Conodont fauna and biostratigraphy of the Honghuayuan Formation (Early Ordovician) of Guizhou,South China

Serratognathus diversus An, Cornuodus longibasis (Lindström), Drepanodus arcuatus Pander, and eleven other less common conodonts, including Cornuodus? sp., Oistodus lanceolatus, Protopanderodus gradatus, Protoprioniodus simplicissimus, Juanognathus variabilis, Nasusgnathus dolonus, Paltodus? sp., Scolopodus houlianzhaiensis, Semiacontiodus apterus, Semiacontiodus sp. cf. S. cornuformis and Serratognathoides? sp., are described and illustrated from the Honghuayuan Formation in Guizhou, South China, concluding revision of the conodont fauna from this unit, which comprises 24 species in total. The most distinctive species in the fauna, S. diversus, consists of a trimembrate apparatus, including symmetrical Sa, asymmetrical Sb and strongly asymmetrical Sc elements. This species concept is supported by the absence of any other element types in a large collection represented by nearly 500 specimens of this species. The fauna indicates a late Tremadocian to mid-Floian age (Early Ordovician) for the Honghuayuan Formation, which was widely distributed on the Yangtze Platform in shallow water environments. Previously published biostratigraphic zonations for the Honghuayuan Formation are reviewed, and revised on the basis of our knowledge of the entire conodont fauna, supporting the establishment of three biozones, Triangulodus bifidus, Serratognathus diversus, and Prioniodus honghuayanensis biozones in ascending order. Species of Serratognathus enable correlation between Ordovician successions of South China, North China (North China Platform and Ordos Basin), Tarim Basin, and further afield into Malaysia and northwestern Australia.     

Middle Cambrian to Lower Ordovician faunas from the Chingiz Mountain Range,central Kazakhstan

Tolmacheva, T.JU., Degtyarev, K.E., Samuelsson, J. & Holmer, L.E., December, 2008. Middle Cambrian to Lower Ordovician faunas from the Chingiz Mountain Range, central Kazakhstan. Alcheringa 32, 443–463. ISSN 0311-5518.

The middle Cambrian to Lower Ordovician back-arc sedimentary succession studied in the Kol'denen River and in the Zerbkyzyl Mountains of the central Chingiz Mountain Range is composed predominantly of siltstones, sandstones and volcaniclastic rocks with rare beds of micritic carbonates, black shales and cherts. Fossil assemblages including conodonts, lingulate brachiopods, arthropods, sponges and probable Tasmanites cysts were recorded both from the carbonate and chert beds showing that richly diverse marine environments existed directly adjacent to the volcanic arcs. The Kol'denen River localities contain a diverse upper Cambrian paraconodont assemblage of the open-sea affinity. The representatives of Rossodus, Cordylodus, Drepanodus and Variabiloconus, having an almost pandemic distribution and characteristic of basinal facies, dominate the Lower Ordovician conodont fauna. The Cambrian–Ordovician boundary transition is characterized by chert production that was more likely caused by a local productivity increase than by general changes in palaeooceanographic and palaeogeographical conditions.     

Early Ordovician conodonts from Zhejiang Province,southeast China and their biostratigraphic and palaeobiogeographic implications

Forty-two conodont species are documented from the Liuxia, Shijiatou and Jingshan formations in Zhejiang Province of southeast China, located palaeogeographically on the Jiangnan Slope offshore to the Yangtze Platform. From these faunas, eight successive conodont biozones of Tremadocian to middle Floian (Early Ordovician) age are recognized, including the Cordylodus lindstromi Biozone, Cordylodus angulatus Biozone, Chosonodina herfurthi Biozone, Paltodus deltifer Biozone, Paroistodus proteus Biozone, Triangulodus bifidus Biozone, Serratognathus diversus Biozone and Prioniodus elegans Biozone. Several zonal index species of the Baltoscandian succession—Paltodus deltifer, Paroistodus proteus and Prioniodus elegans—are described and illustrated in detail for the first time from South China. Co-occurrence of P. proteus and Serratognathus bilobatus in several samples below the appearance of P. elegans also confirms correlation of the S. diversus Biozone (basal Floian) with the upper P. proteus Zone of the Baltoscandian succession. These Zhejiang faunas are dominated by pandemic forms, and are similar to those of the Open-Sea Realm elsewhere, inhabiting deep, offshore environments.     

Ordovician trilobite faunas and depositional history of the Taebaeksan Basin,Korea: implications for palaeogeography

The Taebaeksan Basin occupies the central-eastern part of the Korean peninsula and was a low-relief shallow marine carbonate shelf on which the Cambro-Ordovician Choson Supergroup was deposited. In the Taebaeksan Basin trilobites are among the most dominant fossil groups in the Lower Ordovician, but they become less important in Middle Ordovician faunal assemblages. The Early Ordovician trilobite faunas of the Taebaeksan Basin are characterised by the common occurrence of pandemic genera such as Jujuyaspis, Leiostegium, Asaphellus, Protopliomerops, Hystricurus, Apatokephalus, Shumardia, Asaphopsoides, and Kayseraspis. Biogeographically significant trilobite taxa include Yosimuraspis, Dikelokephalina, Koraipsis, and Chosenia. These Ordovician trilobite faunas, which thrived in shallow marine environments, show a remarkable similarity with faunas from North China, implying that the Taebaeksan Basin was connected through contiguous shallow waters to North China. These Sino-Korean faunas exhibit a close biogeographic connection with Australian faunas, with which they share some endemic genera, whereas they are more distantly related to the faunas of South China, South America, and North America. Based on these palaeobiogeographical features, it is suggested that in the early Palaeozoic much of the present Korean peninsula including the Taebaeksan Basin belonged to the Sino-Korean block, while part of the peninsula was derived from the Yangtze block.     

Middle Ordovician (Darriwilian) conodonts from the Goldwyer Formation of the Canning Basin,Western Australia

Zhen, Y.Y., Normore, L.S., Dent, L.M. & Percival, I.G., 11 July 2019. Middle Ordovician (Darriwilian) conodonts from the Goldwyer Formation of the Canning Basin, Western Australia. Alcheringa 44, 25–55. ISSN 0311-5518

Middle Ordovician conodonts attributed to 46 species were recovered from a stratigraphic interval spanning the Willara, Goldwyer and Nita formations in core sections from the Sally May-2 and Theia-1 petroleum exploration wells in the Canning Basin, Western Australia. The Histiodella serrata, Histiodella holodentata and Eoplacognathus pseudoplanus biozones are recognized in the lower and middle part of the Goldwyer Formation, indicative of an early–middle Darriwilian age. This revised conodont biostratigraphy enables more precise correlation with North America and North and South China. Several biogeographically distinctive conodont species, most likely of North Chinese origin, are recorded from the Goldwyer Formation. Their presence signals a strong palaeobiogeographic connection between the Sino-Korean Craton and the Canning Basin on the western margin of eastern Gondwana during the late Middle Ordovician.

Y.Y. Zhen* [yong-yi.zhen@planning.nsw.gov.au], W.B. Clarke Geoscience Centre, Geological Survey of New South Wales, 947–953 Londonderry Road, Londonderry NSW 2753, Australia; L.S. Normore [leon.normore@dmirs.wa.gov.au]; L.M. Dent [louisa.dent@dmirs.wa.gov.au], Department of Mines, Industry Regulation and Safety, Mineral House, Geological Survey of Western Australia, 100 Plain Street, East Perth, WA 6004, Australia; I.G. Percival [ian.percival@planning.nsw.gov.au], W.B. Clarke Geoscience Centre, Geological Survey of New South Wales, 947–953 Londonderry Road, Londonderry NSW 2753, Australia;     

Middle Ordovician (early Dapingian) conodonts in the Central Andean Basin of NW Argentina

Carlorosi, J., Heredia, S. & Aceñolaza, G, 2013. Middle Ordovician (early Dapingian) conodonts in the Central Andean Basin of NW Argentina. Alcheringa 37, 1–13. ISSN 0311-5518.

This paper describes and analyzes the significance of a conodont fauna from the Alto del Cóndor Formation, exposed in the Los Colorados region of the Argentine Eastern Cordillera. Identified taxa are Baltoniodus triangularis, Baltoniodus sp. cf. B. triangularis, Drepanodus sp., Drepanoistodus basiovalis, Drepanoistodus sp. B., Erraticodon patu, Gothodus costulatus, Oistodus sp., Trapezognathus diprion, T. quadrangulum, Triangulodus sp. and Triangulodus? sp. The presence of Baltoniodus triangularis indicates the base of the Dapingian stage (Middle Ordovician). In addition, we report the coexistence of T. diprion and T. quadrangulum. The conodont association suggests a faunal affinity with Baltica and South China, both belonging to the Shallow-Sea Realm of the Temperate-Cold Domain.

Josefina Carlorosi [josefinacarlorosi77@gmail]com], INSUGEO—Universidad Nacional de Tucumán—CONICET, Miguel Lillo 205, (4000) Tucumán, Argentina; Guillermo F. Aceñolaza [acecha@webmail.unt.edu.ar], Universidad Nacional de Tucumán—CONICET, Miguel Lillo 205, (4000) Tucumán, Argentina; Susana Heredia [sheredia@unsj.edu.ar], CONICET–CIGEOBIO and Instituto de Investigaciones Mineras, Facultad de Ingeniería, Universidad Nacional de San Juan, Urquiza y Libertador, (5400) San Juan, Argentina. Received 22.8.2012; revised 18.10.2012; accepted 24.10.12.     

New,early ostracods from the Ordovician (Tremadocian) of Iran: systematic,biogeographical and palaeoecological significance

New Tremadocian ostracod material from the Alborz Mountains of Iran confirms the early and widespread occurrence of the Ordovician genus Nanopsis, and the apparently simultaneous first appearance of ostracods in the fossil record at the level of the P. deltifer conodont biozone (485.5 Ma) from China to Argentina. Nanopsis pairidaeza sp. nov. adds to the pool of species diversity for the Early Ordovician, though documented Tremadocian ostracod generic diversity remains low, with only four genera. The presence of Early Ordovician ostracods in Alborz, their occurrence elsewhere in palaeocontinental Gondwana, Baltica and China coupled to their marked absence from the Tremadocian of Laurentia and Siberia, supports the notion of the earliest occurrence of ostracods centred on Gondwana/Baltica.     

Palaeobiogeography of the Ordovician trilobite Prosopiscus,with a new species from western New South Wales

Prosopiscus is particularly important in Ordovician palaeobiogeography because of its wide geographic distribution in Gondwana and peri-Gondwanan regions. It appears to have been confined to low palaeolatitudes, representing a characteristic member of the warm water eastern Gondwanan shelf faunas. Trends in the distribution of the Ordovician genus can be observed due to its long stratigraphic range. Prosopiscus was restricted to, and may have originated in, Australia during the late Early Ordovician (Bendigonian-Chewtonian). By the Middle Ordovician (Darriwilian), Prosopiscus had dispersed to other parts of Gondwana and peri-Gondwana, including the North and South China blocks, Tarim, central Himalayas, and the Argentine Precordillera (South America). Possible explanations for the distribution of Prosopiscus are that: (1) there were no oceanic barriers preventing dispersal of trilobites between different regions of Gondwana, thus permitting uninhibited migration over vast distances; (2) Prosopiscus was not restricted to a specific biofacies; (3) a major eustatic transgression during the early Darriwilian may have facilitated the dispersal of Prosopiscus in allowing further development and expansion of marine environments; and (4) a prolonged planktonic larval stage may have permitted wide dispersal.

Prosopiscus lauriei sp. nov. is described from the late Early Ordovician (Bendigonian-Chewtonian) Tabita Formation at Mount Arrowsmith, northwestern New South Wales, Australia. The new species is closely related to P. praecox, from the Nora Formation, Georgina Basin, central Australia, and to P. magicus from northwest China.     

A new fossil genus in Pamphiliidae (Hymenoptera) from China

A new genus with two new species, Scabolyda orientalis gen. et sp. nov. and Scabolyda incompleta sp. nov., assigned to the subfamily Juralydinae in the family Pamphiliidae are described and illustrated. They were collected from the Middle Jurassic Jiulongshan Formation and the Lower Cretaceous Yixian Formation in northeastern China. They represent the first fossil pamphiliids described from China.     

On the integration of Ordovician conodont and graptolite biostratigraphy: new examples from Gansu and Inner Mongolia in China

Wang, Z.H., Bergström, S.M., Zhen, Y.Y., Chen, X. & Zhang, Y.D., 2013. On the integration of Ordovician conodont and graptolite biostratigraphy: New examples from Gansu and Inner Mongolia in China. Alcheringa 37, 510–528. ISSN 0311-5518.

Few Ordovician successions in the world contain both biostratigraphically highly diagnostic conodonts and graptolites permitting an integration between standard biozones based on these fossil groups. The Sandbian Guanzhuang section in the vicinity of Pingliang in the Gansu Province has an outstanding graptolite record through most of the Nemagraptus gracilis and Climacograptus bicornis graptolite biozones. Calcareous interbeds in the succession yield biostratigraphically important conodonts, including some species used for biozonations in Baltoscandia and the North American Midcontinent. Likewise, the middle–upper Darriwilian Dashimen section in the Wuhai region of Inner Mongolia hosts both diverse graptolites of the Pterograptus elegans, Didymograptus murchisoni and lowermost Nemagraptus gracilis biozones, and conodonts of Midcontinent and Baltoscandic types. The distribution patterns of these index fossil groups provide an unusual opportunity to closely correlate conodont and graptolite biozones in the middle to upper Darriwilian to Sandbian interval. For instance, the base of the C. bicornis Biozone is approximately coeval with the base of the Baltoscandic B. gerdae Subbiozone and a level near the middle of the North American P. aculeata Biozone.

Zhi-hao Wang [zhwang@nigpas.ac.cn] Xu Chen [xu1936@gmail.com], and Yuan-dong Zhang [ydzhang@nigpas.ac.cn], Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Stig M. Bergström [stig@geology.ohio-state.edu], School of Earth Sciences, Division of Earth History, The Ohio State University, Columbus, OH 43210, USA; Yong Yi Zhen [yongyi.zhen@austmus.gov.au], Australian Museum, 6 College Street, Sydney NSW 2010, Australia.     

Ordovician trilobites from Deh-Molla,eastern Alborz,Iran

Ghobadi Pour, M., 21 June 2019. Ordovician trilobites from Deh-Molla, eastern Alborz, Iran. Alcheringa 43, 381–405. ISSN 0311-5518

Seventeen species from 14 genera of Tremadocian and Darriwilian trilobites, plus two taxa recognizable only down to family level, have been documented from the Lower to Middle Ordovician succession of the Deh-Molla area, southeast of Shahrud in northern Iran. Two species, Asaphellus intermedius and Conophrys multituberculatus, are new to science. Unlike previously documented Iranian faunas, the early Tremadocian trilobite assemblage is characterized by proliferation of the olenid Chungkingaspis sinensis, which is also known as the eponymous taxon of the basal Ordovician trilobite biozone in South China. This is the first record of the occurrence of the olenid biofacies in the Ordovician of Iran. Overall, both the Tremadocian and Darriwilian trilobite assemblages show distinct similarity to the contemporaneous faunas of South China down to species level. Trilobite-based correlation with the Ordovician succession of South China confirms the existence of a hiatus at the base of the Ordovician succession in the eastern Alborz and a significant gap, with the upper Tremadocian, Floian and Dapingian parts of the succession completely missing in Deh-Molla.

Mansoureh Ghobadi Pour [mghobadipour@yahoo.co.uk and m.ghobadipour@gu.ac.ir], Department of Geology, Faculty of Sciences, Golestan University, Gorgan 49138-15739, Iran. *Also affiliated with Department of Natural Sciences, Natural Museum of Wales, Cardiff, Cathays Park, Cardiff CF10 3NP, UK.     

First soft-bodied fossil from the Ordovician of Peru

Konservat-Lagerstätten are a source of insurmountable information on the diversity of fossil assemblages during the lower Palaeozoic. Soft-bodied fossils are especially rare in South America, but a new locality has been discovered from the Middle Ordovician of Peru that has produced the fairly well-preserved possible palaeoscolecidan Juninscolex ingemmetianum gen. et sp. nov. The distinctive characteristics of this worm make it similar to European taxa within the group.     

Late Ordovician conodont biozonation of Australia—current status and regional biostratigraphic correlations

Zhen, Y.Y. & Percival, I.G. March 2017. Late Ordovician conodont biozonation of Australia—current status and regional biostratigraphic correlations. Alcheringa 41, xxx–xxx. ISSN 0311-5518.

Seven conodont biozones are recognized in the Upper Ordovician of Australia. The Pygodus anserinus, Belodina compressa and Phragmodus undatus–Tasmanognathus careyi biozones are successively represented in the Sandbian. Although the Erismodus quadridactylus Biozone of the late Sandbian North America Midcontinent succession was previously recognized in the Stokes Siltstone of the Amadeus Basin and the Mithaka Formation of the Georgina Basin in central-north Australia, we argue for a middle–late Darriwilian age for these two units. Four conodont biozones, from oldest to youngest the Taoqupognathus philipi, T. blandus, T. tumidus–Protopanderodus insculptus and Aphelognathus grandis biozones, are established in the Katian of eastern Australia. Taoqupognathus species are particularly useful in correlation of the lower–middle Katian successions of eastern Australia with contemporary rocks in other parts of eastern Gondwana and peri-Gondwana, such as with the three major terranes of North and South China and Tarim. These regions, together with Sibumasu and eastern Australia, were part of the Australasian Superprovince during the Late Ordovician, with a strong palaeobiogeographic identity signalled by domination of Taoqupognathus, Tasmanognathus and Yaoxianognathus. Longstanding difficulties for precise correlation with the well-established North American Midcontinent or Baltoscandian successions in the Late Ordovician, owing mainly to strong endemism of the Australian faunas particularly from shallow-water settings, have been resolved by integration of regional conodont biostratigraphic schemes. The conodont biozonation of the Australian Upper Ordovician reviewed herein also provides a crucial chronological reference for better constraining the temporal and spatial range of Late Ordovician tectonostratigraphic events across the intracratonic basins of northern and western Australia and orogenic belts of eastern Australia.

Yong Yi Zhen* [yong-yi.zhen@industry.nsw.gov.au] and Ian G. Percival [ian.percival@industry.nsw.gov.au], Geological Survey of New South Wales, W.B. Clarke Geoscience Centre, 947–953 Londonderry Road, Londonderry NSW 2753, Australia.     

Late Mississippian (Early Carboniferous) brachiopods from the western Daba Mountains,central China

Qiao L. & Shen S.Z., September 2012. Late Mississippian (Early Carboniferous) brachiopods from the western Daba Mountains, central China. Alcheringa 36, 287–309. ISSN 0311–5518.

Fifteen brachiopod species in 12 genera are described for the first time from four intervals in the middle and upper parts of the Zhanpo Formation at the Huoyanxi section near Zhenba in the western Daba Mountains, southern Shaanxi, central China. The Zhenba brachiopod fauna is dominated by diverse and abundant species of Productida, together with some species of Athyridida, Orthida, Orthotetida and Spiriferida. It ranges from late Viséan to Serpukhovian in age based on the presence of Gigantoproductus species in association with diagnostic foraminifera and conodonts. This fauna generally shows palaeobiogeographical links with the palaeoequatorial realm, including Western Europe, the Moscow Basin, the Ural Mountains, Japan, eastern Tibet and South and North China. Its closest palaeobiogeographical affinity is with South China assemblages rather than those of North and Northwest China, therefore, indicating that the Zhenba area was palaeogeographically close to the South China Block and relatively far from the blocks in Northwest China (e.g., the Qilian Mountains and Qaidam Basin, Kunlun Mountains, Tarim Basin and Tianshan Mountains) during the late Viséan–Serpukhovian.     

Downward hydrocarbon migration predicted from numerical modeling of fluid overpressure in the Paleozoic Anticosti Basin,eastern Canada

The Anticosti Basin is a large Paleozoic basin in eastern Canada where potential source and reservoir rocks have been identified but no economic hydrocarbon reservoirs have been found. Potential source rocks of the Upper Ordovician Macasty Formation overlie carbonates of the Middle Ordovician Mingan Formation, which are underlain by dolostones of the Lower Ordovician Romaine Formation. These carbonates have been subjected to dissolution and dolomitization and are potential hydrocarbon reservoirs. Numerical simulations of fluid‐overpressure development related to sediment compaction and hydrocarbon generation were carried out to investigate whether hydrocarbons generated in the Macasty Formation could migrate downward into the underlying Mingan and Romaine formations. The modeling results indicate that, in the central part of the basin, maximum fluid overpressures developed above the Macasty Formation due to rapid sedimentation. This overpressured core dissipated gradually with time, but the overpressure pattern (i.e. maximum overpressure above source rock) was maintained during the generation of oil and gas. The downward impelling force associated with fluid‐overpressure gradients in the central part of the basin was stronger than the buoyancy force for oil, whereas the buoyancy force for gas and for oil generated in the later stage of the basin is stronger than the overpressure‐related force. Based on these results, it is proposed that oil generated from the Macasty Formation in the central part of the basin first moved downward into the Mingan and Romaine formations, and then migrated laterally up‐dip toward the basin margin, whereas gas throughout the basin and oil generated in the northern part of the basin generally moved upward. Consequently, gas reservoirs are predicted to occur in the upper part of the basin, whereas oil reservoirs are more likely to be found in the strata below the source rocks. Geofluids (2010) 10 , 334–350     

Webbygnathus,a new Late Ordovician conodont genus from New South Wales

The new conodont Webbygnathus munusculum gen. et sp. nov. is described from Eastonian (early Late Ordovician) strata from the central part of the Parkes Zone of the Lachlan Fold Belt and the New England Fold Belt in New South Wales. In the type area south of Gunningbland, central New South Wales, the genus occurs associated with macrofossils of the coral/stromatoporoid assemblage Fauna II (early Eastonian or Ea2); in the New England region it has been obtained from strata on both sides of a major structural feature, the Peel Fault, the associated conodont assemblages indicating an age equivalent to that of coral/stromatoporoid assemblage Fauna III or late Eastonian (Ea3). The apparatus of this species, as presently known, comprises two pectiniform elements, one stellate with a four-rayed basal cavity, the other fundamentally pastinate, with a three-rayed basal cavity.     

Ngapakaldia bonythoni (Marsupialia,Diprotodontidae): new material from Riversleigh,northwestern Queensland,and a reassessment of the genus Bematherium

A latest Permian (late Changhsingian) radiolarian fauna is recorded from the upper Talung Formation, Hushan, Nanjing, Jiangsu Province, South China. This fauna includes 24 species belonging to 16 genera; new species are Albaillella hushanensis, Copicyntroides stellatus and Trilonche crassus. The presence of the radiolarian fauna and its taxonomic composition reveal that the Eastern Qinling-Dabie deep sea, which was located along the northern margin of the northeastern Yangtze Basin, persisted at least until the end of the Palaeozoic and that the collision between the North China and South China plates had not occurred by the end of the Permian.     

A possible hydroid from the Lower and Middle Ordovician of Bohemia

A new genus Webbyites from the Lower and Middle Ordovician of Bohemia is described. Its planar, feather-like benthic colonies (or their parts) display possible hydrozoan affinites. Webbyites is interpreted as an inhabitant of the littoral and sublittoral environment, with high energy, oscillating to current zones.     

Early Darriwilian graptolites from central and western China

Taxonomic restudy of Early Darriwilian graptolites from the Yangtze region, Chiadam and Alxa, has enabled a precise correlation of the Undulograptus austrodentatus Zone (including two subzones) across the three regions, and with the Darriwilian GSSP at Huangnitang in the Jiangshan-Changshan-Yushan (JYC) area. Based on specimens from 17 localities in the Yangtze region, the Exigraptus clavus and Undulograptus austrodentatus zones are recognised as replacements respectively of the Undulograptus sinodentatus (Lower) and U. austrodentatus (Upper) zones of Mu et al. (1979). The U. sinicus Subzone, the upper subzone of the U. austrodentatus Zone, is also recognised from the Sichuan-Guizhou area of the Yangtze region. Two subzones of the U. austrodentatus Zone have also been identified from the Chiadam region with more diverse graptolite fauna. The U. austrodentatus Zone fauna also occurs in the Alxa region. A general pattern of changing graptolite diversity from platform through basinal slope to deep basin is proposed, based on early Darriwilian bio- and lithofacies changes from the Yangtze Platform through the Jiangnan belt to the Zhujiang basin. The graptolite diversity increased with water depth and more off-shore setting. Key graptolite species are illustrated.