Volcanic stratigraphy of the southern Prinsen af Wales Bjerge region, East Greenland
H. Hansen, A. K. Pedersen, R. A. Duncan, D. K. Bird, C. K. Brooks, J. J. Fawcett, J. Gittins, M. Gorton, P. O’Day, 2002. "Volcanic stratigraphy of the southern Prinsen af Wales Bjerge region, East Greenland", The North Atlantic Igneous Province: Stratigraphy, Tectonic, Volcanic and Magmatic Processes, D. W. Jolley, B. R. Bell
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The volcanic succession in the inland Prinsen af Wales Bjerge contains the oldest known onshore lava flows (61 Ma) of the Palaeogene East Greenland flood basalt province. These flows and interbedded sediments define the Urbjerget Formation and are found in the southernmost part of Prinsen af Wales Bjerge. Flows of the Urbjerget Formation are chemically similar to the coastal Vandfaldsdalen Formation flows and the two formations may be chronostratigraphical equivalents. The Urbjerget Formation is overlain by the < 57 Ma tholeiitic basalts of the Milne Land Formation. Four regional volcanic formations are found along the Blosseville Kyst, but the Milne Land Formation is the only one present in the southern Prinsen af Wales Bjerge. Flows of the absent formations (Geikie Plateau, Rømer Fjord and Skrænterne formations) may not have been able to enter the area due to local uplift, more distal located eruption sites or possibly topographic features. A high-Si (SiO2 > 52 wt%) lave flow succession in the Milne Land Formation consists of crustally contaminated magmas which were arrested in crustal chambers as the magma supply rate from the mantle decreased, either due to a general lowering of potential mantle temperatures or a decrease in the rate of continental rifting. Tholeiitic high-Ti flows (MgO: 10–15 wt%, TiO2: 5–6 wt%) within the Milne Land Formation are unique to the Prinsen af Wales Bjerge region, and equivalents have not been reported from other flood basalt provinces. Local flow composition variations in the Milne Land Formation can be explained as the result of melting under lithosphere of variable thickness, small-scale variations in mantle composition and mixing in small magma chambers. Unconformably overlying the Milne Land Formation is a succession of c. 53 Ma alkaline flows, known as the Prinsen af Wales Bjerge Formation. Several crater sites are known from this flow succession and this suggests that the Prinsen af Wales Formation was only covered locally by later volcanic or sedimentary units. The duration of alkaline volcanic activity in the Prinsen af Wales Bjerge is not well constrained but may have been less than 2.5 Ma. The hiatus between the Urbjerget and Milne Land formations is a regional feature in the North Atlantic as it occurs at a similar stratigraphic level at Nansen Fjord, the Faroe Islands and in the ODP Leg 152 volcanic succession off SE Greenland at c. 63°N. It represents a 3–4 Ma long cessation of, or very low frequency of activity in East Greenland/Faroese volcanism and may be explained as the time interval between two pulses in the palaeo-Icelandic plume.
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The North Atlantic Igneous Province has been the subject of extensive scientific investigation over the past thirty years, with a wide field of knowledge being accumulated. Recently, recognition of the potential role of Large Igneous Provinces in affecting ocean and atmosphere systems and biotic evolutionary pathways has lead to increased interest in this province. This has been further stimulated by the expansion in the search for oil and gas in Mesozoic and Tertiary sediments along the NE Atlantic Margin. An improved understanding of the interaction between igneous and sedimentary processes is vital for the identification of potential hydrocarbon resources.
The regions covered include continental margin Norway, east and west Greenland, the Faroe-Shetland Basin and the Faroe Islands themselves. The papers in this book contain new data and interpretations of North Atlantic Igneous Province magmatic processes, rift evolution, tectonics, stratigraphy (chemostratigraphy, biostratigraphy, seismic and isotope stratigraphy) and sediment dispersal. Many of the papers adopt a multidisciplinary approach to tha analysis and interpretation of complex volcanic and sedimentary sequences. These new data, and the reviews and compilations of existing data provide the reader with access to current research directions in North Atlantic Igneous Province geology.