- 1 Sugarbrook Member (SGBK)
- 2 References
Sugarbrook Member (Old et al., 1991)
Waterstones (Binney, 1846) Passage Beds (Richardson, 1928) Waterstones Group (Wills, 1970)
Derivation of name
From the Sugarbrook Pumping Station site [SO 961 681], to the south-west of Bromsgrove, Worcestershire.
SO 9619 6816: Sugarbrook No. 3 Borehole (BGS Registered No. SO96NE/30), 22.9 to 67.3 m (Old et al., 1991).
Scarce exposures in the Bromsgrove area, south and east of Kidderminster (Mitchell et al., 1962; Old et al., 1991).
The dominant lithology is pale red-brown and greenish grey sandstones. The sandstones are finer grained than in the underlying Finstall Member and large-scale cross-bedding is virtually absent. Interbedded red-brown and grey-green mudstones and siltstones are more common than in the Finstall Member. The sequence shows repeated fining-upward cycles, from sandstone to mudstone; intraformational conglomerates occur throughout. Sedimentary structures include ripple marks, flute casts, slump structures, mud cracks and convolute bedding. Micaceous bedding planes are common. In the type section bioturbation, plant remains and Euestheria have been found in the lower about15m, and acritarchs and pseudomorphs after halite occur above that level.
The lower boundary is taken above the highest significant (>1 m) bed of sandstone with large scale cross bedding of the underlying Finstall Member.
The upper boundary is taken at the top of the highest significant grey sandstone bed, above which red mudstones and siltstones of the MMG predominate over sandstone.
The thickest known sequence is 24.4 m, in the Sugarbrook No. 3 Borehole.
Anisian (early Mid Triassic)
Tarporley Siltstone Formation (pars.), MMG
The member has only been mapped in the Bromsgrove area of Worcestershire but is likely to extend westwards to Little Witley [SO 78 63], Worcestershire.