Closed Depression Topography Harps Soil, Revisited

Abstract

Accumulation of carbonates around depressions indicates past or present water and solute flow paths out and up from the depressions. The purpose of this study was to determine the pattern of surface carbonates in relation to landscape parameters, depressions, and original Harps map units for 93° 69'W longitude and 41° 59'N latitude. Surface carbonates were determined around each depression or Harps map unit in adjacent field areas (~1650 m wide and 2475 m long) by violent effervescence with 10% HCl. Elevation information for these fields was used to determine slope as well as profile, and plan curvatures for neighborhood points at a 10-m analysis scale, although data were retained for all 1-m elevation points. A 50-m buffer (divided into 10-m-wide strips) around each depression was overlaid with zones that either had or did not have surface carbonates, and the two zones were compared for differences in slope or profile curvature. One-third of the Harps map units overlapped the newly mapped carbonate areas. The newly mapped surface carbonates were located in low-slope regions at “inlet” areas around depressions. Low slope from 10 to 50 m around depressions was associated with surface carbonate zones. Convex areas 10 to 20 m beyond the depression edge were associated with surface carbonates. Redefining “neighborhood” points for 1-m elevation data and evaluating buffers around true depressions were useful tools to define zones with surface carbonates.