Title
Evidence for coal forest refugia in the seasonally dry Pennsylvanian tropical lowlands of the Illinois Basin, USA
Author
Looy, C.V.
Stevenson, R.A.
Van Hoof, T.B.
Mander, L.
Publication year
2014
Abstract
The Moscovian plant macroflora at Cottage Grove southeastern Illinois, USA, is a key example of Pennsylvanian (323-299 Million years ago) dryland vegetation. There is currently no palynological data fromthe same stratigraphic horizons as the plant macrofossils, leaves and other vegetative and reproductive structures, at this locality. Consequently, reconstructions of the standing vegetation at Cottage Grove from these sediments lack the complementary information and a more regional perspective that can be provided by sporomorphs (prepollen, pollen, megaspores and spores). In order to provide this, we have analysed the composition of fossil sporomorph assemblages in two rock samples taken from macrofossil-bearing inter-coal shale at Cottage Grove. Our palynological data differ considerably in composition and in the dominance-diversity profile from the macrofossil vegetation at this locality. Walchian conifers and pteridosperms are common elements in the macroflora, but are absent in the sporomorph assemblages. Reversely, the sporomorph assemblages at Cottage Grove comprise 17 spore taxa (∼16% and ∼63% of the total assemblages) that are known from the lycopsid orders Isoetales, Lepidodendrales and Selaginallales, while Cottage Grove's macrofloral record fails to capture evidence of a considerable population of coal forest lycopsids. We interpret our results as evidence that the Pennsylvanian dryland glacial landscape at Cottage Grove included fragmented populations of wetland plants living in refugia.
Subject
Earth / Environmental
PG - Petroleum Geosciences
ELSS - Earth, Life and Social Sciences
Geological Survey Netherlands
Geosciences
Energy / Geological Survey Netherlands
Paleoecology
Pennsylvanian
Refugia
Vegetation reconstruction
Fossil pollen
Palynology
To reference this document use:
http://resolver.tudelft.nl/uuid:572595be-edb1-440f-8d4d-529d10389ce7
DOI
https://doi.org/10.7717/peerj.630
TNO identifier
520176
Publisher
PeerJ Inc.
ISSN
2167-8359
Source
PeerJ, 2014 (1), 1-15
Article number
630
Document type
article