RUI: Analysis of an Early-Middle Devonian Ecosystem: Trout Valley Formation, Maine

Colby College, Waterville ME

Investigators

Abstract

RUI: Analysis of an Early-Middle Devonian Ecosystem: Trout Brook, Maine Robert Gastaldo and Robert E. Nelson Ear-0087433 The Trout Valley Formation, Maine, preserves one of the few terrestrial ecosystems of the Early to Middle Devonian (Emsian-Eifelian) age. It has been used as the prima facie model of early terrestrial community structure in which a mosaic of opportunist plants populated the landscape. It is thought that these plants were clonal mainly because sexual reproduction in these plants is thought to be relatively rare (based upon the ration between vegetative and sporangium-bearing plants). Within this vegetational mosaic, interactions between plants and animals was restricted to detritus feeding, as deduced from animal morphologies, coprolite distribution, and the nature of plant damage. The interpretation of this landscape is based upon scant published field data, of which the environmental context and depositional setting has been interpreted previously as a brackish delta setting. There appears to be little evidence to support this environmental context, and there are no taphonomic data to support the ecological reconstruction. The proposed research will be conducted by undergraduate majors in Geology as senior independent projects that include both field and laboratory studies. Undergraduates will test four hypotheses focusing on: (1) the stratigraphic sequence of the Trout Valley Formation: (2) the taphonomic signature of plant fossil assemblages; (3) the associated terrestrial macroinvertebrates and early ecosystem structure; and (4) the plant-animal interactions that may be recorded in these assemblages. Students will develop an environmental framework in which the fossil assemblages can be placed for a more accurate understanding of their genesis; constrain the plant and animal taphonomic signatures of the assemblages within the outcrop belt from which a more realistic paleoenvironmental reconstruction can be produced; and investigate the evolutionary level of plant-animal interactions recorded in the Early-Middle Devonian.