About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 64 (1980)

Issue: 5. (May)

First Page: 793

Last Page: 794

Title: Jurassic Sea-Level Changes From Seismic Stratigraphy: ABSTRACT

Author(s): R. G. Todd, P. R. Vail

Article Type: Meeting abstract

Abstract:

End_Page 793------------------------------

Two areas from the northern North Sea, the inner Moray Firth and the north Viking graben, contain sequences defined by seismic stratigraphic techniques which are indicative of Jurassic fluctuations in sea level. The seismic sequences involve Upper Triassic, Jurassic, and Lower Cretaceous strata. Ten sequences have been identified and their geologic ages are: (1) Rhaetian-Hettangian (198-189 Ma); (2) Sinemurian--early Pliensbachian (189-182 Ma); (3) late Pliensbachian-Toarcian (182-174 Ma); (4) Aalenian-Bajocian (174-165 Ma); (5) Bathonian (165-156 Ma); (6) Callovian (156-149 Ma); (7) Oxfordian-Kimmeridgian (149-141 Ma); (8) Tithonian--early Berriasian (141-133 Ma); (9) late Berriasian (133-131 Ma); and (10) Valanginian (131-126 Ma).

High stands of sea level are represented by the Rhaetian-Hettangian, Bathonian, Oxfordian-Kimmeridgian, and Tithonian-lower Berriasian sequences. Distinctive low stands are indicated by the lower Sinemurian, lower Callovian, upper Berriasian, and Valanginian sequences. The remaining sequences are defined by sea-level fluctuations of intermediate magnitude.

The sea-level fluctuations observed in the North Sea have been partly modified by structural activity. Their chronostratigraphic positioning, however, is thought to be caused by sea-level changes on a global scale. Charts of relative changes of sea level generated for the inner Moray Firth and the north Viking graben in the North Sea compare closely with similar charts from northwest Africa, the Gulf of Mexico, and other areas.

End_of_Article - Last_Page 794------------

Copyright 1997 American Association of Petroleum Geologists