The BGS Lexicon of Named Rock Units — Result Details
Gribun Chalk Formation
Computer Code: | GRIB | Preferred Map Code: | GbCk |
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Status Code: | Full | ||
Age range: | Santonian Age (KS) — Campanian Age (KC) | ||
Lithological Description: | Silicified chalk. Reworked chalk and conglomerate as (?) debris flow. Flinty in part. | ||
Definition of Lower Boundary: | Unconformable on the Coire Riabhach Phosphatic Formation or the Lochaline White Sandstone Formation. | ||
Definition of Upper Boundary: | Unconformable with the Clach Alasdair Conglomerate Member of the Strathaird Limestone Formation or Beinn Iadain Mudstone Formation (basal Paleocene age). | ||
Thickness: | c.5m at Gribun, about 1m elsewhere. | ||
Geographical Limits: | Principally on the island of Mull and within the Morvern district. | ||
Parent Unit: | Inner Hebrides Group (IHEB) | ||
Previous Name(s): | Silicified Chalk
(-941)
Silicified Limestone with Flint [Obsolete Name and Code: Use GRIB] (-1574) Gribun Chalk [Obsolete Name and Code: Use GRIB] (-4687) Chalk of Morvern [Obsolete Name and Code: Use GRIB] (-3444) Chalk Of Mull - Morvern [Obsolete Name And Code: See IHEB And GRIB] (CHM) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Section | The Gribun Boulder [NM 457 357], Isle of Mull. | ||
Reference Section | Clachandhu Boulders [NM 4550 3533, NM 4550 3531, NM 4550 3528], Isle of Mull. | ||
Reference Section | Allt na Teangaidh, near Gribun, Isle of Mull. | ||
Type Section | Gribun Stream Boulder, Isle of Mull. | ||
Reference(s): | |||
Braley, S M. 1990. The Sedimentology, Palaeoecology and Stratigraphy of Cretaceous Rocks in N.W. Scotland. Unpublished PhD Thesis CNAA, Polytechnic SouthWest (now University), Plymouth. | |||
Hancock, J M. 2000. The Gribun Formation: clues to the latest Cretaceous history of western Scotland. Scottish Journal of Geology, Vol.36, 137-141. | |||
Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) | |||
Lowden, B, Braley, S, Hurst, A and Lewis, J, 1992. Sedimentological studies of the Cretaceous Lochaline Sandstone, NW Scotland. 159-162 in Parnell, J (editor), Basins on the Atlantic Seaboard: Petroleum Geology, Sedimentology and Basin Evolution. Geological Society of London Special Publication, No.62. | |||
Mortimore, R N, Wood, C J and Gallois, R W, 2001. British Upper Cretaceous Stratigraphy. Geological Conservation Review Series. No. 23. (Peterborough: Joint Nature Conservation Committee.) | |||
Scott. J F. 1928. General geology and physiography of Morvern, Argyll. Transactions of the Geological Society of Glasgow, Vol.18, 149-189. | |||
Judd, J W. 1878. The secondary rocks of Scotland. Third paper. The strata of the Western Coast and Islands. With a note on the foraminifera and other organisms in the Chalk of the Hebrides by T R Jones. Quarterly Journal of the Geological Society of London, Vol.34, 600-743. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
S043 |