Quaternary geology of western and central North Greenland GEUS Report file no. 22490 M. Kelly and O. Bennike GRØNLANDS GEOLOGISKE UNDERSØGELSE Rapport 153 1992 GRØNLANDS GEOLOGISKE UNDERSØGELSE RAPPORT 153 Quaternary geology of western and central Q~ North Greenland ~ ~() Michael Kelly and Ole Bennike 1992 Kelly, M. & Bennike, O. 1992: Quaternary geology of Reworked marine fossils in glacial sediments define the western and central North Greenland. Rapp. Grønlands Hall Land marine event of Eemian and/or Early Weich­ geol. Unders. 153,34 pp. selian age. The Late Weichselian/Holocene marine event (Nyeboe Land event) is abundantly represented The earliest Quaternary event represented is the Kap by deposits whose distribution shows that the limit of Bryant glacial stade of probable Saalian age, in which transgression varied over the area, with a maximum at an ice sheet covered the area out to the shelf. In con­ about 125 m above sea level. Regression from this limit trast, in the Late Weichselian Kap Fulford stade, the occurred during the Holocene, initially at a slow rate. area was only partly glaciated, with outlet lobes from an The fossil biota are described from the marine sedi­ ice sheet occupying the outer fjords. There is some ments and from a small number of terrestrial occur­ evidence of an earlier (Early Weichselian?) slightly renees. more extensive glaciation (Kap Sumner stade). In the early Holocene, the ice margin had retreated to the Authors' addresses: middle regions of the fjords and extensive glaciallakes M. K., Division of Environmental Sciences, Lancaster were forrned in intervening areas. The Late Holocene University, Lancaster LAl 4YQ, U.K. Steensby stade produced a readvanee of the ice sheet at O. B., Geological Museum, øster Voldgade 5-7, the head of the fjords and the growth of local ice caps. DK-1350 Copenhagen K, Denmark. Dansk sammendrag Det ældste Kvartær er repræsenteret ved Kap Bryant lokale iskapper. Omlejrede marine fossiler i smelt­ glaciale stadium, sandsynligvis af saale alder, hvorunder evandssedimenter angiver alderen af den marine trans­ isen dækkede området ud til shelfen. Under Kap Ful­ gression i Hall Land til at være Eem og/eller tidlig ford-stadiet i sen Weichsel var området derimod kun Weichsel. Den marine transgression i sen Weichsel/Ho­ delvist gletscherdækket med udløbere fra et isdække, locæn (Nyeboe Land-transgressionen) er velrepræsente• som omfattede de ydre fjorde. Der er visse tegn på en ret i form af aflejringer, hvis fordeling viser, at grænsen tidligere (tidlig Weichsel?), mere udbredt gletscher­ for transgressionen i området var underkastet varia­ dækning (Kap Sumner-stadiet). I tidlig Holocæn havde tioner med et maksimum på 125 m over havniveau. isranden trukket sig tilbage til den midterste del af Regressionen fra denne grænse foregik i Holocæn ­ fjordene, og store smeltevandssøer dannedes i de mel­ initialt med en lille hævningsrate. Fossilfaunaen er be­ lemliggende områder. Under Steensby-stadiet i sen Ho­ skrevet på grundlag af marine sedimenter og et lille locæn indtraf atter et fremstød af Indlandsisens rand i antal terrestriske forekomster. den inderste del fjordene, og der foregik en vækst af de Imaqarnersiuineq Kvartærip aallartinnerata nalaa, tassa Nunarsuup in­ Steensbymik taaguutillip naiaani kangerlunni qinngor­ gerlaasiani immikkoortoq maanna atuuttoq, qularnann­ linni Sermersuup killinga avasilleqqissimavoq, sermer­ gitsumik saalip naiaani Kap Bryantimi sermersuaqarne­ suaqarfiillu immikkoortut arlallit pinngorsimallutik. Im­ ranik immikkoortinneqarsinnaavoq. Tamatumalu na­ map uumasui ujaranngorsimasut, serrnip aannerata na­ laani sermersuup nunarput ikkannersuit tikillugit laani kinnganernut pinngortunut akulerussimasut matusimavaa. Weishelip naalernerani Kap Fulfordip na­ ersersippaat, Hall Landimi immap killingata qaffannera laani, tassa kingullermik sermersuaqarnerata naiaani, Eemip aammalu/imaluunniit Weichelip aallartinnerata nuna tamassuma ilaanna sermersuup matusimasimava; naiaani pisimasoq. Weichelip naalernerani/Holocæni• kangerluillu avalliit sermeqarfiusumit ningimaneqarfiu­ milu immap killingata qaffannera (Nyeboe Landip qaf­ simallutik. Arlalitsigut siusinnerusumik (Weichelip aal­ fanneranik taaguutillip) annertunerpaamik 125 meterit lartinnerani?) suli annertunerusumik sermersuaqarsi­ tikillugit tamaani allanngorarsimasoq nunami kinngane­ maneianik (Kap Sumnerip naiaani) takussutissaqarpoq. rit kiviorarsimasut ersersippaat. Immap killingata appa­ Holocænip aallartinnerani serrnip killinga kangerluit riarnera Holocænip naiaani arriitsumik pisimavoq. Taa­ qeqqa tikillugu aassimavoq, tamakkulu akornanni ta­ manilu uumasuusimasut ujaranngorsimasut imaani sersuarpassuit serrnip aannerata kinguneranik pinngor­ kinnganernit nunallu qaani qaleriissunit siumorneqarsi­ simapput. Holocænip naalernerani, immikkoortup mapput. Contents Dansk sammendrag - Imaqarnersiuineq ......... 2 Warming Land stade (Early Holocene). ....... 17 Introduction ................................. 5 Steensby stade (Late Holocene). ........... .. 20 Bedrock geology and physiography ........... 5 Alternative stratigraphic models. ........... .. 21 Previous work 5 Reconstructed ice margins and profiles...... .. 23 Methods 8 History and environmental evidence of biota .... 24 Stratigraphy ................................. 9 Pre-Holocene marine'biota ................ .. 24 Kap Bryant stade (Saalian?) ................. 9 Holocene marine biota. ................... .. 24 Hall Land marine event (Eemian - Early Weich- Holocene driftwood ....... .. 25 selian?) ................................ .. 11 Pre-Holocene terrestrial biota. ............. .. 25 Kap Sumner stade (Early Weichselian?). .... .. 11 Holocene terrestrial biota ................. .. 25 Non-glacial terrestrial facies (Weichselian). .. .. 12 Regional correlation ........................ .. 28 Kap Fulford stade (Late Weichselian). ...... .. 12 Acknowledgements ......................... .. 30 Nyeboe Land marine event (end Weichselian - References ................................ .. 30 Holocene) ... .......................... .. 14 Distribution and marine limit. ............. 14 Sea level change and emergence 16 Grønlands Geologiske Undersøgelse Ujarassiortut Kalaallit Nunaanni Misissuisoqarfiat Geological Survey of Greenland The Geological Survey of Greenland (GGU) is a research institute affiliated to the Mineral Resources Administration for Greenland (MRA) within the Danish Ministry of Energy. As with all other activities involving the non-living resources in Greenland, GGU's investigations are carried out within the frarne­ work of the policies decided jointly by the Greenland Home Rule Authority and the Danish State. © GGU, Copenhagen, 1992 ISSN 0418-6559 ar western and 81° N central Nonh G reenland.. Introduetion In 1984 a reconnaissance survey of the Quaternary 1981), indicating the existence of rocks of this age be­ geology of a large part of western and central North neath the ice to the south. Greenland (Fig. 1) was carried out as part of the North Northward flowing outIet glaciers from the Green­ Greenland Project of the Geological Survey of Green­ land ice sheet (Inland Ice) oecupy the inner parts of all land. A preliminary account of some of the results has the major fjords. They are relatively active with surface been published in Kelly & Bennike (1985) and Bennike velocities of 300-900 m/a (Higgins, 1988) and, charac­ & Kelly (1987). teristically, have large thin and partially disjointed ter­ minal zones, due to inhibition of ealf ice production by Bedrock geology and physiography the sea-ice, which is semi-permanent in the fjords, but not in Nares Strait (Koch, 1928a). Local iee caps are The area, stretching from Hall Land in the west to common on the higher ground throughout the area, Nansen Land in the east, forms a strip of land 375 km some in the east having small outIet glaciers whieh reach long by 100-150 km wide between the Arctic Ocean and the sea. The largest ice caps are the Hans Tavsen Is­ the Greenland ice sheet. Northerly trending steep-sided kappe and the ice cap which almost entirely covers fjords divide it into a number of peninsulas and large Freuchen Land, both in the north-east of the region. islands. The major bedrock stratigraphic units strike approximately E-W (Henriksen, 1987), resulting in a Previous work N-S eontrast in the bedrock related topography along the peninsulas. Because of the remoteness and inaccessibility of the The northern parts of the peninsulas west of Nansen region, the study of its Quaternary geology has been Land consist of folded Silurian trough facies turbidites sporadic, although it has a long history. The first expe­ and mudstones with lesser amounts of Cambro-Ordo­ dition to Hall Land, by the United States North Polar vician deep water silieic1astic rocks. The topography of Expedition of 1871-1873, described the presence of these areas is mainly gentIy rounded hills and plateaux raised marine and littoral deposits with shelIs and drift­ around 200-400 maltitude, with a northern zone of wood, as well as the occurrence of erratics (Bessels, higher hills around 600-1000 m above sea level. Rivers 1879). The erratics, however, were interpreted as the flowing to the north across this zone tend to have deeply products of rafting by icebergs or sea-ice (Bessels, 1879; incised sections cut in the floor of broader U-shaped Feilden, 1895). Subsequent investigations have contin­ valleys. Broad lowland areas stretch across the middle ued to concentrate on the more accessibIe