Abstract View

Volume 33 Issue 1 (January 2023)

GSA Today

Article, p. 4-10 | Full Text | PDF

Creating Continents: Archean Cratons Tell the Story

Carol D. Frost*

Dept. of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA

Paul A. Mueller

Dept. of Geological Sciences, University of Florida Gainesville, Gainesville, Florida 32611, USA

David W. Mogk

Dept. of Earth Sciences, Montana State University, Bozeman, Montana 59717, USA

B. Ronald Frost

Dept. of Geology and Geophysics, University of Wyoming, Laramie, Wyoming 82071, USA

Darrell J. Henry

Dept. of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA


The record of the first two billion years of Earth’s history (the Archean) is notoriously incomplete, yet crust of this age is present on every continent. Here we examine the Archean record of the Wyoming craton in the northern Rocky Mountains, USA, which is both well-exposed and readily accessible. We identify three stages of Archean continental crust formation that are also recorded in other cratons. The youngest stage is characterized by a variety of Neoarchean rock assemblages that are indistinguishable from those produced by modern plate-tectonic processes. The middle stage is typified by the trondhjemite-tonalite-granodiorite (TTG) association, which involved partial melting of older, mafic crust. This older mafic crust is not preserved but can be inferred from information in igneous and detrital zircon grains and isotopic compositions of younger rocks in Wyoming and other cratons. This sequence of crust formation characterizes all cratons, but the times of transition from one stage to the next vary from craton to craton.

*Corresponding author: Carol Frost, frost@uwyo.edu

Manuscript received 30 Mar. 2022. Revised manuscript received 27 June 2022. Manuscript accepted 28 June 2022. Posted 4 Aug. 2022.

© The Geological Society of America, 2022. CC-BY-NC.


Cover Image

Cover Image


Search Google Scholar for

Search GSA Today