TRACE FOSSILS FROM THE DIVIDALEN GROUP, NORTHERN SWEDEN - IMPLICATIONS FOR EARLY CAMBRIAN BIOSTRATIGRAPHY OF BALTICA

Trace fossils from the Tornetrask Formation, Dividalen Group, in north ern Sweden indicate that most or all of the succession is Early Cambri an in age. This contrasts with previous work which placed the lower pa rt of the formation in the Vendian, a conclusion based on the occurren ce of the 'medusoid' body fossil Kullingia concentrica. We report here an assemblage of Early Cambrian traces below Kullingia-bearing horizo ns. In addition, we report the body fossil Sabellidites sp. from the u pper Lower siltstone member at the same level as Kullingia. Together t hese fossils indicate correlation with sections in Ukraine attributed to the upper part of the Rovno 'stage'. Late Early Cambrian trilobites in the uppermost part of the Tornetrask Formation occur above a dolom itic horizon with phosphatic pebbles. Below this horizon, no fossils i ndicative of Talsy or younger age were found, suggesting that the phos phatic level may represent a significant unconformity. The age of the oldest deposits of the Tornetrask Formation, including the Lower sands tone member and the basal tower siltstone member, remains uncertain, a s no age-diagnostic fossils were observed. Many of the trace fossils o bserved in this study, including cf. Curvolithus, Treptichnus, Phycode s, and Teichichnus exhibit a three-lobed lower surface on some of the specimens. This feature is common in Early Cambrian traces, but extrem ely rare in younger deposits, suggesting that it represents a signific ant but unknown group of Early Cambrian burrowing animals.