Geological Survey of Denmark and Greenland Bulletin 19 ... - Geus

More documents

Recommendations

Info

Illukunnguaq Ujarasussuk Nuugaarsuk Akunneq Sullorsuaq Vaigat Q E Q E R T A R S U A Q Inngigissoq Pingu D I S K O 69°45’ Sorte Hak Storbræen Frederik Lange Dal Sullorsuaq Kvandalen Aqajaruata Qaqqaa Aqajarua Mudderbugten Daugaard-Jensen Dal Sermersuaq Laksedalen Killussaatsut Kuuat Blåbærdalen K uk Qaamasoq Akuliarutsip Qaqqaa Skorstensfjeldet Gule Ryg Flakkerhuk t 69°30’ Killussaatsut Quaternary cover Maligât Formation Siniffik Kuuk Qaamasoq Tuapaat Qaqqaat Marraat Nuuk Killuusat Innanguit Illunnguaq Tuapaat Aamaruutissat Skansen Innaarsuit Skansen Intrusion Atanikerluk Formation Sandstone Atanikerluk Formation Mudstone Atane Formation Skansen Member Ice Sea/lake Assoq Niuluut 53° 5 km 52°30’ 500 Contour in metres 52° Fig. 124. Geological map showing the distribution of the Atane and Atanikerluk Formations on eastern Disko, simplified from A.K. Pedersen et al. (2001). Note that the outcrops of the Atanikerluk Formation are discontinuous. Contour interval is 200 m. For location, see Fig. 2. 140
In detail, however, the boundary between the Atanikerluk Formation and the volcanic formations can be complex, hyaloclastite breccias and invasive lavas interdigitating with the sedimentary succession. These sediments, interstratified locally with the lowermost volcanic layers, are intimately associated with the uppermost Nuussuaq Group strata and are thus referred to the Atanikerluk Formation where demonstrably related to an interdigitating volcanic–sediment facies front (Figs 17, 131). Two new formations, the Quikavsak Formation and the Atanikerluk Formation, replace the ‘Upper Atani kerd - luk Formation’ of Nordenskiöld (1871), Troelsen (1956) and Koch (1959). The term ‘Upper Atanikerdluk For - mation’ dates back to Nordenskiöld (1871), who used this name for the beds (Öfre Atanekerdluklagren) containing the upper flora in the Atanikerluk area. The plant fossils occur in concretions that are dark grey on fresh surfaces but weather to a dark red colour (Nordenskiöld 1871 pp. 1051–52). Koch (1959) reported that these concretions contain the Upper Atanikerdluk A flora of Heer (1883a, b) and that they occur in his Quikavsak Member, i.e. the Quikavsak Formation of the present paper. The name Atanikerluk Formation is proposed because it does not imply the existence of a ‘Lower Atanikerd luk Formation’. Although a Lower Atanikerdluk Flora was mentioned by Heer (1868), this originated from the Atane Formation as recognised as early as 1871 by Nordenskiöld. Koch (1959) subdivided the Upper Atanikerdluk Formation into five members on Nuussuaq (Fig. 123) but attempted no subdivision of the formation on Disko. His Quikavsak Member is here established as the Qui - kavsak Formation. Two of Koch’s members on Nuus - suaq are retained (the Naujât and Umiussat Members), whereas the Aussivik and Point 976 Members are abandoned and the sediments are referred to the new Assoq Member. The reason for this is that the Aussivik and Point 976 Members are only found in a very small area of south-eastern Nuussuaq (A.K. Pedersen et al. 2007b). On Disko, a subdivision into five members is proposed (the Naujât, Akunneq, Pingu, Umiussat, and Assoq Mem - bers; Fig. 123). The subdivision of the Atanikerluk Formation into five members reflects the dramatic palaeogeographic changes that accompanied the intense volcanic activity. Name. The formation is named after the Atanikerluk peninsula formed by a sill on the south coast of Nuussuaq (Fig. 40). The name was formerly spelled Atanekerdluk or Atanikerdluk. Distribution. The Atanikerluk Formation is known on south-east Nuussuaq (Saqqaqdalen, Atanikerluk, Kingit - toq, Paatuut, and Ataata Kuua), on central Nuussuaq (Nassaat and locally in Aaffarsuaq), on eastern Disko (Assoq, Tuapaat Qaqqaat, Gule Ryg, Pingu, Nuugaarsuk, Frederik Lange Dal) and central Disko (Daugaard Jensen Dal and Sorte Hak; Figs 2, 40, 124). In the Atanikerluk area, the formation was mapped in great detail by Koch & Pedersen (1960). Paleocene siliciclastic sediments are also present on Svartenhuk Halvø, where they are overlain by the volcanic Vaigat and Svartenhuk Formations (J.G. Larsen, personal communication 2008). These sediments remain unstudied in detail and the distribution of marine pre-volcanic, marine synvolcanic and nonmarine synvolcanic deposits is not known at present. In the future, Paleocene non-marine, synvolcanic sediments on Svartenhuk Halvø may be established as one or more members within the Atanikerluk Formation. Type section. The section in the south-facing slope between Atanikerluk and Tartunaq on south-east Nuussuaq is retained as the type section (Figs 125, 126) for the Atanikerluk Formation. This was described in detail by Koch (1959), who defined type sections for several members of the formation in this area. The type section is located at 70° 03.63´N, 52°13.53´W. Reference sections. Reference sections of the Atanikerluk Formation are found at Kingittoq, at Pingu and in the Tuapaat area (Figs 7, 132, 140). The stratigraphic succession in north-east Disko has been compiled from the (mainly sedimentary) sections on both sides of Akunneq and the volcanic succession at Aqajaruata Qaqqaa, south of Akunneq (A.K. Pedersen et al. 2005) (Figs 124, 131). Thickness. The Atanikerluk Formation is up to 500 m thick in a composite section, but individual outcrops reach thicknesses of c. 400 m (Pingu), c. 300 m (Kingittoq, Atanikerluk) and 200–250 m (Saqqaqdalen) (Figs 126, 128). At Tuapaat Qaqqaat, the thickness is difficult to measure due to landslides and interbedding of sediments and invasive lava flows (Fig. 140). Invasive lava flows are discussed below under ‘Lithology’. Lithology. The Atanikerluk Formation comprises mudstones, heterolithic sandstones, and fine-grained, loosely cemented sandstones. Mudstones are dominant in the Naujât and Pingu Members (Fig. 127) and in the lower part of the Assoq Member, whereas very friable sandstones characterise the Akunneq and Umiussat Members and the upper part of the Assoq Member. On a regional 141
Page 1 and 2:
GEOLOGICAL SURVEY OF DENMARK AND GR
Page 4 and 5:
Contents Abstract . . . . . . . . .
Page 7 and 8:
Preface The onshore Cretaceous-Pale
Page 9 and 10:
Introduction The Nuussuaq Basin bel
Page 11 and 12:
chemistry of the Nuussuaq Basin hav
Page 13 and 14:
Fig. 5. Plant fossils from the Atan
Page 15 and 16:
Peak 2010 m Peak 1900 m Peak 1760 m
Page 17 and 18:
A lithostratigraphy for the marine
Page 19 and 20:
to provide further funding for stud
Page 21 and 22:
DGR Geological setting As a result
Page 23 and 24:
TSS 8 Agatdal Fm Eqalulik Fm Kangil
Page 25 and 26:
A Svartenhuk Halvø 50 km B Hinterl
Page 27 and 28:
Nuussuaq Group new group History. T
Page 29 and 30:
ley (Figs 2, 40, 65). The section a
Page 31 and 32:
Central Nuussuaq Agatdalen South co
Page 33 and 34:
3 10 4 6 5 Qorlortorssuaq Slibesten
Page 35 and 36:
volcanic sediments are referred to
Page 37 and 38:
Fig. 20. View from Uummannaq toward
Page 39 and 40:
In the Kuuk area, the sediments ove
Page 41 and 42:
m m 15 14 14 13 12 11 10 9 8 7 6 5
Page 43 and 44:
Kome Formation m 40 30 20 D tial re
Page 45 and 46:
Fig. 28. Reference locality of the
Page 47 and 48:
Vaigat Fm Vesterfjeld Slibestensfje
Page 49 and 50:
Gilbert delta in the Ikorfat area (
Page 51 and 52:
150 300 450 100 250 400 m 550 50 20
Page 53 and 54:
Fig. 36. Outcrop of the Upernivik N
Page 55 and 56:
Correlation. The Upernivik Næs flo
Page 57 and 58:
12’ 09’ 15’ 06’ 03’ Saqqa
Page 59 and 60:
m 0 GGU 247801 200 400 247815 ★
Page 61 and 62:
wave-rippled sand streaked mudstone
Page 63 and 64:
the formation in the marine mudston
Page 65 and 66:
d d Fig. 47. Type locality of the S
Page 67 and 68:
Fig. 49. Cross-bedded medium- to co
Page 69 and 70:
and Qaarsut (Fig. 22). Its wider di
Page 71 and 72:
Fig. 52. Two closely spaced section
Page 73 and 74:
Type section. The type section of t
Page 75 and 76:
Fig. 56. Delta front succession of
Page 77 and 78:
Fig. 59. The Kingittoq Member at Ki
Page 79 and 80:
sh L sh ch delta front Vaigat Forma
Page 81 and 82:
Fig. 63. Type locality of the Itivn
Page 83 and 84:
782 Quaternary cover 54° 888 Malig
Page 85 and 86:
Kuugannguaq-Qunnilik Fault and is o
Page 87 and 88:
and include clasts of intraformatio
Page 89 and 90: deposited in a base-of-slope and ba
Page 91 and 92: VK 53°30’ 53°15’ Niaqornat Tu
Page 93 and 94: Umiivik-1 m Overburden ★ ★ No p
Page 95 and 96: 76). Heavily bioturbated interbedde
Page 97 and 98: Fig. 78. Type locality of the Kussi
Page 99 and 100: A B Itilli Formation Kussinerujuk M
Page 101 and 102: 160 140 120 100 Vaigat Formation Eq
Page 103 and 104: Fig. 85. Mudstones and conglomerati
Page 105 and 106: Fig. 87. Type section of the Kangil
Page 107 and 108: m 150 140 130 120 110 100 90 Kangil
Page 109 and 110: channellised, high-density currents
Page 111 and 112: Thickness. The Annertuneq Conglomer
Page 113 and 114: Fig. 96. A: Type locality of the Oy
Page 115 and 116: On Svartenhuk Halvø, on the east s
Page 117 and 118: Fig. 100. Reference locality of the
Page 119 and 120: Tupaasat Member Atane Formation Fig
Page 121 and 122: ever, have a fluvio-lacustrine orig
Page 123 and 124: etween Tupaasat and Nuuk Qiterleq a
Page 125 and 126: Vaigat Formation sill Quikavsak For
Page 127 and 128: Fig. 112. The sharp boundary betwee
Page 129 and 130: Agatdal Formation Eqalulik Formatio
Page 131 and 132: Fig. 116. Basal conglomerate unit o
Page 133 and 134: heterolithic deposits of the Kangil
Page 135 and 136: GANE#1 Vaigat Fm Anaanaa Mb m Hyalo
Page 137 and 138: Fig. 121. Well reference section of
Page 139: Pedersen 1978). The beds are usuall
Page 143 and 144: Fig. 126. Composite type section of
Page 145 and 146: m m 240 340 m Pingu Member 230 230
Page 147 and 148: Naujât Member Atane Formation, Kin
Page 149 and 150: The TOC [Total Organic Carbon] cont
Page 151 and 152: Fig. 133. Correlation of the member
Page 153 and 154: Fig. 135. Type locality of the Ping
Page 155 and 156: Fig. 137. Lower, sharp boundary of
Page 157 and 158: m 130 125 110 t t invasive lava low
Page 159 and 160: Fig. 141. Upper part of the Assoq M
Page 161 and 162: Brown, R. 1875: Geological notes on
Page 163 and 164: a rosetted spreite trace fossil: Da
Page 165 and 166: ing bark from the Nûgssuaq peninsu
Page 167 and 168: 1998: The syn-volcanic Naajaat lake
Page 169 and 170: Appendix: Place names and localitie
Page 171: Place name Place name P Paatuut sou
show all

Geological Survey of Denmark and Greenland Bulletin 19 ... - Geus

Create successful ePaper yourself

Delete template?

Save as template?