唐古拉山北坡雁石坪群巴柔期双壳类动物群

最近对唐古拉山北坡地层和双壳类化石的研究表明,该区有确凿的侏罗纪巴柔期双壳类动物群。可以认为侏罗纪海侵在巴柔期首次侵入羌塘地区的大部区域。在该区华南常见的侏罗纪淡水双壳类Psilunio-Cunepsis-Lamorotula(Eolamprotulu)动物群之上、下层位均获得丰富的海相巴柔期双壳类为佐证。唐古拉山地区巴柔晚期的双壳类和西藏东部,云南以及缅甸等地双壳类相比,显示出强烈的地方性色彩,和西藏南部同期双壳类动物群相比较却有较大差异。本文描述9属10种,其中大多为国内首次报道。     

贵州遵义地区早—中三叠世双壳类生物地层研究

遵义地区位于扬子板块上扬子台地中部,下、中三叠统发育良好,夜郎组、茅草铺组、松子坎组及狮子山组地层出露齐全。其中遵义巷口剖面是扬子台地区的经典下-中三叠统地层剖面之一,其产双壳类化石尤为丰富,是该沉积相区生物地层和生态系演化研究的关键剖面。迄今已发现双壳类15属55种(亚种)(本次研究鉴定出12属35种),多数属为世界性的分布类型,由下向上可划分出6个双壳类化石带:Pteriaussurica varibilis-Eumorphotis venetiana组合带,Claraiaconcentrica-Claraia wangi组合带,Eumorphotis multiformis顶峰带,Entolium discites microtis顶峰带,Myophoria(Costatoria)goldfussi mansuyi-Asoellaillyrica组合带和Plagiostoma radiata-Palaeoli ma subcostata组合带。其双壳类生态类群的演变与华南其他地区具有一致性。     

泰国、老挝南部和越南中部的非海相白垩纪双壳类生物地层学

泰国、老挝和越南白垩纪沉积全属非海相,它们广泛分布于泰国北部、东北部、西南部和南部,老挝北部、中部和南部,越南东北部、西北部、中部和南部。泰国南部的白垩纪地层分为Lam Thap,Sam Chom和Phun Phin组;其他地区,特别是西北部的呵叻高原地区的白垩系属呵叻群的Phra Wihan,Sao Khua,Phu Phan,Khok Kruat,Maha Sarakham及Phu Thok组。在老挝,万象盆地的白垩系由老挝呵叻群的NamSet,Phu Phanang,Ban Ang,Champa和Ban Thalat组与丰洪群的Thangon和Saysomboun组组成;沙湾拿吉(东兴)盆地的白垩系由南通(河)群的Nam Phouan,Nam Xot,Nam Noy和Nong Boua组组成。越南的白垩系在西北部分为Nam Na,Yen Chau,Van Chan和Ngoi Thia组,东北部为Ban Hang组,中部分为NhaTrang,Mu Gia和Dong Dzuong组,南部则为Phu Quoc组。三国白垩系的岩性普遍以红棕色至浅灰色砂岩、砾(岩质)砂岩、粉砂岩、泥岩和砾岩为主。泥岩中具有钙质结核和硅结砾岩,但盐和石膏仅见于Maha Sarakham,Saysomboun和Yen Chau组内。过去,这些白垩纪地层的生物地层没有经过详细研究。根据地层层序和化石对比,在泰国东北部呵叻高原和南部半岛地区及老挝南部沙湾拿吉(东兴)盆地中识别出了2个标记非海相白垩纪的类三角蚌类化石组合:阿普特期(但可上延至阿尔必期)的Trigonioides(Trigonioides)kobayashi-Plicatounio(Guangxiconcha)suzukii组合,阿普特阿尔必期(但主要为阿尔必期)的Trigonioides(Diversitrigonioides)diversicostatus-Pseudohyria subovalis组合。越南中部可能也产早白垩世阿普特阿尔必期的类三角蚌类双壳类Plisatouniosp.-Trigonioidessp.组合。通过双壳类组合,并结合包括孢粉和恐龙在内的其他化石的对比,泰国北部和南部、老挝南部和越南中部的非海相白垩纪地层得到了定年和对比,从而揭示了东南亚非海相白垩纪盆地的演化历史。     

西藏边坝-洛隆地区下白垩统边坝组的建立及其意义

边坝组是新建立的一个岩石地层单位。该组与下伏下白垩统多尼组呈整合接触,与上覆上白垩统宗给组呈角度不整合接触关系。岩性以紫红色深灰色粉砂质泥岩夹薄层白云岩为特征,深灰色薄层粉砂质泥岩中产丰富的双壳类化石Trigonioides(Diversitrigonioides)xizangensis-Pleuromya spitiensis组合。边坝组的建立完善了该地区下白垩统地层系统,对冈底斯北缘弧后前陆盆地白垩纪岩相古地理研究具有重要意义。     

陕西汉中地区中部下寒武统梅树村阶最早期骨骼动物群

陕西汉中地区南部扬子地台区震旦纪—寒武纪地层发育,是研究我国震旦系—寒武系界线剖面的理想地点。本文记述了该区中部(城固县大盘、南郑县白玉等地)原上震旦统灯影组顶部灰岩中新发现的最早期骨骼动物群及所在地层的分布特征。动物群化石计有软舌螺类、似软舌螺类、球壳类、单板类、开腔骨类、管壳类、原牙形类、棒形骨类、锥石类、刺棒类、齿棒类和小盾类,主要为Anabarites—Protohertzina至Paragloborilus—Siphogonuchites组合带中的分子。同时描述了两类奇特的化石新属种Dentlavula trischa Li(gen、et sp、nov)和Clypecella hexinsis Li(gen、et sp、nov)。新化石产地的发现与研究不仅为区内划分地层,确定时代提供了可靠的依据,而且填补了区内中部地区早寒武世早期在生物地层学上的空白。新属种的发现既丰富了当时生物界的内容,又为研究最早期骨骼动物群的产生及演化规律,提供了珍贵的实物资料。     

鄂尔多斯盆地西缘中宁、乌达地区石炭纪海相双壳类

本文报道的海相双壳类化石采自鄂尔多斯盆地西缘石炭纪海陆交互相含煤地层．经研究，双壳类有１３属，２７种，其中某些属种为我国首次发现，并建立了３个新种：Ｓａｎｇｕｉｎｏｌｉｔｅｓｎｉｎｇｘｉａｅｎｓｉｓ，Ｌｅｐｔｏｄｅｓｍａｓｈｉｋｏｎｇｅｎｓｉｓ和Ｓｔｒｅｂｌｏｃｈｏｎｄｒｉａｄａｓｈｉｔｏｕｊｉｎｇｏｕｅｎｓｉｓ本文采取将石炭系二分方案．研究区上石炭统下部（靖远组和羊虎沟组）海相双壳类特别丰富，有１０属２１种．这一双壳类组合与西欧和北美同期（纳缪尔一维斯发期；宾夕法尼亚的早期）的双壳类面貌相似，与国内山西太原同期的动物群差别很大，而与甘肃靖远和河南固始等地的动物群关系密切，这对恢复当时的古地理有重要意义．     

唐古拉山北坡侏罗纪双壳类化石新材料

唐古拉山地区侏罗系发育良好,是国内侏罗纪双壳类最丰富的地区之一。本文描述其中的8属17种,大多数为国内首次报道的种。由于唐古拉山地区在侏罗纪时正好位于东亚分区(East Asian province)、埃塞俄比亚分区(Ethiopian province)和欧洲分区(European province)3个不同的双壳类生物地理分区接合处,因此本区双壳类显示出一定的混生色彩,具有上述各区的一些特征属或种。但是更值得注意的是自唐古拉山向东南方向,包括西藏东部、云南、缅甸及泰国的侏罗系中,双壳类动物群含有大量的共同分子,并形成特殊的地方性生物群,考虑到侏罗纪古板块的构造格局,对上述特提斯北岸东缘进行进一步研究,将有助于建立侏罗纪的一个新的双壳类生物地理分区。     

云南保山地区中-晚三叠世Budurovignathus及Pseudofurnishius牙形类动物群的发现及意义

Budurovignathus和Pseudofurnishius牙形类动物群是世界上具有重要地层研究价值且比较稀有的牙形类动物群,迄止目前,在滇西保山地区发现:Budurovignathus hungaricus(Kozur et Vigh)、B.mungoensis(Diebel)、B.aff.mungoensis(Diebel)or B.baoshanensis sp.nov.、B.diebeli(Kozur et Mostler)、Pseudofurnishius socioensis(Gullo et Kozur),P.murcianus(Van Den Boogaard)和Pseudofurnishius sp.A等重要的属种,本次发现,为云南保山地区中—晚三叠世地层提供有力的生物年代约束,拓展了三叠世牙形石生物带,同时也丰富了中国这两个牙形类动物群的资料。     

喀喇昆仑山地区三叠纪双壳类

本文描述的双壳类化石共5属13种,分别采自喀喇昆仑山地区9个地点,分别采目下三叠统下河尾滩群、中三叠统上河尾滩群、上三叠统克勒青河组.所描述的该区化石绝大多数为首次报道.早三叠世双壳类动物群无疑地属于南特提斯区,中晚三叠世的双壳类及沉积具有浊流沉积特征,并根据构造研究结果,处于南特提斯区.     

滇西澜沧老厂晚二叠世双壳动物群的发现及其生物区系特征

本文描述了采自云南澜沧老厂的双壳类,共计13属、15种和未定种(其中1新属、4新种)。该动物群地质时代为晚二叠世,其组成既有鲜明的地方特色,又与扬子地区有明显联系,属扬子生物区系,并具亚热带生物特征。     

论福建坂头组的时代及对比

<正> 坂头组系陈恺(1943)命名,未指定建组剖面,以永安城北坂头村一带的岩性为标准。当时称坂头系,时代为早白垩世。坂头组分布在崇安、永安和泰宁举岚等盆地,宁化、安溪、仙游、古田和霞浦等地亦有零星出露。对坂头组的时代归属存在二种意见:福建省区调队(1976—1985)、原福建石油地质队(1978)、顾知微(1980、1982)、王思恩等(1985)归于     

Notes on non-marine bivalve Trigonioides (Trigonioides?) from the mid-Cretaceous Goshoura Group, Kyushu, Japan

Trigonioides goshourensis n. sp. and Trigonioides amakusensis Kikuchi and Tashiro occur in the late Albian Eboshi Formation of the Goshoura Group in Kyushu, Japan. These Albian species are characterized by three radial pseudocardinal teeth on the thick and wide hinge plate, and are probably ancestors of Cenomanian species of Trigonioides (Kumamotoa) with four radial pseudocardinal teeth. This chronological relation may be important for the correlation of non-marine Cretaceous strata in East Asia. In addition, the habitat of T. amakusensis is interpreted as estuarine tidal flats under brackish water conditions, although Trigonioides is generally a freshwater bivalve genus.     

西藏仲巴地区白垩纪末期—始新世早期海相地层

西藏仲巴县北部地区出露有晚白垩世至古近纪的海相地层 ,本次工作新测制了卓勒剖面 ,并对原错江顶剖面上部地层做了再次研究。地层中化石丰富 ,据有孔虫化石研究结果重新厘定曲下组时代为古新世早期、加拉孜组上段属始新世早期 ,认为该区白垩 /古近纪界线位于曲贝亚组与曲下组之间。在这一界面上 ,古新世磨拉石直接覆于晚白垩世的陆棚碳酸盐台地沉积之上 ,其间存在沉积间断 ,为弧前盆地演化后期的重大沉积转变。古新世早期曲下组为近海相磨拉石沉积 ,古新世晚期至始新世早期加拉孜组为残留海盆沉积。加拉孜组顶部为该区最高海相地层 ,其上为冈底斯群的磨拉石不整合覆盖。冈底斯群的时代应晚于始新世中期。     

Ecologic and taxonomic diversification in the Mesozoic brackish-water bivalve faunas in Japan, with emphasis on infaunalization of heterodonts

Mesozoic brackish-water bivalve faunas in Japan diversified in three steps: at the beginning of the Early Jurassic, Early and Late Cretaceous. The Hettangian Niranohama Fauna in northeastern Honshu represents the establishment of a heterodont-dominated brackish-water fauna that persisted until the early Late Cretaceous. No similar composition is known from the Triassic. The infauna consists mostly of non-siphonate and some short-siphonate heterodonts, while the epifauna is represented by diverse pteriomorphian families. In the Early Cretaceous Tetori Group in central Honshu, the long-siphonate heterodonts Tetoria (Corbiculidae) and the semi-infaunal soft-bottom oyster Crassostrea appeared. The evolutionary diversification of the latter, known as the most important element of modern brackish-water faunas, may thus originate at that time. In the early Late Cretaceous (Cenomanian) of the Goshoura and Mifune Groups in west Kyushu, several euryhaline deep-burrowing heterodont families, such as Veneridae and Tellinidae, further diversified in the brackish and marine environments. The Late Cretaceous is characterized by massive shell biolithic beds in which large Crassostrea species are common, a feature common for Cenozoic brackish-water faunas. The long-term changes in the composition of the brackish-water faunas in Japan represents thus an evolutionary record, irrespective of the severe physiological and environmental conditions imposed on the highly conservative nature of the fauna.     

Ecologic and taxonomic diversification in the Mesozoic brackish-water bivalve faunas in Japan,with emphasis on infaunalization of heterodonts

Mesozoic brackish-water bivalve faunas in Japan diversified in three steps: at the beginning of the Early Jurassic, Early and Late Cretaceous. The Hettangian Niranohama Fauna in northeastern Honshu represents the establishment of a heterodont-dominated brackish-water fauna that persisted until the early Late Cretaceous. No similar composition is known from the Triassic. The infauna consists mostly of non-siphonate and some short-siphonate heterodonts, while the epifauna is represented by diverse pteriomorphian families. In the Early Cretaceous Tetori Group in central Honshu, the long-siphonate heterodonts Tetoria (Corbiculidae) and the semi-infaunal soft-bottom oyster Crassostrea appeared. The evolutionary diversification of the latter, known as the most important element of modern brackish-water faunas, may thus originate at that time. In the early Late Cretaceous (Cenomanian) of the Goshoura and Mifune Groups in west Kyushu, several euryhaline deep-burrowing heterodont families, such as Veneridae and Tellinidae, further diversified in the brackish and marine environments. The Late Cretaceous is characterized by massive shell biolithic beds in which large Crassostrea species are common, a feature common for Cenozoic brackish-water faunas. The long-term changes in the composition of the brackish-water faunas in Japan represents thus an evolutionary record, irrespective of the severe physiological and environmental conditions imposed on the highly conservative nature of the fauna.     

西藏岗巴晚白垩世有孔虫动物群与海平面变化

西藏南部岗巴地区上白垩统的有孔虫动物群十分丰富，经鉴定共有52属130种。根据岩性，该地区上白垩统可以划分出三个最基本的岩石地层单位：冷青热组、岗巴村口组及宗山组。依据其中有孔虫的形态结构、生态环境、系统演化及地史分布等特征，可以划分出五个主要的有孔虫动物群，Rotalipora动物群，Whiteinella-Helvetoglobotruncana动物群，Dicarinella-Marginotruncana动物群，Globotruncana-Globotuncanita动物群及Orbitoides-Omphalocyclus动物群。这五个有孔虫动物在晚白垩世相继绝灭，其绝灭与古水深有着十分密切的关系，主要是受海平面变化的影响。     

The Cretaceous/Tertiary boundary: sedimentology and micropalaeontology at El Mulato section, NE Mexico

ABSTRACT In the El Mulato section (NE Mexico), the Upper Cretaceous marly Méndez and the Lower Palaeogene marly Velasco Formations are separated by a clastic unit. Benthic foraminifera from both marly formations indicate lower bathyal depths. The clastic unit, in contrast, contains platform sands, muddy pebbles and neritic (shallow) faunas mixed with microspherules, indicating that it was allochthonously deposited into the deep basin. The diversity and the variability in origin of the components in the clastic unit, and its sedimentological features, support a model of deposition by turbidity currents related to mass-wasting processes triggered by the Cretaceous/Tertiary (K/T) boundary impact. Planktic foraminifera were affected by a catastrophic extinction at the K/T boundary, whereas benthic foraminifera show reorganization of the community structure rather than significant extinction. The benthic faunal turnover may have resulted from the drop in primary productivity after the asteroid impact at the end of the Cretaceous.     

北京地区的白垩系

<正> 北京地区的白垩系主要出露于西山坨里—大灰厂一带,层序清楚,化石丰富,为华北晚期中生代著名的陆相断陷沉积盆地之一(图1)。坨里—大灰厂白垩系沉积盆地位于华北地台燕山台褶带西山拗陷区之东南缘。盆地北、西缘为著名的八宝山—南大寨与黄庄