On the formation of the tunnel valleys of the Superior Lobe, central Minnesota

Auteur :
MOOERS, H. D.

Description :
The Minnesota tunnel valleys are composed of individual segments 10-20 km long, and the segments commonly terminate in subaerial outwash fans at recessional ice margin positions. Eskers, associated with the tunnel valleys, are also composed of short segments, frequently beginning at moulin kames and terminating at the head of outwash fans. The dominant source of the water responsible for tunnel-valley formation was seasonal meltwater from the glacier surface that reached the bed through moulins and crevasses. The apparent continuity of the valleys resulted from the headward development of the englacial drainage system during ice retreat.


Type de document :
Article de périodique

Source :
Quaternary research, issn : 0033-5894, 1989, vol. 32, n°. 1, p. 24-35, Références bibliographiques : 43 réf.

Date :
1989

Editeur :
Pays édition : Etats-Unis, San Diego, CA, Elsevier