A 3-D Seismic Study of Upper Palaeozoic Carbonate and Spiculites Deposition on the Eastern Finnmark Platform (Norway)

Abstract

A 3D seismic study of Upper Palaeozoic carbonate and spiculites deposition on the eastern Finnmark Platform (Norway)

Xiaoxia Huang¹, Farzadi Pourdad², Luciano Cattaneo³, Maria Emilia Tornaghi³, Maria Mutti¹

1.

Institute of Earth and Environmental Science, University of Potsdam, D-14476 Potsdam; contact: [email protected]

2.

Edison Norge AS Troll-Building, Jåttåvågveien 18, 4020 Stavanger, Norway (PO.Box130, 4065 Stavanger)

3.

Edison S.p.A - Foro Buonaparte,31- 20121 Milano

The occurrence of silica-rich deposits in the Permian is a worldwide phenomenon which remains quite elusive. In the Arctic, spiculite-rich beds are widespread at this time and have attracted significant interest for their excellent reservoir properties. A commonly accepted interpretation on the eastern Finnmark Platform is that their deposition reflects an abrupt shift from a warm, shallow water carbonate setting (Gipsdalen Group) to a cooler, deep water carbonate and spiculite-rich environment (Bjarmeland and Tempelfjorden Groups), caused by the northward movement of northern Pangea during the Late Palaeozoic. However, alternative explanations have been suggested.

This study aims to develop a depositional model that improves the general understanding of the processes controlling carbonate deposition during the Late Carboniferous and Early Permian time, and then focusing on factors affecting the spiculites deposition. A new 3D seismic survey and two existing exploration wells 7128/6-1, 7128/4-1 from the eastern Finnmark Platform are used to analyse the different seismic responses of the strata encasing the spiculte-bearing sequences of the Tempelfjorden Group, which have been drilled and widely recognized with different morphologies in the 3D seismic data. They draped on the top of Permian mounds of Tempefjorden Group and show distinct reflectivity changes and different seismic stacking patterns. The distinguished Permian mounds are firstly interpreted as contourites, which were shaped by alongslope currents and wind direction from the eastern Finnmark Platform. The distribution of the mounds is further influenced by pre-existing topography and the NE-SW orientated normal faults, which affect the overlying sedimentary cover, hence interfering with the growth of the mounds. To further constrain the processes, we test the impacts of CO2 changes,

ice buildups and ocean gateways associated with ocean currents on carbonate and spiculites deposition, utilizing General Climate Model calculations run for this specific location.

AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019