Tertiary and Cretaceous Coals in the Rocky Mountains Region: Casper, Wyoming to Salt Lake City, Utah June 29-July 8, 1989
Copyright 1989 American Geophysical Union.
Author(s): Romeo M. Flores, Peter D. Warwick, Timothy Moore, Gary Glass, Archie Smith, Douglas Nichols, Jack Wolfe, Ronald Stanton, Jean Weaver
Published Online: 15 MAR 2013
Print ISBN: 9780875905846
Online ISBN: 9781118669211
Book Series: Field Trip Guidebooks
About this Book
Published by the American Geophysical Union as part of the Field Trip Guidebooks Series, Volume 132.
The Paleocene coal-bearing sequences in the northern Powder River Basin are contained in the Tongue River Member of the Fort Union Formation and include anomalously thick (54 m) subbituminous coals. These thick coals have been the target of exploration and development for the past few decades. For the past decade, these coals have also been the object of depositional modeling studies [Law, 1976; Galloway, 1979; Flores, 1981, 1983, 1986; Ethridge and others, 1981; Ayers and Kaiser, 1984; Warwick, 1985; Ayers, 1986; Moore, 1986; Warwick and Stanton, 1988].
Intensive modeling of these coals has resulted in two major schools of thought. Firstly, Galloway , Flores [1981, 1983, 1986], Ethridge and others , Warwick , Moore , and Warwick and Stanton  believe that the coals formed from peat that accumulated in swamps of fluvial systems. The fluvial systems are interpreted as a basin axis trunk-tributary complex that drained to the north-northeast into the Williston Basin. Secondly, Ayers and Kaiser  and Ayers  believe that the coals formed from peat swamps of deltaic systems. These deltas are envisioned to have prograded east to west from the Black Hills and infilled Lebo lake that was centrally located along the basin axis.