Latest Jurassic-early Cretaceous events and the ''late Cimmerian unconformity'' in North Sea area

Journal Article · Wed Dec 01 04:00:00 EST 1982 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:5500139

Rawson, P F ^[1]; Riley, L A

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1. Queen Mary College, London, United Kingdom

Several regional or local unconformities occur in the latest Jurassic-Early Cretaceous sequences of the North Sea and adjacent areas. Each may have been identified locally as the ''late Cimmerian unconformity,'' a supposed major break at the base of the Valhall Formation (or Rodby Formation where the Valhall is locally absent). Although a major hiatus (or a condensed sequence) may occur at basin margins or above structural highs, over most of the North Sea the base of the Valhall Formation is isochronous, and conformable with underlying sediments. It is detected on seismic reflection profiles because it represents a widespread facies change marking the late Ryazanian transgression. Most of the unconformities and associated sedimentary and/or biologic events are of eustatic origin and, even in the tectonically active areas of the North Sea, the effects of eustatic sea level changes were never completely masked by local tectonics. Thus, in the modeling of individual oil fields, the possibility of sedimentary breaks occurring can be predicted in part by reference to regional or eustatic events.

• OSTI ID: 5500139
• Journal Information: Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 66:12; ISSN AAPGB
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ATLANTIC OCEAN
CRETACEOUS PERIOD
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
JURASSIC PERIOD
MESOZOIC ERA
MINERAL RESOURCES
NORTH SEA
PETROLEUM DEPOSITS
RESOURCES
SEAS
SEDIMENTARY BASINS
SEDIMENTATION
SURFACE WATERS