Written by Jan Ove R. Ebbestad
For the 32nd time the Nordic Geological Winter Meeting was launched, this time hosted by the Geological Society of Finland at the Kumpulan Campus in Helsinki, January 13th – 15th. A well-attended meeting it was, with the wonderful mixture of geological subjects this kind of meetings bring together over the short span of three days. Besides presenting your latest work and projects, much of these conferences is about meeting friends, colleagues, and chat about all aspects of geology. E-mail, Skype and similar cannot compete with the human experience of talking to each other face to face, really.
This time the Digermulen Early Life Research group was only represented by one participant, and a synopsis of the two GSA talks last autumn on the Ediacaran part of the succession was given. Because of new data presented at the meeting, the talk had to be adjusted to accommodate for this.
The breaking news is this: on the Digermulen and Varanger Peninsulas the Mortensnes glacial deposits have traditionally been tentatively correlated with the Gaskier glaciation, that is around 580 million years old, being separated downwards from the Marinoan (Cryogenian) glacial deposits of the Smalfjord Formation by some 400 m of siliciclastics. This very characteristic tripartite succession is typically seen in several places along the Caledonian mountain chain, all the way to the Mjøsa area in southern Norway.
Now, Risto Kumpulainen, Johan Petter Nystuen and colleagues have dated a dike that cross this tripartite package, giving a minimum age of 596 million years. Therefore the Mortensnes equivalent glacial deposits must be older than this and older than the Gaskiers which is at ~580! For our favourite succession, this means that a massive gap should be present somewhere between the Mortensnes Formation and the overlying Stáhpogieddi Formation where we find our Ediacaran fauna. Fascinating possibilities that will lead us to even more questions, no shortage of work for our group in other words.