Home

 

Introduction to the IGCP 575 project

It has become widely accepted that the dramatic decline in the area of the Coal Forests towards the end of Middle Pennsylvanian times was linked with the onset of global climatic warming. The view, particularly expressed in North America (e.g. Gastaldo et al., 1996), has been that climatic warming influenced precipitation patterns in palaeotropical latitudes, and this made conditions less favourable for the growth of the dominant plants of the forests – the arborescent lycophytes. However, this model has been found to conflict with a number of critical observations and it has instead been suggested that the climate change may have been triggered by the loss of a major carbon sink in the form of the Coal Forests (Cleal & Thomas, 1999, 2005; Hilton & Cleal, 2007).

Key to unravelling this ‘chicken and egg’ problem is determining the detailed pattern of changes that took place in the Coal Forests in late Moscovian times, as this should throw light on what was causing the changes in habitat to occur. Could any other factor be found to explain why the Coal Forests contracted so significantly? For instance, could colonization of drier environments by deeper-rooting plants have influenced the hydrological cycle? If not, then perhaps climate was the underlying driving-force behind the changes.

To test these ideas, a 2-year pilot-project (funded through the NATO Science Programme) was started in 1999 to examine the evidence of vegetation-change in three loci across the Variscan Foreland – the Sydney Coalfield in Atlantic Canada, South Wales in southern UK, and Dobrudzha in NE Bulgaria (results reported by Cleal et al., 2007). From this, a second project was developed with a wider remit – IGCP 469 Variscan terrestrial biotas and palaeoenvironments (Cleal, 2004).

IGCP 469 looked at terrestrial biotas and habitats of the Variscan Foreland between Atlantic Canada and the Moesian platform (western Black Sea Coast), and the adjacent intramontane basins of Saar-Lorraine, Zwickau, Central and Western Bohemia, and the Intra-Sudetic Basin. The results provided valuable insights into the ecological dynamics of one of the largest areas of Coal Forest, and how this related to both tectonic events occurring in the area and to climate change. The project also tested various ways of investigating this type of problem, including the analysis of floral and faunal biogeography and biodiversity, vegetation analysis through palynology, basin analysis, and sediment provenance analysis. The full results are currently being prepared as the Final Report of IGCP 469 and will shortly be submitted to The Netherlands Journal of Geosciences. However, the project also resulted in a number of thematic volumes in other journals, notable contributions in which were by Cleal (2004, 2005, 2007, 2008), Dimitrova et al. (2005), Dimitrova & Cleal (2007), Opluštil & Cleal (2007), Thomas (2007), Jarzembowski & Schneider (2007), Schneider et al. (2005), and Schneider & Werneburg (2006).

The results of IGCP 469 clearly pointed to climate change not being the major factor in causing the collapse of the Coal Forests ecosystem. Rather, it was the result of changes in drainage patterns and basin configuration that made conditions less favourable for the dominant plants of the forests (the arborescent lycophytes). But to take these ideas further we need to expand the data available to include a greater area of the Coal Forests in different types of tectonic and palaeoecological setting. The project proposed here aims to do just this, by examining the evidence for late Middle Pennsylvanian biotic and habitat changes in eastern Variscan Euramerica.

The IGCP 575 project is based around the core team that evolved through the work of IGCP 469, with specialists from the UK, Canada, Germany, The Netherlands, Czech Republic, Poland, Romania and Bulgaria providing the expertise in palaeobotany, palynology, palaeozoology, sedimentology and stratigraphy. This core team has also been establishing contacts with colleagues in various parts of eastern Variscan Euramerica, including Austria, Italy, Slovenia, Slovakia, Hungary, Croatia, Romania, Greece, Turkey, the Ukraine and Georgia. Preliminary investigations have already started on the sedimentology of northern Turkey and the Caucasus (Polish team), the macrofloras of Romania and Croatia (UK team) and the macrofloras of Ukraine (Czech team) and this will form the foundation on which the new project will be built.

Aims
The aim will be to bring together the core team of subject-specialists with the local teams of geologists/palaeontologists in the study area, with the following objectives:
• To compile revised biodiversity inventories for the different basins based on both existing collections and newly sourced material.
• To revise the taxonomy of the floras and faunas in those areas they have not been studied in recent years.
• To understand better the relation between Variscan tectonic events and biodiversity
• To identify the main drainage and sedimentation patterns will in each of the basins.
• Where palynological analysis is possible, to determine patterns of vegetation change within the basins, and to correlate this with the changing patterns of sedimentation.
• Also where palynological analysis is possible, to examine evidence of extra-basinal vegetation change from the “exotic” pollen components preserved in the palynofloras.
• To correlate the stratigraphical successions in the basins being studied.
• To integrate the observed biotic and sedimentation patterns in the different basins to form a synthetic picture of the changes in biotas and habitats that took place across the study area.
• To improve the understanding of the distribution of coal deposits across the study area, as an energy resource, and as an indicator of carbon sequestration during Late Carboniferous times.
• To identify key sites reflecting aspects of the geology being studied, which would merit designation for conservation by either national or international (e.g. ProGeo) bodies.

Significance
The IGCP 575 project is significant at a number of levels:
• It will improve understanding of a critical phase in the geological history of Euramerica.
• It will improve the understanding of the relative histories of the coal-basins of eastern Europe and northern Turkey.
• It will enhance our understanding of the later phases of the Variscan Orogeny – one of the most important tectonic ‘events’ to affect Euramerica during Phanerozoic times
• By improving our understanding of the terrestrial biotas in the marine-influenced sequences in places like Ukraine, it should be possible to establish better correlations between the global IUGS chronostratigraphical scheme and the so-called ‘Heerlen Scheme’ still widely used in the western European coalfields.
• It will provide insights into the formation of one of the continent’s most important energy resources (coal) with potential consequences for improved exploitation of those resources in areas where they may have been under-utilised.
• It will provide insights into the interaction between tropical vegetation and climate change in Late Palaeozoic times.
• These insights may help improve our understanding of how vegetation and climate interact today, and thus have implications for the modelling of modern-day climate change.
• It will help encourage collaboration between the establish pool of specialists in Pennsylvanian geology and palaeontology from western and central Europe, and North America, with colleagues in eastern Europe and Turkey.
• It will help foster the transference of skills in these fields to eastern Europe and Turkey, through workshops and training sessions held in association with the main project meetings.
• It will help raise awareness of the potential of the Pennsylvanian successions in eastern Europe and Turkey as a resource for education and geotourism, helping foster ideas relating to sustainable development especially in regions of economic stress.
• Through publicity associated with the project meetings, it will help raise awareness of the issues surrounding climate change and vegetation.
Our experience with IGCP 469 has shown us the value of the ‘IGCP’ brand in helping raise financial support for this type of investigation. A major part of the project will be the development of collaborative links between relevant specialists, requiring some travel expenses to be financed. Being a part of the IGCP should facilitate the sourcing of such funds from third-party organisations.

Bibliography
Cleal, C. J. 2004. IGCP 469 Late Westphalian terrestrial biotas and environments of the Variscan Foreland and adjacent intramontane basins. Geologica Balcanica, 34, 3-10.

Cleal, C. J. 2005. The Westphalian macrofloral record from the cratonic central Pennines Basin, UK. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 156, 387-410.

Cleal, C. J. 2007. The Westphalian-Stephanian macrofloral record from the South Wales Coalfield. Geological Magazine, 144, 465-486.

Cleal, C. J. 2008. Palaeofloristics of Middle Pennsylvanian lyginopteridaleans in Variscan Euramerica. Palaeogeography, Palaeoclimatology, Palaeoecology, 261, 1-14.

Cleal, C. J., Tenchov, Y. G., Dimitrova, T. Kh., Thomas, B. A. & Zodrow, E. L. 2007. Late Westphalian-Early Stephanian vegetational changes across the Variscan Foreland. In Wong, Th. E (ed.) Proceedings of the XVth International Congress on Carboniferous and Permian Stratigraphy. Utrecht, the Netherlands, 10-16 August 2003. Royal Netherlands Academy of Arts and Sciences, Amsterdam, pp. 367-377.

Cleal, C. J. & Thomas, B. A. 1999. Tectonics, tropical forest destruction and global warming in the Late Palaeozoic. Acta Palaeobotanica, Supplement, 2, 17-19.

Cleal, C. J. & Thomas, B. A. 2005. Palaeozoic tropical rainforests and their effect on global climates: is the past the key to the present? Geobiology, 3, 13-31.

Dimitrova, T. Kh., Cleal, C. J. & Thomas, B. A. 2005. Palynology of late Westphalian early Stephanian coal-bearing deposits in the eastern South Wales Coalfield. Geological Magazine, 142, 809-821.

Dimitrova, T. Kh. & Cleal, C. J. 2007. Palynological evidence for late Westphalian – early Stephanian vegetation change in the Dobrudzha Coalfield, NE Bulgaria. Geological Magazine, 144, 513-524.

Gastaldo, R. A., DiMichele, W. A. & Pfefferkorn, H. W. 1996. Out of the Icehouse into the Greenhouse: a Late Paleozoic analog for modern global vegetational change. GSA Today, 6, 1-7.

Hilton, J. & Cleal C. J. 2007. The relationship between Euramerican and Cathaysian tropical floras in the Late Palaeozoic: palaeobiogeographical and palaeogeographical implications. Earth-Science Reviews, 85, 85-116.

Jarzembowski, E. A. N. & Schneider, J. W. 2007. The stratigraphical potential of blattodean insects from the late Carboniferous of southern Britain. Geological Magazine, 144, 449-456.

Opluštil, S. & Cleal, C. J. 2007. A comparative analysis of some Late Carboniferous basins of Variscan Europe. Geological Magazine, 144, 417-448.

Thomas, B. A. 2007. Phytogeography of Asturian (Westphalian D) lycophytes throughout the Euramerican belt of coalfields. Geological Magazine, 144, 457-463.

Schneider, J.W., Hoth, K., Gaitzsch, B.G., Berger, H.J., Steinborn, H., Walter, H. & Zeidler, M. 2005d. Carboniferous stratigraphy and development of the Erzgebirge Basin, East Germany.- Zt. dt. Ges.Geowiss., 156/3: 431-466; Stuttgart.

Schneider, J.W. & Werneburg, R. 2006. Insect biostratigraphy of the European late Carboniferous and early Permian. In: Lucas, S.G., Cassinis, G. & Schneider J.W. 2006 (eds.). Non-marine Permian biostratigraphy and biochronology. Geological Society, London, Special Publications, 265, 325-336.

Page updated on 16 June 2010