东海陆架西湖凹陷宝石一井深层微体化石及地层意义

简要报道东海陆架浙东坳陷西湖凹陷之宝石一井T4°地震反射层以下深部地层 (井深 344 7m以下 )的古生物资料 ,并探讨其年代地层属性。经初步分析研究 ,这深部层位含有有孔虫、钙质超微化石、沟鞭藻和海相介形类等微体化石 ,以及见有尚不能判断是否为原位的孢粉化石。根据微体古生物的地质分布以及其它钻井深层所含微体古生物比较 ,认为宝石一井T4°反射层以下地层为西湖凹陷揭示的一套新的地层 ,其年代属古新世     

中国古生物学会古植物学会第二次代表大会在南京召开

古植物学会第二次代表大会暨1987年度学术讨论会于11月24日至27日在南京市举行.来自全国科研、地质、煤炭、石油、博物馆和大专院校等系统从事古植物学工作的86位代表参加了会议.周志炎副理事长主持了开幕式,理事长李星学教授致开幕词,赵修祜秘书长代表第一届理事会作了工作报告.中国古生物学会秘书长、中国科学院南京地质古生物研究所所长吴望始教授应邀参加了大会.中国古生物学会孢粉学会,微体古生物学会,化石藻类专业委员会,轮藻学科组,江苏省古生物学会和江苏省植物学会均派代表参加了大会.孢粉学会,化石藻类专     

渤海青东凹陷垦利构造新生代微体古生物群特征及古环境分析

本研究先后共选取采自渤海湾盆地垦利构造带的221块样品进行系统古生物分析,其中孢粉藻类样品130块(岩屑),介形类、轮藻、腹足类样品90块(岩屑),钙质超微样品1块,揭示了不同时期沉积序列的生物演化规律及其环境指示意义.深入剖析这些生储油层位的微体古生物群组合,进而揭示了区域古环境特征,对于开展区域地层对比,指导油气勘探和生烃潜力评价等都具有重要的意义.     

介形虫秘史

在古生代地层中,各门类大化石十分发育,因而很少有人去研究微小的介形虫化石。然而在中、新生代地层中,特别是陆相地层和钻井取不到大化石的情况下,介形虫化石已上升成为举足轻重的一个门类了。随着石油、天然气、煤、硫、磷、钾、天然碱等有用矿床的普查、勘探的不断深入,介形虫化石的身价亦与日俱增。什么是介形虫呢?介形虫在古无脊椎动物的分类中,属节肢动物门,甲壳纲,介形虫目。从距今约五亿七千万年的寒武纪开始出现,有的属种一直繁衍至今。介形虫是双壳动物,动物体包隐在左、右两瓣大小相等或不相等的外壳里。一般壳长0.4—4毫米,最大者可达30毫米,属于微体古生物。它们的体形不一,侧视有圆形、半圆形、纺锤形、椭圆形、肾形及菱形等。壳面饰以各种花纹,有的光滑如镜。     

现代珠江三角洲地区晚第四纪海侵的微体古生物记录

海平面波动历史对认识低海拔海岸带地区地质环境演化具有重要的参考意义。在年代测试的基础上,结合岩芯的沉积特征,通过对现代珠江三角洲地区QZK1和QZK4孔微体古生物化石的鉴定分析,发现有孔虫和介形类微体古生物化石均仅出现于两孔全新统的灰色粘土层中。微体化石分布特征显示:现代珠江三角洲地区全新世海侵从早全新世,或稍早的晚更新世开始,而QZK4孔620cm附近可能记录了全新世海平面的最高值,之后海平面开始下降至现代高度;前人报道的晚更新世海侵发生时间内,两孔中发育陆相地层,未发现海侵沉积。     

柴达木盆地北缘昆特依凹陷始新统下干柴沟组微体古生物研究

昆2井是柴达木盆地北部昆特依凹陷区潜伏Ⅰ号构造上的第一口勘探井,为了建立该地区地层层序,对该井的岩屑及岩芯样品进行了系统的微体古生物学研究,仅在下干柴沟组发现少量轮藻化石和零星的介形类化石。下干柴沟组下段出现的轮藻类Gyrogona qianjiangica和Lamprothamnium? brevis是我国中始新世最常见的化石。该层段的轮藻类可命名为Gyrogona qianjiangica-Lamprothamniumcurta-L. brevis组合,时代为中、晚始新世。本文以Gyrogona qianjiangica分布的顶、底界作为昆2井下干柴沟组下段的标志,划分结果与其它轮藻及介形类化石的对比结果基本一致。氯离子含量分布显示,轮藻类化石产出的下干柴沟组是整个地层剖面中含盐度最低的沉积阶段,表明下干柴沟组沉积时期,该地区处于水域比较广阔的淡水湖泊环境,但在个别层段出现咸化环境,产出以喜盐的Austrocypris为代表的介形类化石。     

渤海湾盆地锦州JZ25-1南地区古近纪生物组合及地层特征

本文简要概述了渤海湾盆地锦州25-1南地区古近纪生物组合特征和地层层序,建立了4个孢粉藻类组合,3个介形类化石组合,1个钙质超微化石组合,进而根据化石组合及其特征,讨论了化石组合在地层划分对比中的意义和地层展布及演化情况。     

河南范县三叠纪轮藻

本文记述的轮藻化石,采自河南范县地区三叠系钻孔岩样中,共3属10种,其中3新种,1未定种。中三叠统聊城组含轮藻化石2属7种,下三叠统和尚沟组产轮藻2属4种。这些轮藻化石的发现,为华北地区井下早第三纪沙河街组之下,二叠系石盒子群之上广泛发育厚达2000余米的红色砂泥岩地层的划分对比与地质时代的确定提供了宝贵的古生物依据。     

崛起的门类——钙质超微化石

什么是“超微化石”? 古生物化石大小十分悬殊。一般说,像介形虫、轮藻这种小个体需用显微镜来观察的属于微体化石;“超微化石”是比微体化石还要细小,其直径仅为头髪丝的十分之一,通常借助于扫描电子显微镜进行研究。“超微化石”有钙质的和硅质的两类。硅质超微化石通常指的是硅鞭毛藻,种类不多。而平常所说的“超微化石”主要指的是钙质超微化石(即钙质超微浮游生物化石)。它们种类繁多、数量极大,在地层中广泛分布。钙质超微化石首先指的是颗石类。据研究,颗石是颗石藻身上的骨骼(图一)。颗石藻是一类具有鞭毛的单细胞生物,几乎全是海生浮游的。其大小只有3—35微米,相当于粘土与粉砂的界线。颗石的大小一般在     

发刊词

在开创我国社会主义现代化建设新局面的时候,《微体古生物学报》创刊了,这标志着作为古生物科学一个方面的微体古生物学终于有了自己的出版园地。 我国微体古生物学的研究开始于本世纪20年代初,但在解放前发展缓慢,只有少数学者主要对(竹筳)类进行了研究,另外,还涉及一些非(竹筳)有孔虫、苔藓虫和轮藻化石。新中国成立后,随着大规模地质调查和矿产勘探的开展,特别是能源,如煤、石油,以及综合性多学     

湖北南襄盆地枣阳凹陷第三纪轮藻化石及其地层意义

本文研究了南襄盆地枣阳凹陷第三系玉皇顶组到凤凰镇组轮藻化石。共划分出４个组合,其时代分别属早始新世、中始新世、晚始新世和渐新世。     

Age and stratigraphic reassessment of the fossil-bearing Laguna Umayo red mudstone unit, SE Peru, from regional stratigraphy, fossil record, and paleomagnetism

The thick red mudstone unit that crops out at Laguna Umayo (Puno department, southern Peru), here referred as LURMU, has yielded in different levels a fossil assemblage with plants and vertebrates (including mammals). On the basis of charophytes, the unit was initially assigned to the Vilquechico Formation (Maastrichtian-Danian), of regional extension, and the dinosaurian structure of egg fragments was interpreted as consistent with that age. Revision of the regional stratigraphy leads to reassignment of this unit to the Lower Muñani Formation (Early Tertiary). Mammals from the LU-3 and Chulpas levels present affinities with forms from the Upper Paleocene of South America (Patagonia, Brazil). A bunodont marsupial, Chulpasia, is evidence for chronologic proximity to a transantarctic interchange with Australia at the end of the Paleocene. Furthermore, magnetostratigraphy of the LURMU reveals a single reverse polarity zone of 300 m thickness. Because of the new stratigraphic and paleomammalogic data, this long reverse polarity zone is likely correlative to Chron 26r (early Late Paleocene) or Chron 24r (latest Paleocene-earliest Eocene), or, less likely, to Chron 29r (latest Cretaceous-earliest Paleocene). The arguments previously invoked in favor of a Cretaceous age (charophytes, dinosaurian eggs) are critically evaluated, and correlation to Chron 24r is favored.     

Herpetofaunas from the Upper Paleocene and Lower Eocene of Morocco

Two Upper Paleocene and one Lower Eocene localities from Morocco (Ouarzazate basin) have yielded terrestrial assemblages that stand among the rare herpetofaunas from the Paleogene of the African Plate. The collections include one of the rare frogs and the only lizards known from the Paleogene of Africa. One of the two Upper Paleocene localities, Adrar Mgorn 1, has produced an indeterminate anuran and the most diverse assemblage of squamates from the Mesozoic and Cenozoic of Africa. It has yielded the earliest known scolecophidian snake and the earliest Gekkonidae, amphisbaenians, Tropidophiidae, and perhaps Boidae from Africa. Moreover, a specimen represents either the last sphenodontian or the earliest acrodontan lizard from this continent. One of the amphisbaenians represents a very distinct new taxon, Todrasaurus gheerbranti gen. and sp. nov. Indeterminate scincomorphans, lacertilians, Madtsoidae, and Aniliidae are also present. The fauna from the Lower Eocene is less diverse than that from the Upper Paleocene, but some taxa are common to both levels. Contrary to nearly all other Paleogene herpetofaunas from the African Plate, these Paleocene and Eocene assemblages include taxa that were terrestrial, not aquatic.     

河南潭头、卢氏和灵宝盆地上白垩统一下第三系的划分

在这篇短文中,根据脊椎动物化石的发现,进一步叙述和讨论了豫西潭头、灵宝和卢氏三个盆地的中、新生代地层的划分问题。在这三个盆地的中、新生代堆积物中,属于晚白垩世的有潭头盆地秋扒组和灵宝盆地的南朝组,后一个盆地还可能存在着时代更早的白垩纪地层。在潭头盆地的高峪沟组和大章组中分别找到中古新世的阶齿兽、中兽科和晚古新世的牧兽科、假古猬科化石;在潭头组中发现原恐角兽类和古脊齿兽类化石,时代为早始新世。在灵宝盆地的项城群中尚未找到哺乳类化石,可能包括古新世和始新世早中期的堆积。卢氏盆地的卢氏组和锄钩峪组以及灵宝盆地的川口组和浑水河组的时代为晚始新世。卢氏组下部和川口组或许可延至中始新世。     

THE EARLIEST REMAINS OF GRASSES IN THE FOSSIL RECORD

New fossils provide the earliest unequivocal evidence of grasses. Spikelets and inflorescence fragments with included pollen from the Paleocene/Eocene Wilcox Formation in western Tennessee have a suite of diagnostic characters that limits their affinities to Poaceae. Associated vegetative remains are also suggestive of grasses, but are not well enough preserved for an unequivocal identification. These fossils indicate a minimal time of origin for the family, are consistent with an Upper Cretaceous origin of Poaceae, and suggest that as in wind-pollinated Hamamelididae, wind pollination evolved in grasses or persisted in the grass lineage (if a wind-pollinated grass sister group is presumed) in dry tropical environments.     

Biostratigraphy and geodynamic impact in the uppermost part of the northeastern coastal basin of Togo

Lithological and micropaleontological studies of core-samples from five boreholes drilled in the northeastern part of the coastal basin of Togo allow for a specification of the stratigraphy and the paleogeography of this area during the Maastrichtian and Paleogene. A lithological analysis reveals a marine series consisting of a Lower Maastrichtian unit, a Middle Paleocene to Eocene unit, and an upper unit attributed to the Continental terminal sensu lato. The biostratigraphical study, based on planktonic foraminifera, has led to a characterization of the basin in terms of biozones ranging from the Globotruncana aegyptiaca to the Abathomphalus mayaroensis biozones and biozones P5 to P11, thus specifying a Middle to Upper Maastrichtian, an Upper Paleocene and a Lower to Middle Eocene units. The paleogeographical evolution of the area shows that the series recorded two sedimentary cycles: the first one stops at the end of the Cretaceous and the second one in the Paleogene.     

FILLING A GAP: THE FIRST OCCURRENCES OF EPIPHAXUM (CNIDARIA: HELIOPORACEA: LITHOTELESTIDAE) IN THE EOCENE, OLIGOCENE AND MIOCENE

Abstract:  A new species of the genus Epiphaxum (family Lithotelestidae) is described and illustrated in detail, and compared to other species. Epiphaxum arbuscula sp. nov. has been collected from Upper Eocene (Priabonian), Upper Oligocene (Chattian) and Lower Miocene (Upper Burdigalian) deposits of the Aquitaine Basin, south-west France. Epiphaxum is a poorly documented genus but its fossil record extends back to the Late Cretaceous; it was previously known only from the Paleocene (Danian). Epiphaxum arbuscula differs from all others species of the genus in the form of its colony. In contrast to the creeping colonies of previously known species, it has branched colonies. It is very common at one Upper Oligocene outcrop from which an assemblage with submarine cave remains has been described. A close relationship between the three extant species (two from the Caribbean Sea and one from the Indo-West Pacific region) and the Paleogene species is also noted. These constitute a group that has not undergone any important morphological changes for the last 65 million years.     

Paleoecological patterns in molluscan extinctions and recoveries: comparison of the Cretaceous-Paleogene and Eocene-Oligocene extinctions in North America

Exposures across the Cretaceous-Tertiary (K-T) and Eocene-Oligocene (E-O) boundaries, in Texas and Mississippi, respectively, probably represent the most complete and best-preserved fossil molluscan sequences across these boundary intervals in the world. Outcrops from both boundaries contain pristine aragonitic and calcitic molluscan shells, which were deposited in fine-grained sediments from open marine environments. The K-T and the E-O extinctions exhibit very different recovery patterns, probably reflecting very different causes as well as magnitudes of extinction.The K-T sequence contains a molluscan fossil record that is consistent with an abrupt extinction event at the K-T boundary and a prolonged initial recovery in hostile oceanographic conditions. The uppermost 10 m of Upper Cretaceous sediments contain a diverse (approximately 40 species) molluscan fauna dominated by suspension feeders. The earliest Paleocene sediments immediately above the tsunami bed contain an impoverished fauna dominated by deposit feeders. The Paleocene fauna slowly climbs in diversity but remains relatively impoverished and dominated by deposit feeders for several hundred thousand years after the extinction in conjunction with anomalous δ¹³C values that suggest prolonged suppression of marine primary productivity. Diverse suspension-feeder dominated molluscan assemblages reappear with the resumption of normal conditions of primary production. In the long term, early to middle Paleocene gamma diversity includes evolutionary “bloom taxa,” families that exhibit unusual speciation bursts that subside in the Eocene. Total diversity for the Gulf Coast does not approach Cretaceous levels until the Late Eocene representing a total recovery interval of nearly 25 million years.While the E-O event also reflects a molluscan extinction rate of over 90% in the Gulf of Mexico, there are no signs of hostile environmental conditions in the recovery fauna. Early Oligocene molluscan assemblages are diverse and dominated by suspension feeders characteristic of normal marine conditions. The hiatus at the E-O boundary, however, could have obscured a short-term recovery fauna. There is also no sign of long-term perturbation by the E-O extinction. There are no bloom taxa and gamma diversity approaches pre-extinction levels within a few million years. The overall pattern of the E-O extinction is consistent with extinction (and/or migration) associated with long-term cooling.     

新疆车排子地区孢粉植物群与古气候

通过对新疆准噶尔盆地西北缘车排子地区多口探井样品分析,见丰富的孢粉化石,建立了PiceapollisPodocarpidites-Tsugaepollenites,Parajunggarsporites-Piceaepollenites,Protohaploxypinus-Striatoabieites-Hamiapollenites三个孢粉组合。根据孢粉母体植物形态和生态特征、干湿度环境和气候环境,对其孢粉植物群反映的植被类型、干湿度类型和气候带类型进行了划分,认为晚中新世孢粉植被类型为针叶林,所处的气候环境为湿润的暖温带;早白垩世孢粉植被类型为混交林,所处的气候环境为湿润的亚热带-暖温带;晚石炭世时期其植被面貌是以阔叶植物为主,所处的气候环境为半干旱的暖温带。