内蒙古苏尼特右旗德言其庙剖面二叠纪■类动物群

二叠纪时,内蒙古中部地区位于特提斯古生物地理区北缘的过渡带,是海相暖水动物群与冷水动物群的交汇地带,对研究特提斯古生物地理区系的演化有重要作用。但由于受到后期构造作用的影响,内蒙古中部地区二叠纪灰岩地层出露并不连续,研究程度较差。近年来,我们获取了东部苏尼特右旗德言其庙地区阿木山组、哲斯组丰富的■类化石材料。通过对■类化石的系统研究,共鉴定出■类14属39种。识别出4个■类化石带,由老至新依次为Pseudofusulina acuteata富集带、Chalaroschwagerina inflata延限带、Parafusulina jilegensis-Rugosofusulina intermedia组合带以及Chusenella conicocylindrica富集带,对应时间为早二叠世萨克马尔期至中二叠世罗德期。这一■类动物群的深入研究结果是对北方过渡带海相动物群研究的重要补充。     

西藏普兰县姜叶玛地区瓜德鲁普世晚期■类动物群及其古生物地理意义北大核心

雅鲁藏布江缝合带中自西向东分布着二叠纪灰岩块体,被称为西藏相灰岩外来块体或奇底宗型的二叠系。姜叶玛灰岩是其中之一,位于西藏西部普兰县境内。■类动物群是该灰岩块体中最丰富的生物群之一,其中瓜德鲁普统西兰塔组的■类有10个属,分别为Neoschwagerina,Yangchienia,Armenina,Verbeekina,Paraver-beekina,Kahlerina,Lantschichites,Codonofusiella,Chusenella,Nankinella。Kahlerina,Lantschichites和Codono-fusiella的存在表明西兰塔组■类动物群的时代为Midian期(Guadalupian世晚期),相当于华南的冷坞期。姜叶玛灰岩和仲巴县拉赛拉灰岩、阿曼Batain地区以及巴基斯坦盐岭地区一样,Midian期■类动物群缺少Afghanella-Sumatrina组合,结合当时古地理位置认为,这几个地区处于相对较凉水温控制之中。     

西藏普兰县姜叶玛地区瓜德鲁普世晚期■类动物群及其古生物地理意义

雅鲁藏布江缝合带中自西向东分布着二叠纪灰岩块体,被称为西藏相灰岩外来块体或奇底宗型的二叠系。姜叶玛灰岩是其中之一,位于西藏西部普兰县境内。■类动物群是该灰岩块体中最丰富的生物群之一,其中瓜德鲁普统西兰塔组的■类有10个属,分别为Neoschwagerina,Yangchienia,Armenina,Verbeekina,Paraver-beekina,Kahlerina,Lantschichites,Codonofusiella,Chusenella,Nankinella。Kahlerina,Lantschichites和Codono-fusiella的存在表明西兰塔组■类动物群的时代为Midian期(Guadalupian世晚期),相当于华南的冷坞期。姜叶玛灰岩和仲巴县拉赛拉灰岩、阿曼Batain地区以及巴基斯坦盐岭地区一样,Midian期■类动物群缺少Afghanella-Sumatrina组合,结合当时古地理位置认为,这几个地区处于相对较凉水温控制之中。     

滇西二叠纪Shanita-Hemigordius(Hemigordiopsis)有孔虫动物群

近几年来,在亚洲一些地区二叠系,发现了一个大型有孔虫Shanita,常与Hemigordius(Hemigordiopsis)伴生,组成特提斯海区二叠纪颇具特色的动物群,分布在一定的区域范围,形成了特定的生物地理区。本文主要记述这一动物群在我国滇西地区的发现及其纵横分布情况。本文材料系云南省地质局第一区测队、云南省地质研究所等单位送来我所鉴定的,薄片、照相、绘图均由我所技术室承担,特此致谢。滇西潞西、腾冲、镇康一带二叠系较发育,由巨厚的白云质灰岩、灰岩及泥岩等组成,含有和中国南部其它地区(秦岭地区除外)不尽相同的有孔虫动物群。据云南省地质局第一区域地质测量大队工作结果,此区二叠系自上而下,大致分层如下: 上覆地层:中三叠统或侏罗系     

西藏拉萨地块中部扎布耶茶卡一带中二叠世(蜓)类动物群及其古生物地理意义

对拉萨地块中部扎布耶茶卡北岸的两个剖面开展(虫筳)类动物群系统古生物学及古生物地理研究。鉴定出(虫筳)类 6 属 16 种,包括Yangchienia tobleri Thompson,Yangchienia haydeni Thompson,Chusenella brevipola (Chen),C. schwagerinaeformis Sheng,C. cf. brevis (Chen),C. sp.,Nankinella rarivoluta Wang,Sheng and Zhang,N. complanata Wang,Sheng and Zhang,Kahlerina tenuitheca Wang,Sheng and Zhang,K. pachytheca Kochansky-Devidé and Ramovs,Verbeekina americana Thompson, Wheeler and Danner,V. tenuispira Sheng,Neoschwagerina cheni Sheng,N. colaniae Ozawa,N. craticulifera (Schwager),N. brevis Thompson,Wheeler and Danner。基于Kahlerina属的出现及Neoschwagerina属的厚壁壳体以及第二旋向副隔壁发育较弱的形态特征,判断其时代为二叠纪瓜德鲁普世(Guadalupian)沃德期(Wordian)。该(虫筳)类动物群面貌可与拉萨地块的狮泉河地区、措勤夏东地区、申扎地区、林周地区等对比。拉萨地块从中二叠世开始普遍出现暖水(虫筳)类动物群,这与印度板块北缘特提斯喜马拉雅地区中、晚二叠世时期均以冷水的腕足生物群为主所反映的水体性质有明显的差异。这表明拉萨地块和喜马拉雅地区在晚三叠世之前仍然连在一起的可能性并不大,拉萨地块可能在瓜德鲁普世沃德期以前已经脱离冈瓦纳大陆。     

吉中地区晚古生代腕足动物古生物地理与环境的协同演化*

吉中地区发育了普里道利期—洛霍考夫期Retziella、杜内期通气沟组以及空谷期—沃德期哲斯等腕足动物群。前两者属于"暖水"动物群、后者属于"凉水"动物群。同时参考珊瑚和等动物群分析,说明吉中地区从普里道利期至阿瑟尔期发育"暖水"动物群,从空谷期到沃德期发育"凉水"动物群。"凉、暖"转换是以寿山沟组的Monodiexodina动物群为代表,发生在萨克马尔期。"凉、暖"水动物群的发育及其转换是构造古地理与气候变化双重因素导致的结果。晚志留世—早泥盆世,西伯利亚板块、哈萨克斯坦板块、佳-蒙地块均位于中—低纬度带。吉中地区晚志留世—早泥盆世(乃至中泥盆世)腕足动物群属于"暖水"动物群,古生物地理区划属于中-澳生物地理区。石炭纪,东欧板块东北缘、哈萨克斯坦板块大部分地区、佳-蒙地块南缘属于特提斯洋北缘构造域,发育了特提斯洋北缘腕足动物群,形成了特提斯北缘生物地理区,吉中地区腕足动物群属于这一生物地理区。空谷期—沃德期凉水型哲斯腕足动物群的形成是由于佳-蒙地块西端与塔里木板块以及华北板块西端拼合,形成了西拉木伦洋构造域,以及此时期全球降温事件导致的结果。古生物地理、构造古地理以及古气候之间的协同演化关系表明吉中地区晚古生代地层应属于佳-蒙地块南缘的大陆边缘沉积。     

西藏羌塘中部地区Polydiexodina(竹蜓)类动物群

描述了采自西藏羌塘中部地区筵类化石的一部分,计7属13种,分属4科,两超科。其中Polydiexodina5种,含2新种。筵类动物群面貌与Neoschwagerina带相当,确定产Polydiexodina地层的形成时代属中二叠世茅口期。扩大了Polydiexodina的分布范围,为较大区域性地层的划分、对比提供了生物依据,也为研究古生物地理分区提供了新资料。     

藏南雅鲁藏布江缝合带放射虫研究进展与问题

雅鲁藏布江缝合带是青藏高原上最年轻的一条缝合带,位于青藏高原南端,记录了随着印度大陆向北漂移并最终与欧亚大陆碰撞而消亡的新特提斯洋的演化历史。藏南地区的硅质地层呈东西向断断续续延伸达数千公里,分布于缝合带蛇绿岩南北两侧和特提斯喜马拉雅沉积区。在这些硅质岩地层中发现的放射虫时代从中三叠世安尼期至晚古新世坦尼特期,揭示了特提斯海盆从中三叠世开始,至早白垩世发展为成熟大洋,然后在晚古新世之后闭合的演化过程。不过,目前还欠缺阿普特阶之后到古新世早期的含放射虫深海沉积的确切证据。已报道的晚白垩世的放射虫时代以及萨嘎附近含古新世放射虫地层的时代和构造属性仍存在很大争议。缝合带南北两侧已报道的中-晚三叠世、早-中侏罗世和晚侏罗世-早白垩世早期的放射虫化石均来自于混杂岩中的硅质岩岩块。硅质泥岩和碎屑岩代表了新特提斯洋由远洋环境逐渐到达俯冲边界的重要阶段。目前硅质泥岩基质和碎屑岩中放射虫的研究并未引起足够重视。加强放射虫动物群的全球对比,尤其是东西特提斯洋放射虫动物群的对比,在藏南地区展开系统的高精度的放射虫生物地层研究对完善放射虫化石分带、阐明新特提斯洋的演化、分析特提斯洋俯冲过程和限定印度-欧亚大陆碰撞时限等都具有重要意义。     

华南早-中二叠世(蜓)类分异度变化过程的对比研究

根据复合标准剖面的数据,对华南早-中二叠世鲢类动物群属种分异度的变化过程进行了研究,分析了早、中二叠世动物群属种首现及末现速率的差异。研究结果表明,鲢类动物群属级分异度经历了两次快速上升,一次明显下降,在早、中二叠世出现两个相对独立的高峰,但总体上表现出持续上升趋势,并在中二叠世中期达到最大。早二叠世期间属级分异度的短暂下降主要与鲢类动物本身的演化趋势有关,是动物群属级分类单元更替的结果。物种分异度在二叠纪初急剧增长,至早二叠世Sakmarian期已达到整个早-中二叠世的顶峰。早二叠世的动物群更替事件对物种分异度具有显著影响,并导致物种分异度随后总体呈下降趋势,中二叠世开始物种数虽有所上升,但始终未能恢复到早二叠世鼎盛时期的水平。早二叠世是筵类动物稳定发展时期,动物群中属种首现的总数及速率明显大于中二叠世,属种更替也更为频繁。中二叠世中期开始,筵类动物群属种分异度同时呈现急剧下降的趋势,但是,早、中二叠世华南鲢类动物群中属种末现速率却并无明显差异,表明造成晚期古生代稳定生态系统崩溃的环境变化对筵类动物的成种速率有较大的影响,持续的低成种速率是导致中二叠世筵类动物属种分异度下降的内在因素。     

云南保山地区二叠纪Shanita有孔虫动物群

系统研究了云南保山市卧牛寺附近大凹子组“破灰岩”中的Shanita有孔虫动物群,鉴定出其中特征分子Shanita和Hemigordiopsis8种(包括2新种,不含未定种和比较种),其他非有孔虫10属。研究结果表明,保山地区Shanita动物群的特征属和整体构成与缅甸、泰国和我国西藏等地的Shanita动物群相似,时代为茅口期晚期(冷坞期)至吴家坪期早期。但是,总体属级分异度较低,个别地方性种的出现及共生类的缺失,又使得保山地区的Shanita动物群具有一定的地域色彩。     

Biostratigraphy of Lower Permian foraminiferal assemblages from platform-slope carbonate blocks within the Mersin Mélange,southern Turkey: Paleogeographical implications

The Mersin Mélange (MM) as a part of the Mersin Ophiolitic Complex in southern Turkey is a sedimentary complex including blocks and tectonic slices within a Late Cretaceous matrix. Two blocks (Keven and Cingeypinari) within the MM originated from the northern branch of Neotethys (Izmir-Ankara-Erzincan Ocean) and have been studied in detail using foraminiferal assemblages to correlate them with coeval successions in the Taurides and to approach the Early Permian evolution of the northern branch of the Neotethys. The Keven block includes mainly slope deposits (poorly-sorted carbonate breccia and fossiliferous calcarenite) and dated as late Asselian-Sakmarian, whereas the Cingeypinari block consists of platform deposits (fossiliferous platform carbonate and quartz sandstone alternation) assigned to the Sakmarian-early Artinskian. These Early Permian Cingeypinari and Keven blocks from the Beysehir-Hoyran Nappes are biostratigraphically well correlated to the northerly originated Hadim nappe and its equivalents in the Tauride Belt. Considering recent studies on the Mersin Mélange, a possible mantle plume existed during the Late Carboniferous-Early Permian time interval along the northern Gondwanan margin. This event led to the opening of the northern Neotethys and deposition of the pelagic “Karincali” sequence with volcanic material in the basinal conditions. The data presented suggest that the Keven block relates to the slope and the Cingeypinari block to platform conditions deposited as a lateral equivalent of the Karincali sequences during the Early Permian.     

Middle and Upper Triassic radiolarite components from the Kcira-Dushi-Komani ophiolitic mélange and their provenance (Mirdita Zone,Albania)

The Middle Jurassic Kcira-Dushi-Komani Mélange in the northwestern Mirdita Ophiolite Zone contains blocks of Triassic oceanic crust, radiolarites and open marine limestones. We describe the microfacies and present biostratigraphic data from radiolarite clasts and blocks and from basalt-radiolarite blocks with preserved autochthonous sedimentary cover. The radiolarians yield Middle to Late Triassic (Late Anisian to Late Norian) ages for the oceanic realm from which the ophiolite and radiolarite blocks and clasts derived. Together with limestone blocks, the provenance areas of the components in the Kcira-Dushi-Komani Mélange are determined as the distal shelf and the ocean floor of the Neotethys. In the course of ophiolite obduction, the components were transported by mass movements into newly formed trench-like basins in front of the westward propagating nappe stack. These basins were later incorporated in the nappe stack forming the typical features of a syntectonic mélange. Our radiolarian biostratigraphic data confirm Late Anisian formation of the Neotethys Ocean, parts of which became closed in the Middle Jurassic. The data clearly speak in favour of one Neotethys Ocean to the east, from which the Mirdita ophiolites derived as far-travelled nappes.     

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.     

西藏南部岗巴地区晚白垩世Cenomanian—Turonian集群灭绝事件后有孔虫动物群的复苏

西藏南部岗巴地区Cenomanian-Turonian界线附近发生过一次与大洋缺氧事件有关的集群灭绝事件。其后,随着海水中溶解氧含量的逐渐增加,海洋中微体古生物,尤其是有孔虫逐渐得到了恢复以至繁盛。从Turonian早期至Santonian晚期,有孔虫动物群的复苏过程经历了三个时期：残存期,复苏期及辐射期,其复苏的型式为渐变式复苏。     

Changhsingian (Late Permian) foraminifers from the topmost part of the Xiala Formation in the Tsochen area,central Lhasa Block,Tibet and their geological implications

A foraminiferal fauna consisting of 15 genera and 19 species is documented for the first time from the topmost part of the Xiala Formation in the Aduogabu area in Tsochen County, central Lhasa Block. This foraminiferal fauna is dominated by Colaniella, indicating a broadly Changhsingian age. The presence of Colaniella, Reichelina and absence of the typical tropical fusuline genus Palaeofusulina in the fauna indicate that the Lhasa Block has not merged into equatorial regions during the Changhsingian. More importantly, the widespread Lopingian (Late Permian) marine carbonates with warm-water faunas and the stable platform carbonate sequence through the Guadalupian and Lopingian in the Lhasa Block present an obvious contrast against the contemporaneous sequences in the South Qiangtang Block and Gondwana margin. It suggests that both the Bangong-Nujiang Ocean and the Neotethys Ocean would have opened by the Guadalupian and Lopingian.     

Onset and demise of the Wetterstein Carbonate Platform in the mélange areas of the Zlatibor Mountain (Sirogojno,SW Serbia)

A kilometer-sized block in the Sirogojno carbonate-clastic mélange provides a complete succession of the Wetterstein Carbonate Platform evolution. The platform starts its progradation in Early Carnian times over hemipelagic Late Ladinian cherty limestones with fine-grained allodapic limestone intercalations. Shallow-water reef-slope, reefal to back-reef/lagoonal limestones evolved in the Early Carnian. The top of the platform is recrystallized and partly slightly dolomitized, and in parts karstification is visible. After a period of omission caused by uplift, new subsidence started in the early Late Carnian. This is documented by a flooding respectively drowning sequence of the same age, starting with reefal carbonates and rapidly followed by hemipelagic-influenced limestones. The evolution of the onset and the drowning of the Wetterstein Carbonate Platform prove a paleogeographic derivation of this block from the outer shelf-area facing the Neotethys Ocean, but still in a shallow-water carbonate platform position transitional to the Hallstatt facies zone. This paleogeographic position is especially confirmed by the new pulse of subsidence in the Late Carnian after a long lasting phase of omission. The evolution of the Wetterstein Carbonate Platform in the Inner Dinarides corresponds to successions known from the Northern Calcareous Alps or the southern Western Carpathians. In the Late Triassic both regions belong to the same northeast–southwest striking shelf area facing the Neotethys Ocean to the east and southeast, respectively.     

滇西保山地区石炭纪、二叠纪古动物地理演化

探讨滇西保山地块晚古生代Ｔｉｎｇ类、有孔虫、珊瑚、牙形刺、腕足类等动物群的古生物地理属性,根据牙形刺和Ｔｉｎｇ类化石,确定长期争论的丁家寨组的时代为Ａｒｔｉｎｓｋｉａｎ期,小型单体珊瑚Ｃｙａｔｈａｘｏｎｉａ动物群可出现在从早石炭世到二叠纪的多种沉积环境中,不一定指示冷水冈瓦纳型。根据沉积特征及对环境特别敏感的珊瑚和Ｔｉｎｇ类动物群的分布特点,结合全球构造事件,恢复保山地块的古地理演化模式。早石炭世     

Anisian foraminifers from allochthonous limestones of the Tanoura formation (Kurosegawa Terrane, West Kyushu, Japan)

Thirty-five species belonging to 21 genera of foraminifers are distinguished from allochthonous limestone blocks contained within the autochthonous mudstones and sandstones of the Carnian Tanoura Formation, Kurosegawa Terrane of West Kyushu (SW Japan). These blocks are considered to be Anisian in age, based on the occurrence of two foraminifers widely distributed in the Anisian of the Tethyan Realm, Pilammina densa and Meandrospira dinarica; they are associated with Involutinid-like forms, such as Triadodiscus and Aulotortus, and with other foraminifers. The allochthonous limestones are mostly composed of oolites, abundant bioclasts and detrital quartz grains. They are thought to have been redeposited during the Carnian on the shelf slope of the South Kitakami-Kurosegawa Old Land. Palaeogeographically, this terrane was part of the North Gondwana margin, then isolated eastwards before its Early Cretaceous amalgamation with South China. Three foraminiferal species, Triadodiscus eomesozoicus (Oberhauser), Triadodiscus? tanourensis, n. sp., and Triadodiscus? sp. are described from the Anisian allochthonous blocks.     

福建武平中二叠统童子岩组的小有孔虫

本文首次报道福建武平地区中二叠统童子岩组中与复通道Ｔｉｎ（Ｐｏｌｙｄｉｅｘｏｄｉｎａ）群共生的小有孔虫动物群１８属４４种,其中新种３个,该动物群在国内很少报道。通过这一小有孔虫群的研究,为童子岩组的地层时代时属提供了又一佐证,对该地区童子岩组中的炭岩层古生态特征也作了简单的讨论。     

Early Miocene reef- and mudflat-associated gastropods from Makran (SE-Iran)

A new gastropod fauna of Burdigalian (early Miocene) age is described from the Iranian part of Makran. The fauna comprises 19 species and represents three distinct assemblages from turbid water coral reef, shallow subtidal soft-bottom and mangrove-fringed mudflat environments in the northern Indian Ocean. Especially the reef-associated assemblage comprises largely new species. This is explained by the rare occurrence of reefs along the northern margin of the Miocene Indian Ocean and the low number of scientific studies dealing with the region. In terms of paleobiogeography, the fauna corresponds well to coeval faunas from the Pakistani Balochistan and Sindh provinces and the Indian Kathiawar, Kutch and Kerala provinces. During the early Miocene, these constituted a discrete biogeographic unit, the Western Indian Province, which documents the near complete biogeographic isolation from the Proto-Mediterranean Sea. Some mudflat taxa might represent examples of vicariance following the Tethys closure. The fauna also displays little connection with coeval faunas from Indonesia, documenting a strong provincialism within the Indo-West Pacific Region during early Miocene times. Neritopsis gedrosiana sp. nov., Calliostoma irerense sp. nov., Calliostoma mohtatae sp. nov. and Trivellona makranica sp. nov. are described as new species.