Project 575 - Pennsylvanian Terrestrial Habitats and Biotas of Southeastern Euramerica

The dynamic interaction between vegetation and global climate is today widely accepted, but there remain uncertainties as to exactly how the process works. One way of resolving some of the issues concerned is to examine the geological record for earlier times when changes in vegetation coincided with climate change.

The area known as Variscan Euramerica (the foreland and intramontane basins associated with the Variscan Mountains) supported extensive tropical forests during Middle Pennsylvanian times. These forests resulted in important coal deposits and consequently are often known informally as the Coal Forests. The burial of large quantities of carbon clearly meant that the Coal Forests were a major carbon sink at this time. It is probably not a coincidence, therefore, that when the area of the Coal Forests contracted dramatically towards the end of Middle Pennsylvanian times, there was marked increase in global temperatures, including a contraction of the southern polar icecap in Gondwana.

The changes that took place at this time in the terrestrial habitats of western Variscan Euramerica are relatively well-understood, especially after the recently-completed IGCP 469. For a combination of historical reasons and tectonic complications, however, the terrestrial environments in eastern Variscan Euramerica are less well-understood. This project will therefore look at the evidence in an area stretching from the eastern and southern Alps, through the Balkans and the Black Sea Region (Including northern Anatolia and the Donets) to the Caucasus. This represented the eastern part of the Variscan Foreland, together with a number of intramontane basins, and then extending towards the northern coast of the Palaeotethys Ocean.

IGCP 469 showed the value of plant biodiversity and biogeographical studies for determining patterns of environmental change, and so emphasis will be given in the new project to an investigation of the macrofloral and palynological records. Terrestrial faunas were at this time still of relatively low diversity, but IGCP 469 showed that the fossil insect record also provides valuable insights into environmental changes. Where possible, we will also aim to draw in evidence from other animal groups, notably spiders and fishes. The sediment-provenance, to determine basin morphology and the physical environment that was supporting the biotas. Where possible, this will be correlated with the IUGS Global Chonostratigraphical Scheme by linking the observed patterns with the marine bands and faunas found in some of the basins being considered.

In the first instance, this will allow an improved understanding of the original geographical and temporal relationships between the now-separated basins, and thus to develop improved palaeogeographical models for the area. From this, it will then be possible to integrate the sedimentological and palaeontological records, and to develop a synthetic model of habitat and biotic changes for eastern Variscan Euramerica, allowing an integrated model to be developed for environmental changes across the largest terrestrial carbon-sink of Middle Pennsylvanian age.

The project will help us to gain a better understanding of a critical time in the geological evolution of Europe. It will also throw light on the interaction between terrestrial biotas and global effects in Late Palaeozoic times, with implications for modeling today’s climate. It will help encourage interest in Pennsylvanian geology and palaeontology in areas where these subjects have (at least in recent years) tended to be neglected. It will also improve our understanding of the distribution of Upper Carboniferous coal deposits in the area studied, with possible economic benefits for the countries involved. Finally, the project will look at the potential for developing geoconservation projects in the study areas, in collaboration with the European Association for the Conservation of Earth Heritage (ProGeo), which is particularly active in this region.

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