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

Abstract

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.

Weathering Dynamics Under Contrasting Greenland Ice Sheet Catchments

“…Watson River is composed of two tributaries: Akuliarusiarsuup Kuua (which comprises runoff from Russell Glacier and Leverett Glacier) and Qinnguata Kuussua (receiving runoff from Orkendalen Glacier) (Yde et al, 2014). The bedrock geology of Leverett Glacier and Watson River comprises Archean gneisses and granitoids (van Gool et al, 2002;Henriksen et al, 2009). The "N" Glacier bedrock geology is composed mainly by gabbroanorthosite (Bhatia et al, 2013a).…”

“…We additionally use data from the glacier Kiattuut Sermiat (∼36 km 2 ) (Hawkings et al, 2016) in Southern Greenland. The underlying geology here is composed of granite with complexes of diorite and pyroxene biotite monozonite with basalt intrusions (Henriksen et al, 2009).…”

“…We present data from one small (∼5 km 2 ), one medium (∼36 km 2 ) and one large (∼600 km 2 ) glacial catchment, and from a proglacial river draining several glacier catchments alongside proglacial terrain (∼2800 km 2 ; of which the 600 km 2 glacial catchment is a sub-catchment). The bedrock underlying these catchments is composed of intrusive and metamorphosed Precambrian rocks, representative of >75% of the bedrock underlying the GrIS (Henriksen et al, 2009). These chemical denudation rates are compared with published solute fluxes from Alpine glaciers (Hodson et al, 2000;Wadham et al, 2000;Anderson, 2007), non-glacial catchments (Huh and Edmond, 1999) and major world rivers (Meybeck and Ragu, 2012), to elucidate the potential importance of ice sheet catchments in global chemical weathering.…”

Age of Tertiary volcanic rocks on the West Greenland continental margin: volcanic evolution and event correlation to other parts of the North Atlantic Igneous Province

“…2) comprise up to 6–8 km of Cretaceous to Paleocene fluvio-deltaic to marine sandstones and shales of the Nuussuaq Group (Dam et al 2009). The Nuussuaq Group is overlain by a thick volcanic succession with relatively thin intervals of intra-volcanic sediments (Henderson, Rosenkrantz & Schiener, 1976; Henderson et al 1981; Clarke & Pedersen, 1976; see overview by Henriksen et al 2009). The thickness of the volcanic succession is greatest on Ubekendt Ejland where up to 10 km of volcanic rocks may be present (Larsen, 1977 a ); on Svartenhuk Halvø there is up to c. 7 km of succession present (Larsen & Pulvertaft, 2000) although intense faulting may have caused undetected repetitions in the stratigraphy; and on Disko and Nuussuaq thicknesses are up to more than 5 km (Larsen & Pedersen, 2009).…”

Paleofluvial landscape inheritance for Jakobshavn Isbræ catchment, Greenland

“…The geological setting and glacial history of Greenland yield conditions amenable to the long‐term conservation of subglacial landscapes. The island is dominated by Precambrian crystalline, gneissic shield rocks with limited sedimentary deposits [ Henriksen , ; Henriksen et al , ], and has only been extensively ice covered for about the last 3.5 million years (Ma) [ Kleiven et al , ; Alley et al , ]. To date, most analysis of subglacial geomorphology, and basal landscape origin, has been focused on Antarctica (e.g., the “Ellsworth Subglacial Highlands” [ Ross et al , ] and “preglacial erosional (planation) surfaces” of the West Antarctic Ice Sheet [ Rose et al , ]), with little focus on such associations in Greenland.…”