About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

Rocky Mountain Association of Geologists


The Mountain Geologist
Vol. 43 (2006), No. 1. (January), Pages 65-92

Stacked, “Evolved” Triangle Zones Along the Southeastern Flank of the Colorado Front Range

Edward J. (Ned) Sterne


Faults along the eastern flank of the Colorado Front Range display a diversity of attitudes and juxtaposed age relationships. This paper proposes a modified triangle zone model, one that allows back-thrusts within the intercutaneous wedge, to explain the observed fault data. The “evolved” triangle zone model predicts a variety of characteristic fault types including: 1) foreland-dipping roof thrusts that either show no stratigraphic separation or anomalous younger-over-older relationships; 2) foreland-dipping intercutaneous backthrusts that exhibit both older-over-younger and younger-over-older bedding relationships; and 3) hinterland-dipping floor thrusts that show older-over-younger bedding relationships.

Evolved triangle zones are found at multiple stratigraphic and structural levels along the range. These stacked detachment levels accommodate displacement transfer along the range and give rise to some surprisingly complex but restorable structures. This model may be helpful in understanding apparently anomalous thrust relationships in a variety of tectonic settings.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Protected Document: $10
Internal PDF Document: $14
Open PDF Document: $24