scholarly journals Middle Paleozoic Gaspé Belt (Late Ordovician to Middle Devonian) - Geological framework

2009 ◽  
Author(s):  
N Pinet ◽  
D Lavoie ◽  
S Castonguay
Keyword(s):  
Middle Devonian ◽  
Late Ordovician ◽  
Middle Paleozoic

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 Middle and Upper Devonian callocystitids have been previously reported only from Iowa and Michigan USA with unpublished reports from Missouri USA and the Northwest Territories, Canada.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.

scholarly journals Ediacaran–Middle Paleozoic Oceanic Voyage of Avalonia from Baltica via Gondwana to Laurentia: Paleomagnetic, Faunal and Geological Constraints

2014 ◽  
Vol 41 (1) ◽  
pp. 5 ◽  
Author(s):  
J. Duncan Keppie ◽  
D. Fraser Keppie
Keyword(s):  
Detrital Zircon ◽  
Late Ordovician ◽  
Island Arc ◽  
Paleomagnetic Data ◽  
Backarc Basin ◽  
Early Ordovician ◽  
Middle Paleozoic ◽  
Nw Gondwana ◽  
Geological Constraints

Current Ediacaran–Cambrian, paleogeographic reconstructions place Avalonia, Carolinia and Ganderia (Greater Avalonia) at high paleolatitudes off northwestern Gondwana (NW Africa and/or Amazonia), and locate NW Gondwana at either high or low paleolatitudes. All of these reconstructions are incompatible with 550 Ma Avalonian paleomagnetic data, which indicate a paleolatitude of 20–30ºS for Greater Avalonia and oriented with the present-day southeast margin on the northwest side. Ediacaran, Cambrian and Early Ordovician fauna in Avalonia are mainly endemic, which suggests that Greater Avalonia was an island microcontinent. Except for the degree of Ediacaran deformation, the Neoproterozoic geological records of mildly deformed Greater Avalonia and the intensely deformed Bolshezemel block in the Timanian orogen into eastern Baltica raise the possibility that they were originally along strike from one another, passing from an island microcontinent to an arc-continent collisional zone, respectively. Such a location and orientation is consistent with: (i) Ediacaran (580–550 Ma) ridge-trench collision leading to transform motion along the backarc basin; (ii) the reversed, ocean-to-continent polarity of the Ediacaran cratonic island arc recorded in Greater Avalonia; (iii) derivation of 1–2 Ga and 760–590 Ma detrital zircon grains in Greater Avalonia from Baltica and the Bolshezemel block (NE Timanides); and (iv) the similarity of 840–1760 Ma TDM model ages from detrital zircon in pre-Uralian–Timanian and Nd model ages from Greater Avalonia. During the Cambrian, Greater Avalonia rotated 150º counterclockwise ending up off northwestern Gondwana by the beginning of the Ordovician, after which it migrated orthogonally across Iapetus to amalgamate with eastern Laurentia by the Late Ordovician–Early Silurian. SOMMAIRELes reconstitutions paléogéographiques courantes de l’Édiacarien-Cambrien placent l’Avalonie ,la Carolinia et la Ganderia (Grande Avalonie) à de hautes paléolatitudes au nord-ouest du Gondwana (N-O de l'Afrique et/ou de l'Amazonie), et placent le N-O du Gondwana à de hautes ou de basses paléolatitudes.  Toutes ces reconstitutions sont incompatibles avec des données avaloniennes de 550 Ma, lesquelles indiquent une paléolatitude de 20-30º S pour la Grande Avalonie et orientée à la marge sud-est d’aujourd'hui sur le côté nord-ouest.  Les faunes édicacariennes, cambriennes et de l'Ordovicien précoce dans l’Avalonie sont principalement endémiques, ce qui permet de penser que la Grande Avalonie était une île de microcontinent.  Sauf pour le degré de déformation édiacarienne, les registres géologiques néoprotérozoïques d’une Grande Avalonie légèrement déformée et ceux du bloc intensément déformé de Bolshezemel dans l'orogène Timanian dans l’est de la Baltica soulèvent la possibilité qu'ils aient été à l'origine de même direction,  passant d'une île de microcontinent à une zone de collision d’arc continental, respectivement.  Un tel emplacement et une telle orientation sont compatibles avec: (i) un contexte de collision crête-fosse à l’Édiacarien (580-550 Ma) se changeant en un mouvement de transformation le long du bassin d’arrière-arc; (ii) l’inversion de polarité de marine à continentale, de l’arc insulaire cratonique édicarien observé dans la Grande Avalonie; (iii) la présence de grains de zircons détritiques de 1 à 2 Ga et 760-590 Ma de la Grande Avalonie issus de la Baltica et du bloc Bolshezemel (N-E des Timanides); et (iv) la similarité des âges modèles de 840-1760 Ma TDM de zircons détritiques pré-ourallien-timanien, et des âges modèles Nd de la Grande Avalonie.  Durant le Cambrien, la Grande Avalonie a pivoté de 150° dans le sens antihoraire pour se retrouver au nord-ouest du Gondwana au début de l'Ordovicien, après quoi elle a migré orthogonalement à travers l’océan Iapetus pour s’amalgamer à la bordure est de la Laurentie à la fin de l’Ordovicien-début du Silurien.

The Late Ordovician – Middle Devonian Gaspé Belt in eastern Canada — recent advances

2004 ◽  
Vol 41 (5) ◽  
pp. 483-487 ◽  
Author(s):  
Denis Lavoie ◽  
Michel Malo ◽  
Alain Tremblay
Keyword(s):  
Continental Margin ◽  
Middle Devonian ◽  
Late Ordovician ◽  
Research Progress ◽  
Special Issue ◽  
Eastern Canada ◽  
Recent Research Progress ◽  
Research Endeavour ◽  
Mapping Program ◽  
Organization Research

The Appalachian Forelands and Platform NATMAP (National Geoscience Mapping Program) project in eastern Canada is a multi-discipline and multi-organization research endeavour aimed at the understanding of the evolution and architecture of the ancient continental margin of Laurentia. This Canadian Journal of Earth Sciences Special Issue presents some recent research progress for our knowledge of the Silurian–Devonian Gaspé Belt of that ancient margin.

Taxonomic revision of Hyolitha from the middle Paleozoic of North America

1987 ◽  
Vol 61 (6) ◽  
pp. 1173-1186 ◽  
Author(s):  
John M. Malinky ◽  
Robert M. Linsley ◽  
Ellis L. Yochelson
Keyword(s):  
New York ◽  
North America ◽  
Middle Devonian ◽  
New Genus ◽  
Taxonomic Revision ◽  
Type Specimens ◽  
Middle Paleozoic

Collection of over a dozen specimens of Hyolithes aclis Hall from the Middle Devonian of New York indicates that this species belongs to a new genus, Hallotheca, to which the species Hyolithes halli (Hall) is also assigned. However, the generic assignments of the Silurian species Hyolithes cliftonensis Foerste and the Devonian species H. centennialis Barrett, H. ceratophilus Clarke, H. neapolis Clarke, and H. triliratus Hall are uncertain because of poor preservation of their type specimens. Use of these names should be confined to the types until better preserved topotypes become available. Finally, H. cooperi (Williams) consists of organisms of uncertain affinities, and the type of H. principalis Hall may be a fragment of Devonian sandstone rather than an organism.

Middle Paleozoic paleomagnetism of east Kazakhstan: post-Middle Devonian rotations in a large-scale orocline in the central Ural–Mongol belt

2003 ◽  
Vol 377 (3-4) ◽  
pp. 249-268 ◽  
Author(s):  
Natalia M. Levashova ◽  
Kirill E. Degtyarev ◽  
Mikhail L. Bazhenov ◽  
Adam Q. Collins ◽  
Rob Van der Voo
Keyword(s):  
Middle Devonian ◽  
Large Scale ◽  
East Kazakhstan ◽  
Middle Paleozoic

Silurian deformation and metamorphism of Ordovician arc rocks of the Casco Bay Group, south-central Maine

2003 ◽  
Vol 40 (6) ◽  
pp. 887-905 ◽  
Author(s):  
David P West Jr. ◽  
Heather M Beal ◽  
Timothy W Grover
Keyword(s):  
Middle Devonian ◽  
Elevated Temperatures ◽  
Early Carboniferous ◽  
Low Pressure ◽  
Late Ordovician ◽  
Early Ordovician ◽  
Late Cambrian ◽  
South Central ◽  
Intrusive Activity ◽  
Back Arc

The Casco Bay Group in south-central Maine consists of a sequence of Late Cambrian to Early Ordovician interlayered quartzofeldspathic granofels and pelite (Cape Elizabeth Formation) overlain by Early to Late Ordovician back-arc volcanic (Spring Point Formation) and volcanogenic sedimentary rocks (Diamond Island and Scarboro formations). These rocks were tightly folded and subjected to low-pressure amphibolite-facies metamorphism in the Late Silurian. This phase of deformation and metamorphism was followed by the development of a variety of structures consistent with a period of dextral transpression in Middle Devonian – Early Carboniferous time. Previously dated plutons within the sequence range in age from 422–389 Ma and record a period of prolonged intrusive activity in the region. Similarities in age, volcanic rock geochemistry, and lithologic characteristics argue strongly for a correlation between rocks of the Casco Bay Group and those in the Miramichi belt of eastern Maine and northern New Brunswick. The Cape Elizabeth Formation correlates with Late Cambrian to Early Ordovician sediments of the Miramichi Group (Gander Zone) and the Spring Point through Scarboro formations correlate with Early to Late Ordovician back-arc basin volcanics and volcanogenic sediments of the Bathurst Supergroup. The folding and low-pressure metamorphism of the Casco Bay Group is attributed to Late Silurian to Early Devonian terrane convergence and possible lithospheric delamination that would have resulted in a prolonged period of intrusive activity and elevated temperatures at low pressures. Continued convergence and likely plate reconfigurations in the Middle Devonian to Carboniferous led to widespread dextral transpression in the region.

The Carribuddy Group and Worral Formation, Canning Basin, Western Australia: reassessment of stratigraphy and petroleum potential

2010 ◽  
Vol 50 (1) ◽  
pp. 425 ◽  
Author(s):  
Peter Haines
Keyword(s):  
Middle Devonian ◽  
Late Ordovician ◽  
Source Rocks ◽  
Local Source ◽  
Petroleum Potential ◽  
Canning Basin ◽  
Petroleum Wells ◽  
Reservoir Potential ◽  
Drill Holes ◽  
Reservoir Facies

Reassessment of stratigraphic relationships and biostratigraphic data pertaining to the Carribuddy Group and Worral Formation in all relevant petroleum wells and many mineral drill holes across the southern Canning Basin has led to the following important results. The Carribuddy Group is restricted to the Late Ordovician to earliest Silurian. The overlying Worral Formation is mostly of Silurian age and does not intertongue with the Middle Devonian Tandalgoo Formation, as previously thought. A thin basin-wide chronostratigraphic marker—the Pegasus Dolomite Member (previously referred to as dolomite spike or dolomite marker) of the Sahara Formation—allows improved correlation between salt-bearing sub-basins and adjacent condensed Carribuddy Group successions. The Mallowa Salt is not as extensive as previously thought; rather the Minjoo Salt thickens to become the only salt seal in the eastern and southern Kidson Sub-basin. The Carribuddy Group forms the regional seal to the prospective Larapintine 2 petroleum system, but also contains local source and reservoir facies. The Bongabinni Formation contains extremely rich oil-prone source rocks in local lagoonal facies along the Admiral Bay Fault Zone; these rocks have been linked by other studies to migrated oil in that area. The distribution of the source facies is poorly known, but it may extend down-dip into more mature parts of the Willara Sub-basin, and west into offshore areas. Other local source units may be present in the Mallowa Salt, and possibly the Nibil Formation, but are not well documented. Aeolian sandstone with excellent reservoir potential is locally present in the Nibil Formation, but is more extensive in the lower Worral Formation, particularly the Elsa Sandstone Member.

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