Late Permian- Early Triassic Conodont Biofacies and Bioprovinces in South China and Himalaya

On the basis of existing conodont data, the authors have studied the Late Permian-Early Triassic conodonts of different forms and biofacies in detail. Five conodont biofacies are recognized, from shallow to deep waters 1. Hindeodus conodont biofacies, 2. Pachycladina-Parachi rognathus conodont biofacies, 3. Gondolella -Hindeodus conodont biofacies, 4. Gondolella-Neospathodus conodont biofacies, and 5. Xaniognathus conodont biofacies. Considering the temporal and spatial changes of these conodont biofacies, 3 conodont bloprovinces have been divided. In light of the biofacies changes of each bioprovince, the authors also discuss, in this paper, the regularity of transgression-regression cycles of eastern Tethys and their possible relation to the mass biotic alternation.

Conodont Evidence for the Age of the Panxian Fauna,Guizhou,China

Detailed conodont analysis on the Yangjuan-Chupiwa section, Xinmin, Panxian County, Guizhou Province, revealed a conodont sequence including four Anisian conodont zones, viz. Nicoraella germanica Zone, Nc. kockeli Zone, Paragondolella bifurcata Zone and Neogondolella constricta Zone. These zones indicate that the upper Guanling Formation consists of strata from the Bithynian to the lllyrian of the Anisian. Appearance of Neogondolella constricta suggests that the Anisian/Ladinian boundary might be in the overlying Yangliujing Formation. The Panxian Fauna with well-preserved marine reptile and fish fossils is proved to belong to the lower part of the conodont Nc. kockeli Zone in the studied area. Thus, the age of the Panxian Fauna could be the early Pelsonian of the Anisian.

Conodont Biostratigraphy of the Middle Cambrian through Lowermost Ordovician in Hunan, South China

Since 1985, samples with a total weight of more than 14,000 kg, mainly from three key sections in western and northwestern Hunan, South China, have been processed for conodonts. In strata older than the late Late Cambrian paraconodonts have proved useful for stratigraphic subdivision and correlation. Thirteen conodont zones are proposed in the Middle Cambrian through lowermost Ordovician. The correlation between these zones and those of North China, western U. S.A., western Newfoundland, Canada, and Iran is discussed. In ascending order, these 13 zones are as follows: The Gapparodus bisulcatus-Westergaardodina brevidens Zone, Shandongodus priscus-Hunanognathus tricuspidatus Zone, Westergaardodina quadrata Zone, Westergaardodina matsushitai-W. grandidens Zone, Westergaardodina lui-W. am Zone, Westergaardodina cf. calix-Prooneotodus rotundatus Zone, Proconodontus tenuiserratus Zone, Proconodontus Zone, Eoconodontus Zone, Cordylodus proavus Zone, Cordylodus intermedius Zone, Cordylodus lindstromi Zone, and Cordylodus angulatus Zone (lower part). The Westergaardodina lui-W. ani and Westergaardodina cf. calix-Prooneotodus rotundatus Zones replace the Westergaardodina proligula and Westergaardodina cf. behrae-Prooneotodus rotundatus Zones, respectively, in the lowermost Upper Cambrian. Two new species (Westergaardodina Iui and Westergaardodina ani) and one conditionally identified species (Westergaardodina cf. calix) are described.

Early Permian Conodonts from the Baoshan Block, Western Yunnan, China

The Rabeignathus bucaramangus fauna was recently found from the limestone beds of the top part of the elastics-dominated Dingjiazhai Formation in the Aluotian section, southern Baoshan Block, western Yunnan. With Rabeignathus bucaramangus as the dominant species, this fauna includes Rabeignathus bucaramangus (Rabe), Homeoiranognathus huecoensis (Ritter), Sweetognathus inomatus Ritter, Sweetognathus whitei (Rhodes), Mesogondolella cf. bisselli (Clark and Behnken) and a few of ramiform elements. The characteristies of the fauna suggest that it can be correlated with the upper part of the Sweetognathus whitei Zone and assigned to the Middle Artinskian.

An Update of Conodonts in the Induan-Olenekian Boundary Strata at West Pingdingshan Section,Chaohu,Anhui Province

The Lower Triassic in Chaohu （巢湖） area, Anhui （安徽） Province, China, is well developed and its sequence is typical in South China. After a brief introduction of the Induan-Olenekian boundary of Chaohu, this article presents some new data on conodonts. More than ten times of conodont samplings and investigations have recovered thousands of conodont specimens, which are especially rich in the Induan-Olenekian boundary strata at the West Pingdingshan Section in Chaohu City, Anhui Province. The most distinctive forms are the conodonts of the Neospathodus dieneri group and N. waageni group. The first occurrence of N. waageni eowaageni, which is regarded as the indicator of the Induan-Olenekian boundary, is situated at 40.49 m above the base of Yinkeng （殷坑） Formation. Some key conodonts and seven new specimens are introduced.

Guadalupian (Middle Permian) Conodont Faunas at Shangsi Section,Northeast Sichuan Province

This study recovered the Guadalupian conodont faunas from Shangsi （上寺） Section in Northeast Sichuan （四川）. Four genera and nine species were identified, and three conodont zones were recognized and established; they include Jinogondolella nankingensis Zone, J. aserrata Zone, and J. postserrata Zone. The Roadian and Wordian boundary is set in the interval 5 m from the top of Bed 86 by the first appearance of the conodont J. aserrata. The Wordian and Capitanian boundary is set in the interval 2.3 m from the top of the Bed 95 by the first appearance ofJ. postserrata. Most of the specimens demonstrated low color alteration index （CAI） as 1.5-3, indicating that most part of the Maokou （茅口） Formation may have the suitable thermal conditions for the formation of oil source rocks.

Conodont Biostratigraphy and Age Determination of the Lower-Middle Triassic Boundary in South Guizhou Province,China

The demarcation of the Lower-Middle Triassic boundary is a disputed problem in global stratigraphic research. Lower-Middle Triassic strata of different types, from platform to basin facies,are well developed in Southwest China. This is favorable for the study of the Olenekian-Anisian boundary and establishing a stratotype for the Qingyan Stage. Based on research at the Ganheqiao section in Wangmo county and the Qingyan section in Guiyang city, Guizhou province, six conodont zones have been recognized, which can be correlated with those in other regions, in ascending order as follows： 1, Neospathodus cristagalli Interval-Zone; 2, Neospathodus pakistanensis Interval-Zone; 3,Neospathodus waageni Interval-Zone; 4, Neospathodus homeri-N, triangularis Assemblage-Zone; 5,Chiosella timorensis Interval-Zone; and 6, Neogongdolella regalis Range-Zone. An evolutionary series of the Early-Middle Triassic conodont genera Neospathodus-Chiosella-Neogongdolella discovered in the Ganheqiao and Qingyan sections has an intermediate type named Neospathodus qingyanensis that appears between Neospathodus homeri and Chiosella timorensis in the upper part of the Neospathodus homeri-N, triangularis Zone, showing an excellent evolutionary relationship of conodonts near the Lower-Middle Triassic boundary. The Lower-Middle Triassic boundary is located at 1.5 m below the top of the Ziyun Formation, where Chiosella timorensis Zone first appears in the Qingyan section,whereas this boundary is located 0.5 m below the top of the Ziyun Formation, where Chiosella timorensis Zone first appears in the Ganheqiao section. There exists one nearly 6-m thick vitric tuff bed at the bottom of the Xinyuan Formation in the Ganheqiao section, which is usually regarded as a lithologic symbol of the Lower-Middle Triassic boundary in South China. Based on the analysis of high -precision and high-sensitivity Secondary Ion Mass Spectrum data ,the zircon age of this tuff has a weighted mean 206Pb/238U age of 239.0±2.9 Ma （2σ）, which is a directly measured zircon U-Pb age of the Lower-Middle Triassic boundary. The Ganheqiao section in Wangmo county can therefore provide an excellent section through the Lower-Middle Triassic because it is continuous, the evolution of the conodonts is distinctive and the regionally stable distributed vitric tuff near the Lower-Middle Triassic boundary can be regarded as a regional key isochronal layer. This section can be regarded not only as a standard section for the establishment of the Qingyan Stage in China, but also as a reference section for the GSSP of the Lower-Middle Triassic boundary.

Application of R-Mode Cluster Analysis to Multielement Taxonomy of Early Triassic Conodonts

The multivariate statistical analysis is profitably applicable to the study of conodont multielement taxonomy.R- mode duster analyses of quantitative and 0-1 data are carried out here to classify more than 6000 discrete Lower Triassic conodont specimens belonging to 108 kinds of conodont elements from Western Guangxi . The results of R-mode cluster analysis reveal more directly the relationship among many isolated conodont elements , and they also prove that the results of the logical inference are basically correct,i.e. 108 kinds of conodont elements can be identified into 32 species belonging to 11 genera of conodonts . The application of R- mode duster analysis multielement taxonomy by the method . has brought about 4 significant conclusions , which can be used by conodont researchers as reference .

The First Discovery of the Earliest Devonian Conodont Zonal Fossil from the "Gavuu Member" in Mushgai Area of South Gobi,Mongolia

Conodont Caudicriodus woschimidti woschmidti has been found from a big outcrop (hill) of the Bayan-Kho-shuu Ruins Section which was previously assigned to the Silurian Gavuu Member of the Mandalovoo Formation. This is first time to find the lowermost Devonian conodont zonal fossil in Mongolia. The lower part of the Gavuu Member is Sil-urian. But the strata from where we collected samples M-9～M-12 definitely belong to Lower Devonian (lower Lochko-vian) rather than Lower Silurian. The Mandalovoo Formation should be named Mandalovoo Group, and its three mem-bers should be changed into three formations.

The Conodonts from Carboniferous and Permian of Iran

During the last five years conodont faunas of 6 Carboniferous-Permian sections of the Eastern and Central Iran have been investigated.Recently fusulinids from these sections(Anarak,Zaladu,Halvan,Tangale -Mokhtar,Kaviz and Bage-Vang) were studied by E.Ja.Leven.The provincial Permian scale in the Tethys (Leven,1980) is based on fusulinids.The occurrence of fusulinids and conodonts in the same samples

Conodonts from Lower Silurian Strata of the Subpolar Urals

The distribution of Lower Silurian conodonts from the sections on the Kozhym River was studied first by S.V. Melnikov.After additional studies of the Upper Ordovician-Lower Silurian strata,Oulodus? aff.nathani, Walliserodus cf.curvatus,Panderodus sp.and Ozarkodina sp.were identified by P.M(a|¨)nnik in the Subpolar Urals.Studies of conodonts from the

Conodonts from the Upper Cambrian Sesong and Hwajeol Formations in the Sabuk Area, South Korea

This paper presents a conodont biostratigraphic study on the Upper CambrianSesong and Hwajeol Formations in the Sabuk area, Korea. Two samples near the base of the SesongSlate at the Pukil section contain lower Upper Cambrian conodonts, comprising Furnishina furnishi,F. kranzae, F. pernica?, F. triangulata, Hertzina elongata, Laiwugnathus doidyxus?, Phakeloduselongatus, Muellerodus? obliquus, Westergaardodina matsushitai and W. moessebergensis. This is thefirst conodont record of the Upper Cambrian formations recovered yet in the northern limb of thePaekunsan syncline. The faunal assemblage is correlatable with the lower Upper Cambrian W.matsushitai Zone of North China. Four local biozones are recognized in the Hwajeol Formation, i.e.the Proconodontus, Eoconodontus notchpeakensis, cambrooistodus minutus and Cordylodus proavus Zonesin ascending order. This zonal scheme is essentially equivalent to that of the southern limb of thePaekunsan syncline and they are correlatable with zones in other parts of the world, including NorthAmerica, Australia, Iran and China.

Integrated Radiolarian and Conodont Biostratigraphy of the Middle to Late Permian Linghao Formation in Northwestern Guangxi, South China

The Permian radiolarian zones and their correlations with conodont zones or other chronostratigraphic schemes are still under debate. In this study, four genera, 21 species and two subspecies of radiolarians together with one genus and six species of conodonts were recovered from the Linghao Formation cropping out at the Longwangpo(LWP) section, northwestern Guangxi, South China. Six radiolarian interval zones and one abundance zone are recognized in the section, namely in ascending order, the Follicucullus scholasticus, Albaillella cavitata, A. protolevis, A. levis, A. excelsa, A. triangularis Interval zones and A. yaoi Abundance Zone. They are correlated with the Clarkina dukouensis, C. guangyuanensis and C. orientalis conodont zones recognized at the same section. Based on our data, the F. scholasticus Interval Zone and the lowermost part of A. cavitata Interval Zone are recognized to be upper Capitanian age, whereas the four Albaillella Interval zones are of Lopingian age(Wuchiapingian to the late Changhsingian). Two previously known Changhsingian radiolarian zones, namely the A. triangularis and A. yaoi Interval zones, should be extended down to the uppermost Wuchiapingian in this studied section.

Age of Berh Hairhan Formation of Mongolia dated by conodonts

Conodont Caudicriodus angustus angustus(Steward et al.,1956) and Caudicriodus angustus cauda(Wang et al.,2005) were found from a big limestone lens of the Berh Hairhan Formation in the place of W 150 km to Ulaanbaatar City.The discovery indicates that the Berh Haihan Formation should be assigned to Middle Devonian Eifelian Stage.This conodont fauna was from a shallow cooler water facies in the relatively high latitude.

Late Ordovician and Early Devonian conodonts from Onoo Tolgoi area of Mongolia

Conodont samples were collected from three localities in the Onoo Tolgoi area,Mongolia, and many conodonts have been found. Conodonts from the Onoo Tolgoi Formation (M288-M294) lack index fossils; its age could be Late Silurian. Samples from the Hutul us hudag Formation (M295-M299) contain Ozarkodina pandora alpha Morph. (P element), clearly indicating that this formation is Early Devonian late Lochkovian in age. Samples collected from so-called Silurian Onoo Tolgoi Formation at other localities(M300-M303) yield many Ordovician conodonts, including Icriodella baotaensis, Icriodella cf.baotaensis, Eoplacognathus jianyeensis, Eoplacognathus protoramosus; Baltoniodus alobatus; and ?Ambalodus triangularis; the age is Late Ordovician,more precisely, early-middle Late Ordovician.

Exceptionally Preserved Conodont Natural Assemblages from the Middle Triassic Luoping Biota,Yunnan Province,China:Implications for Architecture of Conodont Feeding Apparatus

Articulated natural assemblages contain direct evidence of the element numbers,morphologies,positions and structures for reconstructing the feeding apparatuses of conodont animals,but these kind of materials are very rare in fossil records.Here we report ten new conodont natural assemblages from Member II of the Guanling Formation in Luoping County,eastern Yunnan Province,southwestern China.These assemblages were obtained from the fossil-bearing layers of the Luoping Biota,dated to the early Middle Triassic Anisian stage(Pelsonian substage).These fossiliferous laminated limestones mainly consist of calcites and dolomites,with platy clay minerals and pyrites as subordinate components,indicating that the conodont assemblages were preserved in a lower energy and anoxic sedimentary environment.The new natural assemblages preserve the primary collapse orientations of the Nicoraella feeding apparatus from the Luoping Biota,showing the relative original positions of the S,M and P elements,that could be further used to refine the architecture of this apparatus in space variable M elements and the position unclear P1 elements.Integrating previously reported three-dimensional and bilaterally symmetrical fused clusters,we statistically analyze the size of the positional homogenous elements within different sized materials,in particular S4,S3,or S2 elements,indicates that elements ontogenic changes do not affect the apparatus architecture.Architecture of Nicoraella apparatus remains stable in the process of ontogeny,so our reconstructed model is credible.It is the first time that ample types of materials have been used to restore a conodont apparatus within one genus,namely natural assemblages(articulated and disarticulated),fused clusters(articulated,disarticulated,compressed,and relatively three-dimensional),and abundant discrete elements,respectively.These materials together record the most complete information on architecture in the gondolelloid apparatuses,thus enabling us to reconstruct a reliable fifteen-element apparatus and propose it as a standard template for gondolelloid apparatus reconstruction.

Conodont Biostratigraphy and Evolution across Permian-Triassic Boundary at Yangou Section,Leping,Jiangxi Province,South China

Series of large conodont samples with 20 species and 3 similar species in 3 genera were collected from the Permian-Triassic （P-T） boundary sequence in a shallow carbonate facies at Yangou （沿沟）, Leping （乐平） County, Jiangxi （江西） Province, South China. On the basis of the distributions of the identified species, seven conodont zones have been recognized in ascending order as follows, Neogondolella changxingensis zone, Neogondolella yini zone, Hindeodus changxingensis zone, Neogon- dolella taylorae zone, Hindeodus parvus zone, Isarcicella staeschei zone, and IsarciceUa isarcica zone. The successive occurrences of Hindeodus changxingensis, NeogondoleUa taylorae and Hindeodus parvus serve as proxies for defining the P-T biostratigraphy boundary at the base of Sub-bed 21-4 of Bed 21 in the Yangou Section. Correlations with the Meishan Section are also discussed in terms of conodont bio-stratigraphy. Three successive conodont faunal assemblages are grouped through the P-T transitional interval to examine the evolution of conodonts across the great transitional event.

北祁连冷龙岭地区上奥陶统扣门子组的时代归属——来自牙形石的证据

本文首次报道了北祁连冷龙岭地区上奥陶统扣门子组牙形石,共识别鉴定出牙形石5属,9种,其中3个未定种,根据牙形石的分布规律,建立了1个牙形石组合:Aphelognathus grandis-Panderodus gracilis组合。笔者通过对研究区牙形石组合与国内外其他地区相同层位的牙形石带对比,并结合扣门子组其它古生物化石资料,将北祁连冷龙岭地区扣门子组的时代重新厘定为晚奥陶世桑比期—赫南特期中期,相当于中国地层年表的艾家山期晚期—钱塘江期中期。

云南保山红岩剖面诺利期牙形石Mockina slovakensis的发现及其对沉积环境的指示

Mockina slovakensis是晚三叠世诺利期一个重要的牙形石属种,除了具有重要的地层学作用之外,它还能够指示特殊的沉积环境。本次研究在云南保山红岩剖面上三叠统大水塘组下段灰岩中发现了大量牙形石M.slovakensis,其在地层中占据统治地位,据此将研究层位的时代限定为晚三叠世诺利期Alaunian晚期。有记录表明,当M.slovakensis在地层中占据统治地位时,往往指示出一种较为局限的沉积环境。综合此次研究在保山红岩剖面发现的大量占统治地位的M.slovakensis牙形石以及前人对保山地块大水塘组沉积环境研究的结果,推测在诺利期Alaunian晚期,保山地区应为拉张背景下形成的较为局限的沉积盆地。该研究成果有助于进一步了解晚三叠世特提斯东部的沉积环境演化。