New late Smithian (Early Triassic) ammonoids from the Lusitandiadalan Member, Vikinghøgda Formation, Svalbard

Veronica Piazza,Romain Jattiot,Øyvind Hammer

doi:10.17850/njg97-2-03

Abstract

A single carbonate concretion from the uppermost Lusitaniadalen Member (‘Fish Niveau’, Vikinghogda Formation) at Stensiofjellet, Spitsbergen, contains a fairly rich assemblage of late Smithian (Early Triassic, Olenekian) ammonoids. The main species identified are Wasatchites tridentinus Spath, 1934, Wasatchites cf. distractus (Waagen, 1895), Anasibirites kingianus (Waagen, 1895), Arctoprionites nodosus (Frebold, 1930), Arctoprionites resseri (Mathews, 1929) and Xenoceltites subevolutus Spath, 1930. Two taxa are here discussed: Prionitid sp. and Arctoceras erebori sp. nov. The assemblage provides new information about the Early Triassic biostratigraphy and palaeogeography of the Boreal Realm. The composition of the Spitsbergen fauna is in good agreement with other assemblages within and outside the Boreal Realm and essentially comprises cosmopolitan taxa. Only Arctoceras erebori sp. nov. and Prionitid sp. are as yet restricted to Spitsbergen. The newly reported occurrence of low paleolatitude taxa from Spitsbergen strengthens the cosmopolitan distribution of ammonoids during late Smithian time, thus improving existing correlation.

Highlights

Triassic palaeogeographic settingA growing interest is focused on the usefulness of Early to Middle Triassic ammonoids of the Boreal Realm as high-resolution biostratigraphic markers, which in part benefit the increased petroleum exploration activity in the region and its need for accurate biochronological correlation
The present paper provides new interpretations of a late Smithian fauna from Spitsbergen, and a new taxon is presented
The Xenoceltidae family is represented by a few specimens of Xenoceltites subevolutus (Fig. 4A–B), but the prionitids (Figs. 4C–I, 5, 6A–D) are dominant (Wasatchites tridentinus, Wasatchites cf. distractus, Wasatchites spp. indet., Anasibirites kingianus, Arctoprionites nodosus and Arctoprionites resseri)

Summary

Introduction

Triassic palaeogeographic settingA growing interest is focused on the usefulness of Early to Middle Triassic ammonoids of the Boreal Realm as high-resolution biostratigraphic markers, which in part benefit the increased petroleum exploration activity in the region and its need for accurate biochronological correlation. During the Mesozoic, the Svalbardian faunas belonged, in a broader palaeobiogeographic perspective, to the Boreal Realm, which included present-day Greenland, Arctic Canada (Sverdrup Basin) and Russia (Siberia). These localities (Fig. 1) were located along the northern margin of Pangaea, making intra-Boreal correlations possible, while British Columbia (Canada) was located at mid-palaeolatitudes (Dagys & Weitschat, 1993a; Tozer, 1994; Vigran et al, 2014). R. 2017: New late Smithian (Early Triassic) ammonoids from the Lusitaniadalen Member, Vikinghøgda Formation.

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Conclusion