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

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Paatuut 1 Qullissat Giesecke M. Inussuk Kingittoq 2 Fjeld 3 Atanikerluk 4 53°W Vaigat Fm Maligât Fm upper Rinks Dal Mb Akuarut unit Skarvefjeld unit lower Rinks Dal Mb Ordlingassoq Mb Naujánguit Mb Subaerial surface Condensed section Condensed section Naujât Mb Assoq Mb Umiussat Mb Naujât Mb Atanikerluk Formation Hareøen 70°N Nuussuaq 1 3 2 4 Disko 10 9 11 8 7 6 5 50 km Anaanaa Mb Eqalulik Fm Skarvefjeld 5 Assoq Marraat 6 Tuapaat 7 Peak 1123 m 8 Fr. Langes Dal 9 Ingigissoq 10 Pingu 11 Vaigat Fm Maligât Fm upper Rinks Dal Mb Akuarut unit Skarvefjeld unit lower Rinks Dal Mb Ordlingassoq Mb 60.7±0.4 60.9±0.4 61.1±0.5 60.7±1.0 Naujánguit Mb 60.8±0.5 Assoq Mb Assoq Mb Umiussat Mb Pingu Mb Akunneq Mb Atanikerluk Formation Anaanaa Mb Subaerial lava flow Subaqueous lava flow Hyaloclastite breccia Entablature zone Columnar jointing Sandstone Lacustrine mudstone Marine mudstone Conglomerate Coal Marine dinoflagellate Fig. 131. Simplified stratigraphic sections showing the relationships between the volcanic rocks (colour coded) of the Vaigat and Maligât Formations (West Greenland Basalt Group) and the Atanikerluk Formation. The upper boundary of the Assoq Member is indicated (dashed line). The invasive, subaqueous lavas are all assigned to the Maligât Formation. The radiometric ages are recalculated from Storey et al. (1998). 148
The TOC [Total Organic Carbon] content is high (up to 11%) and C/S ratios are high (G.K. Pedersen et al. 1998). Perregaard & Schiener (1979) noted that the organic matter is immature, consisting of exinite (c. 50%), vitrinite (c. 35%) and inertinite (c. 15%), and that it is chemically dominated by saturated and aromatic hydrocarbons. A study of palynofacies indicates a predominance of brown and black lignite (Hjortkjær 1991). Fossils. The Naujât Member has yielded well-preserved macroplant fossils, the Upper Atanikerdluk flora A and B of Heer (1883a, b; Koch 1959, 1963). Leaves from deciduous trees are an important constituent in the flora which includes: Cladophlebis groenlandica, Metasequoia occidentalis, Cercidiphyllum arcticum, Dicotylophyllum bellum, Dicotylophyllum Steenstrupianum, Macclintokia Kanei, Macclintockia Lyalli and Credneria spectabilis (Koch 1963). The assemblage of spores and pollen in the Naujât Member was studied by Hjortkjær (1991). The flora is dominated by palynomorphs of terrestrial origin, whereas remains of lacustrine plants and algae are rare. Pollen of Taxodium spp. are abundant. The stratigraphically important mid-Paleocene species Momipites actinus and Caryapollenites wodehouseia are present in this member. Depositional environment. The Naujât Member is interpreted as a succession of lacustrine mudstones (Koch 1959; Schiener & Leythaeuser, 1978; G.K. Pedersen et al. 1998). The lake formed through damming by the volcanic rocks of the Ordlingassoq Member, and it was filled simultaneously by hyaloclastite breccias from the west and siliciclastic mud from the east and south-east (G.K. Pedersen et al. 1998). The abundance of kaolinite among the clay minerals suggests that these have the same provenance as the mudstones of the Cretaceous Atane Formation, probably areas of deeply weathered crystalline rocks east of the basin boundary fault. Boundaries. The lower boundary of the Naujât Member corresponds to the lower boundary of the Atanikerluk Formation in the area where the Naujât Member occurs (Figs 126, 129, 130). Mapping of the lower boundary is difficult in the Paatuut and Ataata Kuua areas where the member overlies marine mudstones of the Eqalulik Formation. In this area, the Naujât Member is also interbedded with the toesets of hyaloclastite breccias of the Ordlingassoq Member (Fig. 17, locality 5). The upper boundary of the Naujât Member is everywhere towards either the Umiussat Member or the Ordlingassoq Member of the Vaigat Formation (Fig. 136). Geological age. Within the resolution of the dating methods, the age of the Naujât Member lies within the age range of the Atanikerluk Formation (i.e. early to mid- Paleocene, see p. 146). Correlation. The Naujât Member is coeval with the volcanic breccias of the Ordlingassoq Member; both members overlie the same lacustrine flooding surface (A.K. Pedersen et al. 1993; G.K. Pedersen et al. 1998). The lacustrine Naujât Member on Nuussuaq correlates with the fluvial Akunneq Member on north-eastern Disko. The palynomorph assemblages of the Naujât, Akunneq and Pingu Members are similar, and the upper part of the Naujât Member correlates with the Pingu Member (Figs 123, 131). Akunneq Member new member History. The sediments now referred to the Akunneq Member were formerly referred to the Upper Atanikerdluk Formation (Koch 1964; Croxton 1978a section C2). Name. The member is named after the Akunneq valley between the Pingu and Inngigissoq mountains on the north-east coast of Disko. Distribution. The Akunneq Member is known from the north-east coast of Disko (Pingu to Nuugaarsuk) and southwards to Gule Ryg (Fig. 124). Type section. The section at Pingu on the eastern side of Akunneq is chosen as the type section (Figs 128, 132). The type section is located at 69°47.53´N, 52°05.43´W. Reference section. The section on the western side of Akunneq is chosen as the reference section. Thickness. The Akunneq Member is c.165 m thick at Pingu but only c.145 m at Nuugaarsuk. Thus the member decreases in thickness towards the west (Fig. 133). Lithology. The Akunneq Member is dominated by very friable sandstone. It comprises a coarse-grained lower part and a finer-grained upper part, separated by a mudstone horizon at 335 m a.s.l. in the Pingu–Akunneq sec- 149
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GEOLOGICAL SURVEY OF DENMARK AND GR
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Contents Abstract . . . . . . . . .
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Preface The onshore Cretaceous-Pale
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Introduction The Nuussuaq Basin bel
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chemistry of the Nuussuaq Basin hav
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Fig. 5. Plant fossils from the Atan
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Peak 2010 m Peak 1900 m Peak 1760 m
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A lithostratigraphy for the marine
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to provide further funding for stud
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DGR Geological setting As a result
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TSS 8 Agatdal Fm Eqalulik Fm Kangil
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A Svartenhuk Halvø 50 km B Hinterl
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Nuussuaq Group new group History. T
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ley (Figs 2, 40, 65). The section a
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Central Nuussuaq Agatdalen South co
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3 10 4 6 5 Qorlortorssuaq Slibesten
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volcanic sediments are referred to
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Fig. 20. View from Uummannaq toward
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In the Kuuk area, the sediments ove
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m m 15 14 14 13 12 11 10 9 8 7 6 5
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Kome Formation m 40 30 20 D tial re
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Fig. 28. Reference locality of the
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Vaigat Fm Vesterfjeld Slibestensfje
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Gilbert delta in the Ikorfat area (
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150 300 450 100 250 400 m 550 50 20
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Fig. 36. Outcrop of the Upernivik N
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Correlation. The Upernivik Næs flo
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12’ 09’ 15’ 06’ 03’ Saqqa
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m 0 GGU 247801 200 400 247815 ★
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wave-rippled sand streaked mudstone
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the formation in the marine mudston
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d d Fig. 47. Type locality of the S
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Fig. 49. Cross-bedded medium- to co
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and Qaarsut (Fig. 22). Its wider di
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Fig. 52. Two closely spaced section
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Type section. The type section of t
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Fig. 56. Delta front succession of
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Fig. 59. The Kingittoq Member at Ki
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sh L sh ch delta front Vaigat Forma
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Fig. 63. Type locality of the Itivn
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782 Quaternary cover 54° 888 Malig
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Kuugannguaq-Qunnilik Fault and is o
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and include clasts of intraformatio
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deposited in a base-of-slope and ba
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VK 53°30’ 53°15’ Niaqornat Tu
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Umiivik-1 m Overburden ★ ★ No p
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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 and 140: Pedersen 1978). The beds are usuall
Page 141 and 142: In detail, however, the boundary be
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: Naujât Member Atane Formation, Kin
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
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Geological Survey of Denmark and Greenland Bulletin 19 ... - Geus

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