青海可可西里盆地雅西措组介形类动物群及其地层意义

青海可可西里盆地是青藏高原腹地最大的沉积盆地。然而对于该盆地新生代地层的沉积时代目前仍然存在争议。可可西里盆地南侧雁石坪地区雅西措组中含丰富的介形类化石,该介形类动物群对青藏高原腹地新生代生物地层对比具有重要意义。文中通过对可可西里盆地南侧雁石坪地区通天河剖面进行系统的采样和室内分析,共获得652枚介形类壳体,共鉴定识别出14属48种,自下而上建立了2个介形类组合带,即Austrocypris cf. posticaudata-Candoniella albicans-Leucocythere tropis组合带和Ilyocypris errabundis- Darwinula stenimpudica组合带。通过与柴达木盆地、伦坡拉盆地、江汉盆地以及渤海湾沿岸等地区的介形类生物地层进行区域对比研究,推测可可西里盆地通天河剖面雅西措组的沉积时代为晚始新世—早渐新世。     

江西清江盆地临江组非海相腹足类化石及时代讨论

一、概述华南地区始新世陆相地层发育,腹足类化石极其丰富,搞清其分布、性质、组合特点及古生态对了解整个华南地区中、新生代区域地质发展、构造运动、沉积环境的演替以及寻找沉积矿产等都有很大意义。笔者对江西清江盆地临江组进行了生物地层和岩石学的工作。初步描述了腹足类化石24属、29种,其中包括1新属、7新种。按照腹足类化石产出层位和分布规律,初步建立了1个腹足类组合和3个亚组合,根据腹足类动物群的性质和组合特点,进行了一些生物地层的对比工作。综合介形类、轮藻、孢粉、鱼、植物的研究,对临江组的地质时代     

山东平邑盆地晚白垩世介形类

山东平邑盆地固城组、卞桥组共发现介形类化石21属21种4比较种13未定种,本文记述了其中的17属16种4比较种9未定种。卞桥组一段下部的介形类可称为Talicypridea reticulata-Mongolocypris longa-Frambocythere fangjiaheensis介形类动物群,含化石地层的时代被确认为晚白垩世最晚期,即马斯特里赫特期的晚期。该动物群的发现,为平邑盆地白垩系/古近系界线的确定提供了十分重要的依据。     

广东南雄盆地上湖组介形类动物群及白垩-第三系界线

南雄盆地上湖组介形类可划分为2个性质不同的动物群及4个化石带:下部为 Porpocypris 动物群,是以中生代属种为主,中、新生代属种混生的过渡性动物群,时代为晚白垩世最晚期;上部为 Cypris 动物群,以 Cypris 属占优势, Sinocypris 属开始出现, Cypridea 等古老属种绝灭为主要特征,时代为早—中古新世.根据介形类演化发展阶段和白垩纪末生物绝灭事件,南雄盆地白垩系与第三系的界线应划在 Porpocypris 与 Cypris 动物群之间,即上湖组坪岭段与下惠段之间.     

湖南衡阳盆地岭茶地区古近纪介形类动物群北大核心

描述衡阳盆地东北部岭茶地区介形类化石9属23种。岭茶地区古近纪介形类动物群以Cypris和Li mnocythere两属最繁盛,可划分为两个化石组合:栗木坪组为Cypris henanensis-Cyprois reniformis-Li mno-cythere honggangensis组合,岭茶组为Li mnocythereirregularis-Cypris favosa-Ilyocypris gaoyouensis组合。岭茶地区栗木坪组与珠江三角洲地区宝月组的介形类动物群相同,岭茶组与华涌组的介形类面貌也基本相同,因此栗木坪组和岭茶组的时代应属晚古新世和早始新世,这与栗木坪组和岭茶组中哺乳动物、古地磁和碳氧同位素的研究结果相一致。     

湖南衡阳盆地岭茶地区古近纪介形类动物群

描述衡阳盆地东北部岭茶地区介形类化石9属23种。岭茶地区古近纪介形类动物群以Cypris和Li mnocythere两属最繁盛,可划分为两个化石组合:栗木坪组为Cypris henanensis-Cyprois reniformis-Li mno-cythere honggangensis组合,岭茶组为Li mnocythereirregularis-Cypris favosa-Ilyocypris gaoyouensis组合。岭茶地区栗木坪组与珠江三角洲地区宝月组的介形类动物群相同,岭茶组与华涌组的介形类面貌也基本相同,因此栗木坪组和岭茶组的时代应属晚古新世和早始新世,这与栗木坪组和岭茶组中哺乳动物、古地磁和碳氧同位素的研究结果相一致。     

柴达木盆地新生界生物地层年代研究

柴达木盆地新生代地层广泛分布,富含油气资源。长期以来,各组时代归属存在较大争议。本文以介形类、孢粉和轮藻微体化石为基础,重新探讨了柴达木盆地新生界各组的地质年代归属:路乐河组为古新世—始新世中期;下干柴沟组沉积时代主体为始新世中晚期,渐新世早期也有部分沉积;上干柴沟组为渐新世早期—中新世早期;下油砂山组为中新世早—中期;上油砂山组为中新世中—晚期;狮子沟组为中新世晚期—上新世晚期;七个泉组为更新世早—中期。柴达木盆地新生界各组地质年代的确定对盆地内油气勘探工作具有重要意义。     

广东三水盆地古近纪的介形类动物群

三水盆地古近系介形类化石主要来自全取芯钻井剖面.据170口钻井3 855个样品统计,发现介形类17属49种,本文描述其中16属47种,包括2个新种.三水盆地古近纪的介形类动物群以Sinocypris,Cyprois,Limno-cythere三属分布最广、最常见,故称Sinocypris-Cyprois-Limnocythere动物群,简称Sinocypris动物群.根据介形类化石纵向分布和富集规律,选择最常见主要属种的鼎盛时期建立5个化石带(顶峰带),自下而上为:Ⅰ.Cyprisconcina带;Ⅱ.Sinocypris pulchra带;Ⅲ.Cyprois reniformis带;Ⅳ.Sinocypris reticulata带;Ⅴ.Limnocythere ir-recularis带.本文把古新统(E1)/始新统(E2)界线放在Ⅲ/Ⅳ带之间,认为Ⅰ-Ⅲ带的莘庄村组、饰心组、宝月组的时代为古新世,分别为早、中、晚期,Ⅳ、Ⅴ两带的华涌组的时代为早始新世.     

江汉盆地古新世的介形类

该文首次报道了江汉盆地可能属于古新世的非海相地层及其中的介形类化石,计有17属30种(其中新种3个),隶属于3个超科。该介形类动物群自下而上可分为:1.Porpocypris(?)-Paraily-ocypris-Cypridea组合;2.Sinocypris-Eucypris-Limnocythere组合。第2组合完全可与广东南雄盆地罗佛寨组的介形类化石群对比,时代可能为古新世晚期;第1组合的介形类是否可与广东南雄盆地上湖组的化石对比的问题,还有待今后发现更为可靠的Porpocypris属的代表分子来解决,这里暂置于古新世早、中期。     

云南东部地区晚新生代介形类

该文研究的介形类化石来自云南东部陆良、曲靖及昆明盆地上第三系茨营组和第四系更新统,计13属、1亚属、22种,其中包括13新种。根据介形类同种分布特征可建立4个化石组合。通过介报类化石组合特征及同种在地层中的分布,将云南东部地区晚新生代地层进行了重新划分。     

西藏聂拉木晚奥陶世的介形类

文中首次报道西藏聂拉木地区亚来水厂剖面上奥陶统甲曲组介形类16属30种,介形类以古足介目类和圆足介目类为主,少量速足介目类。根据该剖面介形类时代特征,可以推断甲曲组应属于晚奥陶世早期,大致为Sandbian期—Katian期。该介形类生态组合为艾菲尔生态型,指示甲曲组在沉积时为近岸浅水环境。晚奥陶世喜马拉雅地层区与华南扬子区及塔里木介形类面貌相似,应属于相同的生物地理分区。     

西藏南部聂拉木地区晚泥盆世—早石炭世的介形类

本文系统描述西藏南部聂拉木地区晚泥盆世–早石炭世介形类共计15属24种。根据介形类的组合面貌及孢子、牙形刺的研究结果推断,亚里剖面上的亚里组时代为晚泥盆世–早石炭世,泥盆系-石炭系界线(D-CB)大致位于亚里东沟段顶部至沟陇日段。亚里组产出的介形类生态组合属于光滑速足目集群或艾菲尔生态型,指示亚里组在沉积时为远岸浅水沉积环境,且在上部腊扎蒲段水深变浅。亚里组介形类面貌与华南泥盆纪介形类相似程度高,与俄罗斯和欧美地区也有相似的属种,说明泥盆纪-石炭纪之交介形类的地理隔离并不显著,在各个板块之间有属种交流的可能。     

A Wuchiapingian (Late Permian) brachiopod fauna from an exotic block in the Indus–Tsangpo suture zone, southern Tibet, and its palaeobiogeographical and tectonic implications

A brachiopod fauna including 19 species of 17 genera from an exotic block in the Indus–Tsangpo suture zone in southern Tibet is described and illustrated. The brachiopod fauna is dominated by Martinia elegans and two new taxa: Jinomarginifera lhazeensis gen. et sp. nov. and Zhejiangospirifer giganteus sp. nov. The fauna is closely comparable with those from the middle and upper parts of the Wargal Formation and the Chhidru Formation in the Salt Range of Pakistan, the Chitichun Limestone in southern Tibet, and the Basleo area of West Timor, and these correlations suggest a Wuchiapingian age. The fauna exhibits substantial links with both peri–Gondwanan and Cathaysian faunas, which may imply that it is a seamount biota originally located in the southern margin of the Neotethys during the Late Permian, and was later (in the early Cenozoic) displaced and became sandwiched into younger marine deposits in the collision process between India and Eurasia.     

广西合浦盆地晚白垩世和古新世的介形类化石

本文报道合浦盆地晚白垩世乌家组和古新世上洋组的介形类化石14属23种(描述1新种),可划分两个化石组合:(1)Rhombicypridea quadrata-Heterocypris hepuensis-Limnocythere sinuata组合,属于Talicypridea动物群,产于乌家组,时代为晚白垩世;(2)...     

新疆准噶尔盆地南缘覆盖区晚白垩世紫泥泉子组介形类动物群

在准噶尔盆地南缘覆盖区的紫泥泉子组普遍见到丰富的晚白垩世介形类化石,自西向东面貌一致,分布稳定,计有10属(包括1亚属)17种4比较种2未定种,可归为一个Talicypridea组合,是覆盖区划分和对比紫泥泉子组的重要标志。     

Woodland in a fluvio-lacustrine environment on the dry Mongolian Plateau during the late Paleocene: Evidence from the mammal bearing Subeng section (Inner Mongolia,P.R. China)

In the understanding of the global faunal turnover during the Paleocene–Eocene transition, an important role has been attributed to the Asian continent, although the Asian fossil record for this period is still incomplete. Here we present a multidisciplinary study of the Subeng section (Inner Mongolia, P.R. China), integrating sedimentological, stratigraphical and diverse palaeontological data, in order to reconstruct the palaeoenvironment and to enhance the understanding of the late Paleocene communities that once thrived on the Mongolian Plateau. The Subeng section starts with the Maastrichtian Iren Dabasu Formation directly covered by the late Paleocene Nomogen Formation. This Nomogen Formation is composed of typical lacustrine deposits at the base, covered by fluvio-lacustrine deposits at the top. Both types of deposits provided rich ostracod and charophyte assemblages, closest to those of the Naran Member, Naran Bulak Formation of Mongolia. Palynomorphs from the lake sediments suggest a local flora at Subeng more wooded and closed than reported from elsewhere in this region. The fluvio-lacustrine deposits of the Nomogen Formation have yielded a vertebrate fauna especially rich in mammals. The mammal fauna from Subeng is close to that from Bayan Ulan and typical for the Gashatan Asian Land Mammal Age. The presence of reworked pedogenic carbonate nodules and mud aggregates suggests an at least seasonally dry regional climate. Combined sedimentological and palaeontological data suggest the late Paleocene Nomogen Formation at Subeng was an isolated woodland in a fluvio-lacustrine environment, representing a locally humid environment on the semi-arid Mongolian Plateau. The mammal fauna reflects these differences and shows a number of relatives to mammals from the more humid northeastern Chinese biotic province as well as some North American immigrants.     

甘肃玉门下沟地区早白垩世下沟组介形类

甘肃玉门下沟地区下沟组介形类化石十分丰富,该地区下沟组介形类化石共计9属4亚属,21种,本文描述了其中4新种,即Cypridea(Cyamocypris)xiagouensissp.nov.,Cypridea(Cypridea)subunicostatasp.nov.,Stenestroemiasubpeculiarissp.nov.和Stenestroemiaxiagouensissp.nov.。该介形类化石组合尤以Cypridea最为繁盛,通过分析介形类属种的形态特征和化石组合特征并结合岩性特征,推断下沟组的地质时代为早白垩世巴列姆期;并认为下沟组为水动力较弱的淡水-微咸水河湖相沉积。     

柴达木盆地西部红柳泉地区晚侏罗世介形类动物群及其古环境意义

在柴达木盆地红柳泉地区红探2井红水沟组中识别出介形类化石3属9种(含2个未定种):Cetacella qaidamensis Li et Yang, 1983、Djungarica tracta Li et Yang, 1983、Djungarica sp.、Alicenula incurva (Bate, 1967)、?A.longicylindrica (Qi, 1985)、A. paramagna (Li et Yang, 1983)、A. maanshanensis (Hou et al., 2002)、A. jinhuaensis (Li,1984)、Alicenula sp.。通过介形类化石生物地层对比,明确红水沟组的沉积时代为晚侏罗世。红水沟组介形类动物群指示晚侏罗世柴达木地区发育淡水湖泊、河流以及季节性的小水塘。     

OSTRACODS AS MARKERS OF THE PERMIAN/TRIASSIC BOUNDARY IN THE KHUFF FORMATION OF SAUDI ARABIA

Abstract:  Ostracods are described for the first time from Permian–Triassic shallow marine sediments of the Khuff Formation of central Saudi Arabia. They were collected using a modified acetolysis technique for releasing calcareous shells from limestones that is described herein. Thirty-four species belonging to 17 genera are recognized. Two new species are described: Arqoviella arabica sp. nov. and A. khartamensis sp. nov. The ostracod fauna supports a Late Permian age for the lower Khartam Member and a probable Early Triassic age for the upper Khartam Member of the Khuff Formation of central Saudi Arabia. This suggests that the Permian/Triassic boundary is located within the Khartam Member, rather than at the major lithological break between the Midhnab and Khartam members. Palaeoecological analysis suggests that the palaeoenvironment of the Khuff Formation was shallow marine (between 1 and 50 m deep) on an internal shelf.