Buchan Formation

Code
ORBU
Status
Formal (Van Adrichem Boogaert & Kouwe 1994).
Lithological description

White to reddish sandstones and red to red-brown and grey claystones and siltstones. Some disseminated anhydrite occurs. A prominent acid extrusive intercalation (rhyolite) and some associated thinner volcanic beds are encountered in the upper part of the formation in the Elbow Spit region (Dutch northern offshore).

Depositional setting

Fluvial setting. The sandstones are stacked channel deposits of a predominantly braided river system.

Definition of lower boundary

Overlies the Patch Formation conformably. The base has been placed at the first occurrence of thick sandstones.

Definition of upper boundary

The transition to the overlying unit (Tayport Formation) is probably gradual. The contact with the Tayport Formation has not been demonstrated in any of the Dutch offshore wells.

Thickness indication
Up to 663 m in A17-01.
Geographical distribution
The limited amount of data available indicate the presence of the formation in the Elbow Spit High area and part of the Mid North Sea High.
Regional correlation
UK: Buchan Formation; GER: unknown; BEL: unknown.
Age
Frasnian - Famennian, assumed for the northern part of the Dutch continental shelf because of its stratigraphic position between the palynologically dated Patch and Tayport Formations. No distinct biomarkers have been recovered from this unit in the Netherlands continental shelf area.
Holostratotype
Depth (thickness) AH:
2084 - 2717 m (633 m)
Origin of name
Named after the British offshore Buchan Field in the UK block 21/1, where these sandstones constitute the principal hydrocarbon reservoir.
Previous name(s)
None.
Reviewed by (date)
Tom van Hoof (2017).
References
Cameron, T.D.J. 1993. Triassic, Permian and Pre-Permian of the Central and Northern North Sea. ln: Knox, R.W.O.B. & Cordey, W.G. (eds.), Lithostratigraphic nomenclature of the UK North Sea 4,-British Geological Survey, Nottingham, 163 p.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1994. Stratigraphic nomenclature of The Netherlands; revision and update by RGD and NOGEPA, Section B, Devonian and Dinantian. Mededelingen Rijks Geologische Dienst, 50, 1-20.
Cite as
TNO-GDN ([YEAR]). Buchan Formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/buchan-formation.