Reappraisal of the sequence stratigraphy of the Humber Group of the UK Central Graben
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Published:January 01, 2010
Abstract
Deposition of the Callovian–Ryazanian Humber Group of the UK Central Graben occurred during rifting and long-term relative sea-level rise, which acted to suppress the formation of eustatically forced Exxon-type sequence boundaries. The superposition of highly variable halokinetically controlled subsidence means that classic, passive-margin derived sequence stratigraphic models are not appropriate to describe stratigraphic evolution in this rift setting. The sequence stratigraphy of the Humber Group has been re-evaluated using a transgressive–regressive sequence model, where maximum regressive surfaces are employed as sequence bounding surfaces. The Humber Group comprises two megasequences which reveal distinct phases of evolution of the basin. The latest Callovian–Kimmeridgian megasequence comprises a conformable sequence stack which lacks significant internal unconformities and records progressive marine flooding and overall backstepping onto the basin flanks during a phase of active rifting. The Volgian–Ryazanian megasequence is condensed and highly fragmentary due to punctuation by a number of unconformities which are consistently recognizable throughout the basin. The onset of this change in architectural style corresponds to the oldest unconformity at the base of the Volgian–Ryazanian succession, termed the Base Volgian–Ryazanian Unconformity, of latest Kimmeridgian to earliest Volgian age. The patterns of erosion of the Callovian–Kimmeridgian megasequence and the intra Volgian–Ryazanian unconformities record the effects of dramatic redistribution of underlying salt accompanied by probable uplift of the Forties–Montrose High and J Ridge, resulting in major modification of the basin morphology and the severing of possible earlier links with the Fisher Bank Basin. The kinematics of this event are equivocal, but it is possible that restricted Volgian–Ryazanian depocentres resulted from localized salt collapse rather than basement extension. Widespread erosion of Callovian–Kimmeridgian Humber Group sediments may have occurred in some areas where Volgian–Ryazanian Kimmeridge Clay deposits now overlie pre-Jurassic strata, and exploration models must incorporate the effects of Volgian reconfiguration in order to accurately predict reservoir distribution.
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Contents
Petroleum Geology: From Mature Basins to New Frontiers – Proceedings of the 7th Petroleum Geology Conference

‘The Proceedings of the 7th Petroleum Geology Conference is the seventh in a series that has become a tradition known as the ‘Barbican’ conferences. They started life over 35 years ago, in 1974, with a focus solely on North-West Europe, and have a reputation, both from the conferences and the accompanying Proceedings volumes, of being at the forefront of petroleum geoscience; the standard reference for successive generations of petroleum geoscientists.
North-West Europe has matured as a petroleum province and, at the same time, the conference series has matured to be a truly global event.
These Proceedings embrace many of the world’s petroleum provinces in a two-volume set. There are sections on Europe, which still provides the heart of the Proceedings; Russia, the former Soviet Union and Circum-Artic; North Africa and the Middle East; Passive Margins; and Unconventional Hydrocarbon Resources.
In addition, the three Geocontroversies debates, highly acclaimed at the conference, are included, as is a summary of the Core Workshop. A DVD complements the books and, in addition to providing electronic versions of all the papers also includes selected posters and video clips from the Virtual Field Trip session; the latter being a major success at the conference. The Proceedings volumes of this seventh conference are therefore a ‘must’ for every petroleum geoscientist’s bookshelf.
GeoRef
- Atlantic Ocean
- basins
- Central Graben
- chronostratigraphy
- depositional environment
- Europe
- Fulmar Formation
- Jurassic
- Kimmeridgian
- Mesozoic
- natural gas
- North Atlantic
- North Sea
- petroleum
- petroleum exploration
- reservoir rocks
- sedimentary basins
- sequence stratigraphy
- structural traps
- traps
- United Kingdom
- Upper Jurassic
- Volgian
- Western Europe
- Humber Group