The Raohe area of Heilongjiang Province,Northeast China belongs to the Nadanhada Terrane,which was in low latitudes of Panthalassa during the Triassic.The composition of the Late Triassic conodont fauna,derived from l...The Raohe area of Heilongjiang Province,Northeast China belongs to the Nadanhada Terrane,which was in low latitudes of Panthalassa during the Triassic.The composition of the Late Triassic conodont fauna,derived from limestone lenses interpreted to formed on seamounts,provides important new information on the pelagic biota in this ocean.New conodont samples collected from sections at Minzhu,Minnan and Chigangbei sections belong to three Norian conodont zones.In ascending order,they are:Mockina postera Zone,Mockina bidentata Zone and Parvigondolella andrusovi Zone.The Norian conodont fauna in the Raohe area has distinct attributes:there are a lot of cosmopolitan species(e.g.,Mockina postera,Mockina bidentata,Parvigondolella andrusovi)which enable good global correlation;endemic conodont species are also present(e.g.,Mockina sakurae,Mockina shamiseni,Norigondolella nadanhadaensis)indicating that Panthalassa Ocean conodont populations also contained unique taxa;and some conodonts belong to taxa with much shorter ranges in surrounding epeiric seas(e.g.,Carnepigondolella pseudoechinata,Neocavitella cavitata and Epigondolella vialovi).The presence of the latter“relicts”indicates that the seamounts were persistently suitable habitats for many millions of years in the Late Triassic.展开更多
Conodonts,as a biotic group,next to ammonoids,pollen and spores,crustaceans and vertebrates,provide proxy clues for environment and age assessments of the rocks in which they occur.Conodonts are widely used for Triass...Conodonts,as a biotic group,next to ammonoids,pollen and spores,crustaceans and vertebrates,provide proxy clues for environment and age assessments of the rocks in which they occur.Conodonts are widely used for Triassic marine biostratigraphy.However,there are various discussions about their multielement taxonomy and evolutionary lineages(e.g.,generation,speciation).Although first studies reported that most Triassic conodont species were unimembrate,studies carried out in the following years maintained that all Triassic conodonts were multimembrate.Although statistical reconstructions of a number of Triassic apparatuses were attempted,the discovery of fused clusters and natural assemblages has subsequently demonstrated that Triassic conodonts are indeed multimembrate,and all of the elements exist together in the same apparatus.The present paper aims to clarify the evolutionary relationship and array of some Lower Triassic conodonts.Columbitella dagisi n.sp.is described.展开更多
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 water...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.展开更多
A new subproject of IGCP 596(Climate change and biodiversity patterns in the Mid-Paleozoic)started in 2015.The Goal of the project is to increase the record of rugose coral biodiversity and to provide a high-resolutio...A new subproject of IGCP 596(Climate change and biodiversity patterns in the Mid-Paleozoic)started in 2015.The Goal of the project is to increase the record of rugose coral biodiversity and to provide a high-resolution biostratigraphy especially of Devonian fossil-rich deposits in western Mongolia.A big step was achieved with the Conodont Workshop held in Graz,Austria(25.09-01.10.2015)exclusively for teaching conodont extraction techniques to colleagues from the Paleontological Center of the Mongolian Academy of Sciences(MAS)and the School of Geology and Petroleum Engineering of the Mongolian University of Science and Technology(MUST).With the knowledge provided during the workshop,in both microfossil laboratories at the MAS and at the MUST units for conodont extraction were established.展开更多
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） C...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.展开更多
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 Zon...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.展开更多
The widespread microbialites deposition that followed the End-Permian mass extinction in the Tethyan realm have been intensively studied because of the evidence they provide on the nature of this crisis and its afterm...The widespread microbialites deposition that followed the End-Permian mass extinction in the Tethyan realm have been intensively studied because of the evidence they provide on the nature of this crisis and its aftermath. However, the age of the microbialite event remains controversial. New conodont collection across the Permian–Triassic（P–T） transition from Dajiang（Guizhou Province, South China） in this study enable us to discriminate four conodont zones, in ascending order, they are： Hindeodus parvus zone, Isarcicella lobata zone, Isarcicella isarcica zone and Hindeodus sosioensis zone. The age of microbialite in the P–T transition at the Dajiang Section is considered to be within the Hindeodus parvus zone and thus to clearly post-date the main extinction crisis. Reviewing the age of onset of microbialites throughout the Tethyan regions reveals two different ages： a Hindeodus changxingensis zone age is dominant in south-western and westernmost Tethys, whilst most other regions show microbialite deposition began in the Hindeodus parvus zone. Our investigation also indicates that two conodont changes occur at this time： an increase of hindeodid species immediately following a sequence boundary and the mass extinction, and a phase of extinction losses in the earliest Triassic Isarcicella isarcica zone during highstand development.展开更多
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 Camb...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.展开更多
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 Rabe...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.展开更多
Deep-water facies sections have advantages of recording complete information across the Permian-Triassic boundary(PTB). Here we present a detailed study on the conodont biostratigraphy and carbon isotope profile range...Deep-water facies sections have advantages of recording complete information across the Permian-Triassic boundary(PTB). Here we present a detailed study on the conodont biostratigraphy and carbon isotope profile ranges from the Wuchiapingian-Changhsingian boundary(WCB) to the PTB of two deep-water facies sections at Zhuqiao and Shiligou in the Middle Yangtze region, western Hubei, South China. Fifteen species and three genera are identified. Eight conodont zones are recognized which in ascending order are the Clarkina orientalis, C. wangi, C. subcarinata, C. changxingensis, C. yini, C. meishanensis, Hindeodus parvus and Isarcicella isarcica zones. The onset of deposition of the deep-water siliceous strata of Dalong Formation in western Hubei began in the Late Wuchiapingian and persisted to the Late Changhsingian. Carbon isotope negative excursions occur near both the WCB and PTB in both sections. The WCB δ13 Ccarb negative excursion is in the C. orientalis and C. wangi zones. The PTB δ13 Ccarb negative excursion began in the C. yini Zone and extended to the I. isarcica Zone. The absence of several Changhsingian zones may indicate the difficulty of extracting conodonts from siliceous strata or the presence of an intra-Changhsingian hiatus.展开更多
Conodonts and ammonoids have played significant roles in the Permian-Triassic time- scale. In order to uncover the nature of the Permian-Triassic mass extinction and subsequent recovery, we studied conodont and ammono...Conodonts and ammonoids have played significant roles in the Permian-Triassic time- scale. In order to uncover the nature of the Permian-Triassic mass extinction and subsequent recovery, we studied conodont and ammonoid biostratigraphies around the Permian-Triassic boundary from Jianzishan of Hubei, South China. A total of four conodont zones and two ammonoid beds are recog- nized. In ascending order, the conodont zones are Late Changhsingian Clarkina changxingensis Zone, Clarkina yini Zone and Griesbachian Hindeodus parvus Zone, Hindeodus postparvus Zone; the ammon- oid beds are Late Griesbachian Ophiceras beds and Early Dienerian Ussuridiscus varaha beds. At Jian- zishan, Ophiceras beds are stratigraphically younger than Hindeodus parvus Zone, but it is likely to be the same level with Hindeoduspostparvus Zone. The Lower Dienerian in Bed 8 in this section is charac- terized by ammonoid Ussuridiscus varaha beds, which is associated with many Late Grieshachian cono- donts including Hindeodus postparvus, Hindeodus praeparvus, Hindeodus typicalis, Hindeodus pisai, Hindeodus latidentatus, Hindeodus parvus, Hindeodus anterodentatus and Isarcicella turgida, indicating these conodont species could pass through the Griesbachian-Dienerian boundary and occurred in the Early Dienerian oceans.展开更多
Fish-bearing-nodules are found in Early Triassic marine strata in many regions, including East Greenland, East Spitsbergen, Northwest Madagascar, Canada, Angola, and South China. A new Olenekian(Early Triassic) conodo...Fish-bearing-nodules are found in Early Triassic marine strata in many regions, including East Greenland, East Spitsbergen, Northwest Madagascar, Canada, Angola, and South China. A new Olenekian(Early Triassic) conodont biostratigraphic study for stratum that contains fish-bearing-nodule levels is conducted based on the Longtan(LT) Section of Nanjing City and the Qingshan(QS) Section of Jurong County, Jiangsu Province, South China. A total of 101 samples were collected at the two sections and three conodont zones were recognized: in ascending order, they are Scythogondolella(Sc.) milleri Zone, Novispathodus(Nv.) pingdingshanensis Zone, and Triassospathodus(Tr.) aff. homeri Zone. The Scythogondolella milleri Zone is globally recognized as the uppermost conodont zone of the Smithian and the base of the Novispathodus pingdingshanensis Zone was previously suggested as the marker of the Smithian-Spathian boundary in the Yangtze region. The fish-bearing-nodule levels of Nanjing and Jurong are within the conodont Scythogondolella milleri Zone, laterally correlated well with the upper part of the Novispathodus waageni Zone in Chaohu of Anhui Province that also contains fish-bearing-nodule levels. The conodont biostratigraphic correlation confirms the Early Triassic fish-bearing-nodule levels in the Lower Yangtze region are coeval, with an end-Smithian in age.展开更多
Almost all aspects of conodont research rely on a sound taxonomy based on comparative analysis.This is founded on hypotheses of homology which ultimately rest on knowledge of the location of elements in the apparatus....Almost all aspects of conodont research rely on a sound taxonomy based on comparative analysis.This is founded on hypotheses of homology which ultimately rest on knowledge of the location of elements in the apparatus.Natural assemblages—fossils that preserve the articulated remains of the conodont skeletal apparatus—provide our only direct evidence for element location,but very few are known from the Late Triassic.Here we describe fused clusters(natural assemblages)from the late Norian limestone beds of the Nanshuba Formation in Baoshan,Yunnan Province,southwestern China.Recurrent arrangements and juxtaposition of S and M elements in multiple clusters reveal the composition of the apparatus of Mockina and,probably,Parvigondolella.They indicate that these taxa had a standard 15 elements ozarkodinid apparatus,and provide new insights into the morphology of the elements occupying the P2,M and S locations of the apparatus.The apparatus comprised a single alate(hibbardelliform)S0 element,paired breviform digyrate(grodelliform)S1 and(enantiognathiform)S2 elements,paired bipennate(hindeodelliform)S3 and S4 elements,paired breviform digyrate(cypridodellifrom)M elements,paired,modified-angulate P2 elements(with reduced or lacking‘posterior’process)and segminiplanate(mockiniform and parvigondolelliform)P1 elements.Our results will allow testing of the hypothesis that Mockina,Parvigondolella and Misikella—critical taxa in Late Triassic biostratigraphy—are closely related and possessed morphologically similar elements in homologous locations.展开更多
Two Permian-Triassic boundary(PTB) sections(Pojue and Dala) are well exposed in an isolated carbonate platform(Napo Platform) on the southwestern margin of the Nanpanjiang Basin, South China. These sections provide an...Two Permian-Triassic boundary(PTB) sections(Pojue and Dala) are well exposed in an isolated carbonate platform(Napo Platform) on the southwestern margin of the Nanpanjiang Basin, South China. These sections provide an insight into the transition across the PTB and a detailed investigation of the conodont biostratigraphy and inorganic carbon isotopes is presented. The PTB at the Pojue Section is placed at the base of Bed 10 B(a dolomitized mudstone found below a microbialite horizon), defined by the first occurrence of Hindeodus parvus. At the Dala Section, four conodont zones occur. They are, in ascending order, the Hindeodus parvus Zone, Isarcicella staeschei Zone, Isarcicella isarcica Zone and Clarkina planata Zone. Comparison with the Pojue Section suggests the PTB at Dala also occurs at the base of dolomitized mudstone below a microbialite horizon, although the first occurrence of Hindeodus parvus is near the top of a microbialite bed: an occurrence that is also seen in other platform sections. The succeeding microbialite beds developed during the ongoing PTB mass extinction phase. This time was characterized by low carbon isotope values, and a microbialite ecosystem that provided a refuge for selected groups(bivalves, ostracods and microgastropods) that were likely tolerant of extremely high temperatures.展开更多
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;...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.展开更多
A continuous sedimentation at the Xinmin Section, Anshun, Guihzou Province, with the Upper Permian Talung Formation dominated by bedded siliceous rocks, and the Lower Triassic Luolou Formation consisting mudstones and...A continuous sedimentation at the Xinmin Section, Anshun, Guihzou Province, with the Upper Permian Talung Formation dominated by bedded siliceous rocks, and the Lower Triassic Luolou Formation consisting mudstones and marls as well as siliceous mudstones at its basal part indicates that it represents a deeper-water basinal facies across the Permian-Triassic boundary. Based on a systematic conodont biostratigraphic work, nine conodont species belong to two genera have been identified in this study. It enable us to establish five conodont zones at this section, in ascending order, they are： Clarkina changxingensis Zone（beds 1-3-4-2）, Clarkina yini Zone（beds 4-3-5-1-1）, Clarkina meishanensis Zone（beds 5-1-2-5-2）, Hindeodus changxingensis Zone（beds 5-3-1-5-3-2） and Hindeodus parvus Zone（beds 5-3-3-5-3-4）, respectively. According to the first occurrence of Hindeodus parvus in bed 5-3-3, the Permian-Triassic boundary is placed at the base of bed 5-3-3. This conodont zonation of the Xinmin Section provides precise biostratigraphic framework for further investigations on the geological events across the Permian-Triassic boundary at this section. In addition, the new conodont data also reveals that several siliceous beds occurred at the basal Triassic. It provides an exception of Early Triassic Chert Gap.展开更多
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 art...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.展开更多
The Late Paleozoic Taiyuan Formation in North China is mainly composed of a mixed shallow-marine carbonate and terrigenous clastic deposits.Its basal limestones have been constrained in the late Pennsylvanian to Early...The Late Paleozoic Taiyuan Formation in North China is mainly composed of a mixed shallow-marine carbonate and terrigenous clastic deposits.Its basal limestones have been constrained in the late Pennsylvanian to Early Permian.To further constrain the age of the lowest Taiyuan Formation,we obtained two genera and 16 species of conodonts from the bottom limestones of the Taiyuan Formation in two sections in Henan Province,southern North China.The fauna includes Idiognathodus hebeiensis,Streptognathodus isolatus,S.elongatus,S.cf.longus,S.acuminatus,S.cf.recreatus,S.cf.cristellaris,S.bellus,S.invaginatus,S.wabaunsensis,S.glenisteri,S.conjunctus,S.binodosus,S.fuchengensis,S.nodulinearis,and S.sp.A genus of Streptognathodus dominated conodont assemblage with some Idiognathodus elements.It indicates a late Gzhelian(latest Pennsylvanian)age for the lowest Taiyuan Formation in southern North China.This is consistent with recently published high-precision zircon U-Pb ages from ash layers.Based on conodont biostratigraphy,the basal limestones of the Taiyuan Formation in Henan Province(southern North China)can be correlated with the upper part of Miaogou limestones of the Taiyuan Formation in Shanxi Province(northern North China).This correlation might reflect a significant sea-level rise in North China,possibly corresponding to a deglaciation event at the Permo-Carboniferous transition.展开更多
A preciously undescribed Lower Triassic sequence of a series of multiple cycles of mud-lime rocks, with the argillaceous content decreasing upward while limestone becomes the dominant lithology in the upper part, cont...A preciously undescribed Lower Triassic sequence of a series of multiple cycles of mud-lime rocks, with the argillaceous content decreasing upward while limestone becomes the dominant lithology in the upper part, contains abundant fossils such as conodonts, ammonoids and bivalves. The Yinkeng Formation is the oldest Triassic unit represented, and it conformably overlies dark-gray thin-bedded argillaceous silicalite and intercalated grayish illite clay interbeds of the Upper Permian of Dalong Formation. Conodont samples collected from west Pingdingshan Section, one of four measured sections in Chaohu, yielded abundant Lower Triassic conodonts from the middle part of the Yinkeng Formation. Most interesting and unusual is the abundant occurrence of Platyvillosus in seven samples from the Flemingites-Euflemingites bearing (Smithian) mudstone, rhyolitic clay and limestone part of the section. The associated conodonts are Neospathodus dieneri type 1, N. dieneri type 2, N. dieneri type 3, N. cristagalli, N. waageni eowaageni (nov. subsp.), N. waageni elongata (nov. subsp.), N. waageni waageni, N. sp. G (nov. sp.), N . sp. L (nov. sp.), N . sp. H (nov. sp.), N. alberti, N. novaehollandiae, N. peculiaris, N . aff. discretus, N. conservativus, Parachirognathodus sp. and ramiform elements. The species Platyvillosus , which is restricted to a 1.32 m interval, reveals great variety in shape and denticle ornamentation pattern on the platform. The morphological study of the samples indicates that all speciemens with denticles on the upper surface can be included in intraspecific variation in Platyvillosus costatus (Staesche). Platyvillosus hamadai (Koike), marked by smooth upper surface, also appears to be connected by transitional forms in some samples. The fauna corresponds closely with that of the Taho limestone in Japan, although the depositional environments differ. The associated lithologies of the Yinkeng Formation within Chaohu area reflect a deeper and low energy remaining basin of the northern edge of the Lower Yangtze block.展开更多
This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dov?ko Section in Slovenia,which represents the eastern part of the ...This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dov?ko Section in Slovenia,which represents the eastern part of the Slovenian Basin.The age of the section ranges from the Lacian 1 to the Alaunian 1.The Lacian part of the succession is predominantly characterized by the representatives of the genus Ancyrogondolella.Transitional morphologies towards Alaunian faunas first appear in the Lacian 3 and become common during the Lacian-Alaunian transition.This evolutionary development coincides with a shift in microfacies from a dominantly radiolarian-bearing mudstone-wackestone-packstone to a filament-dominated wackestone-packstone,and the formation of small neptunian dykes,which may reflect environmental perturbations and/or a change in basin geometry.The proliferation of the genera Epigondolella and Mockina is observed in the Alaunian part of the section,though the genus Ancyrogondolella is still present in this interval.Systematic description of the conodont taxa is provided,and seven new species and two new subspecies are established.The new advances will be of great value in further biostratigraphic studies,especially in areas without ammonoid faunas,and in the reconstruction of the paleogeography of the Slovenian Basin.展开更多
基金supported by the National Natural Sciences Foundation of China(Nos.42372005,41830320,41972033)。
文摘The Raohe area of Heilongjiang Province,Northeast China belongs to the Nadanhada Terrane,which was in low latitudes of Panthalassa during the Triassic.The composition of the Late Triassic conodont fauna,derived from limestone lenses interpreted to formed on seamounts,provides important new information on the pelagic biota in this ocean.New conodont samples collected from sections at Minzhu,Minnan and Chigangbei sections belong to three Norian conodont zones.In ascending order,they are:Mockina postera Zone,Mockina bidentata Zone and Parvigondolella andrusovi Zone.The Norian conodont fauna in the Raohe area has distinct attributes:there are a lot of cosmopolitan species(e.g.,Mockina postera,Mockina bidentata,Parvigondolella andrusovi)which enable good global correlation;endemic conodont species are also present(e.g.,Mockina sakurae,Mockina shamiseni,Norigondolella nadanhadaensis)indicating that Panthalassa Ocean conodont populations also contained unique taxa;and some conodonts belong to taxa with much shorter ranges in surrounding epeiric seas(e.g.,Carnepigondolella pseudoechinata,Neocavitella cavitata and Epigondolella vialovi).The presence of the latter“relicts”indicates that the seamounts were persistently suitable habitats for many millions of years in the Late Triassic.
文摘Conodonts,as a biotic group,next to ammonoids,pollen and spores,crustaceans and vertebrates,provide proxy clues for environment and age assessments of the rocks in which they occur.Conodonts are widely used for Triassic marine biostratigraphy.However,there are various discussions about their multielement taxonomy and evolutionary lineages(e.g.,generation,speciation).Although first studies reported that most Triassic conodont species were unimembrate,studies carried out in the following years maintained that all Triassic conodonts were multimembrate.Although statistical reconstructions of a number of Triassic apparatuses were attempted,the discovery of fused clusters and natural assemblages has subsequently demonstrated that Triassic conodonts are indeed multimembrate,and all of the elements exist together in the same apparatus.The present paper aims to clarify the evolutionary relationship and array of some Lower Triassic conodonts.Columbitella dagisi n.sp.is described.
基金The project supported by the National Natural Science Foundation of China
文摘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.
文摘A new subproject of IGCP 596(Climate change and biodiversity patterns in the Mid-Paleozoic)started in 2015.The Goal of the project is to increase the record of rugose coral biodiversity and to provide a high-resolution biostratigraphy especially of Devonian fossil-rich deposits in western Mongolia.A big step was achieved with the Conodont Workshop held in Graz,Austria(25.09-01.10.2015)exclusively for teaching conodont extraction techniques to colleagues from the Paleontological Center of the Mongolian Academy of Sciences(MAS)and the School of Geology and Petroleum Engineering of the Mongolian University of Science and Technology(MUST).With the knowledge provided during the workshop,in both microfossil laboratories at the MAS and at the MUST units for conodont extraction were established.
基金supported by the National Natural Science Foundation of China(Nos.40830212,40921062)the China Postdoctoral Science Foundation(No.20080430147)+1 种基金the Program of Key Laboratory of Biogeology and the Environmental Geology of Ministry of Education,China University of Geosciences(No.BGEG0802)the Science Project of Education Department in Jiangxi Province(No.GJJ10623)
文摘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.
基金This study was financially supported by grants from the"985"project of Peking University,National Natural Science Foundation of China(grant 40272005)the Major Basic Research Projects of China(grant G2000077700).
文摘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.
基金supported by the Natural Science Foundation of China (Nos. 41172024, 41272044)the "973" Program (No. 2011CB808800)+2 种基金the "111" Project (No. B08030)the ‘Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan)the State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (No. GBL11202)
文摘The widespread microbialites deposition that followed the End-Permian mass extinction in the Tethyan realm have been intensively studied because of the evidence they provide on the nature of this crisis and its aftermath. However, the age of the microbialite event remains controversial. New conodont collection across the Permian–Triassic（P–T） transition from Dajiang（Guizhou Province, South China） in this study enable us to discriminate four conodont zones, in ascending order, they are： Hindeodus parvus zone, Isarcicella lobata zone, Isarcicella isarcica zone and Hindeodus sosioensis zone. The age of microbialite in the P–T transition at the Dajiang Section is considered to be within the Hindeodus parvus zone and thus to clearly post-date the main extinction crisis. Reviewing the age of onset of microbialites throughout the Tethyan regions reveals two different ages： a Hindeodus changxingensis zone age is dominant in south-western and westernmost Tethys, whilst most other regions show microbialite deposition began in the Hindeodus parvus zone. Our investigation also indicates that two conodont changes occur at this time： an increase of hindeodid species immediately following a sequence boundary and the mass extinction, and a phase of extinction losses in the earliest Triassic Isarcicella isarcica zone during highstand development.
基金This study was supported by the National Natural Science Foundation of China(Grants 4037200140072007+3 种基金49772083 to Dong Xiping)by the Laboratory of Paleobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences(Grant 023106 to Dong Xiping)by the Research Fund for Doctoral Program of High Education(Grant 2000000127 to Dong Xiping)by a travel grant from the Ohio State University(to Stig M.Bergstrom).
文摘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.
基金This work is suppoged by the National Natural Science Foundadon of China(Grant No.40232024)Chinese Geological Survey(Grant No.200313000054).
文摘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.
基金supported by the Natural Science Foundation of China(Nos.41572002,41830320,41272044,41472087,4183000426,41802016)
文摘Deep-water facies sections have advantages of recording complete information across the Permian-Triassic boundary(PTB). Here we present a detailed study on the conodont biostratigraphy and carbon isotope profile ranges from the Wuchiapingian-Changhsingian boundary(WCB) to the PTB of two deep-water facies sections at Zhuqiao and Shiligou in the Middle Yangtze region, western Hubei, South China. Fifteen species and three genera are identified. Eight conodont zones are recognized which in ascending order are the Clarkina orientalis, C. wangi, C. subcarinata, C. changxingensis, C. yini, C. meishanensis, Hindeodus parvus and Isarcicella isarcica zones. The onset of deposition of the deep-water siliceous strata of Dalong Formation in western Hubei began in the Late Wuchiapingian and persisted to the Late Changhsingian. Carbon isotope negative excursions occur near both the WCB and PTB in both sections. The WCB δ13 Ccarb negative excursion is in the C. orientalis and C. wangi zones. The PTB δ13 Ccarb negative excursion began in the C. yini Zone and extended to the I. isarcica Zone. The absence of several Changhsingian zones may indicate the difficulty of extracting conodonts from siliceous strata or the presence of an intra-Changhsingian hiatus.
基金supported by the State Key R&D Project of China(No.2016YFA0601100)the National Natural Science Foundation of China(Nos.41622207,41302271,41530104)the 111 Project(No.B08030)
文摘Conodonts and ammonoids have played significant roles in the Permian-Triassic time- scale. In order to uncover the nature of the Permian-Triassic mass extinction and subsequent recovery, we studied conodont and ammonoid biostratigraphies around the Permian-Triassic boundary from Jianzishan of Hubei, South China. A total of four conodont zones and two ammonoid beds are recog- nized. In ascending order, the conodont zones are Late Changhsingian Clarkina changxingensis Zone, Clarkina yini Zone and Griesbachian Hindeodus parvus Zone, Hindeodus postparvus Zone; the ammon- oid beds are Late Griesbachian Ophiceras beds and Early Dienerian Ussuridiscus varaha beds. At Jian- zishan, Ophiceras beds are stratigraphically younger than Hindeodus parvus Zone, but it is likely to be the same level with Hindeoduspostparvus Zone. The Lower Dienerian in Bed 8 in this section is charac- terized by ammonoid Ussuridiscus varaha beds, which is associated with many Late Grieshachian cono- donts including Hindeodus postparvus, Hindeodus praeparvus, Hindeodus typicalis, Hindeodus pisai, Hindeodus latidentatus, Hindeodus parvus, Hindeodus anterodentatus and Isarcicella turgida, indicating these conodont species could pass through the Griesbachian-Dienerian boundary and occurred in the Early Dienerian oceans.
基金funded by the Stratefic Priority Research Program of the Chinese Academy of Science(No.XDA14010404)the National Science Foundation of China(Nos.41572008,U1663201,41372016,40920124002,1402014)+2 种基金the Ministry of Science and Technology(No.2016YFC0503301)the State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)(Nos.123107,143108,173123)the China Geological Survey(No.121201102000150012-09)
文摘Fish-bearing-nodules are found in Early Triassic marine strata in many regions, including East Greenland, East Spitsbergen, Northwest Madagascar, Canada, Angola, and South China. A new Olenekian(Early Triassic) conodont biostratigraphic study for stratum that contains fish-bearing-nodule levels is conducted based on the Longtan(LT) Section of Nanjing City and the Qingshan(QS) Section of Jurong County, Jiangsu Province, South China. A total of 101 samples were collected at the two sections and three conodont zones were recognized: in ascending order, they are Scythogondolella(Sc.) milleri Zone, Novispathodus(Nv.) pingdingshanensis Zone, and Triassospathodus(Tr.) aff. homeri Zone. The Scythogondolella milleri Zone is globally recognized as the uppermost conodont zone of the Smithian and the base of the Novispathodus pingdingshanensis Zone was previously suggested as the marker of the Smithian-Spathian boundary in the Yangtze region. The fish-bearing-nodule levels of Nanjing and Jurong are within the conodont Scythogondolella milleri Zone, laterally correlated well with the upper part of the Novispathodus waageni Zone in Chaohu of Anhui Province that also contains fish-bearing-nodule levels. The conodont biostratigraphic correlation confirms the Early Triassic fish-bearing-nodule levels in the Lower Yangtze region are coeval, with an end-Smithian in age.
基金supported by the National Natural Sciences Foundation of China(Nos.41830320,41972033,41572324)。
文摘Almost all aspects of conodont research rely on a sound taxonomy based on comparative analysis.This is founded on hypotheses of homology which ultimately rest on knowledge of the location of elements in the apparatus.Natural assemblages—fossils that preserve the articulated remains of the conodont skeletal apparatus—provide our only direct evidence for element location,but very few are known from the Late Triassic.Here we describe fused clusters(natural assemblages)from the late Norian limestone beds of the Nanshuba Formation in Baoshan,Yunnan Province,southwestern China.Recurrent arrangements and juxtaposition of S and M elements in multiple clusters reveal the composition of the apparatus of Mockina and,probably,Parvigondolella.They indicate that these taxa had a standard 15 elements ozarkodinid apparatus,and provide new insights into the morphology of the elements occupying the P2,M and S locations of the apparatus.The apparatus comprised a single alate(hibbardelliform)S0 element,paired breviform digyrate(grodelliform)S1 and(enantiognathiform)S2 elements,paired bipennate(hindeodelliform)S3 and S4 elements,paired breviform digyrate(cypridodellifrom)M elements,paired,modified-angulate P2 elements(with reduced or lacking‘posterior’process)and segminiplanate(mockiniform and parvigondolelliform)P1 elements.Our results will allow testing of the hypothesis that Mockina,Parvigondolella and Misikella—critical taxa in Late Triassic biostratigraphy—are closely related and possessed morphologically similar elements in homologous locations.
基金supported by the National Natural Science Foundation of China (No. 41572324)the Special Project on Basic Work of Science and Technology from the National Ministry of Science and Technology of China (No. 2015FY310100-11)the China Geological Survey (No. DD20160120-04)
文摘Two Permian-Triassic boundary(PTB) sections(Pojue and Dala) are well exposed in an isolated carbonate platform(Napo Platform) on the southwestern margin of the Nanpanjiang Basin, South China. These sections provide an insight into the transition across the PTB and a detailed investigation of the conodont biostratigraphy and inorganic carbon isotopes is presented. The PTB at the Pojue Section is placed at the base of Bed 10 B(a dolomitized mudstone found below a microbialite horizon), defined by the first occurrence of Hindeodus parvus. At the Dala Section, four conodont zones occur. They are, in ascending order, the Hindeodus parvus Zone, Isarcicella staeschei Zone, Isarcicella isarcica Zone and Clarkina planata Zone. Comparison with the Pojue Section suggests the PTB at Dala also occurs at the base of dolomitized mudstone below a microbialite horizon, although the first occurrence of Hindeodus parvus is near the top of a microbialite bed: an occurrence that is also seen in other platform sections. The succeeding microbialite beds developed during the ongoing PTB mass extinction phase. This time was characterized by low carbon isotope values, and a microbialite ecosystem that provided a refuge for selected groups(bivalves, ostracods and microgastropods) that were likely tolerant of extremely high temperatures.
基金supported by the SINOPEC project (G0800-06-ZS-319)the National Natural Science Foundation of China (No. 40621002)+1 种基金the Program for Changjiang Scholars and Innovative Research Team (IRT0546)the "111" Project (No. B08030)
文摘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.
基金supported by the Natural Science Foundation of China (Nos. 41372039, 41272044, 41172024)the ‘Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan)’
文摘A continuous sedimentation at the Xinmin Section, Anshun, Guihzou Province, with the Upper Permian Talung Formation dominated by bedded siliceous rocks, and the Lower Triassic Luolou Formation consisting mudstones and marls as well as siliceous mudstones at its basal part indicates that it represents a deeper-water basinal facies across the Permian-Triassic boundary. Based on a systematic conodont biostratigraphic work, nine conodont species belong to two genera have been identified in this study. It enable us to establish five conodont zones at this section, in ascending order, they are： Clarkina changxingensis Zone（beds 1-3-4-2）, Clarkina yini Zone（beds 4-3-5-1-1）, Clarkina meishanensis Zone（beds 5-1-2-5-2）, Hindeodus changxingensis Zone（beds 5-3-1-5-3-2） and Hindeodus parvus Zone（beds 5-3-3-5-3-4）, respectively. According to the first occurrence of Hindeodus parvus in bed 5-3-3, the Permian-Triassic boundary is placed at the base of bed 5-3-3. This conodont zonation of the Xinmin Section provides precise biostratigraphic framework for further investigations on the geological events across the Permian-Triassic boundary at this section. In addition, the new conodont data also reveals that several siliceous beds occurred at the basal Triassic. It provides an exception of Early Triassic Chert Gap.
基金the National Natural Science Foundation of China (Nos. 40621002, 90714010, 40574028)the State Key Laboratory of Geological Processes and Mineral Resources (GPMR2007).
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.41572078,41872106,42072013)the BGEG and GPMR laboratory funds(Nos.GKZ18Y660,GPMR201609)。
文摘The Late Paleozoic Taiyuan Formation in North China is mainly composed of a mixed shallow-marine carbonate and terrigenous clastic deposits.Its basal limestones have been constrained in the late Pennsylvanian to Early Permian.To further constrain the age of the lowest Taiyuan Formation,we obtained two genera and 16 species of conodonts from the bottom limestones of the Taiyuan Formation in two sections in Henan Province,southern North China.The fauna includes Idiognathodus hebeiensis,Streptognathodus isolatus,S.elongatus,S.cf.longus,S.acuminatus,S.cf.recreatus,S.cf.cristellaris,S.bellus,S.invaginatus,S.wabaunsensis,S.glenisteri,S.conjunctus,S.binodosus,S.fuchengensis,S.nodulinearis,and S.sp.A genus of Streptognathodus dominated conodont assemblage with some Idiognathodus elements.It indicates a late Gzhelian(latest Pennsylvanian)age for the lowest Taiyuan Formation in southern North China.This is consistent with recently published high-precision zircon U-Pb ages from ash layers.Based on conodont biostratigraphy,the basal limestones of the Taiyuan Formation in Henan Province(southern North China)can be correlated with the upper part of Miaogou limestones of the Taiyuan Formation in Shanxi Province(northern North China).This correlation might reflect a significant sea-level rise in North China,possibly corresponding to a deglaciation event at the Permo-Carboniferous transition.
基金ThispaperissupportedbytheNationalNaturalScienceFoundationofChina (No .40 0 72 0 1 1 ) ,theMinistryofScienceandTechnology (No .2 0 0 1D2 0 0 2 0 ) ,theChinese"973Program" (No .G2 0 0 0 0 7770 5)andLaboratoryofEarthSurfaceSystem ,HubeiProvince
文摘A preciously undescribed Lower Triassic sequence of a series of multiple cycles of mud-lime rocks, with the argillaceous content decreasing upward while limestone becomes the dominant lithology in the upper part, contains abundant fossils such as conodonts, ammonoids and bivalves. The Yinkeng Formation is the oldest Triassic unit represented, and it conformably overlies dark-gray thin-bedded argillaceous silicalite and intercalated grayish illite clay interbeds of the Upper Permian of Dalong Formation. Conodont samples collected from west Pingdingshan Section, one of four measured sections in Chaohu, yielded abundant Lower Triassic conodonts from the middle part of the Yinkeng Formation. Most interesting and unusual is the abundant occurrence of Platyvillosus in seven samples from the Flemingites-Euflemingites bearing (Smithian) mudstone, rhyolitic clay and limestone part of the section. The associated conodonts are Neospathodus dieneri type 1, N. dieneri type 2, N. dieneri type 3, N. cristagalli, N. waageni eowaageni (nov. subsp.), N. waageni elongata (nov. subsp.), N. waageni waageni, N. sp. G (nov. sp.), N . sp. L (nov. sp.), N . sp. H (nov. sp.), N. alberti, N. novaehollandiae, N. peculiaris, N . aff. discretus, N. conservativus, Parachirognathodus sp. and ramiform elements. The species Platyvillosus , which is restricted to a 1.32 m interval, reveals great variety in shape and denticle ornamentation pattern on the platform. The morphological study of the samples indicates that all speciemens with denticles on the upper surface can be included in intraspecific variation in Platyvillosus costatus (Staesche). Platyvillosus hamadai (Koike), marked by smooth upper surface, also appears to be connected by transitional forms in some samples. The fauna corresponds closely with that of the Taho limestone in Japan, although the depositional environments differ. The associated lithologies of the Yinkeng Formation within Chaohu area reflect a deeper and low energy remaining basin of the northern edge of the Lower Yangtze block.
基金partially supported by the Slovenian Research Agency(No.P1-0011)partially by the NKFIH PD-131536 Project。
文摘This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dov?ko Section in Slovenia,which represents the eastern part of the Slovenian Basin.The age of the section ranges from the Lacian 1 to the Alaunian 1.The Lacian part of the succession is predominantly characterized by the representatives of the genus Ancyrogondolella.Transitional morphologies towards Alaunian faunas first appear in the Lacian 3 and become common during the Lacian-Alaunian transition.This evolutionary development coincides with a shift in microfacies from a dominantly radiolarian-bearing mudstone-wackestone-packstone to a filament-dominated wackestone-packstone,and the formation of small neptunian dykes,which may reflect environmental perturbations and/or a change in basin geometry.The proliferation of the genera Epigondolella and Mockina is observed in the Alaunian part of the section,though the genus Ancyrogondolella is still present in this interval.Systematic description of the conodont taxa is provided,and seven new species and two new subspecies are established.The new advances will be of great value in further biostratigraphic studies,especially in areas without ammonoid faunas,and in the reconstruction of the paleogeography of the Slovenian Basin.
