scholarly journals Fenxiang biota: a new Early Ordovician shallow-water fauna with soft-part preservation from China

2015 ◽  
Vol 60 (8) ◽  
pp. 812-818 ◽  
Author(s):  
Andrzej Balinski ◽  
Yuanlin Sun
Keyword(s):  
Shallow Water ◽  
Soft Part ◽  
Early Ordovician

Iron from continental weathering dictated soft‐part preservation during the Early Ordovician

Terra Nova ◽  
2021 ◽  
Author(s):  
Farid Saleh ◽  
Victoire Lucas ◽  
Bernard Pittet ◽  
Bertrand Lefebvre ◽  
Stefan V. Lalonde ◽  
...  
Keyword(s):  
Soft Part ◽  
Early Ordovician ◽  
Continental Weathering

scholarly journals Early Ordovician trilobites and molluscs from the Poulsen Cliff Formation, Washington Land, western North Greenland

1990 ◽  
Vol 38 ◽  
pp. 11-32
Author(s):  
R. A. Fortey ◽  
]. S. Peel
Keyword(s):  
Shallow Water ◽  
Siberian Platform ◽  
Gastropod Species ◽  
Early Ordovician ◽  
North East ◽  
The North ◽  
Close Relationship ◽  
North Greenland ◽  
Subjective Synonym

A well-preserved, shallow water bathyurid trilobite fauna of early Ordovician age, and associated gastropods and an undetermined hyolith are described from the Poulsen Cliff Formation of Washington Land, western North Greenland. Two new bathyurid species, Licnocephala sminue and Pe/tabellia elegans, and a new gastropod species, Plethospira(?) floweri, are described. Biolgina Maximova is considered a junior subjective synonym of Peltabellia Whittington. The distribution of the genus is an example of close relationship between shallow water trilobite faunas of Laurentia and the North-east Siberian platform in the early Ordovician.

Early Ordovician Trilobites from the Nazareno Area, Northwestern Argentina

2014 ◽  
Vol 88 (5) ◽  
pp. 925-947 ◽  
Author(s):  
M. Franco Tortello ◽  
Susana B. Esteban
Keyword(s):  
New Species ◽  
Shallow Water ◽  
High Energy ◽  
Northwestern Argentina ◽  
Early Ordovician ◽  
First Time

The upper part of the Santa Rosita Formation (Ordovician, Tremadocian) in the Nazareno area, Cordillera Oriental, northwestern Argentina, records the vertical passage of high-energy, shallow water platform environments to offshore settings. Eighteen trilobite species are described from this locality for the first time. Although the taxa from the lower part of the succession (Leptoplastidessp.,Asaphellussp.) are scarce and non-age diagnostic, those from the upper part include diverse assemblages partially assigned to the late TremadocianNotopeltis orthometopaZone. Systematic descriptions of several species (Geragnostus nesossiiHarrington and Leanza,G. callaveiformisHarrington and Leanza,Asaphellus jujuanusHarrington,Notopeltis orthometopa[Harrington],Mekynophrys nannaHarrington,Ceratopyge forficuloidesHarrington and Leanza,Apatokephalus tibicenPřibyl and Vanĕk) are improved, the genusNileusDalman (includingN. australisn. sp.) is first reported from the Tremadocian of western Gondwana, and new species ofAsaphellusCallaway (A. nazarenensisn. sp.),ConophrysCallaway, andApatokephalusBrøgger are described. The trilobites have their closest affinities with faunas from Norway and Sweden.Notopeltis orthometopaandMekynophrys nannaare restricted to the uppermost part of the succession, well above the first records of most other trilobites recognized.

Early Ordovician ostracods from Argentina: their bearing on the origin of binodicope and palaeocope clades

2007 ◽  
Vol 81 (6) ◽  
pp. 1384-1395 ◽  
Author(s):  
María José Salas ◽  
Jean Vannier ◽  
Mark Williams
Keyword(s):  
New Species ◽  
Soft Tissues ◽  
Soft Part ◽  
Sensu Stricto ◽  
The Other ◽  
Carnic Alps ◽  
Shallow Marine ◽  
Early Ordovician

New species of ostracods are described from the Tremadoc of the Cordillera Oriental (Argentina). These are among the earliest well-documented records of Ostracoda sensu stricto. The ostracod assemblages are sourced from shallow marine clastics and are dominated by palaeocopes (Eopilla waisfeldaen. sp.,Nanopsis coquenan. sp.), and the binodicopeKimsella luciaen. gen. and sp.EopillaandKimsellashow affinities with species from paleocontinental Gondwana (e.g., Ibero-Armorica, Turkey, Australia, Carnic Alps), butNanopsisis previously known only from paleocontinental Baltica. This study confirms that two of the major clades of Ordovician ostracods, namely the Binodicopa and the Palaeocopa, were already geographically widespread during the late Tremadoc, suggesting a still earlier origin for these groups, possibly from within the Cambrian to Early Ordovician Bradoriida. Evidence from soft-part anatomy indicates that phosphatocopids, the other group hypothesized to be ancestral ostracods, have apomorphies that preclude them as direct ancestors. The origin of ostracods is more likely to be found within the Bradoriida, a probable polyphyletic group that resembles Early Ordovician ostracods in the external sculpture of their bivalved carapace. Evidence from carapace morphology suggests that the ancestors of true ostracods might lie within the bradoriid groups Beyrichonidae and Hipponicharionidae, a hypothesis that can only truly be tested when more evidence from fossilized soft tissues becomes available.

Evolution of Ordovician terranes in western Ireland and their possible Scottish equivalents

1990 ◽  
Vol 81 (1) ◽  
pp. 23-29 ◽  
Author(s):  
D. M. Williams
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Metamorphic Rocks ◽  
The South ◽  
Sediment Dispersal ◽  
Early Ordovician ◽  
Basin Subsidence ◽  
Western Ireland ◽  
Back Arc

ABSTRACTIn the W of Ireland the Ordovician rocks of South Mayo and Clew Bay are now juxtaposed but a comparison of the sedimentary histories of these two sequences shows that they accumulated in basins which were probably separated during most of their history. The large amount of terrigenous detritus present in the Arenig to Llanvirn elements of the South Mayo succession is not manifest in that of Clew Bay until the Llandeilo/Caradoc, by which time sedimentation in South Mayo had ceased. A comparison of the South Mayo Ordovician with that of Girvan in Scotland demonstrates that both sequences had a similar provenance. This source contained an ophiolite, granites and some (probably pre-Dalradian) metamorphic rocks. Sediment dispersal directions for the two sequences are opposite in sense, being primarily northward in South Mayo and southward at Girvan. The two stratigraphies indicate that basement subsidence behaviour in South Mayo was virtually the opposite of that at Girvan where initial shallow water sedimentation was rapidly succeeded by deep water environments at the end of the Llanvirn. The two basins may thus have been marginal to a single Ordovician arc complex. One reason for the opposite sense of basin subsidence may lie in the suggested reversal of subduction polarity during the Ordovician. In this scenario the South Mayo basin may be envisaged as lying to the N of a northward-facing arc during the early Ordovician. A new, northward, subduction direction instigated during the Llanvirn, resulted in a fore-arc basin at Girvan complemented by a closing back-arc basin in South Mayo.

scholarly journals Stratigraphy and hystricurid trilobites of the Christian Elv Formation (Lower Ordovician) of western North Greenland

1989 ◽  
Vol 144 ◽  
pp. 5-15
Author(s):  
R.A Fortey ◽  
J.S Peel
Keyword(s):  
New Species ◽  
Shallow Water ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
The West ◽  
Early Ordovician ◽  
The North ◽  
Lower Ordovician ◽  
A New Species ◽  
North Greenland

The Christian Elv Formation (Early Ordovician) of Daugaard-Jensen Land, western North Greenland, is formally proposed and recognised from southern Hall Land, in the east, to western Ellesmere Island in the Canadian Arctic Islands, to the west. The formation in its type section includes a shallow water trilobite fauna suggesting a mid-Tremadoc age; conodonts indicate the Rossodus manitouensis Zone af the North American Midcontinent Realm. Two species af hystricurid trilobites are present, of which one, Hystricurus scrofulosus, is dcscribed as a new species. The distribution of Hystricurus followed the early Ordovician palaeo-equator and was not confined by palaeocontinental boundaries. Paraplethopeltis is considered to be a subgcnus af Hystricurus.

Stratigraphy of the Ordovician St. George Group in the Port-Au-Choix Area, Western Newfoundland

1975 ◽  
Vol 12 (4) ◽  
pp. 589-594 ◽  
Author(s):  
H. M. Kluyver
Keyword(s):  
Shallow Water ◽  
Head Group ◽  
Depositional History ◽  
Early Ordovician ◽  
Stratigraphic Subdivision ◽  
History Of ◽  
Depositional Cycles ◽  
Depositional Cycle

Stratigraphic sections were measured in the very complete coastal exposures around Port-au-Choix village in western Newfoundland. A formal stratigraphic subdivision of the Ordovician St. George Group into three formations is proposed. They are, from oldest to youngest: the Barbace Point Formation, a 21 + m thick unit of dense dolostone, showing diagenetic solution features; the Catoche Formation, 100 m thick, consisting of well bedded limestones with shallow-water indications; the Port-au-Choix Formation, 35 m thick, massive sugary dolostones grading into silty dolostones, with diagenetic solution features. Detailed descriptions of all new formations are given, as well as the rationale behind this new nomenclature. The Early Ordovician depositional history of the area is seen as a succession of two erosional and depositional cycles, not completely preserved in the record, whereby the Barbace Point Formation was subjected to subaerial erosion, creating a hiatus between this formation and the overlying Catoche Formation; the latter represents the beginning of a new depositional cycle which was possibly interrupted before the youngest Port-au-Choix Formation was deposited. After Port-au-Choix times, renewed erosion took place before the Table Head Group was formed.

scholarly journals Insights into soft-part preservation from the Early Ordovician Fezouata Biota

2021 ◽  
Vol 213 ◽  
pp. 103464
Author(s):  
Farid Saleh ◽  
Romain Vaucher ◽  
Jonathan B. Antcliffe ◽  
Allison C. Daley ◽  
Khadija El Hariri ◽  
...  
Keyword(s):  
Soft Part ◽  
Early Ordovician

scholarly journals Early Ordovician trilobites from the Wandel Valley Formation, eastern North Greenland

1986 ◽  
Vol 132 ◽  
pp. 15-25
Author(s):  
R.A Fortey
Keyword(s):  
Shallow Water ◽  
Early Ordovician ◽  
Specific Composition ◽  
North Greenland

A small trilobite fauna is described from the Wandel Valley Formation of Kronprins Christian land, eastern North Greenland. It has a specific composition identical to the fauna from the Catoche Formation, western Newfoundland, which is typical of the shallow water bathyurid biofacies of the eastern part of the Ordovician Laurentian palaeocontinent. The fauna is of early Ordovician age, trilobite Zone H, equivalent to the early Arenig.

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