Last modified: 2011-08-16
Abstract
The Scottish Coal Measures Group of the Midland Valley was the proving ground for much of the pioneering palynological work that laid the foundations of European Carboniferous palynostratigraphy (e.g. Knox, 1945-1946, Smith and Butterworth, 1967). This study focuses on two small, relatively unstudied areas of the Midland Valley and western Scotland; the Machrihanish Coalfield on the Kintyre peninsula and Inninmore Bay on Movern. In addition to re-evaluating previously collected material (Love and Neves, 1964), new samples were acquired from two boreholes and newly discovered outcrop sections.
Previous palynological work suggested a Duckmantian to Bolsovian age for the Inninmore Bay sections, which is confirmed by this re-evaluation and by investigations of new sections. Re-evaluation of plant fossil registers from MacGregor and Mason (1934) implies a mid-Duckmantian to early Bolsovian age; in concordance with the palynological age range. Most of the Bolsovian miospore assemblages are dominated by diverse saccate pollen taxa and associations of Auroraspora spp., Colatisporites spp., Knoxisporites spp., Verucosisporites spp. and Convolutispora spp. These assemblages probably represent a “hinterland” vegetation reflecting relatively dry palaeoenvironemnts. Duckmantian assemblages are more typical of coal measures reflecting relatively wet palaeoenvironments.
Miospores from boreholes in the Machrihanish Coalfield prove Langsettian to early Bolsovian Scottish Coal Measures Group, overlying a probable Namurian aged sequence of interbedded basaltic lavas and sedimentary units likely representing the Passage Formation. The unconformable nature of the underlying late Viséan to early Namurian Limestone Coal and Upper Limestone formations is also demonstrated.
In addition to rich assemblages of western European taxa, the Machrihanish populations contain examples of miospore genera such Paleospora and Columinisporites that are characteristic of North America.