118 NGF Abstracts and Proceedings, no. 3, 2006 species form monospecific assemblages. It shows Micropaleontology 25, 169-186. that A. subremotus was particularly tolerant of en- Mørk, A., Dallmann, W.K., Dypvik, H., Johannessen, E.P., Larsen, G.B., Nagy, J., Nøttvedt, A., Olaussen, S., Pchelina, vironmental stress. The critical factor in this case T.M. & Worsley, D. 1999. Mesozoic lithostratigraphy. In was reduced salinity, as small-sized species of Lithostratigraphic Lexicon of Svalbard. (ed. W.K. Ammodiscus, similar in shape to A. subremotus, are Dallmann) Norsk Polarinstitutt, 127- 214. known from both modern and ancient low diversity Nagy, J., Pilskog, B. & Wilhelmsen, R.M. 1990. Facies-controlled distribution of foraminifera in the Jurassic North Sea Basin. assemblages of hyposaline environments: Ammodis- In Paleoecology, Biostratigraphy, Paleoceanography and cus yonsnabensis, a species closely related to A. sub- Taxonomy of Agglutinated Foraminifera. (eds. C. Hemleben, remotus, is highly dominant in Bajocian strata of the M.A. Kaminski, W. Kuhnt & D.B. Scott) Kluwer Academic North Sea Basin, both in the Cloughton Formation Publishers, The Netherlands, 621-657. Scott, D.B., Schafer, C.T. & Medioli, F.S. 1980. Eastern Canadian of the Yorkshire Coast and in the Rannoch Estuarine Foraminifera: a framework for comparison. Formation of the Gullfaks Field. These occurrences Journal of Foraminiferal Research 10 (3), 205-234. are interpreted as indicating strongly delta- influenced hyposaline environments (Nagy et al. 1990). The small-sized modern species Ammodiscus gullmarensis is dominant in low salinity estuarine Triassic conodonts from Svalbard waters of the Drammensfjord (Alve 1995). It is also well-known that species of and their Boreal correlations – A Trochammina can tolerate low salinities, and small- review. sized forms are reported as abundant in modern low 1) 2) 3) diversity brackish water faunas, e.g. in the Hans Arne Nakrem , Michael J. Orchard , Wolfgang Weitschat & Mark Hounslow4) Chezzetcook inlet of eastern Canada (Scott et al. 1980). Other genera of interest, reported as abundant 1) Natural History Museum, University of Oslo, PO Box 1172 in hyposaline environments are Ammobaculites, Blindern, N-0318 Oslo, Norway, [email protected] Reophax and Verneuilinoides. In the Knorringfjellet 2) Geological Survey of Canada, 101-605 Robson Street, Formation, these genera are represented by common Vancouver B. C., V6B 5J3, Canada, [email protected] to sporadic occurrence of the following species: A. 3) Geological-Palaeontological Institute and Museum, University of Hamburg, Bundesstr. 55, D-20146 Hamburg, aff. bivarians, A. sp., R. aff. metensis, R. sp., V. sub- Germany. vitreus and V. aff. kirillae. 4) Department of Geography, Lancaster University, UK The Knorringfjellet foraminiferal succession of [email protected] the Festningen and Marhøgda sections reveal an essentially similar, low diversity agglutinated As based on recently processed samples, as well development of restricted nature. The most marked as published sources [but not all collections differences between the two sections appear when taxonomically revised], the distribution of conodonts we compare the Teistberget member. At Festningen through the Lower and Middle Triassic of Svalbard it shows a high dominance of Ammodiscus and a can be compiled as follows: more reduced diversity than at Marhøgda where Trochammina is dominant; features suggesting that Lower Triassic the Festningen area was more hyposaline than the Vikinghøgda Formation, Deltadalen Member Marhøgda region. From the Lusitania River, southern side of The similarity index which compares the faunal Sassenfjorden, Dagis & Korchinskaya (1987) composition of successive samples through each of reported the presence of Neogondolella carinata the two sections indicates only smaller faunal associated with Otoceras boreale. This conodont discontinuities, in spite of the condensed nature of species indicates a Late Griesbachian age for the the Knorringfjellet Formation and its content of lower part of the Vikinghøgda Formation (Delta- supposed larger hiatuses. Several minor faunal dalen Member) at this locality. discontinuities (smaller drops in similarity) are From a possible higher level in the Deltadalen recognized, and one of these marks the Tverrbekken- Member Dagis & Korchinskaya (1989) added new Teistberget member boundary. The apparently conodont species: Neogondolella sweeti and gradual development and generally restricted nature Neospathodus svalbardensis. This level may be of the faunal succession suggest that essentially the identical to the Myalina beds (=Brevassfjellet Beds same type of hyposaline conditions prevailed in the elsewhere), as Dagis & Korchinskaya refer to the gross region during deposition of the formation, conodonts coming from a sample with abundant recurring at the studied sites after each period of Promyalina degeeri. non-deposition or erosion. Mørk et al. (1999) reported presence of Neogondolella carinata from calcareous nodules 5.0 References and 11.5 meters above the base of the formation. N. meishanensis is also probably present in this sample. Alve, E. 1995. Benthic foraminiferal distribution and recolonization of formerly anoxic environments in These conodonts were found together with Otoceras Drammensfjord, southern Norway. Marine boreale, Claraia stachei, Bellerophon borealis and NGF Abstracts and Proceedings, no. 3, 2006 119 Tompophiceras cf. gracile. Higher up, from a sample 79.0 meters above the base of the formation, Vardebukta Formation, Brevassfjellet Bed Neospathodus cf. svalbardensis was found. Conodonts have been reported from the basal Age of this unit: Early Griesbachian, or even Triassic beds of the Sørkapp-Hornsund area (the latest Permian if identification of Neogondolella Brevassfjellet Myalina Bed of Birkenmajer, 1977) meishanensis is correct. by Birkemajer & Trammer (1975), Nakrem & Mørk Vikinghøgda Formation, Lusitaniadalen (1991) and Luppold (2001). An early - middle Die- Member nerian age was proposed based on the presence of A single sample from the Lusitaniadalen Ellisonia triassica, Neospathodus dieneri, Neo- Member yielded specimens of Neospathodus spathodus peculiaris, and Neospathodus sval- waageni, indicating a Smithian age for this unit. bardensis. Neospathodus dieneri ranges from early Vikinghøgda Formation, Vendomdalen Dienerian to middle Smithian, and in part co-exists Member with Neogondolella elongata (Sweet et al., 1971). Weitschat & Lehmann (1978) reported the Neogondolella elongata is a Spathian species, and presence of the following species in samples the reported occurrences of this species in the collected from the southern shore of Sassenfjorden, Dienerian and Smithian of Svalbard probably repre- close to Botneheia, from the Wasatchites tardus sent a species of Borinella. ammonoid zone: Scythogondolella milleri, Scytho- Conodonts mentioned in Sweet (1970b, p. 216), gondolella mosheri, Borinella buurensis (originally Sweet et al. (1971, p. 451) and Trammer (1978, p. described as Neogondolella planata, Neogondolella 283) from Spitsbergen were supplied by G. Hamar, nevadensis and Neogondolella jubata) and also from samples from the Brevassfjellet Myali-na Neospathodus waageni. The age of this fauna is bed of this area. Smithian. In the current study Neogondolella cf. Vardebukta Formation, Siksaken Member paragondolellaeformis in addition to probably new Clark & Hatleberg (1983) and Hatleberg & Clark species of Neogondolella have been extracted from (1984) processed conodonts from Ahlstrandodden, the middle part (middle Spathian) of the Vendom- Pitnerodden and Reinodden (southern side of Van dalen Member. This unit also contains occurrences Keulenfjorden), Siksaken Member. Conodonts of Neogondolella transita?, Neogondolella indicating a Dienerian age were found: Ellisonia inclinata? and Neogondolella ex gr. constricta? triassica, Neospathodus dieneri, Neospathodus (study in progress). cristagalli, Neospathodus svalbarden-sis, Figure 1. Triassic lithostratigraphy of Svalbard (ex Bjørnøya) and position of previously published conodont occurrences. 120 NGF Abstracts and Proceedings, no. 3, 2006 Neospathodus pakistanensis, Neospathodus Kaosfjellet Member. Conodonts indicating a peculiaris, Neogondolella elongata, and Spathian age were found: Ellisonia triassica, Neo- Neogondolella sp. aff. mombergensis. Ammonoid spathodus collinsoni, Neospathodus homeri, Neo- correlation: Vavilovites. spathodus cf. triangularis, Neogondolella elongata Conodonts were reported from the Myalina and Neogondolella jubata. limestone beds of the Siksaken Member at Tvillingodden Formation, Skilisen Bed Mariaholmen (Bellsund) by Nakrem & Mørk (1991). A sparse collection of conodonts from this unit The conodont fauna from this unit comprises has been published by Nakrem & Mørk (1991) Neogon-dolella elongata, Neospathodus sp. cf. yielding only Neogondolella elongata of rather svalbardensis and Ellisonia triassica. Neogondolella indistinct Early Triassic age. elongata has a fairly long range in the Early Triassic, but is an important species of the Neogondolella Middle Triassic milleri conodont zone (Sweet et al., 1971) and the Botneheia Formation Neospathodus pakistanensis conodont zone (Sweet, Dagis & Korchinskaya (1989) reported the 1970b). These zones are of middle Dienerian and following conodonts from the Botneheia Formation late Dienerian - early Smithian age respectively. of Sassenfjorden (Botneheia): Neogondolella longa, Tvillingodden
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