10: Transect across the northeastern margin of the Mesoproterozoic Belt Basin and Lewis thrust, Glacier National Park, Montana
James W. Sears, John S. MacLean, Stuart D. Parker, 2016. "Transect across the northeastern margin of the Mesoproterozoic Belt Basin and Lewis thrust, Glacier National Park, Montana", Unfolding the Geology of the West, Stephen M. Keller, Matthew L. Morgan
Download citation file:
The Lewis thrust plate in Glacier National Park contains the displaced margin of the Mesoproterozoic Belt Basin, which was transported some 130 km (~80 mi) northeastward during the Late Cretaceous to late Paleocene Laramide orogeny. This two-day field trip examines the Lewis plate on an eastward transect along the Going-to-the-Sun Road, crossing the Continental Divide at Logan Pass. The trip begins in basinal facies of the Belt Supergroup, and crosses eastward into shelf facies. The shelf-to-slope transition coincides with the axis of the Akamina syncline along the Continental Divide. The trip visits classic exposures of the Lewis thrust along the Rocky Mountain front, where the lower Belt Supergroup overlies a duplex zone in the Late Cretaceous marine section.
Figures & Tables
Prepared in conjunction with the 2016 GSA Annual Meeting in Denver, Colorado, this volume contains sixteen guides to field trips in this rich geologic region. The four “Great Surveys” of the late 1800s ventured west to explore and document the region’s unknown natural resources and collect valuable geologic information. Many of the field guides in this volume, aptly titled Unfolding the Geology of the West, will cover the same hallowed ground as the early geologic expeditions. Organized into four sections, this volume spans some of the major subdisciplines of geology: (1) stratigraphy, sedimentology, and paleontology; (2) structure and metamorphism; (3) Quaternary landscape evolution; and (4) engineering and environmental geology.