MORPHOMETRIC ANALYSIS OF RIBBED MORAINES REVEALED BY LIDAR DATA IN THE SEACOAST REGION OF NEW HAMPSHIRE

Ribbed moraines are distinctive regularly spaced ridges that occur in the interior zones of formerly glaciated areas, including regions previously covered by the Laurentide ice sheet in North America. Many hypotheses have been proposed to explain the subglacial origin of ribbed moraines, but their specific formational processes remain a topic of active debate in the literature. Here we present digital elevation models (DEMs) produced using recently acquired high resolution LiDAR data that unveil a series of previously unknown ribbed moraines in the Seacoast region of New Hampshire. The ribbed moraines are expressed as subtle low-relief features on the landscape, and had escaped detection until the processing of the available LiDAR data. The new DEM images show multiple sets of arcuate regularly spaced moraine ridges oriented transverse to former ice flow directions in southeastern New Hampshire. The ribbed moraines in the New Hampshire seacoast region exhibit widths of up to 50 meters and relief ranging from 1-3 meters, and are thus more modest in dimensions than typical morphometric properties of ribbed moraines described in the literature. The first-order details provided by this study on the geographic distribution and morphology of previously unknown ribbed moraines in New Hampshire will provide fresh insight on the process-origin of these features in the Seacoast region. Our case study also contributes to emerging techniques for utilizing LiDAR data and GIS image processing to identify and characterize ribbed moraines in other previously glaciated regions.