Journal of Petroleum Geology, Vol.8, No.3, pp. 273-295, 1985
©Copyright 2000 Scientific Press, Ltd.
JURASSIC FORAMINIFERAL FACIES IN THE STATFJORD
AREA, NORTHERN NORTH SEA -- I
Jenö Nagy*
* Institutt for Geologi, Universitete i Oslo, Postboks
1047, Blindern, 0316 Oslo 3, Norway.
Abstract
Core samples from five wells of the Statfjord area were analysed for
foraminifera. The material covers the middle and upper parts of the deltaic marine Dunlin
Formation and the basal deposits of the deltaic Brent Formation through an interval
ranging in age from Pliensbachian to Toarcian or early Bajocian. The quantitative
distribution of genera and other major faunal parameters define the following five
assemblages which reflect successive steps in the evolution of the depositional basin (in
ascending order): the Dentalina-Nodosaria, Ammodiscus-Dentalina and Marginulina
assemblages developed in a delta-influenced shelf embayment; the Trochammina-Verneuilinoides
assemblage formed under prodelta conditions; the Ammodiscus assemblage deposited
in a delta-front environment. The specific composition of the assemblages is illustrated
by quantitative examples.
