祁连和秦岭地区寒武纪和奥陶纪古生物区系关系的探讨

我国西北地区由不同地体组成,构造运动复杂。由于缺乏充分的古生物学证据,古生物区系的识别和归属一直是有待解决的问题。本文在前人工作的基础上,依据各类动物群特征的分析,较详细地探讨了我国祁连和秦岭地区相关地层区中-晚寒武世和奥陶纪动物群的性质及其古生物类型的归属,确定了过渡型动物群在祁连和秦岭地区的大体分布范围。同时,结合地球动力学和古地理学研究成果的分析,探讨了导致在祁连和秦岭地区中-晚寒武世和奥陶纪时存在着与华南相似过渡类型动物群的两种可能原因。一种可能是中-晚寒武世和奥陶纪时塔里木板块位于扬子板块西边,中朝板块位于扬子板块之北,祁连和秦岭可能位于扬子和塔里木板块之间,存在与华南及华北动物群交流的基本条件,产生了大体相近的动物群。另一种可能是中-晚寒武世和奥陶纪时祁连和秦岭地区存在一些原位于扬子板块北部边缘的地体,在这些沿扬子板块北缘分布的地体上发育了与南部边缘相似的生物群或生物类型。中生代之前,沿扬子板块主体和北部边缘地体之间的走滑活动,可能使扬子板块主体向东移动了几百公里,而其边缘那些属于祁连和秦岭的地体向东移动的幅度不大,从而造成现今祁连和秦岭地区存在与扬子板块东南部地区大体相似的具过渡性质的生物群或生物类型,而扬子板块北部边缘又缺少边缘过渡相带的现状。     

Darriwilian (Middle Ordovician) graptolite faunas of the Sandia Region,southern Peru

Ordovician graptolite faunas of Peru are restricted to a short interval in the Middle to basal Upper Ordovician, found in three regions of the country. All Peruvian graptolite faunas are strongly dominated by shallow water elements of the Atlantic Faunal Realm, represented largely by Didymograptus s. str. and Aulograptus, but a number of faunal elements of the pandemic isograptid biofacies have recently been discovered in the Sandia Region of SE Peru. Peruvian graptolite faunas are reviewed and the new records from the Sandia Region are discussed in detail. The faunas from the Purumpata and Iparo members of the San José Formation range in age approximately from the Undulograptus austrodentatus Biozone to the Holmograptus lentus Biozone (early to middle Darriwilian). The faunas provide a better understanding of faunal composition and diversity in this region and help to correlate shallow water and deeper water graptolite faunas from this time interval. Biserial graptolites are rare in most samples and usually indeterminable, but a single identifiable specimen of Undulograptus austrodentatus was found, indicating a level close to the base of the Darriwilian. A number of specimens of the genera Isograptus and Arienigraptus from the Sandia Region represent pandemic graptolite faunas of the isograptid biofacies, described for the first time from this region. Copyright © 2009 John Wiley & Sons, Ltd.     

Late Olenekian Radiolarians from Bedded Chert of Ashio Terrane, Northeast Japan,and Faunal Turnovers in Western Panthalassa during Early Triassic

Late Olenekian assemblages in the western Panthalassa have been recovered from bedded radiolarian chert sequences of an accretionary complex, the Ashio belt. These faunas are documented and considered in terms of radiolarian diversity and faunal turnover during the latest Permian to Middle Triassic time. The fauna includes 30 radiolarians belonging to Spumellaria or Entactinaria, with two relicts from the Late Permian. This late Olenekian fauna is markedly different from Permian and Asisian faunas, respectively, and is herein named the Minowa fauna. Study of the literaure indicates that radiolarian provinces were significantly disconnected between the western Panthalassa and eastern Tethys during late Olenekian time. Furthermore, 121 of 143 species disappeared during late Olenekian time, and in turn 118 new species appeared in the western Panthalassa around the Olenekian-Anisian boundary. It is concluded that faunal turnover occurred at least three times between the latest Permian and Middle Triassic.The first turnover is the Poalaozoie-type radiolarian extinction at the Permain-Triassic boundary,the second is the diversification of spheroidal Spumellaria and Entactinaria between early and late Olenekian time, and the third is a faunal turnover from the Minowa fauna to the true Mesozoic-type radiolarian famas that are characterized by mulit0segmented Nassellaria.     

滇西保山、泰国西部和南部及澳大利亚悉尼盆地的冈瓦纳相二叠系对比

对滇西保山地块、泰国西部和南部及澳大利亚悉尼盆地的冈瓦纳相二叠纪地层进行了对比。前两者的二叠纪地层岩性和所含生物群面貌基本可以对比 ,皆反映出由冈瓦纳相向特提斯相的转变 ,后者是典型的冈瓦纳相 ,仅早二叠世地层的岩性和所含化石与前两者相似。     

Lower and Middle Ordovician conodonts of Laurentian affinity from blocks of limestone in the Rosroe Formation,South Mayo Trough,western Ireland and their palaeogeographic implication

The Middle Ordovician Rosroe Formation consists of some 1350 m of coarse, mainly siliciclastic to volcaniclastic sedimentary rocks, deposited in a submarine fan environment, and is restricted to the southern limb of the South Mayo Trough, western Ireland. Discrete allochthonous blocks, reaching 5 m in size, are present in the formation at several localities. Conodonts recovered from these blocks, collected from two separate locations, are of late Early and mid Mid Ordovician age. The conodonts have high conodont‐alteration indices (CAI 5) indicative of temperatures as high as 300^o to max. 480 °C; some found in the Lough Nafooey area have abnormally high indices (CAI 6), which correspond to temperatures of about 360^o to max. 550 °C. The oldest fauna is dominated by Periodon aff. aculeatus and characterized by Oepikodus evae typical of the Oepikodus evae Zone (Floian Stage; Stage Slices Fl2–3, Lower Ordovician). The younger conodont assemblage, characterized by Periodon macrodentatus associated with Oistodella pulchra, is referred to the P. macrodentatus conodont Biozone (lower Darriwilian; Stage Slices Dw1–2). The Rosroe conodont assemblages are of Laurentian affinity; comparable faunas are well known from several locations along the east to south‐eastern platform margin of Laurentia and the Notre Dame subzone of central Newfoundland, Canada. The faunal composition from the limestone blocks suggests a shelf edge to slope (or fringing carbonate) setting. The faunal assemblages are coeval with, respectively, the Tourmakeady Formation (Floian–Dapingian) and Srah Formation (Darriwilian) in the Tourmakeady Volcanic Group in the eastern part of the South Mayo Trough and probably are derived from the same or similar laterally equivalent short‐lived carbonate successions that accumulated at offshore ‘peri‐Laurentian’ islands, close to and along the Laurentian margin. During collapse of the carbonate system in the late Mid Ordovician, the blocks were transported down a steep slope and into deep‐water by debris flows, mixing with other rock types now found in the coarse polymict clastics of the Rosroe Formation. The faunas fill the stratigraphical ‘gap’ between the Lower Ordovician Lough Nafooey Volcanic Group and the upper Middle Ordovician Rosroe Formation in the South Mayo Trough and represent a brief interval conducive to carbonate accumulation in an otherwise siliciclastic‐ and volcaniclastic‐dominated sedimentary environment. Copyright © 2015 John Wiley & Sons, Ltd.     

华南下/中奥陶统界线附近笔石相的分异与全球下/中奥陶统界线生物标志的选择

通过对宜昌黄花场(扬子地台中部)大湾组剖面和重庆城口(扬子地台北部)的湄潭组剖面笔石动物群特征的分析,结合江西崇义地区(盆地相)、江南过渡带笔石动物群的研究成果,讨论了华南下／中奥陶统界线附近笔石相分异的现象,并探讨了下／中奥陶统界线附近笔石动物和牙形石的相互关系。认为宜昌黄花场剖面完全具备建立全球下／中奥陶统界线层型剖面和点(GSSP)的条件,牙形石B.triangularis的首次出现(FAD)是良好的界线生物标志。     

Ordovician faunas, island arcs and ophiolites in the Scandinavian Caledonides

Ordovician faunal data from the Scandinavian Caledonides is tested with new geochemical information from zircons to give U/Pb ages and source origins of volcanic arc and ophiolite sequences. Early Ordovician (Arenig-Llanvirn), low latitude, Toquima-Table Head faunas from the upper Upper Allochthon are associated with an island arc system formed adjacent to Laurentia. Contemporaneous mafic magmas were contaminated by crustal material during subduction and associated granites contain inherited zircons of Archaean age. The nearest source for such rocks is on the Laurentian rather than the Baltic side. Higher latitude Celtic province faunas from the upper Upper Allochthon are from one insular site accessible to forms from both Laurentia and Baltica.
The late Ordovician low-latitude Holorhynchus and subtropical Hirnantia faunas occur in overstep sequences above deeply eroded early Ordovician arc complexes. The transgression appears to be coeval with a second generation of spreading-related complexes. Single detrital zircons from sediments show sources from Archaean, Proterozoic and early Ordovician terranes. This suggests that deposition was in a basin situated along the same continental margin (Laurentia) to which the early Ordovician ophiolite/arc sequences had already become accreted. The late Ordovician faunas link both Laurentia and Baltica at a time of narrowing of lapetus.
The new geochemical data together with the faunal information is supported by recent palaeomagnetic studies.     

Coevolution of Brachiopod Paleobiogeography and Tectonopaleogeography during the Early–Middle Permian

A comprehensive compilation and systematic analysis of known early and middle Permian brachiopod faunas shows that the early Permian brachiopod faunas comprise three realms, six regions, and eleven provinces, while those of the middle Permian comprise three realms, four regions, and eight provinces. A comparison and analysis of brachiopod faunal patterns reveal a coevolution between global brachiopod paleobiogeography and tectonopaleogeography during the early–middle Permian. Although temperature/latitude is the main factor controlling the formation of three realms, tectonopaleogeographic factors determine the temperature/latitude in which the continents were located. The ‘continental barrier' of Pangea, as a ‘central axis' continent, divided the three realms into six regions, which indicates that the formation of biogeographic regions was controlled mainly by the tectonopaleogeographic factors. The evolution of tectonopaleogeography was sometimes a long-term process, so that the biogeographic regions(or provinces) controlled by tectonopaleogeography displayed relative stability. Shifts in the nature of biogeographic provinces(e.g., from cool water to warm water, and vice versa), extensions or narrowing of geographical ranges, and recombinations of some provinces were all related to regional tectonic evolution. The study of the coevolution between brachiopod paleobiogeography and tectonopaleogeography not only accounts for the formation mechanisms of brachiopod paleobiogeographic patterns during the early–middle Permian, but also provides evidences for the locations and configurations of oceans and plates(blocks) during this period.     

Recent TIMS dating results from British Late Pleistocene vertebrate faunal localities: context and interpretation

New TIMS dates from British sites underpin and extend the growing model of mammalian faunal history during the Late Pleistocene. The sequence of British faunas during the three successive warm phases of MIS 5 presents a challenging model in which the mammal faunas of the first two temperate phases, 5e and 5c is dominated by species of a classically interglacial character, while that of the final phase, sub‐stage 5a, is dominated by bison and reindeer. This we see as the ‘cold fauna’ appearing in Britain during the cool isotope sub‐stage 5b and subsequently isolated by the rising sea level of isotope sub‐stage 5a. All these three faunas are true island faunas. Copyright © 2007 John Wiley & Sons, Ltd.     

Oxygen and carbon isotope composition of Gordon Group carbonates (Ordovician), Florentine Valley,Tasmania, Australia

The Gordon Group carbonates consist of biota of the Chlorozoan assemblage, diverse non‐skeletal grains and abundant micrite and dolomite, similar to those of modern warm water carbonates. Cathodoluminescence studies indicate marine, meteoric and some burial cements. Dolomites replacing burrows, mudcracks and micrite formed during early diagenesis.

δ¹⁸O values (‐5 to ‐7%ō PDB) of the non‐luminescent fauna and marine cement are lighter than those of modern counterparts but are similar to those existing within low latitudes during the Ordovician because of the light δ¹⁸O values of Ordovician seawater (‐3 to ‐5%o SMOW). The δ¹⁸O difference (2%o) between marine and meteoric calcite indicates that Ordovician meteoric water was similar to that in modern subtropics. Values of δ¹³C relative to δ¹⁸O indicate that during the Early Ordovician there were higher atmospheric CO₂ levels than at present but during the Middle and Late Ordovician they became comparable with the present because of a change from ‘Greenhouse’ to glacial conditions. δ¹⁸O values of Late Ordovician seawater were heavier than in the Middle Ordovician mainly because of glaciation.

Dolomitization took place in marine to mixed‐marine waters while the original calcium carbonate was undergoing marine to meteoric diagenesis.     

扬子区奥陶纪、志留纪四射珊瑚分类、生物地层与生物古地理新认识

对扬子区中奥陶世至晚志留世四射珊瑚已发表的属种进行全面清理和厘定。现统计扬子区中奥陶世至晚志留世四射珊瑚约有117个属,其中以晚奥陶世和早志留世珊瑚属数最多。117个属中至少有30个属最早出现在扬子区中、晚奥陶世和早志留世地层。因此,扬子区被认为是奥陶纪、志留纪四射珊瑚起源中心之一。完善和修订扬子区中奥陶世至晚志留世四射珊瑚组合序列,使地层时代划分上均与国际通行标准(统、阶)接轨。尤其对扬子区早志留世Rhuddanian晚期,Aeronian早、晚期以及Telychian早、晚期四射珊瑚组合的重新建立和细分。最新资料表明晚奥陶世观音桥四射珊瑚动物群不但有更多的北欧同期的珊瑚分子,而且还产有北美标准属种Salvadorea,Brachyelasmasubregulare等说明两者也存在一定的联系。扬子区早志留世(Llandovery)的众多四射珊瑚属均为世界广布的,但也有许多地方性属(约有22个,占总数的23·4%)。就珊瑚生物古地理关系,它与同期的西伯利亚、哈萨克斯坦和澳大利亚珊瑚群较密切。     

中国奥陶纪三叶虫生物地理

三叶虫证据表明,除北疆区的阿尔泰地体和兴安区的额尔古纳-兴安地体与西伯利亚和劳伦陆块在动物群方面紧密关联外,中国奥陶纪的所有板块和大部分地体均系当时东泛冈瓦纳的重要组成部分,在生物地理上彼此密切相关。对这些属于东泛冈瓦纳的中国区块的台地或内陆棚三叶虫动物群的综合分析研究证明,它们在特马豆克期（Tremadocian）以及凯迪晚期-赫南特期（late Katian-Hirnantian）或阿石极期（Ashgill）应归属同一生物地理区,而在弗洛期-凯迪早期（Floian-early Katian）或阿仑尼克期-卡拉多克期（Arenig-Caradoc）则可划分为两个生物地理亚区：一个由华南、塔里木板块和安南或印支地体组成,另一个包括华北板块以及滇缅马、藏南、中天山-北山地体（可能还有海南地体）。饶有趣味的是在凯迪晚期或阿石极期开始发生的生物地理亚区解体之前,有关陆块的深水相三叶虫动物群已经历了从达瑞威尔中期（mid Darriwilian）至凯迪早期的长期频繁交流以及组成逐渐趋于齐一的过程。因此深水动物群之间的属种交流和一体化进程的发生、发展和完成显然均先于浅水一侧的三叶虫。     

Ordovician conodonts of the Tarim Region, Xinjiang, China: Occurrence and use as paleoenvironment indicators

A review of the distribution of different Ordovician conodont faunas in eight areas of the Tarim Region shows that these conodont faunas can be classified into the North China and South China types. The North China type is characterized by Aurilobodus leptosomatus, A. aurilobodus, A. simplex, Tangshanodus tanshanensis, Loxodus dissectus, Parasseratognathus paltodiformis, Microcoelodus symmetricus, Belodina compressa, B. confluens, Pseudobelodina dispansa, Yaoxianognathus yaoxianensis, and Taoqupognathus blandus. These were adapted to shallow, warm-water environments. The South China type is represented by the genera Amorphognathus, Baltoniodus, Cahabagnathus, Eoplacognathus, Lenodus, Microzarkodina, Oepikodus, Paroistodus, Paracordylodus, Periodon, Polonodus, and Pygodus, which were adapted to outer shelf, deeper, and colder water environments. Using the general pattern of conodont distribution, it is possible to interpret the various depositional environments and to reconstruct broad changes in palaeogeography of the Tarim Region during Ordovician time. In general, during Tremadocian to early Middle Ordovician time, most of the Tarim Region was a shallow semi-restricted platform that became deeper towards the north and east, with an open platform in Kalping and in the northern part of Taklimakan Desert. A slope and deep basin existed in the current Tianshan Mountains region. The Tarim sea was shallow during the Early Ordovician and became deeper during “Caradocian” (Sandbian and Early Katian) time, to become shallow again during “Ashgillian” (Late Katian) time, with the exception of part of central Taklimakan, which was a land area during “Caradocian” (Sandbian and Early Katian) time.     

中国南方奥陶—志留纪沉积层序与构造运动的关系

根据对湘西北奥陶纪和黔东北志留纪的层序划分，结合中国南方奥陶－志留纪已确定的构造运动幕次，同时辅以该地区不同期岩相地理的变化，讨论了层序界面与构造运动的关系，研究结果表明，在中国南方二级层序界面的形成更多地受到区域构造运动的影响，而三级层段序界面主要受全球海平面变化的影响，从沉积旋回的观点出发，认为中国南方加里东运动的最后一幕应在中地留世早期，即回星哨期末。     

华南奥陶、志留纪腕足动物群的更替兼论奥陶纪末冰川活动的影响

地史时期大规模的生物群更替与全球大环境的灾难性变化密切相关 ,尽管这种更替在性质、延续时间及等级上各个时期不尽相同。奥陶、志留纪腕足动物群的更替提供了一个重要的实例。全球广布的晚奥陶世较深水叶月贝动物群 ( Foliomena Fauna)和其后浅、凉水的赫南特贝动物群 ( H irnantia Fauna)的灭绝 ,均受控于当时的冈瓦纳大陆冰川活动及其影响效应。志留纪早期 ,以正形贝目和扭月贝目占主导地位的晚奥陶世动物群被一大批新类型 (如无洞贝目、五房贝亚目和石燕目 )所替代 ,组成典型的志留纪动物群。     

Ordovician metagranitoid from the Anatolide‐Tauride Block,northwest Turkey: geodynamic implications

We report a Middle Ordovician metagranitoid from the northern margin of the Anatolide‐Tauride Block, the basement of which is generally characterized by voluminous Latest Proterozoic to Early Cambrian granitoids. The Ordovician metagranitoid forms an ～400‐m‐thick body in the marbles and micaschists of the Tav?anl? Zone. The whole sequence was metamorphosed in the blueschist facies during the Late Cretaceous (c. 80 Ma). Zircons from the metagranitoid give a Middle Ordovician Pb‐Pb evaporation age of 467.0 ± 4.5 Ma interpreted as the age of crystallization of the parent granitic magma. The micaschists underlying the metagranitoid yield Cambro‐Ordovician (530–450 Ma) and Carboniferous (c. 310 Ma) detrital zircon ages indicating that the granitoid is a pre‐ or syn‐metamorphic tectonic slice. The Ordovician metagranitoid represents a remnant of the crystalline basement of the Anatolide‐Tauride Block and provides evidence for Ordovician magmatism at the northern margin of Gondwana. Prismatic Carboniferous detrital zircons in the micaschists indicate that during the Triassic, the northern margin of the Anatolide‐Tauride Block was close to Variscan terranes.     

Gravettian environmental changes in a N — S transect of central Europe

The area defined as the N — S transect of Central Europe encompasses Slovenia, Croatia, Hungary, southern Slovakia, northern Austria, Moravia and southern Poland. Physical and biological environmental analysis have been undertaken for the Gravettian period of the last glacial, between 31 and 22 ka cal BP. Mammal faunas have been recorded from different provinces, which have climatic differences. These climatic differences are reflected in the sediments, the plant cover and the fauna. Over the course of several warm and cold events from 31–22 ka the biodiversity of the individual provinces has remained roughly the same, but important quantitative changes have occurred in the individual faunas.     

临夏盆地晚新生代哺乳动物群演替与青藏高原隆升背景

临夏盆地的晚新生代沉积中富含哺乳动物化石,以晚渐新世巨犀动物群、中中新世铲齿象动物群、晚中新世三趾马动物群和早更新世真马动物群的化石最为丰富。晚新生代是青藏高原快速隆升的时期,临夏盆地的4个主要哺乳动物群在构造剧烈变化的背景下发生了显著的更替。通过对不同动物群所代表的生态特征的分析,恢复了临夏盆地晚新生代以来的气候环境演变过程:晚渐新世以温暖湿润的森林环境为主,间杂有一些开阔地带;中中新世的森林更加茂密,水体更加丰富;晚中新世演变为炎热半干旱的稀树草原环境,季节性变化加强;早更新世气候寒冷而干燥,并伴有显著的海拔升高。青藏高原在晚渐新世的隆升幅度还不足以阻挡大型哺乳动物在高原南北的交流,但到中中新世已成为明显的障碍,至晚中新世对动物迁徙的阻碍作用更加突出,而临夏盆地在早更新世已经达到相当大的高度,产生了一个高原或高山的动物群     

Faunal dating of the late Cenozoic of southern Africa,with special reference to the Carnivora

Since chronometric data comparable to that available from the late Cenozoic succession of East Africa have not, and probably cannot be obtained in southern Africa, faunal dating methods retain their traditional significance in the latter area. Five successive late Cenozoic mammal ages, the Namibian, Langebaanian, Makapanian, Cornelian, and Florisian have been proposed as a framework for discussions relating to the chronology of southern African mammalian faunas. The Namibian fauna is poorly known, but is evidently of Miocene age. It is not discussed in this paper. The Langebaanian fauna is well known only from the prolific occurrence at the type site of Langebaanweg and is Pliocene in age. Makapanian faunas are best represented at the Transvaal Australopithecine sites and probably overlap the Plio-Pleistocene boundary. The Cornelian fauna is not as well known as others, the largest assemblage having been recorded from Elandsfontein, although this assemblage is one which is unfortunately temporally heterogeneous. Florisian faunas have been recovered from a relatively large number of localities, including several for which there are radiometric dates. The recorded southern African fossil Carnivora are listed and the local evolution of this group is discussed in terms of the mammal age chronology. It is concluded that secure faunal dating of individual fossil occurrences is enhanced by an appreciation of the nature of changes undergone in evolutionary lineages, while an uncritical knowledge of recoreded taxa is less useful.