STUDIA GEOLOGICA POLONICA Vol. XUV, Warszawa lws Geological Jtesuit* of the Polish USl-ust, list, mo Spitsbergen Expedition. Edited by K. Btrkenmaier Pt. VII UKD 551.7«.a.M/.78J.12.»2:S51.«.0Sl+531.3S.0511551.242.12(984-14 Ziemta Torella) KRZYSZTOF BIRKENM A JER* JURASSIC AND LOWER CRETACEOUS SEDIMENTARY FORMATIONS OF SW TORELL LAND, SPITSBERGEN (Figs. 1—15; Tabs. 1, 2) Contents Abstract .... 7 Introduction 8 Adventdalen Group 8 Subdivision 8 Stratigraphical Sections 10 Janusfjellet Formation 18 Ingebrigtsenbukta Member 20 Brentskardhaugen Bed 24 Tirolarpasset Member 27 Polakkfjellet Bed . 29 Ullaberget Member 30 Helvetiafjellet Formation 31 Festningen Sandstone Member 33 „Upper Continental Series" 34 Carolinefjellet Formation 35 Discussion .... 35 Triassic-Jurassic Boundary in Torell' Land 35 Upper Kimmeridgian Sedimentary Break in Torell Land 36 Jurassic-Cretaceous Boundary in Torell Land 37 Facies and Thickness Variation 17 Janusfjellet Formation 37 Helvetiafjellet Formation 40 References — Literatura . 40 Streszczenie . 43 Abstract The description of the Jurassic-Lower Cretaceous stratigraphical sequence subdivided into the Janusfjellet, the Helvetiafjellet and the Carolinefjellet for­ mations is given from SW Torell Land, Spitsbergen. A new marker bed — the Polakkfjellet Bed, is distinguished at the base of the Tirolarpasset Member (Ja- * Geological Laboratory, Polish Academy of Sciences 31-002 Krakow Se- nacka 3 (Poland). ' Manuscript received September 30, 1973. ADVENTDALEN GROUP nusfjellet Fm.). Breaks in sedimentation, the result of Meso- and Neocimmerian movements,' are recognized between the Rhaeto-Liassic be Geerdalen Member (Kapp Toscana Fm.) and the basal Callovian (resp. uppermost Bathonian-Callo- vian) unit of the marine Janusfjellet Formation, and another at the base of the Volgian (in Upper Kimmeridgian). Position of the axial zone of marine sedimen­ tary basin of the Janusfjellet Formation in Torell Land is discussed. INTRODUCTION The geological observations on the Jurassic and Lower Cretaceous sedi­ mentary sequence and rocks of SW Torell Land have been assembled by the author during the Polish Illrd International Geophysical Year and International Geophysical Co-operation Expeditions to Spitsbergen of 1958 and 196.0 (Leader Professor S. Siedlecki). A geological map to a 1:50,000 scale has been made in the area between Polakkbreen on the north and inner Hornsund on the south (Fig*. 1, 2), as a direct prolon­ gation of the map to the same scale made in 1934 by S. Z. Rozycki (1959) in NW Torell Land. South-west Torell Land is a highly glaciated area with comparatively poor exposures (mostly in nunataks) of the Jurassic and Lower Creta­ ceous rocks, often strongly folded in the zone of Tertiary diastrophism (Alpine fold belt of Spitsbergen — see Birkenmajer 1972b, c). The most complete, continuous exposures of the rocks in question are those at NE Polakkfjellet (on the north) and at E Hyrnefjellet (on the south). The Jurassic (mainly) and Lower Cretaceous fossils collected by the author in the course of mapping have been determined in papers by Kopik (1968) and Birkenmajer and Pugaczewska (1975). Preliminary information on the stratigraphic succession in SW Torell Land has been presented by Birkenmajer (1959, 1960a). ADVENTDALEN GROUP Subdivision The Jurassic to Lower Cretaceous sequence of SW Torell Land be­ longs to the Adventdalen Group (name introduced by Parker 1967). Its subdivision into formations and members in the central depression of Spitsbergen is presented in Tab. 1 which is a modification of strati- graphic schemes of Nathorst (1910). Rozycki 1959K Suehan et al. (1965), Parker (1967), Harland (1969, Tab. VI). Flood e: al. ,1971) and Birken­ majer (1972a, Tab. 1). A new stratigraphic unit is introduced to the scheme, namely the Polakkfjellet Bed. which is a marker horizon at the base of the Tirolarpasset Member at Polakkfjellet and in NW Torell Land. SUBDIVISION 9 Fig. 1 of the investigated area (shaded) in Svalbard (A) and in Spits bergen (B) 10 ADVENTDALEN GROUP Table 1 Stratigraphic scheme of the Adventdalen Group in Spitsbergen. Modi­ fied from Nathorst (1910), Rozycki (1959), Buchan et AL. (1965), Par­ ker (1967), Harland (1969) and Birkenmajer (1972a). Vertical hatching denotes major breaks in sedimentation NW & SE TORELL LAND NORDENSKIOLD LAND Age I S NATHORST LAND I SABINE LAND ALII AN Carolinefjellet Fm. APT-tAN Lower "Upper Continental Series" Glitrefjellet MB. Cretaceous Helvetiafjellet BARREMIAN Fm. Festningen Sandstone Mb. ! HAUTERIVIAN Ullaberget Mb. Rurikfjellet Mb. VALANGINIAN Janusfjellet Tirolarpasset Mb. Fm. (Aucella shales) Upper KIMMERIOGIAN Jurassic Agardhfjellet Mb OXFOROIAN Ingebrigtsenbukta Mb. CALLOVIAN Brentskardhauqen Bed TTT Middle BATHONIAN Jurassic BAJOCIAN Illiliilli. TOARCIAN -(Toarcian-and Bajocian fossils,, PLENSBACHM LOWEI Jurassic SINEMURIAN I^' B^rSauT'Ud,^ (Liassic) : HETTANGIAN ; i!iiiiMililJ^ RHAETIAN DE Geerdalen MB. Upper NORIAN Triassic CARNIAN Tschermakfjellet MB LADINIAN Middle Triassic Stratigraphical Sections Three stratigraphical sections are presented here, the ones best ex­ posed in the C^a investigated, and representing the widest range of the Jurassic-Lower Cretaceous stratigraphic column, namely the sections at E Hyrnefjellet, at S Fonnryggen and at NE Polakkfjellet (for localiza­ tion see Figs. 2, 3). The Hyrnefjellet section is a good exposure of strongly folded De­ vonian, Carboniferous, Permian, Triassic and Jurassic to Lower Creta­ ceous strata (see Birkenmajer 1960b, 1964, Fig. 2). The Jurassic-Lower Studia Geologica Polonica vol. XLIV LEGEND Faults and minor overthrusts ~M Major overthrusts Carolinefjellet Formation }APTfA N fj^T^ "Upper continen- MXM tal series'* HELVETIA­ FJELLET Festningen Sand­ FORMATION stone Member {BARREMIAN) Ullaberget Member and Tirolarpasset Member JANUSFJELLET Polakkfjellet Bed FORMATION Ingebrigtsenbukta (CALLOVIAN- Member -HAUTERIVIAN) Brent ska rdhaugen Bed KAPP TOSCANA De Geerdalen Member FORMATION Tschermakfjellet Mb. J (LADINIAN ^otnaheia Formation -> "HETTANGIAN) ] Sticky Keep Formation I GRIESBACHIAN Ivardebukta Formation] - ANISIAN Upper Permian Middle Carboniferous -Lower Permian ^SSSI Lower Carboniferous Devonian Hecla Hoek: Precambrian - Ordovician Mesozoic dolerite Somovbreen 77°10 o , —P -77 10 Glashaugen Burgerbukta 0 Emoholmanc -77 77°- 16° 20' 16° Fig. 2 Simplified geological map of SW Torell Land Wydawnictwa Geologiczne 1975 r. Lub. Zakl. Graf. N. 525+75 wsw tNEjjW E|SW NE I WSW ENE|NWSE|WNW /» ESEJSW NE (Braemfjellet) 01 Luciakammen H ' Strykjernet 50 > Hyrnebreen Storbre«n sea 5 level Burgerbu k ta O z Fig. 3 Geological cross-section between Luciakammen and Strykjernet, northern coast of Hornsund (after Birkenmaior 1979W 1 - Eocarnbrian; 2 - Lower Cambrian; 3 - Lower Ordovician (1-3 - Hecla Hoek succession); 4 - Devonian' S L!Z r/rh™ i to HYRNEFJELLET ENE NW SE : WNW ESE : WSW > © Hyrnebreen a I D r> w o w o © ffl c 500m / / © Fig. 4 Geological structure of E Hyrnefjellet X — Lower Carboniferous: 2 — Middle Carboniferous; 3 — Upper Carboniferous and Lower Permian; 4 Upper Permian; 5 — Vardebukta Formation (Lower Triassic: Griesbachian); 6 - Sticky Keep Formation (Lower Triassic, upper part); 7 • Botneheia Formation (Anisian); X — Kapp Toscana Formation, Tschermakfjellet Member (Ladinian-Carnian); 9 — Kapp Toscana Formation, De Geerdalen Member (No- rian-Rhaetian-Hettangian); 10—13 — Janusfjellet Formation: 11 — Ingebrigtsenbukta Member (Callovian-Kimmeridgian) with Brentskardhaugen Bed (ltt) at the base; 12 — Tirolarpasset Member (Volgian-Valanginian); 13 — Ullaberget Member (Valanginian-Hauterivian); 14 — Helve- tiaf'iellet Formation, Festningen Sandstone Member (Barremian). Quaternary: 15 — Moraine; 16 — Talus; 17 Glacier. Thick lines denote faults and overthrusts STRATIGRAPHICAL SECTIONS 13 Cretaceous rocks are visible best on the SE slope of the mountain above Hyrnebreen and Treskelen (Fig. 4). E Hyrnefjellet (Fig. 4) Stratigraphy and lithology Thickness in metres Helvetiafjellet Fm., Festningen Sandstone Mb.: 6. Quartzite and quartzitic sandstone in beds 0.5—1.5 m thick, white, light grey or light greenish, often with rusty coating at the surface. Conglomerate intercalations frequent, consisting of white quartz pebbles, rounded or well rounded, 0.5 3.0 cm, occasionally up to 10 cm in diameter. In the middle part of the member, the sandstones and quartzites are often poorly bedded, yellowish, with poorly preserved plant remains. Some black arenaceous shale intercalations occur, mostly covered by scree. In the upper part of the member, the sandstones and quartzitic sandstones are fine-grained, often well laminated, in plates 0.5—1.5 cm thick, dark-green or greenish, grey-green if weathered with inter­ calations of black arenaceous shale ' 50—60 Janusfjellet Fm., Ullaberget Mb.: 5. Sandstone, fine-grained, in layers 2—50 cm thick, often shaly grey, greenish, sometimes glauconitic, intercalated with arenaceous shale in bands 5—50 cm thick, black or dark-green, with worm trails. Se­ veral intercalations of conglomerate 10—20 cm thick, with rounded quartz pebbles 0.5—2 cm in diameter occur . 10—20 Tirolarpasset Mb.: 4. Shale, argillaceous, sometimes arenaceous (silty), black, splitting into very fine plates. Clay-ironstone or sideritic dolomite intercalations 5—10 cm thick, red and yellow if weathered, occur infrequently . ca 69 Ingebrigtsenbukta Mb.: 3. Shale, argillaceous, often silty, black, with numerous fine mus¬ covite flakes visible at unevenly fractured surfaces. Rare intercalations