Sediment supply comprises a major family
of regime variables that influence geomorphic surface grade. Spatial and
temporal changes in total sediment supply and sediment texture (gravel:sand:mud
ratio) will cause reconfiguration of depositional and erosional profiles,
potentially creating or influencing the sequence stratigraphic framework
of the basin. Sequence grain volume, which is defined as the volume of
sedimentary grains in an individual stratigraphic sequence (total sequence
volume minus cement and porosity volume), has been quantitatively determined
for each of 16 genetic stratigraphic sequences in the North Sea Basin.
Rates of total sediment supply to the basin in both time and space were
then calculated. Sand grain volume and sand:mud ratio were also calculated
for each sequence. These data define four principal episodes of Tertiary
sediment supply. The most significant episode occurred in the late Paleocene
and was followed by secondary episodes in the Eocene and Oligocene. A fourth
Neogene episode extends through the present. All episodes correlate to
source-terrain tectonic pulses related to evolution of the North Atlantic
Basin, to intraplate stress changes associated with successive phases of
the Alpine orogeny, or to the late Cenozoic epeirogenic uplift of Scandinavia.
The major episodes, in turn, contain
©Copyright
1997. The American Association of Petroleum Geologists. All rights reserved.
1Manuscript
received January 16, 1996; revised manuscript received October 15, 1996;
final acceptance February 21, 1997.
2Department
of Geological Sciences, University of Texas at Austin, Austin, Texas. Present
address: International Exploration Branch, Phillips Petroleum Company,
Bartlesville, Oklahoma 74004.
3Department
of Geological Sciences, University of Texas at Austin, Austin, Texas.
We
thank PGS NOPEC AS for providing the seismic grid used in this study. Amoco
Production Company, Marathon Oil Company, Statoil, and BP Exploration provided
financial support. These companies, along with ARCO Oil and Gas Company
and Saga Petroleum a.s., donated well logs. X. Liu is also grateful for
additional financial support from the Geology Foundation, Department of
Geological Sciences, University of Texas at Austin. T. A. McGilvery read
through the manuscript and made useful suggestions. Amanda Masterson's
editing greatly improved the manuscript. Finally, we sincerely thank K.
Biddle, G. T. Bertram, and an anonymous reviewer for their thorough and
critical reviews of the manuscript and useful comments.