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).

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.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

Middle Ordovician Table Head Group of western Newfoundland: a revised stratigraphy

1980 ◽  
Vol 17 (8) ◽  
pp. 1007-1019 ◽  
Author(s):  
Colin F. Klappa ◽  
Paul R. Opalinski ◽  
Noel P. James
Keyword(s):  
Carbonate Platform ◽  
Head Group ◽  
Group Status ◽  
Middle Ordovician ◽  
Iapetus Ocean ◽  
Lower Ordovician ◽  
Head Formation ◽  
New Formation

Lithostratigraphic nomenclature of early Middle Ordovician strata from western Newfound land is formally revised. The present Table Head Formation is raised to group status and extended to include overlying interbedded terrigenoclastic-rich calcarenites and shales with lime megabreccias. Four new formation names are proposed: Table Point Formation (previously lower Table Head); Table Cove Formation (previously middle Table Head); Black Cove Formation (previously upper Table Head); and Cape Cormorant Formation (previously Caribou Brook formation). The Table Point Formation comprises bioturbated, fossiliferous grey, hackly limestones and minor dolostones; the Table Cove Formation comprises interbedded lime mudstones and grey–black calcareous shales; the Black Cove Formation comprises black graptolitic shales; and the Cape Cormorant Formation comprises interbedded terrigenoclastic and calcareous sandstones, siltstones, and shales, punctuated by massive or thick-bedded lime megabreccias. The newly defined Table Head Group rests conformably or disconformably on dolostones of the Lower Ordovician St. George Group (an upward-migrating diagenetic dolomitization front commonly obscures the contact) and is overlain concordantly by easterly-derived flysch deposits. Upward-varying lithologic characteristics within the Table Head Group result from fragmentation and subsidence of the Cambro-Ordovician carbonate platform and margin during closure of a proto-Atlantic (Iapetus) Ocean.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

Subspeciation within a punctuated equilibrium evolutionary event: Phylogenetic history of the Lower-Middle Ordovician Paroistodus originalis—P. horridus complex (Conodonta)

2000 ◽  
Vol 74 (3) ◽  
pp. 492-502
Author(s):  
Guillermo L. Albanesi ◽  
Christopher R. Barnes
Keyword(s):  
Carbonate Platform ◽  
Black Shales ◽  
San Juan ◽  
Carbonate Production ◽  
Middle Ordovician ◽  
Lower Member ◽  
Speciation Event ◽  
Restricted Environment ◽  
Evolutionary Event ◽  
Middle Member

A microevolutionary event involving the conodont Paroistodus lineage is documented in the Gualcamayo Formation (Middle Ordovician), Argentine Precordillera. A detailed sampling of limestones throughout the upper part of the San Juan Formation and the lower member of the Gualcamayo Formation yielded over 14,000 well-preserved conodont elements. Paroistodus originalis (Sergeeva, 1963) was recorded through the upper 230 m of the San Juan Formation and the lower member (10 m thick) of the Gualcamayo Formation. The derived species Paroistodus horridus (Barnes and Poplawski, 1973) was recorded throughout the middle member of the Gualcamayo Formation (65 m thick). The intermediate linking forms between both species are identified as two new taxa: Paroistodus horridus primus Albanesi, 1998b, and P. h. secundus Albanesi, 1998b. They were recorded in the uppermost 70 cm of the lower member. Apparently, the speciation event occurred under stressed environmental conditions with the drowning of the carbonate platform, i.e., the San Juan Formation, and the beginning of a deeper and restricted environment represented by the Gualcamayo black shales. The demise of the carbonate production was caused by a sea level rise and a significant influx of volcanic ashes. The punctuated speciation event occurred within an allopatric setting while the Precordillera occupied an isolated (Iapetus) oceanic position in its overall drift from Laurentia to Gondwana.

Mid-Paleozoic thrusting at the Appalachian deformation front: Port au Port Peninsula, western Newfoundland

1991 ◽  
Vol 28 (12) ◽  
pp. 1992-2002 ◽  
Author(s):  
John W. F. Waldron ◽  
Glen S. Stockmal
Keyword(s):  
Carbonate Platform ◽  
Foreland Basin ◽  
Late Ordovician ◽  
Western Boundary ◽  
Seismic Profiles ◽  
The West ◽  
Deformation Front ◽  
Middle Ordovician ◽  
Triangle Zone ◽  
Map Scale

Structures exposed on Port au Port Peninsula in western Newfoundland record the nature of the Appalachian deformation front, which forms the western boundary of the Humber tectono-stratigraphic zone. The major structures affect the Late Ordovician to Late Silurian Long Point – Clam Bank succession, but not the unconformably overlying Carboniferous rocks; they are probably of Devonian age.At the west coast of the peninsula, Long Point and Clam Bank strata are affected by both east-vergent and west-vergent structures. The basal surface of the succession is interpreted as an east-vergent thrust, forming the upper detachment of a "triangle zone," and correlates with a similarly located contact seen in offshore multichannel seismic profiles. Within the succession, east-vergent deformation zones locally duplicate the stratigraphy. West-vergent structures, including a map-scale overturned fold north of Round Head mountain, are probably younger.Farther south, Middle Ordovician foreland basin sediments are also affected by east-vergent thrusts, which have been variably rotated by west-vergent folds. In the underlying Cambrian–Ordovician platform carbonate succession, east-vergent thrusts duplicate the stratigraphy.These structures are related to telescoping of the carbonate platform and the overlying Humber Arm Allochthon during Devonian westward wedging of the structural triangle zone beneath the Long Point – Clam Bank succession. The platform succession must therefore be allochthonous, and the Humber Arm Allochthon has been transported to the west of its Late Ordovician position.

A mixed isograptid-didymograptid graptolite assemblage from the Middle Ordovician of west Gondwana (NW Bolivia): Implications for graptolite paleoecology

2008 ◽  
Vol 82 (6) ◽  
pp. 1114-1126 ◽  
Author(s):  
Charles Mitchell ◽  
Edsel D. Brussa ◽  
Jörg Maletz
Keyword(s):  
Foreland Basin ◽  
Black Shales ◽  
Low Latitude ◽  
Middle Ordovician ◽  
West Gondwana ◽  
Atlantic Province ◽  
Continental Shelves ◽  
Local Water ◽  
Physical Features ◽  
The Town

Black shales of the Coroico Formation are part of a thick succession of Lower and Middle Ordovician strata that were deposited in the Cordillera Oriental foreland basin along the margin of West Gondwana. The basin was inhabited primarily by a cool-water, Atlantic-type graptolite fauna. Newly discovered material from rocks that crop out near the town of Consata in NW Bolivia include unexpected warm-water or Pacific-type elements such as Parisograptus caduceus and Pseudotrigonograptus within an assemblage dominated by abundant pendent Didymograptus specimens, Cryptograptus schaeferi, and diplograptaceans such as Oelandograptus oelandicus and Hustedograptus bulmani n. sp. Parisograptus caduceus has generally been considered to be restricted to oceanic depths below those of the epipalagic realm that occupied continental shelves, whereas the remainder of the assemblage is more characteristic of relatively shallow water, epicratonic sites. We interpret this mixed assemblage to be the Atlantic Province, West Gondwanan equivalent of the off-shore isograptid biofacies that is much more widely known from low latitude sites around the globe. These results suggest that in this region of West Gondwana, the properties of local water masses (productivity and physical features such as temperature, salinity, or oxygenation) strongly influenced graptolite species distribution and led to biofacies differentiation among coeval assemblages. It also suggests that some isograptids inhabited the epipelagic biotope in mid to high latitude regions. The new species Hustedograptus bulmani is described herein.

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.

Allochthonous slope sequence at Lobster Cove Head: evidence for a complex Middle Ordovician platform margin in western Newfoundland

1987 ◽  
Vol 24 (6) ◽  
pp. 1199-1211 ◽  
Author(s):  
Noel P. James ◽  
Jack W. Botsford ◽  
S. Henry Williams
Keyword(s):  
Deep Water ◽  
Carbonate Platform ◽  
Head Group ◽  
Middle Ordovician ◽  
The North ◽  
Platform Margin ◽  
Taconic Orogeny ◽  
Group Contact ◽  
Carbonate Platform Margin ◽  
Shallow Bay

The upper part of an intact sequence of Lower to Middle Ordovician deep-water sediments, which now form a large, disrupted raft within the Rocky Harbour Mélange at Lobster Cove Head, is interpreted as having been deposited downslope from a drowned carbonate platform margin. The entire 50 m thick section is Arenig (late Canadian or Ibexian to early Whiterock) in age; graptolite biostratigraphy demonstrates a correlation with upper parts of the Cow Head Group to the north. The basal part of the section is a proximal facies of the Cow Head Group (Shallow Bay Formation, Factory Cove Member, Beds 9, 10, and part of Bed 11). The upper part of the section consists of interbedded dolostone and shale and is unlike any other sequence in the Cow Head Group. This upper sedimentary sequence is defined as the Lobster Cove Head Member of the Shallow Bay Formation, Cow Head Group. Contact between the two sedimentary packages is also marked by a faunal break and coincides with emplacement of megaconglomerate Bed 12 at Cow Head.This break marks the change from a uniform to complex carbonate platform margin configuration and is here interpreted as the result of synsedimentary faulting. The margin upslope from Cow Head remained in shallow water during the final stages of Cow Head Group deposition, whereas that upslope from Lobster Cove Head was drowned and shed little sediment into deep water. The synsedimentary faulting, which led to rapid subsidence and platform-margin drowning upslope from Lobster Cove Head and possibly the deposition of megaconglomerate Bed 12 at Cow Head, coincides with the onset of the Taconic Orogeny in western Newfoundland.

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.

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