Gillmore, G.K., Kjennerud, T. and Kyrkjebo, R. (2001) The reconstruction and analysis of palaeowater depths: a new approach and test of micropalaeontological approaches in the post-rift (Cretaceous to Quaternary) interval of the northern North Sea. In: Martinsen, O.J. and Dreyer, T., (eds.) Sedimentary Environments Offshore Norway - Palaeozoic to Recent. Amsterdam, Netherlands : Elsevier. pp. 365-381. (Norwegian Petroleum Society (NPF), Special Publication, (10)) ISBN 9780444502414

Abstract

This paper explores and tests a new ecelectic approach to micropalaeontological data which are used to reconstruct palaeowater depths in the Norwegian North Sea in the period from the Cretaceous to Quaternary. These new ideas and evidence presented here promote a greater understanding of palaeobathymetry and basin evolution. This account focuses in particular upon Cretaceous to Cenozoic sediments in this region although the new approach has general applicability. Such information is important because palaeobathymetric variations and palaeobasin shape are essential for the recognition of tectonic phases, and understanding the distribution of sediments and source rocks. Palaeobathymetric curves with upper and lower depth limits derived in part from statistical analyses of micropalaeontological data were constructed to present the most likely depth variations through time in the region. The palaeobathymetric curves obtained from micropalaeontological investigations are compared with the palaeobathyemtric variations that were suggested by independent structural restorationms for the region. The outcomes of these two approaches are shown to be essentially similar which implies the soundness of this new approach to micropalaeontological data. Both the structural restoration and micropalaeontological results point to the following: a shallowing in the palaeowater depths in the Early Cretaceous; a deepening in the middle Cretaceous; a shallowing in the Late Cretaceous; a deepening in the Palaeogene; a shallowing in the early Neogene, and a deppening in the late Neogene (Pliocene). The Quaternary interval in wells in this study illustrates the complexity of the palaeoenvironmental record over this period of time, with some wells clearlt showing subsidence while others suggesting relative uplift. This complexity is the result of the impact of ice movement and multiple glaciations and subsequent isostatic re-adjustments.

Actions (Repository Editors)

Item Control Page