Kinghorn Volcanic Formation
Kinghorn Volcanic Formation (KNV), Carboniferous, Midland Valley of Scotland
Kinghorn Volcanic Formation is part of the Bathgate Group
Name
From the town of Kinghorn, Fife. The term was introduced by Browne et al. (1999)[1] to replace earlier informal names such as ‘Burntisland lavas’.
Lithology
The Kinghorn Volcanic Formation consists of basaltic lavas, locally with pillows and hyaloclastic textures. Volcaniclastic sedimentary rocks with subordinate tuffs also occur. The lavas are dominantly olivine- and olivine-clinopyroxene-phyric with rare olivine-clinopyroxene-plagioclase-phyric basalts. They are mostly microporphyritic but some macroporphyritic varieties also occur. The limited analyses available suggest that the lavas are mostly hypersthene-normative.
Genetic interpretation
The formation is mainly of subaerial origin but locally subaqueous.
Stratotype
The type section is on the Fife coast between Kinghorn and Kirkcaldy (NT 254 863 to 278 882) where about 460 m of mainly green, olivine-rich, basalt lava can be seen in flows interbedded with tuff, sandstone, mudstone and marine limestone. The lavas are variably vesicular and amygdaloidal, include ophitic textures and pillow structures, and may be scoriaceous (see Geikie, 1900, pp. 53–76[2]; MacGregor, 1968, pp. 248–253[3]; Browne et al., 1999, fig. 2, col. 18[1]).
Lower and upper boundaries
The base and top of the formation are usually transitional to sedimentary units belonging to the Strathclyde Group and possibly the basal part of the Clackmannan Group. In the type area (see above) the formation is known to interdigitate with sedimentary strata of the Sandy Craig and Pathhead formations (Figure 6, Column 4C).
Thickness
Over 422 m in the Seafield No. 1 Shaft (BGS Registration Number NT28NE/35) (NT 2769 8953) just south of Kirkcaldy. The depth range is from about 134 m to the bottom of the hole at about 556.m. The full thickness of the formation is therefore not proved.
Distribution and regional correlation
Fife.
Age and biostratigraphical characterisation
Visean (Asbian–Brigantian). Wilson (1989)[4] favoured equation of the 2nd Abden Limestone within the type section (see above) with the Hurlet Limestone at the base of the Lower Limestone Formation, Clackmannan Group and also suggested that both Abden limestones may be part of a single marine episode that was interrupted by the volcanic activity. The associated shales and limestones themselves are richly fossiliferous yeilding brachiopods, bivalves, gastropods, ostracods, foraminifers, corals and bryozoa. The Hurlet Limestone is distinguished by the faunal sequence (the Macnair Fauna) in the underlying mudstone (Wilson, 1989)[4] and contains typical P2 ammonoids (Currie, 1954[5]).
References
- ↑ 1.0 1.1 Browne, M A E, Dean, M T, Hall, I H S, McAdam, A D, Monro, S K, and Chisholm, J I.1999.A lithostratigraphical framework for the Carboniferous rocks of the Midland Valley of Scotland.British Geological Survey Research Report, RR/99/07
- ↑ Geikie, A.1900.The geology of central and western Fife and Kinross.Memoirs of the Geological Survey, Scotland.
- ↑ MacGregor, A R.1968.Fife and Angus geology: an excursion guide. (Edinburgh: Scottish Academic Press Ltd for the Universityof St Andrews.)
- ↑ 4.0 4.1 Wilson, R B.1989.A study of the Dinantian marine macro-fossils of central Scotland.Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol. 80, 91–126
- ↑ Currie, E D.1954.Scottish Carboniferous goniatites.Transactions of the Royal Society of Edinburgh, Vol. 62, Pt. 2, 527–602.