中国海域区古近纪含煤盆地与煤系分布研究   总被引：1，自引：0，他引：1  

李增学  张功成  李莹  刘海燕  吕大炜  沈怀磊  尚鲁宁 《地学前缘》2012,19(4):314-326

新近纪和古近纪是全球重要的聚煤期。中国古近纪聚煤盆地分布在东部沿海省区,是全球性环太平洋聚煤带的组成部分。中国海域区含煤沉积盆地虽然也属于断陷盆地和坳陷盆地类型,且成群出现,但总体构造背景有利于含煤沉积的持续发展,盆地群连续性好,含煤沉积厚度大,如琼东南盆地、东海海域西湖凹陷,含煤沉积厚度达1 km以上,这是陆上区古近纪含煤盆地所不能相比的。研究表明,海域区的聚煤盆地内大多由若干凹陷组成,为聚煤凹陷,可分为两大类,即半地堑凹陷和地堑凹陷。根据成煤盆地的水体深浅又可分为深水半地堑凹陷和浅水半地堑凹陷,地堑凹陷均为深水凹陷。盆地内表现为明显的两个聚煤带：缓坡聚煤带和陡坡聚煤带,缓坡聚煤带占绝对优势。在潮坪体系的潮上带和潮间带沼泽,利于聚煤作用的广泛发生。泥炭的堆积可能存在两种形式：原地堆积和异地堆积。由于盆地构造的频繁活动异地堆积可能是海域区聚煤盆地成煤作用的重要形式。海域区巨厚的含煤沉积为海域区煤成气成藏提供了丰厚的物质基础。又由于含煤地层埋深大,煤的变质作用程度相对较高,成为良好的烃源岩。  相似文献   

河南省南襄盆地泌阳凹陷古近系核桃园组湖相页岩油储集层特征   总被引：1，自引：0，他引：1       下载免费PDF全文

章新文  王优先  王根林  朱颜  罗曦  陈希敏  贾艳雨 《古地理学报》2015,17(1):107-118

尽管对南襄盆地泌阳凹陷古近系核桃园组湖相页岩采用大型压裂初产已获高产油气流,但是对该湖相页岩储集层特征尚未进行系统研究。文中应用薄片分析及全岩X衍射分析,结合陆相页岩矿物组成特点,将泌阳凹陷湖相页岩划分为块状泥岩、纹层状黏土质页岩、纹层状粉砂质页岩、纹层状灰质页岩及纹层状云质页岩5种类型。根据页岩岩心样品氩离子抛光扫描电镜分析结果,探讨了研究区湖相页岩的储集特征:(1)主要发育溶蚀孔、晶间孔、粒间孔、构造缝、层间页理缝和微裂缝等储集空间类型;(2)孔隙发育具有各向异性;(3)孔隙以中孔体积为主,微孔次之,孔径平均为4.76 nm,有2个峰值区,分别是2～3 nm和71 nm左右。进一步分析表明,岩石类型控制了储集层的储集空间发育特征,研究区以纹层状灰质页岩的溶蚀孔、晶间孔、有机质孔、层间缝等孔隙最为发育,其亦对页岩油储集最为有利。  相似文献   

中国东部断陷湖盆细粒沉积岩岩相划分方案探讨——以渤海湾盆地南部古近系细粒沉积岩为例     

张顺  刘惠民  陈世悦  王永诗  蒲秀刚  张奎华  韩文中 《地质学报》2017,91(5):1108-1119

细粒沉积岩岩相研究是烃源岩和页岩油、致密油储层研究的重要基础,鉴于我国陆相断陷湖盆环境多变和细粒沉积岩类型多样、岩石组合类型复杂的特点,需要进行细粒沉积岩岩相分类。以渤海湾盆地南部古近系细粒沉积岩发育段为研究对象,通过厘米级岩芯观察描述、岩石薄片鉴定、激光共聚焦显微镜观察分析等技术,研究细粒沉积岩基本特征。陆相断陷湖盆细粒沉积岩岩相划分可以按照(1)宏观岩芯精细观察描述,归纳垂向岩石类型组合;(2)分析沉积微环境;(3)对不同岩石类型组合进行X射线全岩矿物衍射和TOC测试,划分岩石类型和岩相大类;(4)微观镜下剖析纹层叠置关系;(5)分析成因和形成机制,对岩亚类细分等5步进行。岩相大类划分要简洁,是为满足油田勘探工作易于操作、建立与常规测井资料之间关系等要求;亚类细分是便于研究微观源储关系、分析沉积微环境和储层微观结构等。  相似文献   

Paleogene magmatism and gold metallogeny of the Jinping terrane in the Ailaoshan ore belt,Sanjiang Tethyan Orogen (SW China): Geology,deposit type and tectonic setting     

《Ore Geology Reviews》2017

The Jinping terrane is situated in the southern segment of the Ailaoshan ore belt, Sanjiang Tethyan Orogen (SW China). The Paleogene intrusions in Jinping consist of syenite porphyry, fine-grained syenite and biotite granite stocks/dikes, and contain relatively low TiO₂ (0.21–0.38 wt%), P₂O₅ (0.01–0.35 wt%), and high Na₂O (2.00–4.62 wt%) and K₂O (4.48–7.06 wt%), belonging to high-K alkaline series. Paleogene gold mineralization in Jinping comprises four genetic types, i.e., orogenic, alkali-rich intrusion-related, porphyry and supergene laterite. The NW–NNW-trending faults and their subsidiaries are the major ore-controlling structures. The orogenic Au mineralization, dominated by polymetallic sulfide-quartz veins, occurs in the diorite and minor in Silurian-Devonian sedimentary rocks. It contains a CO₂-rich mesothermal fluid system generated from the mixing of mantle-derived fluids with crustal-derived metamorphic fluids, and the ore-forming materials were upper crustal- or orogenic-derived. The alkali-rich intrusion-related Au mineralization is hosted in the Ordovician-Silurian sedimentary rocks and minor in the Paleogene alkaline intrusions, and the Au orebodies occur predominantly in the alteration halos. It contains a CO₂-bearing, largely metamorphic-sourced mesothermal fluid system, and the ore-forming materials were derived from the ore-hosting rocks and minor from the alkali-rich intrusions. The porphyry Cu-Mo-Au mineralization occurs in the granite/syenite porphyries and/or along their contact skarn, with the mineralizing fluids being magmatic-hydrothermal in origin. The former two hypogene Au mineralization types in Jinping were mainly formed in the late Eocene (ca. 34–33 Ma) and slightly after the porphyry Cu-Mo-Au mineralization (ca. 35–34 Ma), which is coeval with the regional Himalayan orogenic event. Subsequent weathering produced the laterite Au mineralization above or near the hypogene Au orebodies.  相似文献   

陆相断陷盆地低凸起斜坡带层序划分及其沉积充填演化特征:以埕岛东斜坡古近系为例   总被引：2，自引：2，他引：0  

谢宗奎 《地学前缘》2010,17(4):174-184

层序分级不一致和井震层序不统一都会导致沉积充填演化特征反映的不准确,将制约储盖组合与油气分布的预测。文中应用沉积层序的概念,利用岩心、岩性、测井与地震资料,以层序界面与内部构成特征相结合的原则,从坡下到坡上,对东斜坡古近系进行了层序划分。一级层序相当于系地层单元,与构造运动相对应,层序界面为区域性角度不整合;二级层序相当于统或组地层单元,与构造运动幕相对应,层序界面为局部不整合;三级层序相当于段或亚段地层单元,与构造幕内的次级构造作用相对应,层序界面为超覆不整合面、沉积体系转换面及重力流下切面;四级层序即体系域,相当于油组与砂组,与三级层序基准面旋回的阶段性变化相对应,层序界面为初始洪泛面、最大洪泛面,共识别出SQ1、SQ2、SQ3、SQ4、SQ5和SQ6等6个三级层序及15个体系域。井震统一的层序格架结合了钻井资料纵向高分辨率与地震资料横向好连续性的优点,从而高精度、高分辨率地揭示了层序格架充填演化特征,体现出层序旋回性与体系域及平面沉积相分布的差异性。古近纪埕岛凸起夷平,斜坡及凹陷补齐,发育超覆、披覆沉积;古地形由南低北高向南高北低转换;本地物源、邻近物源、区域物源阶段性变迁;多物源的沉积体系交叉、叠置,沉积相发生了扇三角洲-浊积扇-半深湖-滑塌浊积扇-辫状河三角洲-曲流河泛滥平原演变。埕岛低凸起斜坡带层序及沉积充填演化特征具有陆相断陷盆地的代表性,因而,此项研究对于解决层序地层学面临的工业化应用研究不足的问题以及油气储盖组合预测方面的难点可提供有益参考。  相似文献   

Temporal variations in channel patterns and facies architecture in a gravelly fluvial system: The Paleogene Iwaki Formation on the Joban Coalfield,a forearc basin in Northeast Japan     

Kenichiro Shibata  Makoto Ito  Nagayuki Nemoto  Sakae O'Hara 《Island Arc》2010,19(3):489-505

This paper examined sequence‐stratigraphic features of a gravelly fluvial system of the Iwaki Formation, which developed in a forearc‐basin setting in Northeast Japan during the Eocene through Oligocene. On the basis of three‐dimensional architectural element analysis, we discriminated three major cycles of channel complexes, which contain ten component channel deposits in total in the fluvial succession. Component channel deposits in the uppermost part of each cycle are sandier and associated with overbank muddy deposits and coal beds as compared with those in the lower part of the cycle. Mean clast‐size also decreases upsection in the entire gravelly fluvial deposits. The fluvial succession is interpreted to have been deposited in response to an overall rise in relative sea level that was superimposed by three short‐term relative sea‐level rises on the basis of vertical stacking patterns and component lithofacies features of channel deposits, and of correlation of the fluvial succession with an age‐equivalent marine succession in an area about 50 km offshore. However, geometry and stacking patterns of the channel complexes do not exhibit any distinct temporal variation and amalgamated channel and bar deposits are dominant throughout the transgressive fluvial succession. On the other hand, an overall fining‐upward pattern of the entire Iwaki Formation fluvial deposits in association with three component fining‐upward patterns is distinct, and is interpreted to be consistent with the tenet of the standard fluvial sequence‐stratigraphic models. This indicates that the present example represents one type of variation in the standard fluvial sequence‐stratigraphic models, possibly reflecting the forearc‐basin setting, which is generally represented by higher valley slope, higher shedding of coarse‐grained sediments, and shorter longitudinal profiles to the coastal area as compared with a passive‐continental‐margin setting.  相似文献   

Formation and deformation processes of late Paleogene sedimentary basins in southern central Hokkaido,Japan: Paleomagnetic and numerical modeling approach     

Machiko Tamaki  Shigekazu Kusumoto  Yasuto Itoh 《Island Arc》2010,19(2):243-258

Formation and deformation processes of the late Paleogene sedimentary basins related to a strike–slip fault system in southern central Hokkaido are described by a combination of paleomagnetic study and numerical analysis. After correction of the Miocene counter‐clockwise rotation associated with back‐arc opening of the Japan Sea, paleomagnetic declination data obtained from surface outcrops in the Umaoi and Yubari areas show significant easterly deflections. Although complicated differential rotation is anticipated as a result of recent thrust movements, clockwise rotation in the study areas is closely linked with development of the Paleogene Minami‐naganuma Basin as a pull‐apart depression along the north–south fault system. Numerical modeling suggests that 30 km of strike–slip is required to restore the distribution and volume of the Minami‐naganuma Basin. The relative slip rate on the long‐standing fault system is about 10 mm/yr, which corresponds to global‐scale plate motion. It has inevitably caused regional rearrangement of the eastern Eurasian margin. A rotation field simulated by simplified dextral motion using dislocation modeling basically accords with the paleomagnetic data around the pull‐apart basin.  相似文献   

辽河坳陷西部凹陷南段古近系沙河街组致密砂岩特征与成因机制^*   总被引：1，自引：1，他引：0       下载免费PDF全文

孟元林  王志轩  张凤莲  孟凡晋  焦金鹤  施立冬 《古地理学报》2016,18(4):569-580

渤海湾盆地辽河坳陷西部凹陷南段古近系沙河街组中发现了低产油气流和工业油气流,储集层具有低—特低孔隙度、特低—超低渗透率、低压的特征,属于典型的致密砂岩储集层。应用大量的薄片、扫描电镜、粒度分析、压汞和物性等测试资料,研究了致密砂岩的微观特征,探讨了致密砂岩的形成机理。研究结果表明,致密砂岩(孔隙度小于10.0%)大多发育在凹陷区;矿物成分、粒度、分选、磨圆等沉积学参数与致密砂岩的形成关系不大;致密砂岩的孔隙类型主要为次生孔隙,孔隙结构整体上具有中孔径、微细喉以及喉道分选不均匀等特征;机械压实作用和胶结作用导致了致密砂岩的形成,该致密砂岩属于次生型致密砂岩。  相似文献   

敦密断裂带盆地群油页岩特征及成矿差异分析     

刘招君  孙平昌  柳蓉  孟庆涛  胡菲 《吉林大学学报(地球科学版)》2016,46(4):1090-1099

古近纪敦密断裂带上分布一系列的含油页岩盆地群。根据盆地间构造-沉积充填、岩石组合和油页岩赋存特征,初步确认盆地群中油页岩沉积于湖盆鼎盛阶段,均形成于古近系始新统路特阶。盆地群间油页岩矿床特征存在明显的差别,由西南向东北,油页岩厚度逐渐变小,其沉积环境由深湖到半深湖,再到湖沼,而有机质来源则由湖泊生物为主,到湖泊生物和陆源有机质双向来源,过渡为以陆源高等植物为主。结合含油页岩层系形成于同一时期和相似的古气候背景下,盆地沉降和沉积充填作用是影响油页岩矿床差异的关键因素。长期处于欠补偿环境,可容纳空间大的湖盆利于巨厚油页岩的形成,随着可容纳空间的减少、陆源碎屑供给的增多,油页岩厚度减薄,分布也变得相对局限。深湖和湖沼成因油页岩品质较好,半深湖油页岩品质较差。  相似文献   

藏北阿里地区改则县雀康一带纳丁措组火山岩锆石U-Pb年龄和地球化学特征   总被引：2，自引：2，他引：0       下载免费PDF全文

褚慧力 《中国地质调查》2016,3(6):37-48

纳丁措组火山岩分布于班公湖—怒江结合带以北,属于羌塘—三江复合板片内多玛地层分区雀康地层小区的火山岩地层,代表了羌南地区古近纪的火山活动,为一套粗安岩-粗面岩的岩石组合。在地层区采集了3件岩石年龄样品,测年结果分别为(35.99±0.29) Ma、(37.2±0.65) Ma、(35.23±0.37) Ma。样品中SiO₂含量均较高,介于58.7%~65.51%之间; 铝饱和指数A/NFC为0.046~1.029,普遍较低,显示偏铝岩石的特性; MgO含量普遍略高,介于1.10%~2.95%之间。稀土元素(rare earth element,REE)特征显示,样品中REE总量为243.38×10^-6~313.48×10^-6,说明岩石属于稀土元素偏高型,其中∑[w(Ce)]/∑[w(Y)]为15.24~20.61,属于轻稀土富集型; [w(La)/w(Yb)]_N为26.34~52.01,说明轻、重稀土分异明显; δEu为0.77~0.91,属于弱负异常。Rb、Th等大离子亲石元素富集度高,而Hf和重稀土元素等高场强元素丰度值较低,绝大部分样品分析结果显示Ti、Ta、Nb亏损明显,w(La)/ w(Sm)值较为稳定,w(Sm)/ w(Yb)为4.3~6.7,比值较低。根据岩石地球化学特征,判断纳丁措组火山岩原始岩浆来源于青藏高原加厚陆壳之下与岩石圈地幔之上的特殊壳幔过渡带,形成环境为造山带附近的大陆拉张的板内初始裂谷环境。  相似文献