Paleoenvironmental Reconstruction Based on Horn Corals, with an Example from the Late Ordovician of North America

Palaios ◽  
1988 ◽  
Vol 3 (1) ◽  
pp. 22 ◽  
Author(s):  
Robert J. Elias ◽  
Ronald G. Zeilstra ◽  
Thomas N. Bayer
Keyword(s):  
North America ◽  
Late Ordovician ◽  
Paleoenvironmental Reconstruction

scholarly journals Origin of the Late Ordovician Lepidocyclus brachiopod fauna in North America and its biogeographic significance

1992 ◽  
Vol 6 ◽  
pp. 149-149
Author(s):  
Jisuo Jin
Keyword(s):  
North America ◽  
Sea Level ◽  
North American ◽  
Plate Tectonics ◽  
Late Ordovician ◽  
Sea Level Changes ◽  
Stepping Stones ◽  
Shell Size ◽  
Larval Stages ◽  
The North

Three rhynchonellid brachiopod genera, Hiscobeccus, Lepidocyclus, and Hypsiptycha, are the most diagnostic elements of the Lepidocyclus fauna of North America in Late Ordovician time. These are characterized by relatively large, strongly biconvex to globular shells with coarse imbricating growth lamellae and, internally, with septiform cardinal processes in brachial valves. Among the three genera, Hiscobeccus appears the earliest, now known from rocks of late Trentonian-Edenian age in the Canadian Rocky Mountains and Mackenzie Mountains. Morphologically, Hiscobeccus is distinguished from the other two genera by its open delthyrium in the pedicle valve. Early forms of Hiscobeccus show close morphological similarity to Rhynchotrema in their non-globular biconvex shells covered by strong growth lamellae only in the anterior portions. It has been suggested that Hiscobeccus evolved from the Rhynchotrema wisconsinense stock through increase in shell size, globosity, and strength of growth lamellae. Earliest species of Rhynchotrema has been documented convincingly from rocks of early Trentonian age, and the derivation of Hiscobeccus most likely took place during the mid-Trentonian. Lepidocyclus and Hypsiptycha evolved from either Rhynchotrema or Hiscobeccus by developing a pair of deltidial plates covering the delthyrium.Rhynchotrema and other rhynchonellids that evolved before mid-Trentonian time are common to the North American (Laurentian) and the Siberia-Kazakhstan paleocontinents. In contrast, Hiscobeccus, Lepidocyclus, and Hypsiptycha that evolved after the mid-Trentonian are virtually restricted to Laurentia. Therefore, Rhynchotrema marked the last successful intercontinental migration of rhynchonellids during their Llandeilian-Caradocian cosmopolitanism. The pronounced provincialism of the North American Lepidocyclus fauna may have been caused by a number of factors. Facies control is not likely the explanation because these rhynchonellids occur in nearly all the inland and marginal platform seas of Laurentia and commonly are found together in the same types of rocks. Plate tectonics and sea-level changes are considered major causes. The Ordovician rhynchonellids lived in shallow marine (intertidal-subtidal) environments and were incapable of crossing vast, deep oceanic barriers because of their sedentary mode of life and short-lived motile larval stages. The widening of the ocean between North America and Siberia, coupled with high sea-level stand, may have created a sufficiently wide oceanic barrier to interrupt faunal mixing between the two paleocontinents by late Trentonian time. Moreover, the rise in sea level would have resulted in the disappearance of island faunas, which could have served as stepping stones for intercontinental migration of shallow-water benthic faunas during low sea-level stand.

Flexible crinoids from the Upper Ordovician Maquoketa Formation of the northern midcontinent and the evolution of early flexible crinoids

2001 ◽  
Vol 75 (2) ◽  
pp. 370-382 ◽  
Author(s):  
James C. Brower
Keyword(s):  
New Species ◽  
North America ◽  
Late Ordovician ◽  
Upper Ordovician ◽  
Middle Ordovician

Three flexible crinoids occur in the Upper Ordovician Maquoketa Formation of Illinois, Iowa, and Minnesota:Protaxocrinus girvanensisRamsbottom, 1961,Clidochirus anebosnew species, andProanisocrinus oswegoensis(Miller and Gurley, 1894).Protaxocrinus girvanensisis also found in the Upper Ordovician of Scotland which indicates that the ocean was narrow enough to allow at least one crinoid species to cross the barrier. The Upper Ordovician of North America and Scotland also share many common crinoid genera. Both phenetic and cladistic methods result in similar phylogenies of flexible crinoids.Protaxocrinuswas derived from a cupulocrinid ancestor during the Middle Ordovician.Clidochirusevolved fromProtaxocrinusor its ancestral stock prior to the Richmondian of the Late Ordovician. The RichmondianProanisocrinusand later anisocrinids are most closely related toClidochirusor its immediate predecessor. Thus, three major lineages of flexible crinoids,Protaxocrinus(taxocrinid group),Clidochirus(icthyocrinid), andProanisocrinus(anisocrinids and homalocrinids), appeared during the Ordovician. Despite their rarity during the Ordovician, all three flexible lineages survived the Latest Ordovician extinction, whereas their more abundant and successful cupulocrinid ancestors were eliminated.

Early Silurian paleopole for redbeds and volcanics of the King George IV Lake area, Newfoundland

1989 ◽  
Vol 26 (10) ◽  
pp. 1904-1917 ◽  
Author(s):  
K. L. Buchan ◽  
J. P. Hodych
Keyword(s):  
North America ◽  
Late Ordovician ◽  
Paleomagnetic Data ◽  
Atlantic Canada ◽  
Lake Area ◽  
Consistent Direction ◽  
Canadian Appalachians

Redbeds and felsic and mafic volcanics of the King George IV Lake area of the Dunnage Zone in southwestern Newfoundland have been studied paleomagnetically. After unfolding, both hematite and magnetite carry a consistent direction of magnetization (D = 29.6°; I = 1.0°; k = 19.3; α95 = 11.3°) corresponding to a near-equitorial paleolatitude (0.5°N ± 6°) and yielding a paleopole at 84.6°E, 35.9°N (dm = 11.3°; dp = 5.6°). A positive fold test shows that the remanence was acquired before Devonian deformation. A positive conglomerate test and a reversal of the magnetization in a continuous redbed sequence demonstrates that the remanence was acquired at the time of formation, which has been assigned to the Early Silurian on the basis of a U–Pb zircon date of 431 ± 5 Ma.No other undisputed primary or pre-fold remanence has been reported from Atlantic Canada for the Late Ordovician – Silurian period. Therefore, from paleomagnetic data it is not yet possible to estimate the amount of post-Silurian movement within the Canadian Appalachians. Pre-fold magnetizations from Late Ordovician and Silurian rocks of cratonic North America predict a paleolatitude of 16°S ± 12 °for Newfoundland. However, further results are necessary to determine whether any significant displacement has occurred between Newfoundland and the craton since the Early Silurian.

scholarly journals Widespread, prolonged late Middle to Late Ordovician upwelling in North America: A proxy record of glaciation?: Comment and Reply

Geology ◽  
2003 ◽  
Vol 31 (1) ◽  
pp. e28-e29 ◽  
Author(s):  
Stephen A. Leslie ◽  
Stig M. Bergström
Keyword(s):  
North America ◽  
Late Ordovician ◽  
Proxy Record

An enigmatic blastozoan echinoderm fauna from central kentucky

2009 ◽  
Vol 83 (5) ◽  
pp. 739-749 ◽  
Author(s):  
Colin D. Sumrall ◽  
Carlton E. Brett ◽  
Troy A. Dexter ◽  
Alexander Bartholomew
Keyword(s):  
North America ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Fossil Record ◽  
Foreland Basin ◽  
Late Ordovician ◽  
Upper Devonian ◽  
Range Extension ◽  
First Report ◽  
Appalachian Foreland

A series of small road cuts of lower Boyle Formation (Middle Devonian: Givetian) near Waco, Kentucky, has produced numerous specimens of three blastozoan clades, including both “anachronistic” diploporan and rhombiferan “cystoids” and relatively advanced Granatocrinid blastoids. This unusual assemblage occurs within a basal grainstone unit of the Boyle Limestone, apparently recording a local shoal deposit. Diploporans, the most abundant articulated echinoderms, are represented by a new protocrinitid species, Tristomiocystis globosus n. gen. and sp. Glyptocystitoid rhombiferans are represented by isolated thecal plates assignable to Callocystitidae. Three species of blastoids, all previously undescribed, include numerous thecae of the schizoblastid Hydroblastus hendyi n. gen. and sp., the rare nucleocrinid Nucleocrinus bosei n. sp., and an enigmatic troosticrinid radial. The blastoid Nucleocrinus is typical for the age; however, the callocystitid, schizoblastid, and protocrinitid are not. Hydroblastus is the oldest known schizoblastid. Middle and Upper Devonian callocystitids have been previously reported only from Iowa and Michigan USA with unpublished reports from Missouri USA and the Northwest Territories, Canada. This occurrence is thus the first report of a Middle Devonian rhombiferan from the Appalachian foreland basin. Tristomiocystis is the first known protocrinitid in North America and the only protocrinitid younger than Late Ordovician. This occurrence thus represents a range extension of nearly 50 million years for protocrinids. This extraordinary sample of echinoderms in a Middle Devonian limestone from a well-studied area of North America highlights the incompleteness of the known fossil record, at least in fragile organisms such as echinoderms.

Proconchidium from Late Ordovician strata of Brodeur Peninsula, Baffin Island, Arctic Canada

1989 ◽  
Vol 63 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Rong Jia-Yu ◽  
Brian Jones ◽  
F. W. Nentwich
Keyword(s):  
North America ◽  
Late Ordovician ◽  
Baffin Island ◽  
Arctic Canada ◽  
Internal Structures ◽  
Biogeographic Provinces ◽  
Recorded Occurrence

Proconchidium brodeurensis n. sp. occurs 212 m above the base of member B of the Baillarge Formation on Brodeur Peninsula, Baffin Island, 8 m below the Ordovician–Silurian boundary. Study of Proconchidium shows that it can be easily distinguished from Eoconchidium but possesses many characters that are similar to those in Tcherskidium. Analysis of internal structures suggests that the three genera can be distinguished from each other and belong to Virgianidae. Tcherskidiidae is a synonym of Virgianidae and should be abandoned.This represents the first recorded occurrence of Proconchidium in North America. Although this genus and its related genera Tcherskidium Sapelnikov, 1972, and Eoconchidium Rozman, 1967, are common in Ashgill strata of Eurasia, they have not been recorded or illustrated from North America. This led to the suggestion that distinct brachiopod biogeographic provinces may have existed during the Ashgill. The occurrence of these genera probably indicates that they may have lived in mostly tropical and subtropical zones.

Designation of a neotype and paraneotype for Conularina triangulata (Raymond, 1905) (Upper Ordovician, eastern North America)

2020 ◽  
Vol 94 (4) ◽  
pp. 796-797
Author(s):  
Heyo Van Iten ◽  
Mario E. Cournoyer ◽  
Michelle Coyne
Keyword(s):  
New York ◽  
North America ◽  
Late Ordovician ◽  
Quebec City ◽  
Eastern North America ◽  
Upper Ordovician ◽  
Thrust Sheet ◽  
City Formation ◽  
Early Late

Conularina triangulata (Raymond, 1905), the genotype of Conularina Sinclair, 1942, is a rare, early Late Ordovician conulariid (Cnidaria, Scyphozoa; Van Iten et al., 2006) having three sides or faces instead of four (Sinclair, 1942, fig. 9; Van Iten, 1992, text-fig. 3E). Originally described from the Valcour Formation (early Sandbian; Dix et al., 2013) on Valcour Island, New York (Sinclair, 1942), C. triangulata has since been found in laterally equivalent strata of the upper Laval Formation (‘Upper Chazy’; Sinclair, 1942) in Laval, Québec, Canada (Sinclair, 1942). From this same unit and area, Sinclair (1942) erected three new, four-sided species of Conularina (C. irrasa, C. raymondi, and C. undosa), and he erected a single four-sided species (C. narrawayi) from the Ottawa Formation (now the Sandbian–Katian Ottawa Group; Dix et al., 2013) at Tétreauville (now Gatineau), Québec. Subsequently, Jerre (1994) reported the occurrence of two species of Conularina in the Upper Ordovician of Sweden. Jerre (1994) also proposed that Eoconularia? forensis Sinclair, 1946 from the Upper Ordovician Citadelle Formation (‘Quebec City’ Formation; Sinclair, 1946) in Québec City, Québec (Promontoire de Québec thrust sheet, Appalachian Humber Zone, Allochtonous Domain; Castonguay et al., 2002) is a species of Conularina.

EARLIEST PETROXESTES BORINGS FROM SANDBIAN (EARLIEST LATE ORDOVICIAN) BRYOZOANS OF NORTHERN ESTONIA

Palaios ◽  
2019 ◽  
Vol 34 (10) ◽  
pp. 453-457
Author(s):  
OLEV VINN ◽  
MARK A. WILSON ◽  
URSULA TOOM
Keyword(s):  
North America ◽  
Late Ordovician ◽  
Type Material ◽  
Hard Substrates

ABSTRACT The earliest Petroxestes borings were excavated in large trepostome bryozoans in the Sandbian (earliest Late Ordovician) of Estonia. The Estonian specimens are morphologically similar to the type material from the later Katian of North America. Petroxestes pera is rare in the Sandbian of Estonia and occurs only in biogenic hard substrates. Petroxestes borings occur in muddy environments that were preferred by macroborers in the Hirnantian and early Silurian of North America. It is possible that muddy environments supported higher bioerosion intensities and higher diversity of bioerosional traces in the shallow epicontinental seas of the Late Ordovician. The discovery of Petroxestes in the Sandbian of Estonia supports the idea that there was an earliest Late Ordovician peak in the diversification of borings in Baltica. It is possible that there was a migration of bioerosional trace makers from Baltica to Laurentia in the Late Ordovician.

Conodonts of Caradocian (Late Ordovician) age from the Cliefden Caves Limestone, southeastern Australia

1990 ◽  
Vol 64 (5) ◽  
pp. 821-831 ◽  
Author(s):  
Norman M. Savage
Keyword(s):  
New Species ◽  
North America ◽  
Southeast Asia ◽  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
Eastern Siberia ◽  
Southeastern Australia ◽  
South Wales ◽  
Eastern Australia

New species of Aphelognathus, Belodina, Taoqupognathus, and Yaoxianognathus have been identified in the Late Ordovician Cliefden Caves Limestone Group in central-western New South Wales, Australia. Of the Aphelognathus species, Aphelognathus percivali n. sp. and A. webbyi n. sp. occur in the basal Gleesons Limestone Member and A. packhami n. sp. and A. stevensi n. sp. occur 30 m higher in the Wyoming Limestone Member. It seems likely from the similarity of several of the elements that A. packhami is closely related to A. percivali, and A. stevensi to A. webbyi. Yaoxianognathus wrighti n. sp. occurs in the Gleesons Limestone Member but not in the Wyoming Limestone Member. Belodina confluens, Belodina hillae n. sp., Belodina n. sp., Panderodus gracilis, Taoqupognathus philipi n. sp., and Phragmodus? tunguskaensis occur at both horizons. The conodonts suggest a middle to late Caradocian (mid-Shermanian to mid-Edenian) age for the lowest part of the Cliefden Caves Limestone. The occurrence in southeastern Australia of the forms Taoqupognathus, Yaoxianognathus, and Phragmodus? tunguskaensis suggest affinities to coeval faunas in China and eastern Siberia. The four new species of Aphelognathus are distinct from known species in the Late Ordovician of North America and Europe but they may help characterize a paleobiogeographic region that includes eastern Australia and southeast Asia.

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