Discussion. zonation and age of the Kapp Starostin Formation (Central Spitsbergen)

LARS STEMMERIK

Stemmerik, L. 1988: Discussion. Brachiopod zonation and age of the Permian Kapp Starostin Formation (Central Spitsbergen). Polar Research 6, 179-180. Lars Stemmerik, Grgnlands Geologiske Unders~geke,0ster Voldgade 10, 0-1350KQbenhaun K, Denmark; May 1988.

The following discussion will concentrate on the rhynchus kempei, and Muirwoodia greenlandica stratigraphical implications of the brachiopod for the Megousia weyprechti Zone and Ptero- zonation proposed by Nakamura et al. (1987). No alatus, Pleurohorridonia scoresbyensis, such brachiopod zonation can be recognised in Choristites s#derberghi, and Odontospirifer mir- Greenland where in contrast diagnostic abilis for the Pterospirifer alatus Zone (Nakamura of the upper zones in the Kapp Starostin For- et al. 1987, p. 213). Furthermore, Liosotella spitz- mation co-occur throughout the entire section. bergiana, Paeckelmannia toulai and Kochi- It is therefore concluded that the correlations productus plexicostatus confined to the uppermost proposed by Nakamura et al. (1987) are not valid. zones in the Kapp Starostin Formation are found At best the overall similarities of the East Green- in East Greenland. land and Svalbard faunas may indicate a Kaz- The work of Dunbar (1955) does not imply a anian-early Tatarian age for the upper part of the two-fold zonation of the in the Fold- Kapp Starostin Formation. vik Creek Group in East Greenland. As discussed The paper of Nakamura et al. (1987) has wide below the different collections described by Dun- stratigraphic implications both for local cor- bar (1955) include a mixture of species diagnostic relation of the Foldvik Creek Group (sensu for the Megousia weyprechti Zone, Pterospirifer Surlyk et al. 1986) in East Greenland and for alatus Zone and possibly even the Haydene wil- correlation of the Kapp Starostin Formation to czeki Zone in Spitsbergen. the standard Permian subdivision (Nakamura et The brachiopods diagnostic for the Megousia al. 1987: Fig. 5 and Table 1). The brachiopod weyprechti Zone ;re mainly confined to the area zonation is based on work in the Kapp Starostin north of Kong Oscars Fjord. Exceptions are one Formation on Spitsbergen but the interpretation collection described from Scoresby Land by Fre- of the zonation as stratigraphic rather than ecol- bold (1931) (in Dunbar 1955) and the frequent ogic as previously suggested by Malowski & Hoff- occurrence of Muirwoodia greenlandica to the man (1979) is entirely dependent on the presumed south. Only two species diagnostic for the Ptero- occurrence of similar distinct brachiopod assem- spirifer alatus Zone are found in the northern blages in central East Greenland (Nakamura et area. Dunbar (1955) found a single specimen of al. 1987, pp. 212-215). Pterospirifer alafus in a collection from Fiskeelv, Nakamura et al. (1987, p. 213) distinguish two Clavering 0. In contrast, Pleurohorridonia brachiopod zones in the Foldvik Creek Group scoresbyensis was found frequently in the col- comparable to their Megousia weyprechti Zone lections from this area. This species, however, co- and upper Pterospirifer alatus Zone based on the occurs virtually everywhere with species of the work of Dunbar (1955) and Maync (1942). The Megousia weyprechti Zone (most commonly diagnostic species recognising these zones in East Muirwoodia greenlandica but also Strepto- Greenland are Waagenoconcha payeri, Strepto- rhynchus kempei and Waagenoconcha payeri, 180 L. Stemmerik

(Dunbar 1955, pp. 24, 27, 32, 33, 34)). Also part of the Kapp Starostin Formation in very Kochiproductus plexicostatus, Liosotella spitz- general terms as Kazanian-early Tatarian (for bergiana and Paeckelmannia toulai occur in these more detailed discussion of the age of the Foldvik assemblages implying that the Greenland fauna Creek Group see Stemmerik & Piasecki 1988). consists of a mixture of that found in the younger None of the species diagnostic for the Horridonia parts of the Kapp Starostin Formation but without timanica Zone in the lower part of the Kapp any zonation. This view is further substantiated Starostin Formation have been found in the Fold- by data from Scoresby Land (Dunbar 1955). vik Creek Group. This may indicate that this Here, the fauna is dominated with respect to fauna is older than that found in the upper part diagnostic species (sensu Nakamura et al. 1987) of the formation and in the Foldvik Creek Group by species of the Pterospirifer alatus Zone, includ- in East Greenland. The assignment of the Hor- ing Kochiproductus plexicostatus and Liosotella ridonia timanica Zone to the latest Early Permian spitzbergiana. Most collections described by Dun- or the earliest Late Permian (Nakamura et al. bar (1955) show, however, co-occurrence of this 1987) is in agreement with the present view of fauna with Muirwoodia greenlandica (Dunbar similar faunas in North Greenland (Hbkansson & 1955, pp. 16, 17, 20, 21). Stemmerik 1984; Stemmerik & Hbkansson 1988). Although it is difficult to determine the exact stratigraphical location of many of the collections discussed by Dunbar (1955), enough information is available to ensure that the collections represent References the entire depositional sequence of the Wegener Halvcd (former Limestone-Dolomite Member) Balme, B. E. 1979: Palynology of Permian- boundary and Ravnefjeld (former Posidonia Shale, here beds at Kap Stosch, East Greenland. Meddr. Grmnland 200 (6). 37 PP. including Productus Limestone and Martinia Dunbar, C. 0. 1955: Permian Brachiopod Faunas of Central Limestone) Formations. Surlyk et al. (1986) East Greenland. Meddr. Gr0nland 110 (3). 169 pp. showed that the Wegener Halvcd and Ravnefjeld Frebold, H. 1931: Das marine Oberkarbon Ostgronlands. Formations are partly time equivalent units repre- Meddr. Gr0nland 84 (2). 88 pp. Hhkansson, E. & Stemmerik, L. 1984: Wandel Sea Basin - the senting marginal platform and basin sedimen- North Greenland equivalent to Svalbard and the Barents tation, respectively. Both formations are overlain Shelf. Pp. 97-107 in Spencer, A. M. et al. (eds.): Pefroleum by younger Permian clastic sediments. The Geology of the North European Margin. Norwegian Pet- brachiopods described by Dunbar (1955) occur in roleum Society (Graham & Trotman Ltd.). Malowski, K. & Hoffman, A. 1979: Semi-quantitative facies beds which are time equivalent to shales dated to model for the Kapp Starostin Formation (Permian), be of Kazanian - early Tatarian age based on the Spitzbergen. Acfa Palaeonf. Polon. 24, 217-230, PI. 2-3. presence of a Vittatina assemblage (Balme 1979; Maync, W. 1942: Stratigraphie und Faziesverhaltnisse der Ober- Piasecki 1984). Diagnostic species of the upper- permiscben Ablagerungen Ostgronlands (Oh‘Oberkarbon- most three zones in the Kapp Starostin Formation Unterperm’) zwischen Wollaslon Forland und dem Kejser Franz Josephs Fjord. Meddr. Granland 215 (2). 128 pp. are thus in East Greenland occurring together Nakamura, K., Kimura, G. & Winsnes, T. S. 1987: Brachiopod throughout the entire Kazanian-early Tatarian zonation and age of the Permian Kapp Starostin Formation sequence. This indicates that the zonation of (Central Spitsbergen). Polar Research 5 n.s., 207-219. Nakamura et al. (1987) has no stratigraphic sig- Piasecki, S. 1984: Preliminary palynostratigrapby of the Perm- ian-Lower Triassic sediments in Jameson Land and Scoresby nificance but rather represents changes in the Land, East Greenland. Bull. Geol. SOC. Denmark 32, 139- depositional environment. The reason that a simi- 144. lar ecological zonation is not seen in East Green- Stemmerik, L. & Hikansson, E. 1988: Stratigraphy and depo- land is that all the brachiopod bearing beds are sitional history of the Upper Paleozoic and Triassic sediments gravity flows containing brachiopods from a wide in the Wandel Sea Basin, eastern North Greenland. Bull. Grpnlands Geol. Unders. (in press). range of environments. Stemmerik, L.& Piasecki, S. 1988: The Upper Permian of East Although the zonation seen in the upper part of Greenland - a Review. Geol. Jb. D. (in press). the Kapp Starostin Formation is not stratigraphic, Surlyk, F., Hurst, J. M., Piasecki, S., Rolle, F., Scholle, P. A,. the similarities between the brachiopod fauna of Stemmerik, L. & Thomsen, E. 1986: The Permian of the the upper part of the Kapp Starostin Formation Western Margin of the Greenland Sea - Future Exploration Target. Pp. 629-659 in Halbouty, M. T. (ed.): Future pet- and the Foldvik Creek Group may imply overall roleum provinces of the world. Am. Assoc. Petrol. Geologists correlation of the two units, thus dating the upper Mem. 40.