GEOMORPHIC MAPPING AND SUBSURFACE CHARACTERIZATION OF THE SPRINGSTON PRE-HISTORIC DUNES, CANTERBURY, NZ

There is a substantial lack of research on the inland dunes of the Canterbury Plains, New Zealand. The goal of this project is to characterize the surface expressions and subsurface architecture of river dunes in the Canterbury Plains, near and around Springston, and explore the implications of the dunes on geomorphic river development over the past tens of thousands of years. The study takes advantage of newly available Light Detection and Ranging (LiDAR) data and satellite imagery to map eolian, fluvial, and relevant coastal features, drawing comparisons with existing, published maps. In addition, we conduct ground-penetrating radar (GPR) surveys and collect hand-auger logs to construct subsurface cross-sections. Of the dunes surveyed, slip-faces were predominately facing Southeast, and some dune re-working was evident. We identify two major dune complexes, visible through a Digital Elevation Model (DEM). The Northern complex is composed of mostly barchan, parabolic, and linear dune features, and is clearly truncated by a paleo-shoreline, while the Southern complex exists only on the seaward side of the paleo-shoreline and is composed mostly of less distinct dune features that are parallel to the migrating shoreline. The morphologies of the dunes and their interactions with the paleo-shoreline suggest a contradiction with the accepted age of the Waimakariri River deposit surfaces. In addition, we note a number of minor precision discrepancies between slope-defined geomorphic features and the existing, available maps of such features. The descriptions and maps arising from this project provide insight into local processes and add to the growing, global field of eolian-fluvial interactions. Moreover, the questions we outline constitute a robust platform for further research.