Diachronous tectonic collapse of the Ordovician continental margin, eastern Canada: comparison between the Quebec Reentrant and St. Lawrence Promontory

1994 ◽  
Vol 31 (8) ◽  
pp. 1309-1319 ◽  
Author(s):  
Denis Lavoie
Keyword(s):  
Continental Margin ◽  
Foreland Basin ◽  
Head Group ◽  
Upper Ordovician ◽  
Eastern Canada ◽  
Middle Ordovician ◽  
Carbonate Sedimentation ◽  
Shallow Subtidal ◽  
Thickness Variations ◽  
Trenton Group

The Upper Ordovician Trenton Group of southern Quebec represents the last Taconian foreland basin carbonate unit in the Quebec Reentrant, prior to final collapse of Laurentia's continental margin and its burial under synorogenic flysch. The Trenton Group, either conformably or unconformably, overlies the Black River Group and is in turn conformably overlain by the Utica Shales. The tripartite Trenton carbonate unit records progressive deepening: (1) very shallow to shallow subtidal, (2) shallow to deep carbonate ramp, and (3) shallow to deep outer shelf. Regional facies distribution, lithotectonic elements, and thickness variations indicate that the Trenton shelf was dissected by extensional faults delineating blocks subsiding at various rates. This scenario compares favourably with Taconian foreland basin development in the Middle Ordovician Table Head Group at the St. Lawrence Promontory, Newfoundland. A similar stratigraphic succession and tectono-sedimentary history occurring 10–15 Ma earlier at the St. Lawrence Promontory than in the Quebec Reentrant argues for a primary tectonic control for the demise of carbonate sedimentation at the margin. The diachroneity in the foreland evolution can be related to the irregular morphology of the Laurentia continental margin.

The stratigraphy of the Lower Ordovician St. George Group, western Newfoundland: the interaction between eustasy and tectonics

1987 ◽  
Vol 24 (10) ◽  
pp. 1927-1951 ◽  
Author(s):  
Ian Knight ◽  
Noel P. James
Keyword(s):  
Sea Level ◽  
Continental Margin ◽  
Carbonate Rock ◽  
Outer Edge ◽  
Low Latitude ◽  
Middle Ordovician ◽  
Lower Ordovician ◽  
Shallow Subtidal ◽  
Eustatic Fluctuations ◽  
Equal Thickness

The St. George Group is a ~500 m thick sequence of carbonate rock that accumulated during Early and early Middle Ordovician time in a series of shallow subtidal and peritidal environments near the outer edge of a low-latitude continental margin. Lithological variations, in the form of two megacycles, reflect deposition in response to eustatic fluctuations in sea level preceding and during the early stages of Taconic orogenesis.Strata are grouped into four formations of roughly equal thickness. The newly named basal Watts Bight Formation is a lower sequence of peritidal limestones and dolostones and an upper thicker, commonly dolomitized succession of burrowed carbonates distinguished by large digitate thrombolite mounds. The overlying Boat Harbour Formation (new) is a series of muddy, peritidal, shallowing-upward sequences of limestone and dolostone. A widespread subaerial disconformity near the top of the formation, reflecting eustaic sea-level fall and the end of the first megacycle, is marked by breccia, quartz-pebble conglomerate, paleokarst, and (or) extensive dolomitization and is succeeded by higher energy peritidal limestones called the Barbace Cove Member (new). The succeeding, thick, monotonous Catoche Formation (revised) is a succession of fossiliferous subtidal limestones with scattered thrombolite mounds whose upper part is locally affected by extensive, multigeneration dolomitization and Pb–Zn mineralization. The St. George Group is capped by the newly defined Aguathuna Formation, a stack of peritidal dolostones and minor limestones and shales deposited during a period of repeated exposure and synsedimentary faulting. An erosional disconformity, resulting from regional compressional tectonics and eustatic sea-level fall, locally marks the top of the St. George and the second megacycle.

Integrated chitinozoan, conodont, and graptolite biostratigraphy from the upper part of the Cape Cormorant Formation (Middle Ordovician), western Newfoundland

2001 ◽  
Vol 38 (3) ◽  
pp. 387-409 ◽  
Author(s):  
Roberto Albani ◽  
Gabriella Bagnoli ◽  
Jörg Maletz ◽  
Svend Stouge
Keyword(s):  
Early Stage ◽  
Foreland Basin ◽  
Black Shales ◽  
Head Group ◽  
Middle Ordovician ◽  
Head Groups ◽  
Taconic Orogeny ◽  
Low Diversity ◽  
Conodont Fauna ◽  
Abundance And Diversity

The Cape Cormorant Formation of the Table Head Group exposed on the Port au Port Peninsula, western Newfoundland, is composed of dark-brown to black shales with interbeds of thin calcareous silty and sandy distal turbidites. Distinctive carbonate conglomerates and breccias derived from the foundering shelf are occasionally found in the formation. The sediments accumulated in the foreland basin formed during the early stage of the Taconic orogeny. The faunas from the upper part of the Cape Cormorant Formation include graptolites, conodonts, and chitinozoans. The graptolites are well preserved, but are of low diversity and are referred to the Darriwil Pterograptus elegans Zone. Conodonts recorded from the distal turbidites are rare and fragmented. The faunas include taxa that are known from the St. George and Table Head groups. The conodont fauna is tentatively assigned to the Histiodella kristinae Phylozone and to the younger, unzoned interval. The chitinozoans are well preserved and the yield is high. The fauna is assigned to the Cyathochitina jenkinsi Zone and to an undefined interval. The abundance and diversity of the chitinozoan assemblages display a cyclic pattern, which is related to changes of the oceanic watermass in the foreland basin. The new chitinozoan species Belonechitina nevillensis n. sp., Belonechitina uniformipunctata n. sp., and Cyathochitina cormorani n. sp. are described.

Biostratigraphic significance of lower Paleozoic microfaunas from eastern Canada

2004 ◽  
Vol 41 (5) ◽  
pp. 489-505 ◽  
Author(s):  
Esther Asselin ◽  
Aïcha Achab ◽  
Azzedine Soufiane
Keyword(s):  
New Brunswick ◽  
Lower Devonian ◽  
Head Group ◽  
Upper Ordovician ◽  
Eastern Canada ◽  
Lower Paleozoic ◽  
Anticosti Island ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula ◽  
Mapping Program

Chitinozoan studies recently carried out in the “Appalachian Forelands and St. Lawrence Platform” National Geoscience Mapping Program (NATMAP) project have confirmed the regional biostratigraphic value of a number of chitinozoan species and led to a better documentation of their stratigraphic and geographic distribution in eastern Canada. The typical Darriwilian microfaunas first described from the Table Head Group of western Newfoundland and containing Conochitina chydaea are now recognised in the Rivière Ouelle Formation at Les Méchins, Gaspé Peninsula. In the Upper Ordovician successions of the St. Lawrence Platform at Neuville and in the Charlevoix area, Quebec, Conochitina primitiva is indicative of the multidens–pre-americanus graptolite zonal range, Hercochitina duplicitas of the americanus Zone, and Hercochitina spinetum and Acanthochitina cancellata characterize the ruedemanni – lower spiniferus zonal interval. The occurrence of Cyathochitina vaurealensis and Hercochitina crickmayi in turbidite deposits of the Grog Brook Group of northwestern New Brunswick confirms the minimal facies dependence of these two Richmondian index species. Eisenackitina dolioliformis, characteristic of the late Aeronian and Telychian successions of Arctic Canada, Gaspé Peninsula, and Anticosti Island, is now recognised in samples from the Upsalquitch Formation of northwestern New Brunswick and the Cabano Formation of the Rimouski area in Quebec. The palynological data from Devonian successions of the Matapedia Valley, the Rimouski area, and the Beauce – Eastern Townships region show that the succession of Lower Devonian chitinozoan assemblages of the Forillon Peninsula based on short-ranging species can be used in establishing regional correlations in the Gaspé Belt.

scholarly journals Middle–Upper Ordovician and Silurian stratigraphy and basin development in southernmost Scandinavia

1969 ◽  
Vol 35 ◽  
pp. 39-42 ◽  
Author(s):  
Niels H. Schovsbo ◽  
Arne T. Nielsen ◽  
Mikael Erlström
Keyword(s):  
Foreland Basin ◽  
Upper Ordovician ◽  
Middle Ordovician ◽  
Lower Silurian ◽  
Basin Development ◽  
Caledonian Orogeny

A complete log-stratigraphical breakdown of the Middle Ordovician to lower Silurian shale-dominated succession is presented for the Bornholm–Skåne–Kattegat area in southernmost Scandinavia. A wireline log zonation developed for the onshore Bornholm Palaeozoic shales is extended to include the offshore Palaeozoic shales in the adjacent Rønne Graben. A complete log zonation scheme for the Cyrtograptus shale (late Llandovery–Wenlock) and the lower part of the Colonus shale (Ludlow) is presented including correlation within the Bornholm–Skåne–Kattegat area. The Cyrtograptus shale in the Bornholm area is estimated to be 400 m thick and marks the shift to a rapidly subsiding foreland basin, heralding the Caledonian Orogeny.

Thermal maturity and burial history of Paleozoic rocks in western Newfoundland

1998 ◽  
Vol 35 (11) ◽  
pp. 1307-1322 ◽  
Author(s):  
S Henry Williams ◽  
Elliott T Burden ◽  
P K Mukhopadhyay
Keyword(s):  
Vitrinite Reflectance ◽  
Point Group ◽  
Black Shales ◽  
Source Rocks ◽  
Head Group ◽  
Published Data ◽  
Burial History ◽  
Upper Ordovician ◽  
Middle Ordovician ◽  
Paleozoic Rocks

Palynomorphs and graptolites from Paleozoic strata in western Newfoundland are examined and correlated with previously published data to identify fossils which are characteristic of proven and suspected source rocks. Measurements of colour alteration of acritarchs and spores (acritarch alteration index and thermal alteration index), random graptolite reflectance, and vitrinite reflectance are applied to determine regional thermal maturation and burial history. General trends of increasing maturity from south to north along the Northen Peninsula and from west to east across the Port au Port Peninsula are observed. Within these general trends, a more detailed distribution of thermal maturities can be recognized. In the south, Upper Ordovician rocks of the Long Point Group, western Port au Port Peninsula, exhibit the lowest maturity values found in western Newfoundland and are considered immature or marginally mature. Middle Ordovician rocks of the Goose Tickle and Table Head groups and the Lower Ordovician St. George Group are marginally mature. Cambrian strata on the Port au Port Peninsula are mature. Maturation levels increase to the east; Goose Tickle Group black shales in the vicinity of Black Cove, east of Port au Port, are mature. Equivalent sediments extending for another 15-20 km to the east lie within the oil window. Beyond that area, the equivalent rocks are overmature. The best potential source rocks belonging to the allochthonous Cow Head Group contain abundant acritarchs and Gloeocapsamorpha sp. These rocks are marginally mature to mature within Gros Morne National Park; maturation levels increase farther north (e.g., Parsons Pond), becoming overmature somewhere south of Port au Choix. It is concluded that neither the allochthonous Ordovician rocks presently exposed in Gros Morne nor the autochthonous strata exposed on the Port au Port Peninsula have ever been covered by significant thicknesses of overburden (probably 3 km or less), either in the form of structural slices or other sedimentary units since their original deposition.

Carbonate platform to foreland basin: revised stratigraphy of the Table Head Group (Middle Ordovician), western Newfoundland

1990 ◽  
Vol 27 (1) ◽  
pp. 14-26 ◽  
Author(s):  
Sheila R. Stenzel ◽  
Ian Knight ◽  
Noel P. James
Keyword(s):  
Carbonate Platform ◽  
Foreland Basin ◽  
Black Shales ◽  
Head Group ◽  
Western Margin ◽  
Middle Ordovician ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Three Stages ◽  
Uplift And Erosion

Carbonates of the Table Head Group and associated strata were deposited along the western margin of a foreland basin during initial stages of the Taconian Orogeny and record collapse and cannibalization of a long-lived carbonate platform. The stratigraphy of Klappa, Opalinski, and James is here revised to reflect better understanding of lithologic units within this complex tectono-stratigraphic assemblage. The Table Head Group now contains only three formations: the Table Point and Table Cove formations, as originally defined, and the Cape Cormorant Formation, redefined and restricted to western Port au Port Peninsula. Black Cove Formation shales are removed from the Table Head. Distinctive conglomerates once placed in the Cape Cormorant are now recognized as separate units within the overlying flysch and called the Daniel's Harbour Member.The foreland basin developed in three stages: (1) fragmentation, uplift, and erosion of the platform and subsequent deposition of shallow-water limestones (Table Point) on a tectonically unstable shelf; (2) foundering of platform blocks and deposition of deep-water-slope carbonates (Table Cove), basinal black shales (Black Cove), or conglomerates of older shelf carbonates shed from submarine cliffs (Cape Cormorant); and (3) siliciclastic sedimentation interrupted by sediment gravity flows of Table Head clasts shed from submarine escarpments (Daniel's Harbour).

In situ lingulids from deep-water carbonates of the Middle Ordovician Table Head Group of Newfoundland and the Trenton Group of Quebec

1984 ◽  
Vol 21 (2) ◽  
pp. 194-199 ◽  
Author(s):  
R. K. Pickerill ◽  
T. L. Harland ◽  
D. Fillion
Keyword(s):  
Deep Water ◽  
Fossil Record ◽  
Environmental Indicators ◽  
Outer Shelf ◽  
Head Group ◽  
Middle Ordovician ◽  
Trenton Group ◽  
Water Depths ◽  
Upper Slope

Specimens of in situ lingulids have been discovered in carbonates of the Middle Ordovician Table Head Group of northwestern Newfoundland and Trenton Group of the St. Lawrence Lowland of Quebec. The discoveries have two important implications regarding Palaeozoic lingulid ecology. First, they represent one of the few recordings of in situ lingulids in carbonate substrates of Palaeozoic age and, second, they occur mainly in outer shelf and upper slope sediments (Grondines Member of Neuville Formation, Trenton Group, and Table Cove Formation, Table Head Group), deposited in presumed considerable water depths. Caution must be observed with the use in the fossil record of lingulids as palaeo-environmental indicators.

scholarly journals SHRIMP U–Pb zircon evidence for age, provenance, and tectonic history of early Paleozoic Ganderian rocks, east-central Maine, USA

2018 ◽  
pp. 335-387
Author(s):  
Allan Ludman ◽  
John Aleinikoff ◽  
Henry N. Berry IV ◽  
John T. Hopeck
Keyword(s):  
Foreland Basin ◽  
Volcanic Eruptions ◽  
Detrital Zircons ◽  
Upper Ordovician ◽  
Middle Ordovician ◽  
Tectonic History ◽  
Late Cambrian ◽  
Quartz Arenite ◽  
History Of ◽  
Host Rocks

SHRIMP U–Pb zircon ages from Ganderia in eastern Maine clarify the ages and provenance of basement units in the Miramichi and St. Croix terranes and of cover rocks in the Fredericton trough and Central Maine/Aroostook-Matapedia basin (CMAM). These new data constrain timing of orogenic events and help understand the origin of the cover rock depocenters.Detrital zircon data generally confirm suggested ages of the formations sampled. Zircon grains with ages of ca. 430 Ma in both depocenters, only slightly older than their host rocks, were probably derived from the earliest volcanic eruptions in the Eastport-Mascarene belt. Their presence indicates that unnamed CMAM sandstone units may be as young as Pridoli and their absence from the Appleton Ridge and Digdeguash formations suggests that these formations are older than initial Eastport-Mascarene volcanism. Detrital and volcanic zircon ages confirm a Late Cambrian to Middle Ordovician age for the Miramichi succession and date Miramichi volcanism at 469.3 ± 4.6 Ma. In the St. Croix terrane, zircon grain with an age of 477.4 ± 3.7 Ma from an ashfall at the base of the Kendall Mountain Formation and age spectra and fossils from overlying quartz arenite suggest that the formation may span Floian to Sandbian time. The main source of CMAM and Fredericton sediment was recycled Ganderian basement from terranes emergent after Late Ordovician orogenesis, supplemented by Silurian tephra. Zircon barcodes and lithofacies and tectonic models suggest little, if any, input from Laurentia or Avalonia.Zircon- and fossil-based ages indicate coeval Upper Ordovician deformation in the St. Croix (ca. 453 to 442 Ma) and Miramichi (ca. 453 to 446 Ma) terranes. Salinic folding in the southeastern Fredericton trough is bracketed between the 421.9 ± 2.4 Ma age of the Pocomoonshine gabbro-diorite and 430 Ma detrital zircons in the Flume Ridge Formation. Zircon ages, lithofacies analysis, and paleontological evidence support the origin of the Fredericton trough as a Salinic foredeep. The CMAM basin cannot have been an Acadian foreland basin, as sedimentation began millions of years before Acadian subduction.

Rousseauspira: new gastropod operculum from the Ordovician of Alaska and California

1987 ◽  
Vol 61 (2) ◽  
pp. 284-289 ◽  
Author(s):  
David M. Rohr ◽  
A. W. Potter
Keyword(s):  
New Genus ◽  
New Genus And Species ◽  
Upper Ordovician ◽  
Middle Ordovician ◽  
Shallow Subtidal

Rousseauspira teicherti, a new genus and species of an unusual, untwisted, horn-shaped gastropod operculum from shallow-subtidal limestones of the Upper Ordovician of Alaska and the Middle Ordovician of California, is described and compared to two other Ordovician opercula,CeratopeaUlrich, 1911, andTeiichispiraYochelson and Jones, 1968. The shell to which the operculum belonged is not yet known.

scholarly journals Systematic ichnology of the Middle Ordovician Trenton Group, St Lawrence Lowland, eastern Canada

10.4138/1572 ◽  
1984 ◽  
Vol 20 (1) ◽  
Author(s):  
D. Fillion ◽  
R. K. Pickerill
Keyword(s):  
Eastern Canada ◽  
Middle Ordovician ◽  
Trenton Group
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