Mega-terracettes and related ungulate activities in Loess Hills, Iowa, USA
Weihs, Brandon J.; Shroder, John F.
published: Mar 1, 2011
ArtNo. ESP022005501004, Price: 29.00 €
Terracettes are small, quasi-parallel, staircase-like, stepped landforms generally <1 m in tread width and riser height, as long as 300 m, and located transversely along slopes. Numerous theories purport to explain causal mechanisms, including animal disturbance, soil creep, solifluction (gelifluction), slumping and rotational slippage, regolith and vegetation control, subsidence, and anthropogenesis or tectonism. Terracettes in the western Iowa Loess Hills were characterized morphogenetically, with field observations suggesting high association with ungulate activities. A new class of mega-terracette is recognized that characterizes studyarea forms orders of magnitude larger than those discussed by others. This addition to the prior terracette morphologies adds to understanding of concepts of equifinality in which terracettes result from multiple processes. These mega-terracettes are related to ungulate activities of geophagy, soil transport from hooves, compaction, smearing, pawing, and wallowing (dust bathing) as well as the effects of variable soil moisture on erosion of the forms.