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

More documents

Recommendations

Info

Kangilia Formation Fig. 72. Unconformity between the Itilli Formation (Umiivik Member) and the overlying Kangilia Formation with the resistant pale-weathering Annertuneq Conglomerate Member at the base. North coast of Nuussuaq, at Annertuneq. Base of conglomerate is at c. 300 m a.s.l. For location, see Fig. 74. Itilli Formation is no lithological contrast at the boundary between the Itilli and Kangilia Formations and in these areas bio - stratigraphic data may be essential for the distinction between the Turonian to lower Maastrichtian Itilli Formation and the mainly Danian Kangilia Formation. On Svartenhuk Halvø, the formation is overlain by hyaloclastite of the Vaigat Formation or, as observed on the east slope of Firefjeld, by a conglomeratic unit that may be correlated with either the Agatdal Formation or with the Quikavsak Formation. The upper boundary of the Itilli Formation is not exposed on northern Disko. On the north coast of Nuussuaq and in the GANT#1 and GRO#3 wells, the Itilli Formation is unconformably overlain by the Kangilia Formation (Figs 67, 72, 87). Along the Aaffarsuaq valley, the upper boundary is ambiguous and can be difficult to identify. East of Qilakitsoq, however, Campanian deposits of the Itilli Formation are overlain by a Paleocene conglomerate/sandstone unit referred to the Eqalulik Formation (Fig. 83) thus indicating a major unconformity. At Nassaat, a tributary on the south-eastern side of Agatdalen, the presence of Upper Santonian mudstones with Sphenoceramus was reported by Rosenkrantz (1970); this succession is now referred to the Itilli Formation. At this locality, the mudstones are overlain by pebbly sandstones and bituminous mudstones, a unit that referred to the Agatdal Formation by Rosenkrantz (1970 fig. 4c) but to the Upper Atanikerdluk Formation (Quikavsak Formation of this paper) by Koch (1959 fig. 37). No new data are available from this outcrop. Geological age. A ?Late Turonian to early Maastrichtian age range for the formation is indicated by the ammonite fauna (Fig. 16). Palynomorph data are generally in accordance with the ammonite data, but local discrepancies occur, probably due to redeposition of ammonites from the underlying deposits. At Asuk and Kussinerujuk on northern Disko, the Itilli Formation is of Cenomanian–Turonian age (Fig. 16; Bojesen-Koefoed et al. 2007) whereas on Svartenhuk Halvø, the formation is of Turonian to Early Campanian age (Fig. 16; Nøhr-Hansen 1996, unpublished data; Dam et al. 1998b). Strata of Campanian age referred to the Hilli Formation are also exposed on Nuussuaq (Itilli, Aaffarsuaq, Agatdalen; Birkelund 1965; Sønderholm et al. 2003). The Maastrichtian part of the formation is only known from Kangilia and Aaffarsuaq (Birkelund 1965; Rosenkrantz 1970; Nøhr-Hansen 1996) and has been dated in the GRO#3 well (Sønderholm et al. 2003). Detailed information on the age of the various members is found in the description of the members below. Correlation. The pre-Early Campanian part of the formation is coeval with the Atane and Upernivik Næs For - mations (Fig. 16). Subdivision. Four members are recognised, the Anariartorfik, Umiivik, Kussinerujuk, and Aaffarsuaq Members, of which the Anariartorfik Member is found only west of the Kuugannguaq–Qunnilik Fault. The Anariartorfik Member consists of interbedded turbidite channel sandstones and mudstones deposited in a faultcontrolled slope environment. The Umiivik Member is the northernmost representative of the Itilli Formation. It is finer grained than the Anariartorfik Member, and dominated by major coarsening-upward successions 88
deposited in a base-of-slope and basin-floor fan environment. Both the Anariartorfik and Umiivik Members record deposition from probably the Cenomanian to the Maastrichtian. The Kussinerujuk Member is only exposed on northern Disko at Asuk and Kussinerujuk and represents a Cenomanian transgressive event on top of the Atane Formation. The Aaffarsuaq Member crops out east of the Kuugannguaq–Qunnilik Fault on central Nuussuaq and comprises a relatively thin wedge of Lower to Middle Campanian strata that are distinctly different from the Anariartorfik Member with regard to their large content of intraformational clasts, the overall lack of fine-grained mudstones and the lenticular shapes of the thinly interbedded sandstone and mudstone units. The sediments of the Aaffarsuaq Member were deposited in a deep marine, channellised footwall fan system. Anariartorfik Member new member History. Strata referred here to the Anariartorfik Member were described informally as the Itilli Formation by J.M. Hansen (1980b). Detailed studies of strata assigned to the Anariartorfik Member were published by Dam & Sønderholm (1994) and Madsen (2000). Name. The member is named after the Anariartorfik valley leading into the Itilli valley (Fig. 65). Distribution. The Anariartorfik Member is exposed in the Itilli valley and is present in the subsurface west of the Kuuganguaq–Qunnilik Fault in the western part of Nuussuaq (Fig. 11). Type section. The type section is the same as for the Itilli Formation in the southern part of the Itilli valley (Figs 65, 66, Plate 2). The base of the type section is located at 70°36.35´N, 54°13.79´W. Reference sections. Well-exposed reference sections are located in the northern part of the Itilli valley and in the adjoining Tunorsuaq valley (Figs 2, 65, 74). The member was cored in the FP94-9-01 borehole between 32 and 522 m in the central part of the Itilli valley (Fig. 65; Madsen 2000); the cores are stored at GEUS in Copenhagen. The member was drilled but not cored in the GRO#3 well between 959 m and 2996 m (Figs 65, 67; Kristensen & Dam 1997). Thickness. The member has a thickness (including intrusions) of at least 2037 m in the GRO#3 well. Approxi - mately 1400 m are exposed in two incomplete sections in the Itilli valley (Fig. 65, Plate 2). Lithology. In the type section, the Anariartorfik Member is dominated by mudstones and thinly interbedded sandstones and mudstones, chaotic beds, amalgamated beds of coarse-grained to very coarse-grained sandstones, and giant-scale cross-bedded sandstones (Figs 66, 68, 69, 70, Plate 2; Dam & Sønderholm 1994). These lithological contrasts create a characteristic blocky pattern in the petrophysical log of the GRO#3 well (Fig. 67; Kristensen & Dam 1997). The mudstones are dark grey to black, show parallel lamination and occur in intervals up to 15 m thick in the type section. Persistent layers of early diagenetic ankerite concretions occur in most mudstone intervals. The thinly interbedded sandstone and mudstone units comprise laterally extensive graded laminae and beds of fine- to very coarse-grained sandstone capped by parallel-laminated mudstones; this facies forms successions several tens of metres in thickness (Plate 2). The sandstone beds range in thickness from less than 1 cm to 80 cm, have flat, locally scoured bases and show normal grading; the beds may be structureless near their base or may be parallel- or cross-laminated throughout. The sand stone beds are laterally persistent at outcrop scale (> 100 m) and there is generally no systematic variation in thickness. Convolute bedding and slump structures are common. Early diagenetic ankerite concretions are common in the mudstone units. The chaotic beds are up to 30 m thick and consist of contorted, laminated mudstone, thinly interbedded sandstone and mudstone, and homogenised mudstone with scattered sand grains, reworked early diagenetic ankerite concretions, semi-indurated mudstone and sandstone clasts and occasional basement clasts. The chaotic beds invariably underlie a thick unit of amalgamated sandstone beds and are often associated with sandstone dykes (Fig. 66, Plate 2). The amalgamated sandstone beds form up to 50 m thick channel-shaped bodies that can be followed for 1–2 km along strike (Figs 66, 68, 70, Plate 2). The sandstone units are erosionally based and locally show welldeveloped flute casts and channel-shaped scours at the base. The sandstone units may show a thinning-upward trend and have a gradational or sharp, but non-erosional contact to the overlying interbedded sandstone and mudstone units. Internally, the sandstone units are dominated by amalgamated, normally graded, medium-grained 89
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 include clasts of intraformatio
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
show all

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

Create successful ePaper yourself

Delete template?

Save as template?