Early Devonian vertebrates from Hall Land, North Greenland

Bendix-Almgreen, Svend Erik; Peel, J.S

doi:10.34194/rapggu.v65.7377

Cited by 2 publications

(2 citation statements)

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“…Silurian(Pridoli) to Early Devonian age(Bendix-Almgreen & Peel 1974;Blom 1999). In Ellesmere Island this phase of turbidite deposition persisted into the Lower Devonian; farther to the west in the Canadian Arctic Islands clastic sedimentation associated with the advance of Ellesmerian deformation continued through the Devonian into the earliest Carboniferous.…”

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confidence: 99%

Greenland from Archaean to Quaternary. Descriptive text to the 1995 Geological map of Greenland, 1:2 500 000. 2nd edition

et al. 2009

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The geological development of Greenland spans a period of nearly 4 Ga, from Eoarchaean to the Quaternary. Greenland is the largest island on Earth with a total area of 2 166 000 km2, but only c. 410 000 km2 are exposed bedrock, the remaining part being covered by a major ice sheet (the Inland Ice) reaching over 3 km in thickness. The adjacent offshore areas underlain by continental crust have an area of c. 825 000 km2. Greenland is dominated by crystalline rocks of the Precambrian shield, which formed during a succession of Archaean and Palaeoproterozoic orogenic events and stabilised as a part of the Laurentian shield about 1600 Ma ago. The shield area can be divided into three distinct types of basement provinces: (1) Archaean rocks (3200–2600 Ma old, with local older units up to> 3800 Ma) that were almost unaffected by Proterozoic or later orogenic activity; (2) Archaean terrains reworked during the Palaeoproterozoic around 1900–1750 Ma ago; and (3) terrains mainly composed of juvenile Palaeoproterozoic rocks (2000–1750 Ma in age). Subsequent geological developments mainly took place along the margins of the shield. During the Proterozoic and throughout the Phanerozoic major sedimentary basins formed, notably in North and North-East Greenland, in which sedimentary successions locally reaching 18 km in thickness were deposited. Palaeozoic orogenic activity affected parts of these successions in the Ellesmerian fold belt of North Greenland and the East Greenland Caledonides; the latter also incorporates reworked Precambrian crystalline basement complexes. Late Palaeozoic and Mesozoic sedimentary basins developed along the continent–ocean margins in North, East and West Greenland and are now preserved both onshore and offshore. Their development was closely related to continental break-up with formation of rift basins. Initial rifting in East Greenland in latest Devonian to earliest Carboniferous time and succeeding phases culminated with the opening of the North Atlantic Ocean in the late Paleocene. Sea-floor spreading was accompanied by extrusion of Palaeogene (early Tertiary) plateau basalts in both central West and central–southern East Greenland. During the Quaternary Greenland was almost completely covered by ice, and the present day Inland Ice is a relic from the Pleistocene ice ages. Vast amounts of glacially eroded detritus were deposited on the continental shelves around Greenland. Mineral exploitation in Greenland has so far encompassed cryolite, lead-zinc, gold, olivine and coal. Current prospecting activities in Greenland are concentrated on gold, base metals, platinum group elements, molybdenum, iron ore, diamonds and lead-zinc. Hydrocarbon potential is confined to the major Phanerozoic sedimentary basins, notably the large basins offshore North-East and West Greenland. While reserves of oil or gas have yet to be found, geophysical data combined with discoveries of oil seeps onshore have revealed a considerable potential for offshore oil and gas.

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Greenland from Archaean to Quaternary. Descriptive text to the 1995 Geological map of Greenland, 1:2 500 000. 2nd edition

et al. 2009

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“…According to , the Remigolepis Group forms part of the Mount Celsius Supergroup and comprises the Aina Dai, Wiman Bjerg and Britta Dai Formations. Of these, the Aina Dai and Britta Dai Formations are richly fossiliferous, yielding the tetrapods lchthyostega and Acamhostega and fishes such as the osteolepi-Meddelelser om GrS<Jnland, Geoscience 31 • 1994 form Eusthenodon, the porolepiform Holoptychius, the dipnoan Soederberghia and the placoderm Remigolepis (Bendix-Almgreen 1976). Associated with the Acanthostega material collected in 1987 were a small number of ctenacanth shark spines (J.…”

Section: Geological Setting Palaeoenvironment and Palaeoecologymentioning

confidence: 99%

Acanthostega gunnari, a Devonian tetrapod from Greenland; the snout, palate and ventral parts of the braincase, with a discussion of their significance

Clack

1994

Meddr Grønland. Geosci.

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The snout, including the naris and choana, and the palate, ventral parts of the brain case and suspensorium of Acanthostega gunnari are described from three-dimensional specimens and sections. The naris is low on the snout, and the choana and vomerine dentition resemble those of osteolepiform fishes. The braincase is ossified in two portions in ventral view, with the ventral cranial fissure still evident. Dorsally, however, the otic region and sphenethmoid are co-ossified, so there was no movement possible between them. The palate is "closed" as in osteolepi forms and primitive tetrapods, and the parasphenoid is grooved as in some osteolepiforms. It is argued that the low naris and divided braincase represent the primitive condition for tetrapods, and that the condition of the naris and choana most closely resemble those of panderichthyid fishes among sarcopterygians.

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Early Devonian vertebrates from Hall Land, North Greenland

Cited by 2 publications

References 5 publications

Greenland from Archaean to Quaternary. Descriptive text to the 1995 Geological map of Greenland, 1:2 500 000. 2nd edition

Greenland from Archaean to Quaternary. Descriptive text to the 1995 Geological map of Greenland, 1:2 500 000. 2nd edition

Acanthostega gunnari, a Devonian tetrapod from Greenland; the snout, palate and ventral parts of the braincase, with a discussion of their significance

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