山锡矿田矿床地质特征及矿床成因

大东山锡矿田矿化类型复杂,其中矽卡岩型锡矿规模大,可分含锡矽卡岩型和硫化物矽卡岩型。岩体区有脉状和面状云英岩产出,前者多具锡矿化,后者具钨矿化。燕山第四期花岗岩是锡(钨)成矿母岩,含SiO274.96%~75.28%,K2O+Na2O7.37%~8.54%,K2O>Na2O,与南岭地区钨锡成矿岩体具有相似的岩石化学特征。锡矿成因类型可划分为接触交代型、侵入岩浆热液型和风化矿床。根据成矿地质条件,认为在接触带寻找硫化物矽卡岩、硫化物型锡矿有较大前景,而在岩体区具有寻找云英岩型钨矿的潜力。     

现代微区测试技术在确定宝玉石产地来源中的应用及其研究进展

宝玉石产地来源的研究是近几年地质学、宝石学和考古学界的热门话题之一。一方面,不同产地来源的宝玉石可能具有不同的品质特征及经济价值,其研究有助于珠宝首饰价值的判断,为各国海关执法提供技术支持;另一方面,古代宝玉石产地的确定对了解古代宝玉石的开采与古代科技的发展水平及不同区域的文化交流均具有重要意义。在总结前人研究成果的基础上,结合现代微区测试技术的最新研究成果,从微量元素、包裹体以及同位素分析等方面探讨总结了微区测试技术在确定宝玉石产地来源研究中的应用。当前的研究结果显示,不同的技术方法对确定宝玉石的产地来源均有一定的意义,但宝玉石产地来源的最终确定往往需要依赖更大范围和更深入地对宝石矿床的地球化学进行多技术手段的交叉分析。显然,确定各种不同类型宝玉石产地来源的标型特征及建立相关重要宝石产地的地球化学数据库,是最终解决宝玉石产地来源鉴定问题的关键。     

大兴安岭东北部哈拉巴奇花岗岩体锆石U-Pb年龄及其成因

哈拉巴奇岩体主要由二长花岗岩钾长花岗岩和花岗闪长岩组成。样品的LAICPMS锆石UPb年龄测定和主量及微量元素的分析结果表明,哈拉巴奇岩体为两次侵位的早古生代花岗岩体,其中二长花岗岩钾长花岗岩的侵位时间较早(500Ma),花岗闪长岩的侵位时间相对较晚(461Ma);岩体具有后造山花岗岩类的岩石组合特征和地球化学特征,为额尔古纳地块与兴安地块碰撞拼贴作用结束后的后造山阶段的产物;二长花岗岩钾长花岗岩和花岗闪长岩起源于相同的岩浆源区,其源区物质可能是中元古代期间地幔中新增生的地壳物质,二者地球化学特征的差别是源岩部份熔融程度不同所致。     

云南砚山晚二叠世煤中V、Cr、Mo和U的丰度与赋存状态

运用电离耦合等离子体质谱(ICP-MS)和逐级化学提取(SCEE)的方法测定了云南砚山晚二叠世煤中金属元素的含量,发现煤中高度富集V、Cr、Mo和U,含量分别为621 μg/g、315 μg/g、198 μg/g和167 μg/g.逐级化学提取结果表明,这4种元素主要赋存在有机质和硅铝化合物中,反映其是在泥炭聚集期间或成岩作用早期进入到泥炭沼泽而富集的.     

福建大田—漳平地区构造-热对煤系石墨成矿及赋存的控制探讨

福建省大田—漳平地区位于东部滨太平洋构造带上,不同时期的岩浆热液作用和复杂多变的构造形变格局,为该地区形成丰富的石墨矿床提供了良好的成矿条件。为了查明大田—漳平地区煤系石墨的成矿控制因素及分布规律,通过工业分析、元素分析、X射线衍射和激光拉曼光谱等实验,对不同矿区不同变质程度的煤和煤成石墨的化学组成及微观结构特征等煤成石墨化特征进行了研究,并将不同变形特征的样品划分为煤成石墨、煤成半石墨和石墨化无烟煤三大类。研究表明：煤的变形特征与煤成石墨的演化类型基本一致,且韧性变形样品的石墨化程度最高,说明构造应力作用能促进煤的石墨化作用;煤成石墨的分布受到岩浆-构造活动的控制,石墨矿床多产出于岩浆岩侵入体外接触带或附近断裂带的有利围岩地层中,且大田—漳平地区煤系石墨矿具有明显的成区、成带分布特点,煤成石墨成矿区主要集中在闽西南坳陷南部的漳平一带;而北部大田一带分布的矿区矿体石墨化程度较漳平一带低,多为煤成半石墨或石墨化无烟煤,研究结果可为该地区煤系石墨矿产综合勘探开发利用提供有利依据。     

Modes of Occurrence and Geological Origin of Beryllium in Coals from the Pu'an Coalfield, Guizhou, Southwest China

The concentration, modes of occurrence and geological origin of beryllium in five workable coal beds from the Pu'an Coalfield of Guizhou were studied using the inductively coupled-plasma mass spectrometry (ICP-MS), floating and sinking experiments (FSE) and sequential chemical extraction procedures (SCEP). The results show that the average concentration of beryllium in coals from the Pu'an Coalfield is 1.54μg/g, much lower than that in most Chinese and worldwide coals. Beryllium in the Pu'an coals was not significantly enriched. However, it should be noted that the No. 8 coal bed from the study area has a high concentration of beryllium, 6.89μg/g, three times higher than the background value of beryllium in coal. Beryllium in coal mainly occurs as organic association and has predominantly originated from coal-forming plants when its concentration is relatively low. The concentration of beryllium occurring as organic association is close to that distributed in inorganic matter when beryllium concentration of coal is similar to its background value, and in addition to coal-forming plants, beryllium is mainly derived from detrital materials of terrigenous origin. When beryllium is anomalously enriched in coal, it mainly occurs as organic association and is derived from volcanic tonsteins leached for a long geological time and then adsorbed by organic matter in peat mire.     

Modes of Occurrence and Geological Origin of Beryllium in Coals from the Pu''an Coalfield, Guizhou, Southwest China

The concentration, modes of occurrence and geological origin of beryllium in five workable coal beds from the Pu'an Coalfield of Guizhou were studied using the inductively coupled-plasma mass spectrometry (ICP-MS), floating and sinking experiments (FSE) and sequential chemical extraction procedures (SCEP). The results show that the average concentration of beryllium in coals from the Pu'an Coalfield is 1.54μg/g, much lower than that in most Chinese and worldwide coals. Beryllium in the Pu'an coals was not significantly enriched. However, it should be noted that the No. 8 coal bed from the study area has a high concentration of beryllium, 6.89μg/g, three times higher than the background value of beryllium in coal. Beryllium in coal mainly occurs as organic association and has predominantly originated from coal-forming plants when its concentration is relatively low. The concentration of beryllium occurring as organic association is close to that distributed in inorganic matter when beryllium concentration of coal is similar to its background value, and in addition to coal-forming plants, beryllium is mainly derived from detrital materials of terrigenous origin. When beryllium is anomalously enriched in coal, it mainly occurs as organic association and is derived from volcanic tonsteins leached for a long geological time and then adsorbed by organic matter in peat mire.     

Modes of Occurrence and Geological Origin of Beryllium in Coals from the Pu''''an Coalfield, Guizhou, Southwest China

The concentration, modes of occurrence and geological origin of beryllium in five workable coal beds from the Pu'an Coalfield of Guizhou were studied using the inductively coupled-plasma mass spectrometry (ICP-MS), floating and sinking experiments (FSE) and sequential chemical extraction procedures (SCEP). The results show that the average concentration of beryllium in coals from the Pu'an Coalfield is 1.54μg/g, much lower than that in most Chinese and worldwide coals. Beryllium in the Pu'an coals was not significantly enriched. However, it should be noted that the No. 8 coal bed from the study area has a high concentration of beryllium, 6.89μg/g, three times higher than the background value of beryllium in coal. Beryllium in coal mainly occurs as organic association and has predominantly originated from coal-forming plants when its concentration is relatively low. The concentration of beryllium occurring as organic association is close to that distributed in inorganic matter when beryllium concentration of coal is similar to its background value, and in addition to coal-forming plants, beryllium is mainly derived from detrital materials of terrigenous origin. When beryllium is anomalously enriched in coal, it mainly occurs as organic association and is derived from volcanic tonsteins leached for a long geological time and then adsorbed by organic matter in peat mire.