Ymchil

Traethawd ymchwil

Devonian tropical plant assemblages from the Arctic Svalbard

Project Background

The Devonian period (419-359 million years ago) is the critical time in Earth history when land plants evolved from being ankle-high simple branched naked twigs to being leafy trees growing in complex forest ecosystems (Stein et al. 2012, Berry & Marshall, 2015). The evolution of large plants during this time had a profound impact on the Earth system, affecting weathering rates, atmospheric carbon dioxide levels, terrestrial sediment accumulation and ecosystem dynamics (Morris et al. 2015). However, the plants which are responsible for these impacts remain relatively poorly known, especially in the palaeotropics. The fossil flora of Svalbard is important because 1) it is (palaeo) tropical (usually a hotspot of plant diversity and evolution) and 2) includes a sequence of plant fossils that probably date from the late Silurian right through to the early Late Devonian. Several seasons of fieldwork in the Devonian basin of central and northwestern Spitsbergen, the largest island of the Svalbard archipelago, have yielded several hundred specimens of plant fossils, including collections of very poorly known plants, and several probable new species.

Project Aims and Methods

The Svalbard Devonian Flora has previously been systematically described by Høeg (1942) and Schweitzer (1965-8 summarised 1999), the key material having been collected by Norwegian expeditions in 1925-8. Our new and recent collections, including the first to be made from the original localities, will be supplemented by further collecting in central Spitzbergen towards the end of the second year. The primary objective of the project is to make systematic descriptions and reconstructions of new plant fossil taxa from Spitsbergen collections and make redescriptions of Høeg and Schweitzer’s taxa in the light of considerably advanced contemporary understanding of Devonian plants (as e.g. Berry 2005). Unique to this project is the prospect of familiarity with plant fossils that cover most of the evolutionary development of vascular plants before seed plants. The plant fossils will be placed into a new palyno-stratigraphic framework for the Svalbard Devonian based on the work of co-supervisors Marshall and Wellman. Where possible, in situ spores recovered from sporangia will be described using palynological techniques. The record of the Svalbard Devonian flora will then be compared with those established from other localities to assess the importance of the palaeo tropics in Devonian plant evolution, with the ultimate aim of understanding whether the palaeo tropics were actually the cradle of early land plant evolution, as previously thought

Ffynhonnell ariannu

National Environmental Research Council (NERC)

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