Scotland Chalk nomenclature (Scottish Chalk Province) - Inner Hebrides Group: Lochaline White Sandstone Formation
Name
The Loch Aline Glass Sand of Rawson et al. (1978) and the Lochaline Sandstone Member in Braley (1990). The formation as named above proposed by Mortimore et al. (2001).
Type section
Lochaline Mine adit section [NM 6800 4535], Morvern.
Primary Reference Section
Loch Aline three sections given in Braley (1990) at waterfalls around the loch [NM 6935 4595, NM 6869 4665, NM 6935 4535], Beinn Iadain [NM 6917 5490 and NM 6965 5645] all in the Morvern district. At various sites in Mull e.g. Auchnacraig Cliff [NM 7440 2989] in Braley (1990) and Alt na Teangaigh [NM 453 328] in Mortimore et al. (2001).
Formal subdivision
None
Lithology
Very pure white to pale yellow brown well-sorted medium-grained quartz sandstone. Massive with laminated and shelly beds to base. Most comprehensively described by Humphries (1961) at its type-site.
Definition of upper boundary
Unconformable beneath the Gribun Chalk Formation or Coire Riabhach Phosphatic Formation.
Definition of lower boundary
Conformable (?) on the Morvern Greensand Formation.
Thickness
Up to 40 feet (12.2 m) on the West side of Loch Aline according to Humphries (1961).
Distribution
Known from the Morvern district and the Isle of Mull.
Previous/equivalent names
Loch Aline Glass Sand (Loch Aline) (map code of h5’) as on Lismore 44E, Eastern Mull 44W.
White Sandstone (map code of h5’) as on Iona 43.
White Sandstone (≡Loch Aline Glass Sand) (map code of LAWS) as on Staffa 43N.
Loch Aline White Sandstone.
Parent
Inner Hebrides Group.
Age and biostratigraphy
Upper Cretaceous, Cenomanian; Turonian to Santonian in Mortimore et al. (2001).
References
Braley (1990); Lowden, Braley, Hurst and Lewis (1992); Mortimore, Wood and Gallois (2001). (In this volume a number of the correlations in the earlier works are adjusted and the dating of the sequence refined. The term Lochaline White Sandstone Formation appears first in this volume as one of the adjustments to the terminology and correlation of the sequence of Braley, 1990).