A revised ammonite zonation of the Boreal Oxfordian and its application in northeast Greenland

Publisher Website
Google Scholar
Abstract
A revised ammonite zonation for use in the Middle-Upper Oxfordian of the Boreal province is put forward. The zonation is used to date late Jurassic sediments in the Wollaston Forland area of NE Greenland. The sediments broadly comprise basinal mudstones and shallow marine and shoreline sandstones, which were deposited in westerly tilted fault blocks during 3 transgressive pulses. On the peneplaned surfaces of wide tilted fault blocks a thick sequence of tidally and fluvially influenced marine sandstones of Middle Jurassic age was deposited. In the Upper Jurassic deposition initially took place in the center of the basin where 80 m of shoreface sandstones accumulated (Jakobsstigen Member). In the 2nd pulse the upthrown margin of the next fault block to the west was transgressed and deposition of basinal mudstones (Bernbjerg Formation) commenced in the basin center on the main part of the dip-slope of the eastern block. Finally the crestal areas of the block on Kuhn O were inundated in Kimmeridgian times, and then subsided rapidly.