A chitinozoan biostratigraphy of the Upper Ordovician and lower Silurian strata of the Girvan area, Midland Valley, Scotland

Abstract

Forty-six samples, taken from the Upper Ordovician and lower Silurian strata of the Girvan district, Midland Valley of Scotland, yield moderately well-preserved and diverse assemblages of chitinozoans. The area was chosen to study the composition of the chitinozoan assemblages, rarely described before in Scotland, which lay at the south-eastern margin of the Laurentia palaeocontinent. These assemblages are compared with those of the same age on other palaeocontinents, representing a critical time when both the Iapetus and Tornquist oceans were closing, thus forming the Caledonide and associated orogens. It is possible to correlate the chitinozoan occurrences at Girvan with those of other parts of Laurentia (Quebec area), other palaeocontinents such as Baltoscandia (Sweden, Estonia), Avalonia (Wales, Brabant Massif) and some parts of Northern Gondwana (Saudi Arabia). For the lower Silurian, it is possible to correlate with the global chitinozoan biozonation, and a calibration between the chitinozoan occurrences and the graptolite biozonation of Girvan is established. Several levels within the Balclatchie, South Shore, Three Mile, Shalloch, Wood Burn, Lauchlan, Drumyork Flags and other formations are accurately dated.

Integrated Telychian (Silurian) K-bentonite chemostratigraphy and biostratigraphy in Estonia and Latvia

“…From the same graptolite level, A. longicollis has been found also in the subsurface of Gotland (Grahn 1995), in sections in the Prague Basin, Bohemia (Dufka et al. 1995), Girvan area, Scotland (Vandenbroucke et al. 2003) and Yangtze region, China (Geng et al.…”

A summary and revision of the East Baltic Silurian chitinozoan biozonation

“…It is missing in the eastern-and northernmost cores, in strata representing more shallow shelf sediments (Nestor 1998), partly due to a subregional hiatus. Spinachitina maennili is rather widely distributed: southern Ohio, USA (Grahn 1985), Brabant Massif, Belgium (G. Van Grootel, unpublished data), subsurface of Gotland (Grahn 1995), Saudi Arabia , southern Baltic Sea (Samuelsson et al 2001), Girvan area, Scotland (Vandenbroucke et al 2003).…”

Upper Llandovery–Wenlock (Silurian) palynology of the Pentland Hills inliers, Midland Valley of Scotland

“…Marine and non-marine palynomorphs are also present, but although terrestrial palynomorphs and associated plant microfossils (cryptospores, miospores, filaments, tubular structures and cuticle) have been documented from several of the inliers aligned close to the southern margin of the Midland Valley (Wellman & Richardson 1993;Wellman 1995), there are few published accounts of the marine palynomorphs (acritarchs, chitinozoa), and those that have been published have focussed on the Girvan succession (Dorning 1982;Vandenbroucke et al 2003). …”