Skip to Main Content
Book Chapter

3: The Permian-Triassic transition in Colorado

By
James W. Hagadorn
James W. Hagadorn
Department of Earth Sciences, Denver Museum of Nature & Science, 2001 Colorado Boulevard, Denver, Colorado 80205, USA
Search for other works by this author on:
Karen R. Whiteley
Karen R. Whiteley
Department of Earth Sciences, Denver Museum of Nature & Science, 2001 Colorado Boulevard, Denver, Colorado 80205, USA
Search for other works by this author on:
Bonita L. Lahey
Bonita L. Lahey
Department of Earth Sciences, Denver Museum of Nature & Science, 2001 Colorado Boulevard, Denver, Colorado 80205, USA
Search for other works by this author on:
Charles M. Henderson
Charles M. Henderson
Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N1N4, Canada
Search for other works by this author on:
Christopher S. Holm-Denoma
Christopher S. Holm-Denoma
Central Mineral and Environmental Resources Science Center, U.S. Geological Survey, Box 25046, MS 973, Denver, Colorado 80225, USA
Search for other works by this author on:
Published:
January 01, 2016

Abstract

The Lykins Formation and its equivalents in Colorado are a stratigraphically poorly constrained suite of redbeds and intercalated stromatolitic carbonates, which is hypothesized to span the Permian-Triassic boundary. Herein we present a preliminary detrital zircon geochronology, new fossil occurrences, and δ13C chemostratigraphy for exposures along the Front Range and in southeastern Colorado, to refine understanding of the unit’s age and depositional history.

Detrital zircons from the uppermost Lykins Formation and an overlying eolianite consist of a complex and highly diverse primary and multi-cycle grain population transported from Laurentian and Gondwanan terranes, potentially both by wind and water. Youngest concordant zircons do not rule out deposition of the uppermost Lykins Formation during a portion of Early Triassic time. Conodonts from the lower Lykins Formation require Middle Permian (Guadalupian) deposition. Conodont alteration indices of 1 indicate the unit has a shallow burial history and is amenable to paleomagnetic inquiry. Conodonts, together with other vertebrate, invertebrate, microfossil, and trace fossils, suggest a very shallow to emergent marine origin for the unit’s most substantial carbonates, and hint at a marine origin for the unit’s intercalated gypsum-anhydrite members. Chemostratigraphy corroborates field evidence of emergence and karst development capping certain units, like the Forelle Limestone Member of the Lykins Formation, where potential sequence boundaries appear to be punctuated by a short-lived meteoric signature.

Results presented here are a progress report of ongoing work in these successions. This field trip consists of a brief tour through exposures of the Lykins Formation, in which we will examine well-known localities as well as view new ones for which we seek insights.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Field Guide

Unfolding the Geology of the West

Stephen M. Keller
Stephen M. Keller
Colorado Geological Survey Colorado School of Mines 1801 19th Street Golden, Colorado 80401, USA
Search for other works by this author on:
Matthew L. Morgan
Matthew L. Morgan
Colorado Geological Survey Colorado School of Mines 1801 19th Street Golden, Colorado 80401, USA
Search for other works by this author on:
Geological Society of America
Volume
44
ISBN print:
9780813756448
Publication date:
January 01, 2016

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal