Western North Greenland Research Articles

Lithostratigraphy of the Portfjeld Group (Ediacaran – lowermost Cambrian) of North Greenland

The Portfjeld Formation, as originally defined, is the lowermost lithostratigraphic unit of the mainly Lower Palaeozoic Franklinian Basin in southern Peary Land, central North Greenland. The unit crops out semi-continuously from Valdemar Glückstadt Land to Nordenskiöld Fjord but is also recognised locally in northern parts of Peary Land and Wulff Land (western North Greenland). Regionally, it provides a key record of the early, pre-break-up history of the basin. The type succession in southern Peary Land has thus been the focus of recent biostratigraphical, sedimentological and geochemical study. This has demonstrated the composite nature of the unit, a lower interval (c. 190 m thick) of carbonate ramp deposits of Neoproterozoic (late Ediacaran) age being overlain at a karstic unconformity by a shallow marine, mixed carbonate–siliciclastic interval (c. 100 m thick) of probable earliest Cambrian age. Lithostratigraphic revision of this succession is presented here. The Portfjeld Formation throughout North Greenland is elevated to the rank of group, and two new formations are defined in this group in southern Peary Land and immediately adjacent areas: the Ediacaran carbonate-dominated unit is referred to the Slusen Formation, the upper mixed siliciclastic–carbonate unit to the Glaciologelv Formation.

The Ordovician System in Greenland

Abstract Ordovician strata in Greenland are extensively exposed in North Greenland and northern East Greenland; additional small traces (loose blocks) are recorded from the craton of West Greenland. The western North Greenland succession is nearly identical to that of the Franklinian Basin exposed on Ellesmere Island, Arctic Canada; the eastern North Greenland represents the (present) northeastern corner of Laurentia and provides the connection to the East Greenland Caledonian platform. The northern East Greenland succession is the natural northern extension of the Caledonian platform of northern Europe and the Appalachian platform of eastern North America. During the Ordovician Greenland occupied a palaeogeographical subtropical to tropical position with a faunal assemblage typical of Laurentia. A prominent faunal peak of diversification occurred in the Late Ordovician. The stratigraphical succession of Greenland is summarized and age relationships are discussed with reference to the fossil faunas and breaks in the successions and correlation between the locations and regions are provided.

The karst and palaeokarst of North and North-East Greenland – physical records of cryptic geological intervals

Carbonate rocks of Neoproterozoic to Silurian age are abundantly distributed around the coasts of North and North-East Greenland. Palaeokarst horizons are particularly well developed within the Portfjeld Formation (Ediacaran – earliest Cambrian) and beneath the Buen Formation (Cambrian Series 2), and there are caves within Ordovician limestones infilled by Caledonian molasse of Middle Devonian age. The youngest karst is a series of caves distributed from Hall Land in western North Greenland to Kronprins Christian Land in eastern North Greenland. Caves within Ordovician carbonates in Freuchen Land are currently the northernmost documented karst caves globally. The caves are mainly open phreatic conduits, any fill that is present is unlithified, and cave collapse is limited to minor breakdown associated with frost shattering. These geologically young caves are consistently located up to a few 100 m beneath the distinctive plateau that characterises the topography of the northern coast, and their identical context suggests that they developed in a single phase of speleogenesis. The caves are exposed where the plateau has been incised by outlet glaciers from the Greenland ice sheet. The timing of cave development in North Greenland is constrained by the mid- to late-Miocene (15–5 Ma) uplift of the plateau surface and the onset of fjord-forming glaciation in the latest Pliocene – earliest Pleistocene (c. 2.7–2.5 Ma). The evidence suggests that phreatic caves in the southern part of North-East Greenland, on C. H. Ostenfeld Nunatak, are of a broadly similar age. The caves of North and North-East Greenland offer a glimpse of large-scale phreatic drainage systems that developed below an uplifted coastal peneplain during Neogene time. They preserve an important part of the geological history of North and North-East Greenland that is otherwise absent from the physical geological record.

Holdfasts of Sphenothallus (Cnidaria) from the early Silurian of western North Greenland (Laurentia)

ABSTRACT Well-preserved holdfasts and early growth stages of the tubular cnidarian Sphenothallus are described from the early Silurian (Llandovery Series) of Washington Land, North Greenland. The diameter of the holdfast is determined by the formation of a basal disc attached to the substrate, upon which the initially conical, but subsequently tubular shell is formed. The characteristic opposing longitudinal thickenings are developed at each angular margin as the initially circular tube acquires an elliptical form.

Trilobite fauna of the Telt Bugt Formation (Cambrian Series 2–Miaolingian Series), western North Greenland (Laurentia)

Trilobites dominantly of middle Cambrian (Miaolingian Series, Wuliuan Stage) age are described from the Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland (Laurentia), which is a correlative of the Cape Wood Formation of Inglefield Land and Ellesmere Island, Nunavut. Four biozones are recognised in Daugaard-Jensen Land, representing the Delamaran and Topazan regional stages of the western USA. The basal Plagiura–Poliella Biozone, with Mexicella cf. robusta, Kochiella, Fieldaspis? and Plagiura?, straddles the Cambrian Series 2–Miaolingian Series boundary. It is overlain by the Mexicella mexicana Biozone, recognised for the first time in Greenland, with rare specimens of Caborcella arrojosensis. The Glossopleura walcotti Biozone, with Glossopleura, Clavaspidella and Polypleuraspis, dominates the succession in eastern Daugaard-Jensen Land but is seemingly not represented in the type section in western outcrops, likely reflecting the drastic thinning of the formation towards the north-west. The Ehmaniella Biozone, with Ehmaniella, Clappaspsis, Blainia and Blainiopsis, is the youngest recognised biozone. The presence of Drumian Stage strata reported elsewhere in North Greenland and adjacent Ellesmere Island has not been confirmed in Daugaard-Jensen Land. Lower beds of the Cass Fjord Formation, which directly overlie the Telt Bugt Formation, are assigned to the Guzhangian Stage. New species: Fieldaspis? iubilaei, Ehmaniella tupeqarfik.

Middle Cambrian trilobites (Miaolingian, Ehmaniella Biozone) from the Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland

A small fauna of middle Cambrian trilobites is described from the upper Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland, and the formation is formally defined. Blainiopsis holtedahli and Blainiopsis benthami, originally described from the equivalent Cape Wood Formation of Bache Peninsula, Nunavut, Canada, are documented in an assemblage assigned to the Ehmaniella Biozone (Topazan Stage of North American usage), Miaolingian Series, Wuliuan Stage, of the international standard. Two new species are proposed: Ehmaniella sermersuaqensis and Clappaspis tupeq.

Late Ordovician brachiopods from eastern North Greenland: equatorial offshore migration of the Red River fauna

Abstract: Late Ordovician rhynchonelliformean brachiopods, typical of the North American Red River fauna, are found sporadically in the Børglum River Formation of the Centrum Sø area, Kronprins Christian Land, eastern North Greenland. The geographical distribution of this characteristic brachiopod fauna is thus extended to the easternmost extremity of the Laurentian craton. The assemblage compares specifically with the Hiscobeccus brachiopod fauna, based on key taxa such as notably Hiscobeccus gigas (Wang, 1949), and indicates a late Katian age for this part of the succession. For the first time, this typically inland, shallow‐water fauna is found associated with genera like Bimuria, suggesting a transitional marginal facies with outer shelf benthos. The current study describes a Hiscobeccus fauna that lived at the seaward edge of its preferred habitat. Furthermore, an unpublished Hiscobeccus fauna, from the Børglum River Formation of Peary Land, central North Greenland, as well as several occurrences from the Kap Jackson and Cape Calhoun formations in various parts of Washington Land, western North Greenland, are described here. These show a distinct shift from older strata containing H. capax (Conrad, 1842) to younger strata exclusively yielding specimens of H. gigas. As H. gigas occurs in the upper part of the Cape Calhoun Formation in Washington Land, it indicates that the upper boundary of the Cape Calhoun Formation is considerably younger than previous estimates, reaching into the uppermost Katian (middle Cautleyan–Rawtheyan). The Cape Calhoun Formation correlates with the upper member of the Børglum River Formation and further demonstrates that the Hiscobeccus fauna was widespread in Laurentian marginal settings of North Greenland. Even though the Hiscobeccus fauna was pan‐continental during the late Katian (Richmondian), it possesses a strong provincial signal during the later Ordovician. The new occurrences indicate that this fauna extended to the north‐eastern margin of the Laurentian Craton. It lived in close association with cosmopolitan faunal elements that may have been the earliest sign of the succeeding invasion of migrants from Baltica that arrived later during the Hirnantian. The offshore migration of this atypical Hiscobeccus fauna likely demonstrates the path of warm‐water currents as the Centrum Sø locality was located at the equator during the Late Ordovician.

Late Quaternary history of Washington Land, North Greenland

During the last glacial stage, Washington Land in western North Greenland was probably completely inundated by the Greenland Ice Sheet. The oldest shell dates from raised marine deposits that provide minimum ages for the last deglaciation are 9300 cal. yr BP (northern Washington Land) and 7600 cal. yr BP (SW Washington Land). These dates indicate that Washington Land, which borders the central part of Nares Strait separating Greenland from Ellesmere Island in Canada, did not become free of glacier ice until well into the Holocene. The elevation of the marine limit falls from 110 m a.s.l. in the north to 60 m a.s.l. in the southwest. The recession was followed by readvance of glaciers in the late Holocene, and the youngest shell date from Neoglacial lateral moraines north of Humboldt Gletscher is 600 cal. yr BP. Since the Neoglacial maximum, probably around 100 years ago, glaciers have receded. The Holocene marine assemblages comprise a few southern extralimital records, notably ofChlamys islandicadated to 7300 cal. yr BP. Musk ox and reindeer disappeared from Washington Land recently, perhaps in connection with the cold period that culminated about 100 years ago.

A new volcanic province: evidence from glacial erratics in western North Greenland

Mapping and regional geological studies in northern Greenland were carried out during the project Kane Basin 1999 (see Dawes et al. 2000, this volume). During ore geological studies in Washington Land by one of us (B.T.), finds of erratics of banded iron formation (BIF) directed special attention to the till, glaciofluvial and fluvial sediments. This led to the discovery that in certain parts of Daugaard-Jensen Land and Washington Land volcanic rocks form a common component of the surficial deposits, with particularly colourful, red porphyries catching the eye. The presence of BIF is interesting but not altogether unexpected since BIF erratics have been reported from southern Hall Land just to the north-east (Kelly & Bennike 1992) and such rocks crop out in the Precambrian shield of North-West Greenland to the south (Fig. 1; Dawes 1991). On the other hand, the presence of volcanic erratics was unexpected and stimulated the work reported on here.

Notes on the late Cenozoic history of the Washington Land area, western North Greenland

Information on Late Tertiary and Quaternary deposits in the Washington Land area is extremely limited. This is perhaps surprising since, as a central part of Nares Strait separating Greenland and Canada, the Washington Land area is crucial to the understanding of the much debated Late Quaternary history of the region. Three shell samples, two wood samples and a peat sample, collected in the mid 1970s, have been radiocarbon dated and discussed by Weidick (1977, 1978), Jepsen (1982), Blake (1987) and Bennike & Jepsen (in press); wood samples collected in 1997 were described by Bennike (1998). Much more information is available from Inglefield Land to the south, and Hall Land to the north (Nichols 1969; Dawes 1987; Blake et al. 1992; Kelly & Bennike 1992). Thus, when the opportunity to carry out field work in the Washington Land area arose in connection with the project Kane Basin 1999 (see Dawes 2000a, this volume), the chance was taken to attempt to fill this knowledge gap. The main aim was to locate the source of the wood – hopefully within a sedimentary sequence. In addition, observations and sampling of Quaternary deposits and landforms were planned. However, since the source of the wood proved impossible to locate, more time was spent on Quaternary deposits than originally expected.

Airborne geophysical surveys in central West Greenland and central East Greenland in 1997

In order to stimulate mining exploration activity in Greenland the Government of Greenland decided in 1993 to finance a five-year programme of airborne electromagnetic surveys over selected regions of Greenland, Project AEM Greenland 1994–1998. By the end of 1996 three surveys had been undertaken in various parts of Greenland (Stemp & Thorning 1995a, b; Stemp 1996a, b; Stemp 1997a, b). In 1992 the Danish Government financed a small aeromagnetic survey (Project Aeromag 1992; Thorning 1993). Regional aeromagnetic surveying was taken up again when the governments of Denmark and Greenland jointly financed two aeromagnetic surveys in 1995 and 1996 – the projects Aeromag 1995 and Aeromag 1996 (Thorning & Stemp 1997). To this suite of airborne geophysical surveys of selected regions in Greenland were added two surveys in 1997, both financed by the Government of Greenland. The fourth year of Project AEM Greenland 1994–1998 encompassed a transient electromagnetic (GEOTEM) and magnetic survey over northern Jameson Land, central East Greenland, while Project Aeromag 97 added a regional aeromagnetic survey over Disko Bugt – Nuussuaq, central West Greenland. As in previous years, commercial geophysical contractors carried out the survey operations in Greenland according to an agreement with the Geological Survey of Denmark and Greenland (GEUS) entered into after international tendering following rules of the European Union. GEUS manages the projects and organises the distribution and use of the results. The new maps and digital data from the two 1997 surveys, a total of 85 252 line kilometres of data covering 51 414 km2, were released to the public on 1 March 1998. This note provides some introductory information about the two surveys. Further information can be found in reports by Stemp (1998) and Thorning (in press); both include a number of full-page colour anomaly maps from the survey areas.
 The airborne geophysical programme will continue in 1998, and the areas to be surveyed have already been selected. The final year of Project AEM Greenland 1994–1998 will include combined GEOTEM and magnetic surveys over two regions in North Greenland: Washington Land in western North Greenland, where operations are expected to start in May 1998 operating out of Alert in Canada, and later in the season over J.C. Christensen Land in central North Greenland operating out of Station Nord in eastern North Greenland. Project Aeromag 1998 will continue the regional aeromagnetic survey programme in West Greenland, extending the coverage by including most of the region from 63°45′N to 66°N in southern West Greenland. This project will be based at Nuuk and start in March 1998. The Government of Greenland will finance all surveys in 1998. Figure 1 shows all survey areas for the electromagnetic and magnetic surveys of Project AEM Greenland 1994–1998 and the aeromagnetic survey areas of Project Aeromag 1992, 1995, 1996, 1997 and 1998.

Floristical and ecological characterization of the polar desert zone of Greenland

Abstract. Species composition and biomass of four plant communities were investigated in two coastal polar desert areas in eastern North Greenland, bordering the North East Water Polynya ‐ an ice‐free sea area kept open by upwelling ‐ and compared with inland areas in North Greenland. Herb barren, the poorest type, has a species richness of 6 species/m2, a cover of 0.7 %, and an aboveground biomass of 0.6 g/m2 (vascular plants). The richest type, Saxifraga oppositifolia snowbed, has 10 species/m2, 5.0 % cover, and 11.2 g/m2 biomass.A floristic and vegetation boundary exists a few kilometres from the coast. The coastal areas bordering the North East Water Polynya had an impoverished flora and vegetation compared to areas near the ice‐covered sea, possibly caused by very low summer temperatures and high frequency of clouds.A new delimitation of the polar deserts of Greenland is proposed on the basis of the number of vascular plant species, the occurrence of species with a specific inland distribution in North Greenland and the dominating life forms. At present the polar desert zone includes only areas within a zone up to ca. 15 km from the outer coast of high arctic Greenland ‐ north of ca. 80° N. Large areas formerly classified as polar deserts in eastern North Greenland, as well as in Washington Land in western North Greenland, are excluded. New floristic data confirm that Greenland is correctly included in the Canadian province of the arctic polar deserts, whereas there is no reason for subdividing the polar deserts of the Canadian province.

Petroleum geological investigations in East Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’

The multidisciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). In 1996, the hydrocarbon-related studies focused on the sedimentary basins in East Greenland between latitudes 71°N and 74°N (Fig. 1) where nine field teams worked for six weeks in July and August supported by a Hughes 500 helicopter. Within the framework of the project, additional hydrocarbon-related field studies were undertaken in 1996 in western North Greenland, and ore-geological studies were carried out in much of North Greenland (Kragh et al., 1997; Stemmerik et al., 1997). The 1996 field work in East Greenland concentrated on integrated structural, sedimentological and biostratigraphical studies of the Upper Permian and Mesozoic successions. Two Ph.D. projects focused on the sedimentology of the Lower Triassic Wordie Creek Formation and the diagenesis of the Middle and Upper Jurassic succession. Post-doctorate studies were carried out on the Mesozoic–Tertiary structural development of the basin and the mineralisation of the Upper Permian Ravnefjeld Formation. Three student projects on Lower Triassic and Middle Jurassic ammonite stratigraphy, Upper Permian sedimentology, and fault-associated mineralisation were also included in the work. The most important new results arising from the 1996 field work are: 1) Re-interpretation of the Upper Permian Schuchert Dal Formation as a lowstand turbidite unit within the Ravnefjeld Formation; 2) Recognition of Middle Jurassic deposits and thick lowermost Cretaceous sandstones on Hold with Hope; 3) Interpretation of a full spectrum of scarp-derived coarse-clastic mass movement deposits interbedded with Cretaceous shales on eastern Traill Ø; 4) The presence of a thick sand-rich Cretaceous turbidite succession on eastern Traill Ø; 5) Re-interpretation of the Mesozoic–Cenozoic fault systems on Traill Ø and Geographical Society Ø.

Palaeo-oil field in a Silurian carbonate buildup, Wulff Land, North Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’

The multi-disciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). During the 1996 field season, hydrocarbon-related studies within the project were focused on the sedimentary basins of East Greenland (Stemmerik et al., 1997), while field work in the Franklinian Basin of North Greenland from which the observations reported here derive, was limited to two weeks in early August. The project also includes research related to the ore geology of North Greenland, especially focused on the zinc-lead deposit at Citronen Fjord (Fig. 1). This aspect of the project is covered by Langdahl & Elberling (1997) and Kragh et al. (1997). The work on the Franklinian Basin succession was based at Apollo Sø in eastern Wulff Land (Fig. 1), with the main emphasis on sedimentological and sequence stratigraphic studies of carbonates of the Cambrian portion of the Ryder Gletscher Group and the Silurian Washington Land Group. These two carbonate-dominated shelf successions are equivalent in age to the main source rocks for liquid hydrocarbons in the basin, and have been suggested as potential reservoir units in the conceptual reservoir models proposed for the basin (Christiansen, 1989). Earlier investigations in the region have shown that small occurrences of bitumen are widespread in western North Greenland, although typically closely associated with nearby source rocks (Christiansen et al., 1989a). Notable exceptions are the asphalt seepages in southern Warming Land and southern Wulff Land (Fig. 1); in these cases, long distance migration of the order of 75–100 km is envisaged (Christiansen et al., 1989a). During the 1996 field season, a palaeo-oil field was identified in a carbonate buildup in eastern Wulff Land (Victoria Fjord buildup), thus demonstrating for the first time that Silurian buildups have formed large-scale reservoirs for generated hydrocarbons in the geological past.

An enigmatic cap-shaped fossil from the Middle Cambrian of North Greenland

Nyeboeconus robisoni gen. et sp. nov., is described from the Middle Cambrian Henson Gletscher Formation of western North Greenland. Some authors have interpreted similar shelIs as chondrophorine hydrozoans or invertebrate fossils of uncertain systematic position. The coiled, cap-shaped shell and the presence of an internal plate, or pegma, suggest, however, that this new form is the second genus to be described of the Family Enigmaconidae MacKinnon, 1985 (Mollusca, Class Helcionelloida), otherwise known only from rocks of similar age in New Zealand.

Gordia nodosa isp nov and other trace fossils from the Cass Fjord Formation (Cambrian) of North Greenland

A new ichnospecies, Gordia nodosa isp. nov., is figured and described from member D of the Cass Fjord Formation of Daugaard-Jensen Land, western North Greenland. Strata of Member D are Dresbachian in age and thus the new trace fossil is from the latest Middle Cambrian or earliest Late Cambrian. Two additional stabs from underlying members B and C of the Formation contain, respectively, the ichnotaxa Diplichnites Dawson, 1873, cf. Monocraterion Torell, 1870 and Palaeophycus tubularis, Hall, 1847, and Cruziana problematica (Schindewolf, 1921). These ichnotaxa are figured and described briefly.

A Silurian trilobite fauna dominated by Calymene from Kap Tyson, western North Greenland

The Silurian trilobites described here are referred to 5 genera and 5 species-level taxa of which Calymene iladon is new. The composition of the fauna is unusual for North Greenland in that it is overwhelmingly dominated by specimens of Calymene. Other elements of the fauna are known from other areas of North Greenland, and at least closely related forms of one of them have cosmopolitan distributions.

A composite tectonic–eustatic origin for shelf sandstones at the Cambrian–Ordovician boundary in North Greenland

Shelf sandstones deposited at the Cambrian–Ordovician boundary in central and western North Greenland have a sheet-like large-scale geometry, and extend for over 300 km along strike within a shallow marine, carbonate-dominated, platform sequence. Conodont faunas from units above and below the most extensive sand sheet, the Kap Coppinger Member of the Cass Fjord Formation and the Permin Land Formation, indicate that deposition of the sands spanned the proavus, intermedius and lindstromi conodont biozones. Sand was derived by reworking of older, quartzite-dominated formations following the uplift and unroofing of a platform bulge to the east. During the Cambrian, this sediment was transported northwards from the uplifted area across an unstable platform into a deep-water trough. However, during sea-level lowstands within the Cambrian–Ordovician boundary interval this clastic material was deflected westwards and transported across the stable platform by progradation of tide- and storm-dominated shorelines. Facies sequences in the thickest part of the Permin Land Formation suggest at least three such regressive cycles combined to form a composite sand body. Each regressive cycle comprises a shallowing upward transition from tide- and storm-deposited marine sediments to clean sandstones of marine or terrestrial origin. The cycles are separated by thin but laterally extensive dolomites interpreted to represent drowning events. Thinner sequences further to the east are attributed to reduced accommodation space as a consequence of lower subsidence rates close to the uplifted source area, whilst thin sequences in the west are ascribed to the effect of increasing distance from the sediment source so that only the youngest of the three regressive cycles is present.

Early Ordovician trilobites and molluscs from the Poulsen Cliff Formation, Washington Land, western North Greenland

A well-preserved, shallow water bathyurid trilobite fauna of early Ordovician age, and associated gastropods and an undetermined hyolith are described from the Poulsen Cliff Formation of Washington Land, western North Greenland. Two new bathyurid species, Licnocephala sminue and Pe/tabellia elegans, and a new gastropod species, Plethospira(?) floweri, are described. Biolgina Maximova is considered a junior subjective synonym of Peltabellia Whittington. The distribution of the genus is an example of close relationship between shallow water trilobite faunas of Laurentia and the North-east Siberian platform in the early Ordovician.

The Morris Bugt Group (Middle Ordovician - Silurian) of North Greenland and its correlatives

The Morris Bugt Group, originally proposed in western North Greenland, is now extended across the whole of North Greenland. One new formation, the Kap Jackson Formation, is described; it includes two members, the Gonioceras Bay and Troedsson Cliff Members, which correspond to earlier formations of the same names. In the Washington Land - western Peary Land region the group comprises the Kap Jackson, Cape Calhoun and Aleqatsiaq Fjord Formations. The Børglum River and Turesø Formations of the Peary Land - Kronprins Christian Land region are here added to the group. New data on the age of the formations based on conodont biostratigraphy are given, and correlations with Arctic Canada, East Greenland and Svalbard are discussed.