THE LIMESTONE PAVEMENTS OF CHAUMONT: DESCRIPTION AND CLASSIFICATION

The North American Alvar Barrens are well known for their ecology, but little is known about their geology. This unique ecosystem boasts stripes of limestone pavement that are visible in aerial photography. A detailed study was performed on these pavements in Chaumont NY in order to describe them and elucidate their origin. Five subpopulations of fractures were observed, which trended 44,138,202, 222, and 312 degrees. Cross cutting relationships and fracture widths indicate that the population of fractures that trend 222 degrees (primary) formed first. The fracture populations show bimodality in their origin from primary and secondary causes. Large elongate antiforms, called “pop-up ridges” occur in some of these pavements. These are oriented sub-parallel to the primary fractures and appear to be asymmetrical with their north-west side being steeper. Based on fracturing, micro relief and style of weathering, the Chaumont Barrens appear to contain four distinct types of limestone pavement that repeat cyclically. These types include 1) Flat limestone with fractures, 2) Limestone exhibiting popup ridges, 3) Flat limestone with rare fractures, and 4) Weathered Flat limestone with rare fractures. The pavements contain many of the same features described by studies of limestone pavement in the United Kingdom, including “Grikes”, “Clints” and “Runnels”.