The BGS Lexicon of Named Rock Units — Result Details

Hackness Rock Member

Computer Code: HACR Preferred Map Code: notEntered
Status Code: Full
Age range: Callovian Age (JC) — Callovian Age (JC)
Lithological Description: Comprises up to 2 m of grey marl and siltstone and sandstone passing up to pale bluish grey limestone (weathering pale brown) with beds of berthierine (chamosite)-rich ooids, commonly bioturbated with small horizontal and vertical burrows; ammonites including Kosmoceras spinosum, Quenstedtoceras spp. and Reineckeia (Collotia) sp. indicate an age ranging from latest Athleta Zone to Lamberti Zone (Wright, 1968b, 1978).
Definition of Lower Boundary: none recorded or not applicable
Definition of Upper Boundary: none recorded or not applicable
Thickness: Up to 2 m.
Geographical Limits: none recorded or not applicable
Parent Unit: Osgodby Formation (OSBY)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Wright, J.K. 1968b. The Callovian succession at Peckondale Hill, Malton, Yorkshire. Proceedings of the Yorkshire Geological Society, 37, 93-97. 
Wright, J.K. 1978. The Callovian succession (excluding Cornbrash) in the western and northern parts of the Yorkshire Basin. Proceedings of the Geologists' Association, 89, 259-261. 
Barron, A J M, Lott, G K, and Riding, J B. 2012. Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf. British Geological Survey Research Report RR/11/06. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable