The planar shape of drumlins

Matteo Spagnolo, Chris D. Clark, Anna L. C. Hughes, Paul Dunlop, Chris R. Stokes

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

The asymmetry of the planar shape of drumlins is an established paradigm in the literature and characterizes drumlins as resembling tear drops with a blunt (bullet-shaped) stoss end and a tapering (pointed) lee end It is widely cited and never been seriously questioned In this paper the planar shape of 44 500 drumlins mapped in various regional settings from drumlin fields in North America and Northern Europe were objectively analysed by means of Geographic Information System tools Two parameters were considered The first (denoted here as As-pl) focuses on the relative position of the point of intersection between the axes of the maximum length and the maximum width It is defined as the distance between the upstream (ie beginning of the drumlin) and the intersection point (measured along the longitudinal axis) divided by the entire length of the long axis Results indicate that the intersection point of the majority of drumlins (64%) is very close to the longitudinal midpoint (0 33<As-pl<0 66) The second parameter (As-pl_A) is defined as the ratio between the area of the upstream half of the drumlin to that of the entire drumlin Results show that for most drumlins (81%) the upper half area is almost as large as the down-half (0 45<As-pl_A<0 55) Taken together these results concordantly indicate that drumlin planar shape has a strong tendency to be longitudinally symmetric and that the long-established paradigm of their plan form is false (C) 2010 Elsevier BV All rights reserved

Original languageEnglish
Pages (from-to)119-129
Number of pages11
JournalSedimentary Geology
Volume232
Issue number3-4
Early online date11 Apr 2010
DOIs
Publication statusPublished - 15 Dec 2010

Keywords

  • Glacial geomorphology
  • Quantitative geomorphology
  • Drumlin
  • Planar shape
  • Lemniscate loop
  • GIS
  • Remote sensing
  • Fast ice flow
  • Subglacial bedforms
  • Field
  • Landform
  • Saskatchewan
  • Location
  • Dynamics
  • Origin
  • Stream
  • Floods

Cite this

Spagnolo, M., Clark, C. D., Hughes, A. L. C., Dunlop, P., & Stokes, C. R. (2010). The planar shape of drumlins. Sedimentary Geology, 232(3-4), 119-129. https://doi.org/10.1016/j.sedgeo.2010.01.008