scholarly journals Upper Ordovician – Upper Silurian conodont biostratigraphy, Devon Island and southern Ellesmere Island, Canadian Arctic Islands, with implications for regional stratigraphy, eustasy, and thermal maturation

2016 ◽  
Vol 53 (9) ◽  
pp. 931-949 ◽  
Author(s):  
Shunxin Zhang ◽  
Khusro Mirza ◽  
Christopher R. Barnes
Keyword(s):  
Canadian Arctic ◽  
Hydrocarbon Exploration ◽  
Upper Ordovician ◽  
Conodont Biostratigraphy ◽  
Thermal Maturation ◽  
Devon Island ◽  
The North ◽  
Cape Phillips Formation ◽  
Upper Silurian ◽  
Local Range

The conodont biostratigraphy for the Upper Ordovician – Upper Silurian carbonate shelf (Irene Bay and Allen Bay formations) and interfingering basinal (Cape Phillips Formation) facies is established for parts of Devon and Ellesmere islands, central Canadian Arctic Islands. Revisions to the interpreted regional stratigraphic relationships and correlations are based on the stratigraphic distribution of the 51 conodont species representing 32 genera, identified from over 5000 well-preserved conodonts recovered from 101 productive samples in nine stratigraphic sections. The six zones recognized are, in ascending order, Amorphognathus ordovicicus Local-Range Zone, Aspelundia fluegeli Interval Zone, Pterospathodus celloni Local-Range Zone, Pt. pennatus procerus Local-Range Zone, Kockelella patula Local-Range Zone, and K. variabilis variabilis – Ozarkodina confluens Concurrent-Range Zone. These provided a more precise dating of the members and formations and, in particular, the range of hiatuses within this stratigraphic succession. The pattern of regional stratigraphy, facies changes, and hiatuses is interpreted as primarily related to the effects of glacioeustasy associated with the terminal Ordovician glaciation and smaller Early Silurian glacial phases, the backstepping of the Silurian shelf margin, and the geodynamic effects of the collision with Laurentia by Baltica to the east and Pearya to the north. Conodont colour alteration index values (CAI 1–6.5) from the nine sections complement earlier graptolite reflectance data in providing regional thermal maturation data of value in hydrocarbon exploration assessments.

scholarly journals Upper Ordovician graptolites from the Cape Phillips Formation, Canadian Arctic Islands

1987 ◽  
Vol 35 ◽  
pp. 191-202
Author(s):  
M. J. Melchin
Keyword(s):  
Great Britain ◽  
Shallow Water ◽  
Depositional Environment ◽  
Canadian Arctic ◽  
Late Ordovician ◽  
Outer Shelf ◽  
Upper Ordovician ◽  
The World ◽  
Cape Phillips Formation ◽  
Varying Length

Ashgill age graptolites have been collected from seven sections of the Cape Phillips Formation across most of its outcrop belt. The earliest graptolite zone recognisable is that of Orthograptus fastigatus. It is correla­ted with the Dicellograptus ornatus · Zone of the northern Canadian Cordilllera and the Dicellograptus complexus Subzone of the Dicel/ograptus anceps Zone of Great Britain although no dicellograptids have been found at any of the present sections. The overlying zone is that of Paraorthograptus pacificus, an ea­sily recognisable zone around much of the world. Graptolites of the C/imacograptus extraordinarius and Glyptograptus persculptus zones appear to be en­tirely absent from this formation. This is attributed to the Late Ordovician glaciation which has induced regression and submarine erosion in many areas worldwide. The earliest recognisable Silurian zone varies from section to section due to buried or barren intervals and/or hiatuses of varying length. The Parakidograptus acuminatus Zone has been recognised at only one section. At the others, the Atavograptus atavus, the Lagarograptus acinaces-Coronograptus gregarius, the Monograptus convolutus or the Monograptus spiralis Zone (s.1.) are the earliest recognisable Silurian fau­nas. Relatively low fauna! diversities in the Ashgill and lowest Llandovery portion of the section and the to­tal lack of dicellograptids are interpreted to be due to relatively shallow water, outer shelf or carbonate ramp depositional environment.

LANCASTER SOUND SHIPBORNE MAGNETOMETER SURVEY

1966 ◽  
Vol 3 (2) ◽  
pp. 223-235 ◽  
Author(s):  
D. L. Barrett
Keyword(s):  
Canadian Arctic ◽  
Vertical Movement ◽  
Baffin Island ◽  
Total Field ◽  
Sharp Rise ◽  
Near Surface ◽  
Baffin Bay ◽  
Devon Island ◽  
The North ◽  
Half Graben

The total magnetic field and the depth of water were measured along a ship's track of about 1 000 nautical miles during a shipborne magnetometer survey in Lancaster Sound and Baffin Bay in the eastern part of the Canadian Arctic Archipelago.Several magnetic anomalies on the extreme northern and southern boundaries of Lancaster Sound as well as to the east of Devon Island in Baffin Bay are characteristic of near-surface features. There is little magnetic relief in the center of the sound. The intensity of the total field decreases from south to north and then rises sharply immediately south of Devon Island. This sharp rise trends northeasterly in Baffin Bay.Several features are indicated by these data; (1) a near-surface basement on Devon and Baffin Islands, (2) a basement flexure north of Baffin Island, the whole of Lancaster Sound being downwarped with vertical movement of as much as 8 km in the north, (3) a regional fault extending along the south coast of Devon Island and trending northeast in Baffin Bay.It is concluded that this half-graben structure in. Lancaster Sound may be associated with a postulated median ridge between Greenland and North America.

Thermal maturation of the Lower Palaeozoic strata of northern Greenland from conodont colour alteration index (CAI) data: implications for burial history and hydrocarbon exploration

1994 ◽  
Vol 131 (2) ◽  
pp. 219-230 ◽  
Author(s):  
H. A. Armstrong ◽  
M. P. Smith ◽  
R. J. Aldridge ◽  
S. J. Tull
Keyword(s):  
Carbonate Platform ◽  
Hydrocarbon Exploration ◽  
Thermal Maturity ◽  
Burial History ◽  
Thermal Maturation ◽  
The North ◽  
Conodont Colour Alteration Index ◽  
Lower Palaeozoic ◽  
Colour Alteration ◽  
North Greenland

AbstractConodont colour alteration data for the Lower Palaeozoic strata of the North Greenland carbonate platform indicate a pattern of increased thermal maturity northwards within the Franklinian Basin. There is little variation in values through the Canadian–Llandovery (Lower Ordovician–Lower Silurian) interval at any given locality. A simplified thermal model for the platform suggests that the predominant control of conodont colour alteration and thermal maturation was maximum depth of burial, which occurred during the mid- to late Silurian. A preliminary integrated scheme for conodont and organic thermal maturity indicators can be compiled from the data now available from North Greenland.

Atrypoidea species from the Canadian Arctic islands

1981 ◽  
Vol 18 (10) ◽  
pp. 1539-1561 ◽  
Author(s):  
Brian Jones
Keyword(s):  
New Species ◽  
Morphological Analysis ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Evolutionary Trends ◽  
Arctic Canada ◽  
Separate Species ◽  
Devon Island ◽  
Upper Silurian ◽  
The Relationship

Species of Atrypoidea have the potential of being biostratigraphically useful for the Upper Silurian strata of Arctic Canada. Critical to any biostratigraphic scheme is the relationship between A. phoca (Salter, 1852) and A. scheii (Holtedahl, 1914) since there is disagreement as to whether these species are synonymous, or distinct and stratigraphically separate species. Detailed morphological analysis of topotype A. scheii from Goose Fiord, Ellesmere Island shows that it falls within the range of morphological variation displayed by topotype A. phoca from Cape Riley, Devon Island. Consequently, A. scheii is maintained as a synonym of A. phoca.Other new species that may prove to be biostratigraphically useful include Atrypoidea gigantus n.sp. from an unnamed formation at Goose Fiord and A. netserki n.sp. from member C of the Read Bay Formation on Beechey Island. Atrypoidea gigantus, the largest species of Atrypoidea so far reported from Arctic Canada, is closely related to Atrypoidea foxi (Jones, 1974). Atrypoidea netserki is morphologically closest to A. phoca.Although the Atrypoidea sequences in the Ludlovian and Pridolian strata of Arctic Canada are now better known it is still difficult to delineate exact evolutionary trends, possibly because the various species have a facies- as well as a time-controlled distribution.

New record of the trimerellid brachiopod Gasconsia, a rare Silurian lazarus taxon

2002 ◽  
Vol 76 (1) ◽  
pp. 185-186 ◽  
Author(s):  
Rodney Watkins
Keyword(s):  
New Record ◽  
Upper Ordovician ◽  
The North ◽  
North Side ◽  
Upper Silurian

Gasconsia Northrop, 1939, is a rare trimerellid that appears in the Upper Ordovician (Ashgill) and then reappears in the Upper Silurian (Wenlock/Ludlow) (Hanken and Harper, 1985; Popov and Holmer, 2000). This note is the first documented report of Gasconsia from the type Ludlow of the Welsh Borderland. Gasconsia transversus (Salter) occurs in the Lower Bringewood beds (upper part of Gorstian stage) in a small quarry on the north side of the Holloway to Upper Millichope road, directly opposite the entrance to Millichope Park (grid ref. SO 52748911). The material consists of internal and external molds of one brachial valve and one articulated individual (Fig. 1). This species was described as Obolus Davidsoni var. transversus [Salter MS] by Davidson (1866) from the Wenlock (Homerian stage) of the Dudley and Woolhope areas of the English Midlands and Welsh Borderland. Davidson and King (1874) subsequently referred to it as Dinobolus transversus (Salter), and Cocks (1978), in selecting a lectotype of transversus, retained its assignment to Dinobolus. However, illustrations of transversus in Davidson (1866, pl. 5, figs. 1-6) and Davidson and King (1874, pl. 18, fig. 12) clearly show that it belongs in Gasconsia rather than Dinobolus.

Conodonts from the Cape Clay Formation (Lower Ordovician), southern Devon Island, Arctic Archipelago

1981 ◽  
Vol 18 (10) ◽  
pp. 1609-1628 ◽  
Author(s):  
Ed Landing ◽  
Christopher R. Barnes
Keyword(s):  
Northwest Territories ◽  
New Taxa ◽  
Great Basin ◽  
Canadian Arctic ◽  
Dolomitic Limestone ◽  
Devon Island ◽  
The North ◽  
Lower Ordovician ◽  
Conodont Fauna ◽  
Clay Formation

As part of a program involving the Ordovician conodont faunas of southern Devon Island, Northwest Territories, 22 samples were processed from the Cape Clay Formation and lowest Nadlo Point Formation near Dundas Harbour. The Cape Clay Formation is 85 m thick and composed of bluff-forming mottled limestone and dolomitic limestone. A small but diverse conodont fauna of 229 elements was recovered in which 23 form and multielement species are represented. Several new taxa are described in open nomenclature, and multielement Utahconus? bassleri (Furnish) is discussed. The fauna is considered to represent Fauna C of the North American Midcontinent Faunal Province and is indicative of a late Tremadocian age. This fauna, in a unit with few macrofossils, indicates correlation of the Cape Clay Formation near Dundas Harbour with the upper Turner Cliffs Formation of the Foxe Basin, with the upper Copes Bay and (or) lower Baumann Fiord formations of Cornwallis, northwest Devon, and Ellesmere Islands of the Canadian Arctic, and with some portion of Ross–Hintze trilobite Zones A – lower D of the Great Basin.

Balizoma and the new genera Aegrotocatellus and Perirehaedulus: Encrinurid trilobites from the Douro Formation (Siluiran, Ludlow) of the central Canadian Arctic

1995 ◽  
Vol 69 (4) ◽  
pp. 736-752 ◽  
Author(s):  
Jonathan M. Adrain ◽  
Gregory D. Edgecombe
Keyword(s):  
Type Species ◽  
Canadian Arctic ◽  
The Arctic ◽  
New Genera ◽  
Devon Island ◽  
Cape Phillips Formation ◽  
Somerset Island ◽  
Cornwallis Island

Species of two new genera of Encrinuridae occur in the Ludlow Douro Formation at Goodsir Creek, Cornwallis Island, Gamier Bay, Somerset Island, and Prince Alfred Bay, Devon Island. The encrinurine Aegrotocatellus n. gen. includes four highly autapomorphic species, and is most closely related to Balizoma Holloway, 1980. Separate taxa are recognized at low and high stratigraphic intervals at Goodsir Creek (the type species, Aegrotocatellus jaggeri n. gen. and sp., and Aegrotocatellus n. sp. A, respectively), at Gamier Bay (Aegrotocatellus n. sp. B), and at Prince Alfred Bay (Aegrotocatellus nankerphelgeorum n. gen. and sp.). Perirehaedulus n. gen. is a coronocephaline most closely related to the Chinese upper Llandovery taxon Kailia Chang, 1974. The type species, Perirehaedulus caprus (Thomas in Thomas and Narbonne, 1979) from Goodsir Creek, is distinct from P. richardsi n. gen. and sp. at Garnier Bay. The upper Wenlock–Ludlow range of Balizoma is extended into the Arctic by Balizoma aff. B. variolaris (Brongniart, 1822) from Homerian rocks of the Cape Phillips Formation near Abbott River, Cornwallis Island, and by Balizoma sp., from the late Ludlow Douro Formation at Goodsir Creek.

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