Bernard Owens

A revised palynozonation of British Namurian deposits and comparisons with eastern Europe

Abstract Existing schemes for the palynozonation of the Namurian deposits in western Europe require updating to reflect improvements in both independent biostratigraphical calibration and species distribution data. New biozonation proposals are presented which include the accurate positioning of all biozonal boundaries and the establishment of new sub-biozonal units within the Pendleian – Alportian sections. The base of the renamed Cingulizonates cf capistratus – Bellispores nitidus (CN) Biozone is placed within the late Brigantian and a new unit, the C. cf. capistratus (Cc) Sub-Biozone, with an upper boundary coincident with the Viséan – Namurian Stage boundary is proposed. The Pendleian part of the revised CN Biozone is established as the Verrucosisporites morulatus (Vm) Sub-Biozone. Additional data from the Lycospora subtriquetra – Kraeuselisporites ornatus (SO) Biozone, in the interval adjacent to the proposed Mid - Carboniferous Boundary, permits the establishment of L. subtriquetra – Apiculatisporis variocorneus (SV)Sub-Biozone in the upper part of the Arnsbergian Stage and the L. subtriquetra – Cirratriradites rarus (SR) Sub-Biozone which occupies the Chokierian and most of the Alportian stages. The base of the Crassispora kosankei – Grumosisporites varioreticulatus (KV) Biozone is repositioned into the upper part of the Alportian Stage. Comparable assemblages described from the Silesian Coal Basins of Poland are discussed and correlations between the palynozonations of both areas are suggested.

REAPPRAISAL OF THE MISSISSIPPIAN PALYNOSTRATIGRAPHY OF THE EAST FIFE COAST, SCOTLAND, UNITED KINGDOM

Abstract Palynomorph assemblages from an extended succession of Mississippian (Viséan) sediments ranging in age from probable late Arundian to the latest Brigantian exposed on the East Fife coast of Scotland, United Kingdom have been investigated. The stratigraphical distribution of miospores closely reflects that established elsewhere in central and southern Scotland. The occurrence of certain stratigraphically significant miospore taxa permits the assignment of chronostratigraphic ages to locally defined lithostratigraphic units. The latest Asbian to Brigantian (VF miospore Biozone) age of the upper part of the Sandy Craig, Pathhead and Lower Limestone formations is confirmed. The Pittenweem Formation and remainder of the Sandy Craig Formation are both assigned to the NM miospore Biozone of Asbian age and the Anstruther Formation is assigned a late Arundian or Holkerian (TC miospore Biozone) age. The Fife Ness Formation, originally assigned to the early Asbian and considered older than the Anstruther Formation, yielded evidence of both the uppermost part of the TC and lower NM miospore biozones and is suggested to be a member of the Pittenweem Formation.

A STRUCTURAL REINTERPRETATION OF THE ENIGMATIC CARBONIFEROUS MIOSPORE PTERORETIS FELIX & BURBRIDGE 1961 EMEND. NOV.

Abstract The structure of the enigmatic Carboniferous miospore genus Pteroretis Felix & Burbridge 1961 is reinterpreted based on well-preserved assemblages from Pennsylvanian (Duckmantian–Bolsovian) strata in the Machrihanish Coalfield, Kintyre, western Scotland. The genus is emended herein, and evidence is presented of a proximal operculum to justify assignment of the genus to the Infraturma Epitygmati. The complex arrangement of wings, originally described as being perpendicular to the equatorial margin from pole to pole, are demonstrated to be concentric structures in the equatorial and subequatorial regions. Wings developed on the distal surface commonly form a cuppa structure similar to that developed in Fragilipollenites Konyali 1965 emend. McLean 1997. A comparison is made with Vestispora (Wilson & Hoffmeister 1956) Wilson & Venkatachala 1963, the only other operculate Carboniferous miospore genus. Comparisons are also made with other genera such as Columinisporites Peppers 1964 and Fragilipollenites, which are costate and cuppa-bearing respectively. Previous records of Pteroretis from Europe and North America are reviewed, and indicate a Late Mississippian (Late Viséan–Chesterian) to Mid Pennsylvanian (Bolsovian) age. Paleobotanical evidence suggests a sphenophyllalean origin, with Pteroretis miospores being recovered from the fructifications of several species of Bowmanites Binney 1871.

Comparative palynostratigraphy of the early Arnsbergian (Namurian) sequences between Great Britain and northwest China

Abstract The proposed stratotype section for the Pendleian–Arnsbergian stage boundary, located at Slieve Anierin in Ireland, contains diagnostic ammonoids but the sediments are thermally too mature to permit the recovery of palynomorphs. Detailed investigations undertaken on a prospective parastratotype section at Mirk Fell Gill in northern England however offers the prospect for the precise palynostratigraphic calibration of this boundary. Limited ammonoid and conodont data are available to support these conclusions. Previous work in the British Isles has equated this stage boundary with that between the Bellispores nitidus–Reticulatisporites carnosus (NC) and Stenozonotriletes triangulus–Rotaspora knoxi (TK) miospore zones of Owens et al. [Proc. Yorks. Geol. Soc. 41 (1977) 381–398] and Clayton et al. [Meded. Rijks Geol. Dienst 29 (1977) 1–71]. Data from the Mirk Fell Gill section will be compared with datasets from deposits of similar age in China to assess the degree of change in palaeobiogeographical composition across the Euramerican landmass.

Palynostratigraphy of the Upper Carboniferous Langesttian-Duckmantian Stage Boundary in Britain

Abstract A critique of palynostratigraphic zonation schemes associated with the Langsettian-Duckmantian Stage boundary shows that, at high levels of stratigraphic resolution, most criteria used as palynological proxies for the position of the boundary are unsuitable. Most importantly, in the Duckmantian stratotype section the highest stratigraphic occurrence of the index species Schulzospora rara is above (rather than below or within) the Vanderbeckei Marine Band, the base of which defines the Duckmantian Stage. A cored section through the boundary in southern North Sea well 44/22-1 displays comparable microfloral distributions. While data are as yet too sparse to provide detailed answers, the findings have implications for understanding how marine flooding events affected Carboniferous microfloral evolution and extinction. Ultimately this influences how microfloral biozone boundaries relate to the regional European Upper Carboniferous stage boundaries, which are largely defined in relation to strata deposited during marine flooding events similar to that associated with the Langsettian-Duckmantian boundary. The miospore genus Sinuspores Artüz is emended, and two new taxa are described: Gondisporites bulboides sp. nov. and Hymenospora murdochensis sp. nov.