Metallogenic mechanisms of super-large Cu and Au deposits in the Dexing region and simulating experiments

Based on the results of previous studies and under the direction of the theory of “ore deposit genesis”, the authors made use of high temperature and high pressure experimental facilities and conditions at the Tectono-geochemistry Research Room under the State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, and put the focus on the multi-source of tectonically controlling ore-forming materials, the characteristics of multi-stage and multi-episode hydrothermal activities and mineralization and the characteristics of multi-genesis and multi-ore deposition so as to shed light on the metallogenic mechanisms of super-large Cu and Au deposits. In addition simulating experiments were made on multi-stage and multi-episode tectonic activities and rock and ore deformation, multi-stage and multi-episode tectonic activities and mobilization and migration of ore-forming materials, and multi-stage and multi-episode tectonic activities and superimposition and enrichment of ore-forming materials. The experimental results showed that under the action of multi-stage and multi-episode tectonic stress the deformation and fragmentation of not only rocks and ores have been intensified, and but also the ore-forming materials originally disbursed in the rocks and ores have been mobilized and migrated and superimposed and enriched. The experimental results also provided the scientific experimental data and grounds for deep-going research on the rules of metallogenesis and geneses of super-large ore deposits in the Dexing region, Jiangxi Province.     

松辽盆地三肇地区扶杨油层油气成藏过程主控因素及成藏模式

从多元地质条件及其时空匹配关系的角度出发,对三肇地区扶杨油层油气成藏过程中的主控因素进行分析。结果表明:上覆青山口组一段源岩有效排烃范围、超压和T₂反射层油源断裂组合关系控制了油气垂向向下“倒灌”的运移范围、距离及层位;古构造背景、T₂断层与储层砂体配置关系控制着油气侧向运移的方向、通道和距离;基准面旋回、沉积微相类型与现今构造配置关系控制着油气的垂向聚集层位及平面分布规律。在此基础上,结合构造发育史、油源条件及沉积微相研究成果,对研究区扶杨油层油气成藏模式进行了总结,认为研究区扶杨油层主要存在4种成藏模式:源内--顶生下储式油气成藏模式、近源--短距离侧向运移--斜坡带断层遮挡油气成藏模式、源外--长距离侧向运移--继承性构造隆起带油气成藏模式、多源--多方式侧向运移油气成藏模式。     

Comparison of the Ordovician-Carboniferous Boundary Between Korea and NE China: Implications for Correlation and Tectonic Evolution

There is a great hiatus between Ordovician and Carboniferous strata in the Northeast China and Korean Peninsula. In order to understand geology and tectonic evolution, and to find out the similarities and differences in both regions, two sections in the Western Hill near Beijing in NE China and several sections in the Korean Peninsula were selected to examine their geologic boundaries between Lower and Upper Paleozoic strata to compare their characteristic features. At four sites in the two sections in the Western Hill near Beijing were examined their contact relations. The Hui Yu section is the same horizon where one site is top of a quarry hill and the other of down hill. Mid-Carboniferous Qingshuijian Formation rests on the Ordovician Majiagou Formation. Limestone beds are more commonly intercalated with shale and sandstone at site 2 of the Hui Yu section, while at site 1, conglomerate beds are dominant. Site 1 of the Se Shu Fen section shows eroded and concealed karst topography and conglomerate beds are intercalated within shale beds. Silurian and Devonian strata are absent in these areas. In the Korean Peninsula, most O-C contacts occur between Ordovician limestone formation and Carboniferous strata, although Silurian strata occur beneath the Carboniferous strata in the Jeongseon area and Pyeongnam Basin. Most contact relations are parallel unconformity and angular unconformity is rarely seen. The O-C relations in both regions are similar to each other, and these indicate that the Korean Peninsula was located near or belonged to the Sino-Korean paraplatform during Paleozoic time.     

新疆准噶尔地区泥盆系火山碎屑岩中放射虫的发现及其地质意义

泥盆系课题组,在准噶尔地区发现20余层含放射虫的火山碎屑岩,放射虫均产于被化石证明了的下、中、上泥盆统中.在火山碎屑岩中产放射虫,国外已有报导,国内尚无正式报导.从而对该区岩相古地理提出了新认识.     

安徽铜陵地区中生代侵入岩成因及成矿意义

安徽铜陵矿集区是我国最著名的铜、金、铁产地之一,成矿与岩浆作用关系密切.本次对铜陵地区中生代侵入岩进行了系统的矿物学、岩石学和元素地球化学研究.结果表明:①本区岩浆岩主要为辉石(二长)闪长岩( SiO2≤55％)、石英(二长)闪长岩(SiO255％～65％)和花岗闪长岩(SiO2≥65％)三种岩石组合,其矿物成分主要为...     

下扬子区二叠系烃源岩评价与生源环境

基于下扬子区海域-陆域钻井岩心和露头岩样, 通过有机岩石学和有机地球化学方法, 应用有效指标参数, 从不同维度综合分析下扬子区上二叠统大隆组、龙潭组和下二叠统孤峰组、栖霞组4套烃源岩在纵向及平面上的有机地球化学特征、生烃潜力和生源环境。根据测试数据及前人研究资料, 栖霞组和大隆组烃源岩的有机质丰度为中等-好级别, 龙潭组烃源岩的有机质丰度为一般-中等级别, 孤峰组烃源岩有机质丰度达到很好级别。下二叠统烃源岩有机质丰度在平面展布上表现出海域优于陆域的特点, 上二叠统则反之。根据干酪根碳同位素特征, 栖霞组烃源岩有机质类型最好, 为Ⅰ~Ⅱ型; 其他3套烃源岩均为Ⅱ~Ⅲ型母质类型。4套烃源岩成熟度参数镜质体反射率主频分布范围为1.3%~2.0%, 均达到高热演化阶段, 在平面展布上表现出明显的非均一性。二叠系4套烃源岩生物来源以低等水生生物为主, 有机质均在贫氧的弱还原-弱氧化条件下保存, 其中大隆组沉积的水体动荡频繁和生物变化较明显。综合认为, 下扬子区二叠系烃源岩有机质丰度高, 类型较好, 具有形成大型油气田的良好物质基础, 尤其是以往被忽略的孤峰组烃源岩评价等级被提高, 是一套潜在的优质烃源岩, 其对该区进一步的油气勘探具有重要的指导意义。     

甘肃北山南带前红泉金矿的发现及其找矿意义

甘肃北山南带是中国西北地区重要的金属矿床富集区,已发现多处韧性剪切带型金矿床或与韧性剪切带有关的金矿床,但近年来该区有关韧性剪切带型金矿的研究和找矿勘查工作陷入沉寂。前红泉金矿是在基础地质调查工作的基础上通过大比例尺化探手段逐步发现的中型金矿床。通过野外勘查和室内综合研究发现,该金矿床产于长城纪古硐井群千糜岩、千枚岩和千枚状板岩中,严格受NWW向韧性剪切带控制,硅化、毒砂化、绢云母化、黄铁矿化是与之关系密切的矿化蚀变。区内金化探异常高值区及相关矿化蚀变可作为该矿床主要的找矿标志。前红泉金矿的发现对北山南带寻找与韧性剪切带有关的金矿具有重要的指导意义,尤其是在勘查方法手段选择、找矿思路及方向上具有一定的借鉴价值。文章提出已有矿床外围、深部及重要化探异常区是下一步找矿突破的重点区域。     

山东烟台地区苹果果园土壤中DDTs和HCHs残留分布特征与来源解析

为研究不同土壤类型中有机氯农药的残留特征、降解程度和来源途径,采集了山东烟台9个不同地质单元苹果园根系土壤和剖面土壤样品,用电子捕获检测器气相色谱法测定其中的滴滴涕(DDTs)和六六六(HCHs)。结果表明,研究区所有类型根系土壤中DDTs和HCHs均未超出《土壤环境质量标准》的二级土壤限值(500 ng/g);土壤中DDTs的残留量及检出率均高于HCHs,DDTs检出率为100%,平均残留量为71.7ng/g,而HCHs的检出率为19.70%,平均残留量为7.9 ng/g;根系土壤中DDTs各异构体平均浓度依次为p,p’-DDT>p,p’-DDE>o,p’-DDT>p,p’-DDD,而HCHs大部分以α-HCH形式存在,部分以β-HCH、γ-HCH存在。不同类型土壤中有机氯农药残留分布特征明显不同:DDTs在棕壤土(臧家庄)中最高(145.5 ng/g),在中粗粒砂土(武宁)中最低(24.1 ng/g);而HCHs在细砂质壤土(蛇窝泊)中最高(27.9ng/g)。各剖面土壤DDTs均在<20 cm层位中残留最高。DDTs和HCHs来源解析表明:研究区土壤为好氧条件;麻砂棕壤(官道和桃村)、黏细壤土(牟平)、细砂质壤土(蛇窝泊)和棕壤土(臧家庄)近年来仍有新的DDTs输入;大部分根系土壤均未发现HCHs新来源,但麻砂棕壤(桃村)在HCHs禁用后可能仍存在林丹的使用。     

不等长工作面台阶区域覆岩运动诱冲机制及防治

针对阳城煤矿不等长工作面台阶区域发生冲击地压灾害问题,基于工作面特殊布置方式及覆岩赋存特征,采用理论分析、数值模拟和现场实测等方法,分析了台阶区域覆岩结构运动特征和围岩应力演化规律,研究了台阶区域冲击地压诱发机制。研究结果表明：1304工作面台阶区域覆岩经历了“OX-S-C”型较为复杂的结构演变,覆岩空间结构由OX向S型转换时,顶板岩层大面积破断下沉,在台阶区域形成多个悬臂梁结构,越往高位,悬臂梁长度越大;受覆岩运动和采动应力场叠加影响,煤岩体形成高应力集中区,在顶板岩层动载冲击作用下,煤岩体弹性应变能突然释放,诱发冲击地压。采用COMSOL软件对不同卸压钻孔参数下煤体应变能分布特征进行模拟研究,优化了台阶区域卸压钻孔参数。根据模拟结果,随着钻孔孔径、孔深增大及间距减小钻孔卸压效果越明显,考虑工程实际,确定孔径为150 mm、孔深为30 m、间距为1 m为合理有效的卸压钻孔参数,并应用于1302工作面台阶区域的冲击地压防治,取得了较好的防冲效果。     

冀东柳赞地区油气成藏中断层的作用

冀东油田柳赞地区断裂构造发育,在面积约为40km2范围内;发育着30多条断层,而这些断裂是什么时期产生的,它们在油气聚集成藏中起着什么作用,是先有油气聚集、后有断裂,还是先有断裂后才发生油气聚集。这些问题不仅是油气成藏过程研究的焦点,而且还直接影响到对该地区的评价和有利油气聚集带的确定。本文通过研究发现,本区断裂的形成和分布主要受柏各庄、溯河、高柳三条边界断裂活动的控制,并且断裂的产生是有次序的,不同时期形成的断层对油气藏的形成具有不同的作用。