TRIASSIC DINOFLAGELLATE CYSTS OF THE PRESENT ARCTIC – A REVIEW

During the Triassic Period, a major embayment formed on the northern coast of the Pangea Supercontinent in what is now the Barents Sea. During the Late Triassic much of this embayment was gradually filled by sediment derived mainly from the erosion of the recently uplifted Uralian Mountains. These sediments formed a huge prograding delta which gradually converted into a paralic platform until a major transgression in the Norian resulted in a dramatic change in the depositional regime.

A palynological study aiming at a better framework for dating, correlation and improved palaeo-environmental understanding of the Late Triassic succession of the Norwegian Arctic has, although mainly focusing on the terrestrial palynology, revealed relatively rich dinoflagellate cyst assemblages from parts of the succession. Occurring for the first time in the geological record during the late Carnian and becoming abundant in the Norian succession in this part of the Triassic world, improved understanding of how and why they occur is triggering. Increased knowledge will improve our understanding of the palaeoenvironment as well as provide a powerful tool in correlation given that their exact stratigraphical position is known.

We will present a first, preliminary review of their relationship in time and space and compare these with published dinoflagellate cyst occurrences in the Canadian Arctic and Alaska. These areas were situated on similar palaeolatitudes further west and their relationship with the Norwegian Arctic is therefore highly relevant in order to understand the palaeogeographical development. It should, however, be noted that so far few papers are published from these areas.