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

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iments of the Atane Formation pass westwards into marine, fault-controlled slope deposits. These sediments are referred to the Itilli Formation, of Cenomanian to Maastrichtian age, and comprise mainly homogeneous mudstones, thinly interbedded mudstones and sandstones, and turbidite channel sandstones. In the Aaffarsuaq valley, an angular unconformity separates the deltaic Atane Formation from Campanian turbidite deposits of the Itilli Formation (Dam et al. 2000). Major uplift during the Maastrichtian resulted in incision of underlying units; submarine canyon incision is seen at several localities on Nuussuaq, viz. at Ataata Kuua, at Kangilia, in Agatdalen and west of the Kuuganng - uaq–Qunnilik Fault (Fig. 15, see Plate 3). At these localities, the valley and canyon fill consists of successions of homogeneous sandstones and conglomerates, in many instances resulting from catastrophic gravity flow deposition. Intercalated mudstones represent deposition from turbidity currents. These deposits are referred to the Kangilia Formation. Renewed uplift during the Danian generated new incision and fluvial to tidal valley deposits separated by lacustrine sediments filled the fluvial valleys. The lacustrine deposits comprise thin coarseningupward successions composed of mudstones and sand - stones with in situ and drifted tree trunks. These sed i - ments are referred to the Quikavsak Formation (Dam 2002). The pre-volcanic phase culminated with major subsidence of the basin and deposition of sandstones from sediment gravity flows (the Agatdal Formation). During this period, the Disko area was characterised by sedimentary bypass. The next phase of Nuussuaq Group sedimentation coincided with submarine volcanism west of Nuussuaq. The oldest rocks of the West Greenland Basalt Group are hyaloclastic breccias of the Vaigat Formation (Hald & Pedersen 1975; A.K. Pedersen 1985; A.K. Pedersen et al. 1993, 1996, 2002, 2006b; G.K. Pedersen et al. 1998). The contemporaneous siliciclastic marine sediments com prise mudstones, thinly interbedded sandstones and mudstones and chaotic beds. Volcaniclastic sandstones and conglomerates deposited from turbidity currents are common in this part of the succession. The marine syn- Vaigat Formation Itilli Formation E Atane Formation Slibestensfjeldet Formation Kome Formation Precambrian Fig.18. The sediments onlapping and overlying the basement high at Ikorfat on the north coast of Nuussuaq (view towards the south) represent the base of the Nuussuaq Group. The basal sediments are represented by the Kome Formation overlain by the Slibestensfjeldet and Atane Formations. The highest peak is c. 2000 m a.s.l.; for location, see Fig. 22. E, Eqalulik Formation. 34
volcanic sediments are referred to the Eqalulik Formation from the latest Danian (Nøhr-Hansen et al. 2002). As the Early Paleocene volcanic breccias of the Vaigat For mation (West Greenland Basalt Group) prograded eastwards from sources west of the present coastline, the formerly marine basin was dammed and large lakes formed on eastern Nuussuaq and Disko. The lakes were filled from the west by hyaloclastite breccias while siliciclastic sedimentation continued from the south-east. These sediments are re - ferred to the Atanikerluk Formation and consist of shales with thin tuff beds and fine-grained sandstones deposited in two coarsening-upward successions. the Nuussuaq Group span the Albian to the Upper Danian – Selandian. Brackish-water dinocysts from sediments onlapping the basement indicate a pre-Late Albian age, and this is supported by the scarcity of angiosperms Quaternary m 30 40 FP93-3-1 Fossils. A rich flora and fauna from the group has been described. The fauna numbers several hundred species including bivalves, gastropods, nautiloids, ammonites, belemnites, echinoderms, cirripeds, brachiopods, corals, decapod crustaceans, serpulids, fish, ostracods, foraminifera, bryozoans and insects. Fossil invertebrates are best known from the Itilli, Kangilia and Agatdal Formations. The rich flora comprises more than 600 species of plant leaves, wood, fruits, spores, pollen and dinoflagellate cysts (hereafter named dinocysts). Well-preserved plant fossils are mainly found in the Kome, Atane, Quikavsak, Agatdalen and Atanikerluk Formations (for summary of studies, see section on ‘Previous work’ above). Dinocysts form the basis of biostratigraphy and correlation in recent studies. Atane Formation 50 60 70 80 90 Boundaries. The lower boundary of the group is only exposed on the north coast of Nuussuaq at Kuuk, Vest - erfjeld, Talerua and Ikorfat (Fig. 18), on the east coast of Itsaku and on Svartenhuk Halvø where the group overlies metamorphic basement that locally is strongly weathered. The boundary was also penetrated in the FP93-3-1 borehole on northern Disko where the Atane Formation overlies a basement high (Fig. 19). The upper boundary with the West Greenland Basalt Group is diachronous (Hald & Pedersen 1975; A.K. Pedersen et al. 1993). During the Paleocene, volcanic breccias of the Vaigat Formation prograded eastwards from offshore sources and isolated the formerly marine basin in eastern Nuussuaq and Disko, eventually onlapping the Precambrian basement east of the Ikorfat fault zone (L.M. Larsen & Pedersen 1992; A.K. Pedersen et al. 1996, 2002; G.K. Pedersen et al. 1998). Geological age. Dating of the exposed and drilled parts of the basin is mainly based on ammonites, corals, foraminifera, coccoliths, spores, pollen, dinocysts and macroflora fossils. The fossils indicate that outcrops of Precambrian gneiss 100 110 120 130 Strongly weathered surface vf f m c vc f m c clay silt sand pebbles Fig. 19. Detailed sedimentological log of the Atane Formation overlying weathered gneiss basement in the the FP93-3-1 core in the Kuugannguaq valley on north-west Disko. The well dips 60° and driller’s depths are shown. The stratigraphic thickness of the Atane Formation is c. 50 m; the sediments are not referred to a member. For location, see Fig. 2. Depositional environments are indicated by colours in the left column of the log (see Plate 1). 35
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: 3 10 4 6 5 Qorlortorssuaq Slibesten
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 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 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
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Geological Survey of Denmark and Greenland Bulletin 19 ... - Geus

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