Cambrian and Ordovician linguliform brachiopods from the Shallow Bay Formation (Cow Head Group), western Newfoundland

2001 ◽  
Vol 75 (2) ◽  
pp. 241-260 ◽  
Author(s):  
Sean P. Robson ◽  
Brian R. Pratt
Keyword(s):  
New Species ◽  
Continental Slope ◽  
Head Group ◽  
Lower Paleozoic ◽  
Middle Cambrian ◽  
Middle Ordovician ◽  
Upper Cambrian ◽  
Three New Species ◽  
Brachiopod Fauna ◽  
Shallow Bay

Linguliform brachiopods were recovered from the Upper Cambrian Downes Point Member (lower Sunwaptan) and from the Middle Ordovician Factory Cove Member (Arenig) of the Shallow Bay Formation, Cow Head Group, of western Newfoundland. These rocks are a series of Middle Cambrian to Middle Ordovician conglomerates, lime mudstones, and shales that formed a sediment apron at the base of the lower Paleozoic continental slope of Laurentia. The linguliform brachiopod fauna consists of sixteen species assigned to twelve genera. Three new species are described: Picnotreta lophocracenta, Neotreta humberensis, and Siphonotretella parvaducta.

The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada

1988 ◽  
Vol 125 (4) ◽  
pp. 381-414 ◽  
Author(s):  
C. R. Barnes
Keyword(s):  
New Species ◽  
Shallow Water ◽  
Head Group ◽  
Middle Cambrian ◽  
Middle Ordovician ◽  
Green Point ◽  
Group A ◽  
Conodont Fauna ◽  
Three New Species

AbstractSections exposing the Cambrian–Ordovician Boundary interval at Broom Point in western Newfoundland have been proposed earlier for a global systemic boundary stratotype. These lie within the Cow Head Group, a late Middle Cambrian to early Middle Ordovician allochthonous unit of limestone, shale, and conglomerate deposited at the toe of the ancient continental slope and on the adjacent continental rise. Several recent studies have further investigated the stratigraphy, sedimentology, and palaeontology of the Cow Head Group and others are under way on magnetostratigraphy and chemostratigraphy. These aspects are reviewed for six key boundary sections representing proximal to distal facies: Cow Head Ledge, Broom Point South, Broom Point North, St Pauls Inlet Quarry, Martin Point, and Green Point. In particular, new data are presented from 260 conodont samples that yielded 15500 conodonts. This intense sampling has allowed the discrimination of minor hiatuses in the proximal to intermediate facies where conglomerates have eroded and cannibalized underlying strata. New conodont data from Broom Point North have lowered the base of the C. lindstromi Zone into unit 74 conglomerates, thereby making this section unsuitable as a boundary stratotype. New collections from Green Point have yielded abundant conodonts and over 9400 conodonts have been recovered from 77 samples.The conodont, graptolite, and trilobite biostratigraphy through the boundary interval is documented allowing accurate correlation between sections and more precisely revealing small hiatuses in the proximal and intermediate facies. The sequence of conodont zones is: Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedius, C. lindstromi and C. angulatus. These can be correlated with trilobite zones established from both in situ and clast faunas from the proximal to intermediate facies and with graptolite assemblages (of Cooper 1979) especially in the intermediate to distal facies. Three new species of Cordylodus are described (C. andresi, C. hastatus and C. tortus) and the full apparatus of Iapetognathus preaengensis is illustrated.The criteria for selecting a global boundary stratotype and point (GSSP) are reviewed in terms of the Cow Head sections. The Green Point section is shown to meet, and largely surpass, the prerequisites required of a stratotype. The Green Point section is proposed to be the global boundary stratotype with the base of the Ordovician System defined at the base of unit 23, which is the base of the Broom Point Member, Green Point Formation, at a level coincident with the base of the Cordylodus lindstromi Zone. In addition to an abundant and superbly preserved conodont fauna, this section preserves the best sequence of earliest planktic graptolites through a 40 m interval; the first nematophorous graptolites (of Assemblage 1) occur in unit 25, 6.9 m above the base of the C. lindstromi Zone. This level can be readily correlated into the proximal facies where both deep and shallow water trilobites (in situ and in clasts, respectively) show the base of the C. lindstromi Zone to lie within the Symphysurina brevispicata trilobite Subzone.

Évolution paléogéographique de la marge nord-ouest de l'Afrique du Cambrien à la fin du Carbonifère (du Maroc au Libéria)

1991 ◽  
Vol 28 (7) ◽  
pp. 1121-1130 ◽  
Author(s):  
Michel Villeneuve ◽  
Jean-Jacques Cornée
Keyword(s):  
West African ◽  
The West ◽  
Lower Paleozoic ◽  
West African Craton ◽  
Middle Cambrian ◽  
Early Devonian ◽  
Middle Ordovician ◽  
The North ◽  
Marine Platform ◽  
General Regression

Paleogeographic reconstructions of Paleozoic time are presented for the northwest margin of the West-African Craton. An extensional regime and a marine transgression were dominant during the Early Cambrian. During the Middle Cambrian, the Rokélides orogen was responsible for the sea regression to the south, while the proto-Atlantic opening was active to the north of the Reguibat shield. A large stable marine platform was present during Early and Middle Ordovician. A general regression and the formation of the West-African Inlandsis took place during the Late Ordovician. During Silurian time, this sea transgressed over most of the African platform. Incipient Hercynian deformations during the Early Devonian produced horsts and grabens in Morocco. At the end of the Devonian and the beginning of the Carboniferous, the sea was restricted to isolated basins and tectonic trenches. Collision between West Africa and North America during the Late Carboniferous transformed the Lower Paleozoic margin into an Hercynian orogenic belt, whose structure is controlled by the presence of crustal blocks, generated as early as the Cambrian, and probably reflecting, in turn, older Panafrican zones of weakness. [Translated by the Journal]

Graptolites from the Lower–Middle Ordovician St. George and Table Head groups, western Newfoundland, and their correlation with trilobite, brachiopod, and conodont zones

1987 ◽  
Vol 24 (3) ◽  
pp. 456-470 ◽  
Author(s):  
S. Henry Williams ◽  
W. Douglas Boyce ◽  
Noel P. James
Keyword(s):  
Head Group ◽  
Middle Ordovician ◽  
Faunal Assemblages ◽  
Head Groups ◽  
Brachiopod Fauna ◽  
Lower Slope

Faunal assemblages of the autochthonous, shelf carbonate sequences belonging to the St. George and Table Head groups are dominated by shelly macrofossils and conodonts. Rare, usually monotypic graptolitic horizons enable correlation with the allochthonous Cow Head Group, which was deposited on the middle to lower slope, and the shelly, conodont, and graptolitic zonal schemes elsewhere in North America.The Catoche Formation of the St. George Group is of Ibexian (Canadian) age and yields graptolites indicative of the Tetragraptus approximatus and Tetragraptus akzharensis zones (early Arenig). The basal Aguathuna Formation belongs to the Pendeograptus fruticosus Zone, whereas higher parts span the Ibexian–Whiterock boundary. Graptolites suggest that the Table Head Group entirely postdates the Cow Head Group. This is supported by a Whiterock (early Llanvirn) trilobite, conodont, and brachiopod fauna.

Review of the deep-water asellote genus Notopais Hodgson, 1910 (Crustacea: Isopoda: Munnopsididae) with description of three new species from the south-western Pacific.

Zootaxa ◽  
2004 ◽  
Vol 513 (1) ◽  
pp. 1 ◽  
Author(s):  
KELLY L. MERRIN
Keyword(s):  
New Species ◽  
New Zealand ◽  
Continental Slope ◽  
Deep Water ◽  
Type Species ◽  
Ventral Side ◽  
Western Pacific ◽  
The South ◽  
South Eastern ◽  
Three New Species

The munnopsidid genus Notopais Hodgson, 1910 is taken out of synonymy with Echinozone Sars, 1897. The type species Notopais spicata Hodgson, 1910 and Notopais quadrispinosa (Beddard, 1886) are redescribed and three new species described: Notopais beddardi n. sp. collected from Antarctica at a depth of less than 37 metres; Notopais minya n. sp. collected from the south-eastern Australian continental slope between the depths of 429 466 metres; and Notopais zealandica n. sp. collected from the Chatham Rise between the depths of 1386 1640 metres, off the south-eastern New Zealand coast. Notopais is distinguished from Echinozone by three defining characters: the flattened appearance of the ventral side of the cephalon, the presence of pedestal setae on the pereonites and antenna 2 article 1 with produced distolateral angle with prominent spine and distal robust seta. This genus is exclusively found in the Southern Hemisphere and is known from Antarctica and the south-western Pacific.

Carbon-isotope stratigraphy of the SPICE event (Upper Cambrian) in eastern Laurentia: implications for global correlation and a potential reference section

2018 ◽  
Vol 156 (08) ◽  
pp. 1311-1322 ◽  
Author(s):  
Karem Azmy
Keyword(s):  
Carbon Isotope ◽  
Head Group ◽  
Upper Cambrian ◽  
Green Point ◽  
Global Correlation ◽  
Isotope Profile ◽  
Isotope Stratigraphy ◽  
Lowermost Part ◽  
Spice Event ◽  
Shallow Bay

AbstractThe δ13C profile from the lower interval of the Martin Point section in western Newfoundland (Canada) spans the Upper Cambrian (uppermost Franconian – lowermost Trempealeauan). The investigated interval (∼110 m) is a part of the Green Point Formation of the Cow Head Group and consists of the upper part of the Tucker Cove Member (topmost part of the Shallow Bay Formation) and the lowermost part of the Martin Point Member (bottom of the Green Point Formation). It is formed of rhythmites of marine carbonates alternating with shales and minor conglomeratic interbeds. Multiscreening petrographic and geochemical techniques have been utilized to evaluate the preservation of the investigated lime mudstones. The δ13C and δ18O values of the sampled micrites (−4.8 ‰ to +1.0 ‰ VPDB and −8.2 ‰ to −5.3 ‰ VPDB, respectively) have insignificant correlation (R2= 0.01), as similarly do the δ13C values with their Sr counterparts (R2= 0.07), which supports the preservation of at least near-primary δ13C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ13C profile exhibits two main negative excursions: a lower excursion (∼4 ‰) that reaches its maximum at the bottom of the section and an upper narrow excursion (∼6 ‰) immediately above the boundary of the Tucker Cove/Martin Point members (Shallow Bay Formation – Green Point Formation boundary). The lower excursion may be correlated with the global SPICE event, whereas the upper excursion may match with a post-SPICE event that has been also recognized in profiles of equivalent sections on different palaeocontinents.

Middle Ordovician (Whiterockian) gastropods of western Newfoundland: Macluritoidea and Euomphaloidea

2001 ◽  
Vol 75 (2) ◽  
pp. 284-294 ◽  
Author(s):  
David M. Rohr ◽  
E. A. Measures
Keyword(s):  
Head Group ◽  
Middle Ordovician ◽  
First Time ◽  
Shallow Bay

Gastropods that occur in the Anomalorthis brachiopod zone in the Spring Inlet Member of the Table Point Formation and in the Orthidiella brachiopod zone of the Shallow Bay Formation of the Cow Head Group are documented. Gastropods from western Newfoundland comprise part of the Toquima-Table Head fauna, and six of the seven genera described here are also found in Whiterockian strata of Nevada. Four species assigned to Monitorella Rohr, 1994, Maclurites Le Sueur, 1818, and Malayaspira Kobayashi, 1958, originally described by E. Billings in 1865 from Middle Ordovician (Whiterockian) strata of Newfoundland are revised. Five species of Helicotoma Salter, 1859, Malayaspira Kobayashi, 1958; Lytospira Koken, 1896; Rossospira Rohr, 1994; and Pachystrophia Perner, 1903, not previously reported from Newfoundland are also described. The probable opercula of Monitorella crenulata (Billings, 1865), and Maclurites emmonsi (Billings, 1865), are also illustrated for the first time.

Middle Ordovician (Whiterockian) trilobites from the Sunblood Formation, District of Mackenzie, Canada

1991 ◽  
Vol 65 (5) ◽  
pp. 801-824 ◽  
Author(s):  
James V. Tremblay ◽  
Stephen R. Westrop
Keyword(s):  
New Species ◽  
North America ◽  
The South ◽  
Middle Ordovician ◽  
Low Diversity ◽  
Shallow Subtidal ◽  
Three New Species

In the South Nahanni River area of the District of Mackenzie, the Middle Ordovician Sunblood Formation comprises mainly limestones and dolostones of intertidal and shallow-subtidal origin, as indicated by the presence of desiccation polygons, fenestral fabric, and oncolites. Faunas of well-preserved, silicified trilobites from a low-diversity, nearshore, Bathyurus-dominated biofacies are compositionally distinct from faunas in correlative strata around North America that represent different shelf to upperslope biofacies. A temporal biostratigraphy applicable to nearshore biofacies through much of the Whiterockian Series consists of five zones, in ascending order: Bathyurus mackenziensis, B. sunbloodensis, B. margareti, B. nevadensis, and B. granulosus. Twenty-six species are assigned to 18 genera, of which Ludvigsenella is new. Three new species of Bathyurus are B. mackenziensis, B. sunbloodensis, and B. margareti.

The Trilobite Genus Holasaphus Matthew, 1895 in the Middle Cambrian Rocks of Nova Scotia and Eastern Turkey

1972 ◽  
Vol 9 (3) ◽  
pp. 266-279 ◽  
Author(s):  
W. T. Dean
Keyword(s):  
New Species ◽  
Nova Scotia ◽  
Type Species ◽  
Middle Portion ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
Eastern Turkey ◽  
New Material ◽  
Additional Support ◽  
A New Species

Holasaphus centropyge Matthew, 1895, the type species of the genus, is redescribed using known and new material from the Middle Cambrian of Nova Scotia. A new species, Holasaphus mesopotamicus, described from the Derik–Mardin district of southeastern Turkey, marks the only other known occurrence of the genus. The presence there of Holasaphus and the agnostid Peronopsis in the middle portion of the Sosink Formation suggests that the latter may be no younger than Middle Cambrian and lends additional support to evidence for the probable regional absence of Upper Cambrian strata.

scholarly journals Middle Cambrian through lowermost Ordovician conodonts from Hunan, South China

2017 ◽  
Vol 91 (S73) ◽  
pp. 1-89 ◽  
Author(s):  
Xi-ping Dong ◽  
Huaqiao Zhang
Keyword(s):  
New Species ◽  
South China ◽  
Total Mass ◽  
Histological Investigation ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
Western Hunan

AbstractSince 1986, samples with a total mass of more than 14,000 kg, mainly from three key sections in western Hunan, South China, have been processed for conodonts. Previous work mainly focused on biostratigraphy, but the taxonomy has been performed only on the faunas of the middle Cambrian. Described herein are conodonts of the upper Cambrian (Furongian Series) through lowermost Ordovician from Hunan, South China. Conodonts of the middle Cambrian are redescribed, based on material that has been recovered for more than three decades. The fauna consists of 82 species belonging to 36 genera. Newly established genera areLugnathusn. gen.,Miaognathusn. gen.,Millerodontusn. gen.,Tujiagnathusn. gen.,Wangcunellan. gen. andWangcunognathusn. gen. New species areCoelocerodontus hunanensisn. sp.,Furnishina wangcunensisn. sp.,Laiwugnathus hunanensisn. sp.,Laiwugnathus transitansn. sp.,Lugnathus hunanensisn. gen. n. sp.,Miaognathus multicostatusn. gen. n. sp.,Millerodontus intermediusn. gen. n. sp.,Prosagittodontus compressusn. sp.,Tujiagnathus gracilisn. gen. n. sp.,Wangcunella conicusn. gen. n. sp.,Wangcunognathus elegansn. gen. n. sp.,Westergaardodina dimorphan. sp.,Westergaardodina gigantean. sp., andWestergaardodina solan. sp. The taxonomy of some conodont genera is revised. In the light of histological investigation, genera are assigned to euconodonts, paraconodonts, or protoconodonts. The 13 conodont zones previously proposed in the middle Cambrian through lowermost Ordovician remain the same, but taxa within these conodont zones are documented more clearly because of the revised taxonomy proposed herein.

scholarly journals Middle Ordovician (middle Darriwilian) Archaeospicularia and Entactinaria (radiolarians) from the Table Cove Formation, Piccadilly Quarry, Newfoundland, Canada

2021 ◽  
pp. 1-31
Author(s):  
Sarah Kachovich ◽  
Jonathan C. Aitchison
Keyword(s):  
Computed Tomography ◽  
New Species ◽  
Three Dimensional ◽  
Detailed Examination ◽  
Micro Computed Tomography ◽  
Lower Paleozoic ◽  
X Ray ◽  
Middle Ordovician ◽  
Radiolarian Assemblage ◽  
Taxonomic Groups

Abstract New, distinctive, well-preserved and previously undescribed constituents of a Middle Ordovician (middle Darriwilian, Dw2) radiolarian assemblage from the Table Cove Formation in Newfoundland are described. Three-dimensional X-ray micro-computed tomography (μ-CT) facilitates detailed examination of key specimens revealing hitherto unknown details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has previously impeded resolution of higher taxonomic rankings. Twenty-seven archaeospiculid and entactinarian taxa are described and illustrated including six new species: Westernbrookia polygonata n. sp., Neopalaeospiculum piccadilliensis n. sp., Ramuspiculum laxum n. sp. Spongentactinia nazarovi n. sp., Aspiculum irregulare n. sp., and Nyfrieslandia ramosissima n. sp. The investigation extends the known ranges of the species: Pararcheoentactinia reedae Won and Iams, 2002; Sphaeroentactinia robusta Won and Iams, 2015; Varispiculum ectospiculatum Won and Iams, 2015; and Svalbardospiculum multifurcatum (Won, Iams, and Reed, 2005), together with the genus Echidnina to the mid-Darriwilian. UUID: http://zoobank.org/74826b7b-bb86-45d5-ad23-e6e65e0706df.

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