A new magnetostratigraphic framework for the Lower Miocene (Burdigalian/Ottnangian, Karpatian) in the North Alpine Foreland Basin

Oligocene–Miocene chronostratigraphic correlations within the Paratethys domain are still highly controversial. This study focuses on the late Early Miocene of the Swiss and S-German Molasse Basin (Late Burdigalian, Ottnangian–Karpatian). Previous studies have published different chronologies for this time interval that is represented by the biostratigraphically well constrained Upper Marine Molasse (OMM, lower and middle Ottnangian), Upper Brackish Molasse (OBM, Grimmelfingen and Kirchberg Formations, middle and upper Ottnangian to lower Karpatian, MN 4a–MN 4b) and Upper Freshwater Molasse (OSM, Karpatian–Badenian, MN 5). Here, we suggest a new chronostratigraphic framework, based on integrated magneto-litho-biostratigraphic studies on four sections and three boreholes. Our data indicate that the OBM comprises chrons 5D.1r and 5Dn (Grimmelfingen Fm), chron 5Cr (lower Kirchberg Fm) and the oldest part of chron 5Cn.3n (upper Kirchberg Fm). The OSM begins during chron 5Cn.3n, continues through 5Cn, and includes a long reversed segment that can be correlated to chron 5Br. The OMM-OSM transition was completed at 16.0 Ma in the Swiss Molasse Basin, while the OBM-OSM changeover ended at 16.6 Ma in the S-German Molasse Basin. As the lower Kirchberg Fm represents a facies of the Ottnangian, our data suggest that the Ottnangian–Karpatian boundary in the Molasse Basin is approximately at 16.8 Ma, close to the 5Cr–5Cn.3n magnetic reversal, and thus 0.4 Myr younger than the inferred age of 17.2 Ma used in recent Paratethys time scales. Notably, this would not be problematic for the Paratethys stratigraphy, because chron 5Cr is mainly represented by a sedimentation gap in the Central Paratethys. We also realise, however, that additional data is still required to definitely solve the age debate concerning this intriguing time interval in the North Alpine Foreland Basin. We dedicate this work to our dear friend and colleague Jean-Pierre Berger (8 July 1956–18 January 2012).     

汾河裂谷晋中盆地内第四纪沉积序列与沉积环境恢复

晋中盆地是位于汾渭地堑系中部的新生代陆内断陷沉积盆地,研究晋中盆地第四纪的沉积序列对于进一步认识该盆地区域构造和区域气候环境变化具有重要意义。为查明晋中盆地第四纪沉积序列结构、研究揭示晋中盆地第四纪沉积环境及演化,通过构造岩相学方法,对晋中盆地地表和钻孔内第四纪沉积物和沉积环境进行了研究。结果表明：晋中盆地清徐地区地表第四纪沉积序列结构为盆地内部沱阳组河床相和河漫滩相-盆地边缘汾河组河流相—盆山过渡带峙峪组河流相、汾河组冲积扇相及马兰组风积相-基岩山地（盆地外围）二叠系浅海相。钻孔岩芯内第四纪沉积序列结构为下更新统浅湖相和滨湖相—中更新统浅湖相和河流相—上更新统河流相和冲积扇相—全新统冲积扇相。研究认为晋中新生代陆内断陷盆地内沉积序列和演化结构为早更新世陆相湖盆沉积环境—中更新世萎缩湖泊环境—晚更新世强烈萎缩的湖泊和河流环境—全新世再度沉降的陆相湖盆;陆相湖盆从中心向山地沉积环境分带为湖泊沉积环境—河流和湖泊沉积环境—冲积扇沉积环境（盆地边缘出山口区）。盆山过渡带地区上更新世沉积物错位现象与同沉积活动断裂有关,断裂活动性揭示了晋中盆地阶梯式断陷成盆的动力学机制。这些研究成果为区域气候环境变化和晋中盆地区域构造研究提供了新证据,也为太原市城市群建设中工程场址的选择提了供参考。     

关中盆地上新世地层形成时代、层序划分及沉积相特征研究

关中盆地位于华北板块西南缘,为一新生代断陷盆地,具典型地堑形态,沉积巨厚的新生代地层。针对盆地新近纪上新世地层形成时代有争议、地层层序划分不明确、沉积相界定较笼统等问题,利用钻测井资料及野外调研,结合前人研究成果,对盆地新生代地层进行了重新划分,明确了上新世各地层形成时代及其地层层序划分和沉积相类型。研究结果表明,上新统可划分为蓝田组(11Ma—7 Ma)、灞河组(7.3 Ma—2.6 Ma)、张家坡组(3.4 Ma—2.6 Ma);新生代层序地层可划分为古近系构造层序、中新统构造层序、上新统构造层序和第四系构造层序等4个一级层序,存在6个构造层序界面。蓝田组以"三趾马红黏土"的风成沉积为特征。灞河组沉积时期,关中盆地的西安凹陷为一套冲(洪)积相、河流、三角洲相沉积,固市凹陷为一套冲(洪)积、河流、三角洲及滨浅湖相沉积;盆地边部开始出现小范围的风成黏土沉积。张家坡组以河湖相沉积为主,沉积中心向南移;盆地南北两侧或边部为冲(洪)积扇相、河流相及三角洲相沉积,边部也有小范围的风成黏土沉积。     

可可西里盆地中新统五道梁群湖相碳酸盐岩岩石学特征与沉积环境分析

湖相碳酸盐岩在可可西里盆地的古、新近纪地层中分布广泛,更是中新统五道梁群沉积的主要组成部分。五道梁群湖相碳酸盐岩分为生物粘结灰岩(叠层石)、泥晶灰岩、颗粒灰岩与泥晶白云岩四大类,反映出沉积环境为一个具有浅水—半深水、高盐度、半封闭—封闭特点的综合湖泊系统。     

苏北盆地高邮—金湖凹陷古近系阜宁组细粒沉积岩纹层特征与成因*

深水细粒沉积物不仅可作为烃源岩,也可成为非常规油气的储集层。以苏北盆地高邮—金湖凹陷古近系阜宁组阜二段半深湖—深湖水平层理细粒沉积岩为研究对象,通过高精度厘米级岩心观察描述、薄片鉴定、X射线衍射全岩矿物分析、微量元素测试及扫描电镜等手段,分析了岩石纹层特征并尝试探讨其成因。结果表明: 高邮—金湖凹陷阜宁组二段半深湖—深湖细粒沉积岩岩性复杂,多种物质组分的混合及叠置形成了不同颜色的纹层。水平层理可根据纹层厚度进一步分为薄纹层状和厚纹层状2类沉积构造,两者的宏观与微观结构、物质组成等均存在差异。纹层成因复杂,但主要受形成和保存2个方面因素影响。在纹层形成过程中,各物质组分的产生与沉淀均具有季节性意义;纹层的保存主要与水体深度有关。     

Characteristics and forming mechanism of laminae fine-grained sedimentary rock of the Paleogene Funing Formation in Gaoyou and Jinhu sags,Subei Basin

The deep-water fine-grained deposits can be not only the source rock,but also the reservoir of unconventional oil and gas. Combined with high-precision centimeter-scale core observation,thin section identification,X-ray diffraction whole rock analysis,trace element test and scanning electron microscopy(SEM)analysis,the laminae characteristics and the genesis mechanism of semi-deep to deep lake fine-grained sedimentary rocks in the Member 2 of the Funing Formation are investigated in the Gaoyou and Jinhu sags of the Subei Basin. The results show that the semi-deep and deep lake fine-grained sedimentary rocks of the Member 2 of the Funing Formation in the Gaoyou and Jinhu sags are complex in lithology,and the laminae with different colors are formed by the mixture and superposition of various material components. The horizontal bedding developed in the fine-grained sedimentary rocks can be further divided into thin-laminated and thick-laminated sedimentary structures,whose macroscopic,microscopic characteristics and the composition are different. The complex forming mechanism of laminae includes two aspects: Formation process and preservation process. The generation(or the input)and the precipitation of each component have seasonal significance during the formation of laminae,whereas the preservation of the laminae could be mainly related to the water depth in the study area.     

松辽盆地姚家组-嫩江组地层层序及沉积演化

松辽盆地姚家组-嫩江组是晚白垩世形成的一套完整的水进-水退沉积旋回,分为2个二级层序,6个三级层序,持续时间约4Ma。嫩江组二段最大湖泛期在底部形成了盆地范围内稳定分布的油页岩,其不仅是层序及地层对比的标准界面,而且是重要的烃源岩层和盖层。姚家组与嫩江组一段是水进期大型退积型三角洲沉积,嫩江组三段是水退期大型湖泊与快速进积大型三角洲沉积。嫩江组在水进期长轴物源方向发育大型重力流水道及末端浊积扇,水道延伸距离64km,最大宽度600m;在水退初期短轴方向发育滑塌浊积扇,扇体有复合式和单体式,滑塌最小古坡度为5%~12‰,表面均发育弧状滑塌波纹,波纹密度4~10条/km,最小滑移距离2~10km。     

Biostratigraphy and sedimentology of the Fluviatile Untere Serie (Early and Middle Miocene) in the central part of the North Alpine Foreland Basin: implications for palaeoenvironment and climate

The Early to Middle Miocene Fluviatile Untere Serie lithostratigraphic unit of the Upper Freshwater Molasse (UFM) in the North Alpine Foreland Basin (NAFB) crops out in a 40 m long section at Untereichen-Altenstadt (central part of the NAFB). This section yields a unique superposition of two vertebrate assemblages belonging to different biostratigraphic units: early part OSM C + D (Karpatian) and OSM E (Early Badenian). Detailed taxonomic analyses reveal different diversity patterns in the two assemblages. Nine small mammal and six ectothermic vertebrate taxa occur in the older level UA 540 m, while 20 small mammal and 23 ectothermic vertebrate taxa are recorded for the younger level UA 565 m. From the latter locality comes a small-sized representative of the biostratigraphically significant Megacricetodon lappi lineage. This evolutionary level has not been documented previously for the eastern part of the NAFB. Bioclimatic analysis combined with lithofacies and architectural element analysis indicates that significant changes in the fluvial sedimentation style, surface-water runoff and tectonics occurred between the Early Karpatian and Early Badenian. A meandering fluvial system (marly unit) is erosively overlain by sandy braided river deposits (sandy unit). Overbank deposits of the marly unit revealed that the older vertebrate fossil assemblage (UA 540 m) is deposited in an animal burrow that was presumably produced by owls. Both reptilian and mammalian taxa are indicative of a relatively open environment and dry, probably semi-arid climate. Conversely, vertebrates from the sandy unit (UA 565 m), which are accumulated in channel fill deposits, suggest closed as well as open habitats with a subtropical humid climate and mean annual rainfall of about 1,000 mm. According to the sequence stratigraphic analysis the marly unit is interpreted as a highstand-system-tract of the TB 2.2 global 3rd order sequence. The new results add support to the hypothesis that the erosional unconformity between both sedimentary units spanning the Karpatian-Badenian transition corresponds to the pre-Riesian hiatus, which has been interpreted as part of the Styrian Tectonic Phase, and was previously identified only in the eastern and northeastern part of the NAFB. The biostratigraphic data further indicate that this hiatus lasted longer in the eastern than in the central part of the basin.     

敦煌盆地五墩凹陷侏罗系层序地层格架与沉积体系分布

敦煌盆地是一个处于石油勘探早期阶段的中生代的断陷盆地,油气资源勘探潜力较大,搭建层序地层格架、阐明沉积体系分布是发现油气资源的基础.本文利用露头、钻测井、岩心和地震资料,综合考虑构造演化、物源体系、岩心特征等多种因素,明确了敦煌盆地五墩凹陷侏罗系沉积相类型及分布规律.研究表明,本次研究的主要目的层中下侏罗统可以划分为2...     

松辽盆地松科1井上白垩统四方台组沉积序列厘米级精细刻画：岩性·岩相·旋回

中国白垩纪大陆科学钻探松科1井北孔连续取四方台组岩心心长209．02m,岩心收获率为97．5％,是迄今获取的最连续完整的沉积记录。文章对此进行了厘米级（分层厚度2～5cm）沉积地质描述。四方台组沉积时期对应中一晚坎潘期。通过对松科1井四方台组岩心的精细描述,揭示其岩性-岩相-旋回的沉积序列及其过程。四方台组共识别出8种...     

塔里木盆地东河砂岩沉积和储层特征及综合分析

东河砂岩是一套海侵初期的沉积产物，东河砂岩不是一个等时沉积体，相当于晚泥盆世晚期至早石炭世早期沉积，具体沉积时间各地有差异。由于东河砂岩是覆盖广泛的海侵初期沉积，因此具有海侵初期填平补齐的特征，其沉积相决定于海侵的速度、沉积物的供给和海侵前的古地貌。塔北地区受塔北古隆起的阻挡，海水在古隆起周围滞留时间较长，又有较粗粒的物源供给，其沉积产物主要是滨岸海滩沉积；塔中地区由于地形复杂，沉积类型也比较复杂，底部砾岩段有河流相沉积，而块状砂岩段和砂砾岩段有河口湾和滨岸海滩沉积，不同段在成分、分选性和粒级上有较大的差异；而其它低平地区主要是海侵期快速的滨岸和陆架沉积。受沉积因素影响，东河砂岩有效储层的分布具有地域性；除沉积因素外，低的地温梯度和短期的深埋藏是优质储层发育的重要控制因素。     

哈萨克斯坦楚-萨雷苏盆地热兹卡兹甘地区构造运动与沉积演化

本文基于对楚-萨雷苏盆地热兹卡兹甘地区的构造运动、相应动力学机制、沉积地层的研究,对楚-萨雷苏盆地盆地上古生界沉积演化做了阐述,提出了热兹卡兹甘地区晚古生代经历了早中泥盆世火山盆地-晚泥盆世(成盆初期)滨海冲积平原、局限台地-早石炭世(海侵期)台地、台缘斜坡、陆棚-中晚石炭世(海退期)海陆交互相三角洲-早二叠世(干旱气候期)干盐湖-晚二叠世盐湖的沉积演化。     

万安盆地构造沉降与沉积速率及其油气资源前景

万安盆地是南海重要的新生代含油气盆地之一,是较为典型的新生代走滑拉张盆地。根据对横穿盆地的地震反射剖面的平衡剖面模拟和构造沉降速率、沉积速率的计算,认为万安盆地曾经历了3次快速的构造沉降。2.6Ma以来,沉积速率最大。万安盆地的沉降与沉积速率和盆地构造演化过程密切相关,各构造演化阶段分别控制了盆地中油气的生成、运聚和保存等成藏条件与过程。     

河南卢氏盆地张家村组粒度特征与沉积环境研究

本文对河南卢氏盆地中始新世张家村组河湖相沉积进行了粒度分析。结果表明：1）从底到顶,张家村组沉积岩粒度总体上由粗变细,平均粒径由约6φ（16μm）减小到8φ（4μm）左右,指示沉积动力由强到弱的变化;2）粒度频率分布曲线整体为近对称分布,且从底到顶由双峰逐渐变为单峰特征;3）沉积颗粒以悬浮和跳跃组分为主,不含或含少量滚动组分。粒度和岩性综合分析表明,张家村组下段为河流相沉积,中段为河漫滩相或滨湖相沉积,上段为滨湖和浅湖相沉积。张家村组沉积可能记录了卢氏古湖逐渐形成的过程。     

松辽盆地松科1井上白垩统嫩江组三～五段沉积序列厘米级精细刻画：岩性·岩相·旋回

中国白垩纪大陆科学钻探松科1井连续取嫩江组三～五段岩心长532．07rn,岩心收获率为94．8％,是迄今获取的最连续完整的沉积记录。文章对此进行了厘米级沉积地质描述（分层厚度2～5cm）。嫩三～五段沉积时期与坎潘阶中期对应。通过对松科1井嫩三～五段岩心的精细描述,揭示其岩性一岩相一旋回的沉积序列及其过程。嫩三～五段识别...     

柴达木盆地西部西岔沟剖面湖相碳酸盐岩岩石学特征与沉积环境分析

湖相碳酸盐岩在柴达木盆地西部古、新近系地层中广泛出露,在研究区西岔沟地区主要分布在下干柴沟组、上干柴沟组的顶部,下油砂山组及上油砂山组的底部。通过实测西岔沟剖面、岩性分析、岩相组合特征、生物特征、沉积构造、室内薄片鉴定等研究对西岔沟剖面的碳酸盐岩进行了分析,识别出西岔沟剖面的碳酸盐岩的类型主要有鲕粒灰岩、介壳灰岩、藻叠层石灰岩、泥晶灰岩、砂质灰岩等,沉积环境主要属滨浅湖,并在岩石学特征的基础上对其成因进行了研究。     

北羌塘盆地长蛇山油页岩剖面烃源岩生烃潜力及沉积环境

提要：北羌塘盆地长蛇山油页岩位于目前中国最大规模的胜利河—长蛇山海相油页岩带北东,长蛇山南麓,其剖面主要岩性为油页岩、泥晶灰岩、黑色页岩和泥灰岩。本文通过对20件样品进行多项地球化学指标测试,详细评价了长蛇山油页岩剖面烃源岩的有机质丰度、类型及成熟度等指标,并分析了其沉积环境。结果表明：长蛇山油页岩的生烃潜力最好,其次为黑色页岩和泥晶灰岩。总有机碳含量在烃源岩中为0.41%~9.49%,平均为4.02%,在油页岩内含量最高,达到4.53%~9.49%,平均为7.74%;氯仿沥青“A”含量为0.0252%~0.3403%,在油页岩内平均为0.27%,总体为中等—较好烃源岩;有机元素和有机显微组分分析显示干酪根类型以Ⅱ1型为主,少数为Ⅱ2和Ⅲ型;Ro的分布范围为1.08%~1.43%,平均值为1.27%,有机质热演化程度为成熟—过成熟,且在垂向上有机质演化程度逐渐变高。该剖面的烃源岩沉积于盐度较高的还原环境,有机质母质主要以低等水生生物为主。     

The Early and Middle Miocene transgression at the southern border of the North Sea Basin (northern Belgium)

The Lower–Middle Miocene Berchem Formation of northern Belgium is an essentially sandy sequence with a varying glauconite content and often abundant shelly intervals. The formation was deposited in a shallow marine environment and rests unconformably on stiff Rupelian clays or Chattian sands. The lithological recognition of the four members (Edegem Sands, Kiel Sands, Antwerpen Sands and Zonderschot Sands members) of the Berchem Formation solely based on lithological criteria proved to be difficult, especially in boreholes. The geometry of the Formation in the subsurface of northern Belgium remained largely unknown. Diverse and well preserved dinoflagellate cyst associations have been recovered from the four members in seven boreholes and two outcrops, and allow a refinement of the biostratigraphy of these deposits. A Miocene biozonation defined in mid‐latitude shallow marine deposits in the Atlantic Coastal Plain of the USA (Salisbury Embayment, Maryland) is readily applicable to this material, and has led to a detailed stratigraphic assessment of each member. Three detailed profiles depicting the distribution of the biozones in the subsurface of northern Belgium allow the reconstruction of the geometry and depositional history of the Berchem Formation. The oldest Miocene deposits are of early Burdigalian age and they testify to a transgression, which invaded Belgium from a north–northwestern direction. The maximum flooding took place during early Serravallian times. The upper boundary of the formation is a major erosional surface of late Serravallian or (slightly) younger age. Copyright © 2005 John Wiley & Sons, Ltd.     

库车盆地古近系-新近系蒸发岩沉积旋回识别及对比

库车盆地古近纪-新近纪发育巨厚的蒸发岩沉积,根据蒸发岩沉积旋回的变化,即由于盐湖水体
从淡-咸-盐-咸-淡的旋回变化,相应地沉积物发生由碎井的屑岩-膏岩-盐岩-膏岩-碎屑岩的变化。考
虑钻井的分布位置及其剖面在时代上的完整性,选取盆地中 13口井的钻井剖面进行沉积旋回识别和对比,共识
别出 5个蒸发岩沉积旋回,其中库姆格列木群两个,苏维依组一个,吉迪克组两个。通过对比,确立了以东秋8井剖面为库车盆地蒸发岩沉积旋回对比的标准剖面,初步分析认为,盆地蒸发岩沉积旋回的沉积区迁移特征,
应受盆地基底控制和南北向构造挤压应力变化的影响。古近系蒸发岩主要分布在盆地西部,新近系吉迪克组沉
积时期,盆地西北部转为陆源碎屑岩沉积 （ 西南部发育少量蒸发岩） ,而东部发育巨厚的蒸发岩,显示出东西分
带的特点。在始新世末印度板块和欧亚板块碰撞的远距离效应影响下,库车盆地自苏维依组沉积时期蒸发岩沉
积中心就已经开始迁移,迁移中心一分为二,自盆地北西分别向南、向东移动,形成两个沉积区,吉迪克组沉
积时期在上述两个沉积区继续发育盐岩、膏岩沉积。     

河北阳原盆地中更新世湖相地层顶部文石的发现及其科学意义

位于河北省西北部的阳原盆地在第四纪期间长期被泥河湾古湖所占据,堆积了巨厚的第四纪河湖相地层,其中夹有多层化学沉积。文中对广泛分布于盆地西端河湖相地层顶部的白色化学沉积进行了深入研究,通过野外调查和年代测试、电子显微镜扫描观察、X射线粉晶衍射、常量和微量元素分析,以及硅藻和介形类化石鉴定等一系列实验手段,确认北梁地区地层中的灰白色化学沉积主要由文石组成,其年龄大致在270 ka前后,属中更新世晚期,是在当时比较温干的气候环境下,湖泊逐渐萎缩、湖水不断咸化、文石类矿物大量析出的结果。该地区的泥河湾古湖于中更新世晚期消亡。本研究首次发现了中更新世晚期的化学沉积,在时代上明显区别于以前发现的晚更新世晚期化学沉积。该化学沉积的发现为探讨泥河湾古湖消亡过程和原因提供了直接的沉积学证据,对于重建我国北方中更新世晚期的古环境也具有重要的科学意义。