INTRODUCTION

Fusulinids are widely distributed in Middle Carboniferous to Lower Permian shallow marine deposits of Spitsbergen, the main island of Svalbard Archipelago (Fig. 1). Upper Paleozoic strata exist throughout the archipelago, but the largest outcrops occur in the central Spitsbergen region. In this area the Carboniferous-Permian succession is relatively unaffected by post-Paleozoic tectonic activity. Middle- and Upper Carboniferous fusulinid zones in deposits from Spitsbergen have been reported previously by Forbes (1960), Cutbill and Challinor (1965), Sossipatrova (1967), Nilsson (1988, 1993), Nilsson and Davydov (1992, 1997) and Igo and Okamura (1992). New data presented here focus on the fusulinid fauna from the uppermost Moscovian and lower to middle Kasimovian beds at the Kolosseum locality (Fig. 1). Data from this section are of special interest because a relatively thick unit represents the Moscovian-Kasimovian boundary beds, and well-preserved fusulinids are recorded from many levels within the section. The frequent occurrence and unique preservation of fusulinids in these strata offers an opportunity to study the process of the fusulinid evolution in transitional Middle to Upper Carboniferous beds based on their ontogeny.

The problem of Moscovian/Kasimovian boundary recognition has been considered for several years by the Moscovian/Kasimovian Working Group (formerly WG 5) of the Subcommission on Carboniferous Stratigraphy (SCCS) (Villa et al. 1994). The efforts of the WG members from different areas have concentrated on working out detailed biozonation in the boundary beds and tracing this zonation as widely as possible. The fusulinid faunas of Spitsbergen have important paleobiogeographic implications as they act as faunal links between the diverse faunas known from Russia (e.g., Russian Platform, Timan-Pechora Basin and Urals) in the east and Northeast Greenland (Wandel Sea Basin) and the Canadian Arctic (Sverdrup Basin) in the west. These basins were included in the Franklinian Shelf in fusulinacean paleobiogeographic reconstruction of Ross (1995). New fusulinid data from Spitsbergen are regarded as being of great importance for resolving the problem of the Middle/Upper Carboniferous boundary recognition.