藏北羌塘盆地侏罗纪含颗石藻黑色岩系地球化学特征与地质意义

藏北羌塘盆地侏罗系发育一套富含有机质的黑色岩系,化石较为丰富而倍受地质学家关注。本文选择双湖地区毕洛错剖面,从有机地球化学和元素地球化学方面分析富含颗石藻黑色岩系特征。研究表明,研究区黑色岩系有机碳含量为2.84%~3.71%,氯仿沥青"A"含量为0.18%~0.29%。有机质类型为Ⅱ1型,母质主要来源于浮游生物及少量陆生植物,Tmax为429~435℃,显示该套岩系处于未成熟阶段。研究区样品的主量元素Si、Al、Ca等元素较富集,表明该套黑色岩系以陆源碎屑输入为主;V/Cr、U/Th、Ni/Co、V/(Ni+V)特征比值、U和Mo的富集以及Eu和Ce无明显异常,反映了该套黑色岩系主要沉积在弱还原环境,有利于有机质保存。以上研究表明,研究区含颗石藻黑色岩系为较好的烃源岩,保存条件较好,可以作为进一步勘探开发的有利烃源岩层。     

中国南方泥盆系发现颗石藻

颗石藻作为一种超微远洋浮游生物,出现于侏罗纪里阿斯世(Lias),繁盛于晚白垩世至第三纪。最近又有所进展。哈克(Hag,1981)面告,最老的颗石藻出现于石炭纪和二叠纪。本文所报道之颗石藻发现于晚泥盆世,是截至目前为止最老的颗石藻化石。 颗石藻演化迅速,分布广泛,形态特征明显,而且数量众多,对划分对比海相地层有一定的意义。本文只对研究区所采标本的颗石藻进行鉴定、描述和分类。     

中国南方泥盆系的颗石藻

本文鉴定和描述了中国南方泥盆系的颗石藻化石,计有两个新属,八个新种和一个未定种。其中中华甲球藻属(新属)(Sinothoracosphaera gen.nov.)包括盘桃中华甲球藻(新种)(S.placenta sp.nov.)和异孔中华甲球藻(新种)(S.heteromorphicpororata sp.nov.);始驳船球石属(新属)(Eopontosphaera gen.nov.)只一个新种,即背篓形始驳船石(新种)(E.basketa sp.nov.)其它五个新属是瘤刺篮石(新种)(Scyphosphaera verruca-cras-sispina sp.nov)、小卷螺海石颗石藻(新种)(Helicopontosphaera snaila sp.nov.)、口盖无缘帽形石(新种)(Calyptrolithus operculum sp.nov.)、口孔棒球藻(新种)(Rhabdosphaerabucca-pororata sp.nov.)、柿子颗石藻(新种)(Coccolithus persimmonus sp.nov.)。一个未定种是篮石未定种(Scyphosphaera sp.)。这些化石均是在深水断槽相中发现的。     

藏北安多地区侏罗纪菊石动物群及其古地理意义

藏北安多地区新发现2套以黑色页岩、深灰色钙质泥岩和泥灰岩为主的舍菊石化石的侏罗纪地层，它们与羌塘地区广泛分布的雁石坪群无论在化石组合或沉积特征方面都明显不同．岗尼乡剖面地层中产太阳菊石科的菊石，主要有Sonninia，Dorsetensia，Witchellia等。、这套地层是双湖地区色哇组的东延部分，时代确定为中侏罗世早中巴柔期114道班剖面中羌姆勒曲组的菊石化石大多归属于Virgatosphinctinae科，计有Aulacosphinctes、Virgatosphinctes等，均为上侏罗统菊石化石的典型分子，产出层位应归于提塘阶中、上部。藏北安多-改则以北一线的侏罗系深水黑色岩系虽不十分连续，但从有化石证据的土阿辛阶到巴柔阶再到提塘阶都有零星出露，它们同属一个沉积相区。侏罗纪时羌塘南部可能存在一套大陆边缘型沉积地层，因此有必要对该区的构造属性和演化历史重新进行解释。     

新疆塔里木板块西北缘早二叠世深水遗迹化石的发现及意义

在新疆塔里木板块西北缘下二叠统比尤勒提群中部首次发现了大量深水遗迹化石,主要包括Glockeria Ksiazkiewicz 1968,Helminthoida sp., Megagrapton sp., Paleodictyon sp., Paleodictyon (Glenodictyum) Croaticum Ulchman 1995, Planolites sp., Protopaleodictyon sp., Scalarituba missouriensis Weller 1899, Spirophycus sp.等,代表典型深海环境的Nereites遗迹相。根据对温古尔剖面的研究,比尤勒提群下部为浅海陆棚相砂泥质灰岩、粉砂质泥岩、粉砂岩、泥晶灰岩等;而含丰富遗迹化石的比尤勒提群中部为一套深海海底扇沉积的浊积岩系夹少量硅质岩,并且在浊积扇的不同位置所产遗迹组合类型也明显不同,扇根以觅食迹为主,含大量穿相分子,扇中开始出现牧食迹,扇梢则出现特征的耕作迹;比尤勒提群上部为浅海陆棚－滨海相沉积的硅质灰岩、泥晶灰岩和砂质灰岩及粉砂质泥岩、钙质砂岩等。该套遗迹化石组合与深海浊积事件密切相关,同时表明塔里木板块西北缘早二叠世时期存在一个陆棚浅海－深海盆地沉积环境,晚二叠世时期海水向西退去形成陆相沉积。     

山东下第三系碳酸盐岩中发现颗石藻

<正> 一、颗石藻的发现及其形态特征颗石藻(Coccolithaceae)是属于金藻门的漂浮钙藻类生物,形态多为圆、椭圆、卵圆、盘状、星状、盘星状、钩状、玫瑰花状及弯曲的小线状等。其化石产于侏罗纪以来的海相沉积岩内。单个颗石由方解石微晶(直径常在0.25—1微米)以错综复杂的构造构     

新疆塔里木板块西北缘早二叠世深水遗迹化石的发现及意义

在新疆塔里木板块西北缘下二叠统比尤勒提群中部首次发现了大量深水遗迹化石,主要包括Glockeria Ksiazkiewicz1968,Helminthoida sp.,Megagrapton sp.,Paleodictyon sp.,Paleodictyon(Glenodictyum)Croaticum Ulchman1995,Planolites sp.,Protopaleodictyon sp.,Scalaritubamissouriensis Weller1899,Spirophycus sp.等,代表典型深海环境的Nereites遗迹相。根据对温古尔剖面的研究,比尤勒提群下部为浅海陆棚相砂泥质灰岩、粉砂质泥岩、粉砂岩、泥晶灰岩等;而含丰富遗迹化石的比尤勒提群中部为一套深海海底扇沉积的浊积岩系夹少量硅质岩,并且在浊积扇的不同位置所产遗迹组合类型也明显不同,扇根以觅食迹为主,含大量穿相分子,扇中开始出现牧食迹,扇梢则出现特征的耕作迹;比尤勒提群上部为浅海陆棚-滨海相沉积的硅质灰岩、泥晶灰岩和砂质灰岩及粉砂质泥岩、钙质砂岩等。该套遗迹化石组合与深海浊积事件密切相关,同时表明塔里木板块西北缘早二叠世时期存在一个陆棚浅海-深海盆地沉积环境,晚二叠世时期海水向西退去形成陆相沉积。     

云南省晋宁梅树村地区不寒武统发现颗石藻化石

在我国云南省晋宁县梅树村地区下寒武统发现了颗石藻化石，计有两个新属四个新种：微细管碟星藻属包括昆阳微细管碟星藻和蜂巢微细管碟星藻；始四枝碟星藻属包括银杏叶始四枝碟星藻和管柱始四枝碟星藻。下寒武统的颗石藻化石是迄今为止世界各国已报道的最老的颗石藻化石。     

云南省晋宁梅树村地区下寒武统发现颗石藻化石

 在我国云南省晋宁县梅树村地区下寒武统发现了颗石藻化石,计有两个新属四个新种:微细管碟星藻属(新属)(Microtubediscoaster gen.nov.)包括昆阳微细管碟星藻(新属新种)(Microubediscoaster kunyangensis gen.et sp.nov.)和蜂巢微细管碟星藻(新属新种)(Microtubediscoaster honeycomb gen.et sp.nov.);始四枝碟星藻属(新属)(Eotetralithus gen.nov.)包括银杏叶始四枝碟星藻(新属新种)(Eotetralithus ginkgolabulatus gen.et sp.nov)和管柱始四枝碟星藻(新属新种)(Eotetrailthustube Pillar gen.et sp nov.).下寒武统的颗石藻化石是迄今为止世界各国已报道的最老的颗石藻化石。     

宜昌地区寒武系水井沱组(第二统第三阶)生物组合面貌及其地层分布

近年来随着“鄂宜页1井”高产气井的突破,寒武系水井沱组(第2统第3阶)已成为中扬子区页岩气勘查开发新的主力层系。本文旨在前人研究的基础上,通过对水井沱组中主要生物类型、古生物组合面貌及其时空分布的简要总结,为鄂西地区的页岩气勘探提供对比借鉴。宜昌地区寒武纪地层发育完整,广泛出露于宜昌、秭归、长阳、兴山等地,古生物化石较为丰富,是开展寒武纪地层及古生物研究的经典地区之一。埃迪卡拉纪—寒武纪过渡时期的地质记录中保存了寒武纪大爆发和后生动物多样化事件的化石证据,从寒武系纽芬兰统到第二统,自下而上发现了岩家河生物群、水井沱生物群(包括清江生物群)、石牌生物群和京山布尔吉斯页岩型生物群等,它们化石类群多样,浮游生物和底栖生物丰富,而在长阳发现的清江生物群更是具有典型布尔吉斯页岩型动物群特异埋藏化石库的特点,出现了大量高保真度的软躯体类群,代表了远离海岸的较深水环境,为寒武纪大爆发研究打开了一个新的窗口。从岩性、生物类型以及构造运动来看,宜昌地区水井沱组发育一套以黑色页岩或钙质页岩夹碳质灰岩为主的黑色岩系,其中海绵化石在黑色岩系中呈现出较高的丰度和多样性,显示当时深水低氧的沉积环境。同时繁盛的微体...     

CONTRAST STUDY OF OIL AND GAS EXPLORATION POTENTIAL FOR QIANGTANG, CHANGDOU AND WEST YUNNAN BASIN DURING JURASSIC

CONTRAST STUDY OF OIL AND GAS EXPLORATION POTENTIAL FOR QIANGTANG, CHANGDOU AND WEST YUNNAN BASIN DURING JURASSIC     

Characteristics of the Middle Jurassic marine source rocks and prediction of favorable source rock kitchens in the Qiangtang Basin of Tibet

We have evaluated the hydrocarbon-bearing potential of Middle Jurassic marine source rocks in the Qiangtang Basin, Tibet, through a comprehensive study of samples from a large number of surface outcrops in different structural units, and from the Qiang-D2 Well in the southern Qiangtang Depression. Data that were acquired, including the depositional environment, thickness of sedimentary units, and organic geochemistry, are used to identify the principal controlling factors and predict the location of favorable hydrocarbon kitchens. The source rocks are mainly platform limestone of the Middle Jurassic Buqu Formation. This formation comprises a suite of intra-platform sag marls, micrites, and black shales that were deposited in a deep-water and restricted depositional environment. The marls form hydrocarbon-rich source rocks with organic matter that is mainly type II and in the mature to highly mature stage. In the Dongco–Hulu Lake and Tupoco–Baitan Lake deep sags, limestone also forms a medium-level source rock. In the Qiangtang Basin, limestone is the favorable source rock kitchen and is more significant in this regard than mudstone. The results provide important constraints on evaluating the hydrocarbon potential of Jurassic marine source rocks and for locating petroleum resources in the Qiangtang Basin.     

青藏高原羌塘盆地油气生成特征

本文从沉积、地球化学的角度分析了羌塘盆地的油气生成特征.羌塘盆地的沉积及古地理环境控制了多层系生油岩的形成,但主要为三叠系和侏罗系以海相沉积为主的碳酸盐烃源岩和泥质烃源岩,厚度巨大,有机质丰度高,热演化程度较高,生烃潜力大,构成了羌塘盆地主力烃源岩.综合分析认为盆地南北坳陷连接处的鞍部为含油气远景最有利区.     

羌北双壳类祁阳蚌组合的发现及其地层学意义

藏北羌塘盆地独雪山地区,在原先认为不整合于早侏罗世火山岩系之上的“中侏罗统雀莫错组”中, 新近发现了一套早侏罗世淡水双壳类祁阳蚌(Qiyangia)组合,表明羌北盆地存在早侏罗世沉积地层,其为一套海陆交互相沉积的粗碎屑岩→灰岩→细碎屑岩夹灰岩,下侏罗统与中侏罗统为连续沉积。据此资料,该区侏罗系目前采用的岩石地层单位系统及地层的对比认识存有问题,文章对此套早侏罗世沉积的岩石地层划分方案进行了讨论, 指出雁石坪地区的侏罗系岩石地层系统作为等时的地层单位运用于羌北盆地北西部并不适宜,羌北盆地已有的地层系统格架有必要重新认识。     

Study of the Factors Affecting the Abundance of Organic Matter in Jurassic Carbonate Rocks in Qiangtang Basin, Tibet

Field and laboratory analyses of carbonate rock samples from the Qiangtang Basin,Tibet, indicate that carbonate source rocks are mainly developed in the Middle Jurassic Xiali Formation and Upper Jurassic Suowa Formation. Comprehensive studies showed that the Suowa Formation carbonate source rocks have a favorable hydrocarbon-generating potential. The abundance of organic matter in the carbonate rocks is controlled mainly by sedimentary environment and inorganic compounds in the rocks, which is higher in the restricted platform facies than in the open platform facies. Organic carbon contents decrease with increasing CaO contents in the source rocks.     

PETROLOGY AND GEOCHEMISTRY OF CENOZOIC VOLCANIC ROCKS FROM THE CENTRE OF QIANGTANG,TIBET

PETROLOGY AND GEOCHEMISTRY OF CENOZOIC VOLCANIC ROCKS FROM THE CENTRE OF QIANGTANG,TIBET     

藏北色哇地区索布查组、曲色组岩石地层、层序地层、生物地层特征及三叠系与侏罗系界线

对藏北羌塘盆地南缘色哇地区的三叠纪与侏罗纪地层进行研究,在下侏罗统曲色组之下发现了一套以灰岩为主的地层,建立了索布查组,该组下部产晚三叠世腕足类、双壳类、六射珊瑚,上部产早侏罗世菊石,因此确定索布查组地质时代为晚三叠世—早侏罗世。三叠系-侏罗系界线应在索布查组之内,三叠系与侏罗系可能为整合接触。     

西藏双湖托纳木区块油气成藏条件分析与评价

托纳木地区位于西藏北羌塘盆地的南缘,通过综合油气地质评价,认为该区块内的晚侏罗世地层中存在有效的储集层和储集体;生储盖组合配置较好;烃源岩生烃强度高;具有适时有效的圈闭构造,对油气保存条件有利;托纳木背斜为该区块内最具勘探前景的圈闭构造。     

Elemental geochemistry of the early Jurassic black shales in the Qiangtang Basin,eastern Tethys: constraints for palaeoenvironment conditions

The early Jurassic black shales are the most important source rocks in the Qiangtang Basin, Tibet. These black shales may provide a useful example for understanding the sedimentary conditions during the early Jurassic in the eastern Tethys. Thirty‐two black‐shale samples were collected from the Qiangtang Basin to reconstruct the depositional environments during the early Jurassic in the eastern Tethys. The palaeoclimate index Σ(Fe + Mn + Cr + Ni + V + Co)/Σ(Ca + Mg + Sr + Ba + K + Na) varies between 0.58 and 1.14, together with low Sr/Ba (0.20–0.60) and Sr/Cu (1.68–7.88) ratios, indicating a warm humid to semi‐humid climatic condition during black‐shale deposition. The early Jurassic black shales exhibit slight Ce anomalies (0.89–0.94) and Mn enrichment (EF = 1.2), suggesting a slightly oxic depositional environment. The conditions of the sedimentary water system during black‐shale deposition were apparently brackish as evidenced by middle B/Ga (3.96–5.73) and Th/U (3.96–6.51) ratios. Copyright © 2015 John Wiley & Sons, Ltd.     

BASIN-RANGE TRANSITION AND GENETIC TYPES OF SEQUENCE BOUNDARY OF THE QIANGTANG BASIN IN NORTHERN TIBET

BASIN-RANGE TRANSITION AND GENETIC TYPES OF SEQUENCE BOUNDARY OF THE QIANGTANG BASIN IN NORTHERN TIBET