Skip to Main Content
Book Chapter

Layered intrusions of the Duluth Complex

By
James D. Miller
James D. Miller
Department of Geological Sciences and Precambrian Research Center, University of Minnesota, Duluth, Minnesota 55812, USA
Search for other works by this author on:
Published:
January 01, 2011

ABSTRACT

A diverse range of plutonic to hypabyssal intrusions related to the 1.1 Ga Mid-continent Rift occurs in northeastern Minnesota. These intrusions are grouped into two complexes based on their structural occurrence within the North Shore Volcanic Group (NSVG, a comagmatic volcanic edifice) and their range of emplacement ages. The better known Duluth Complex is composed of gabbroic, anorthositic, and granitic intrusions that were emplaced into the base of the NSVG between 1108 and 1098 Ma. The Beaver Bay Complex is composed of a comparable range of intrusions that were emplaced into more medial sections of the NSVG between 1098 and 1095Ma.

This field trip will profile the igneous stratigraphies of two of the best-studied mafic layered intrusions associated with the Midcontinent Rift. The Sonju Lake intrusion is a 1-km-thick lake intrusion associated with the Beaver Bay Complex that shows a classic Skaergaard-type cumulate stratigraphy indicative of closed-system fractional crystallization of a tholeiitic magma. The Layered Series at Duluth (DLS) is a well-differentiated, 4-km-thick sheet-like intrusion that is the type-intrusion of the Duluth Complex. Phase and cryptic layering through the DLS indicates that it evolved as a more open system due to periodic recharge and venting.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Field Guide

Archean to Anthropocene: Field Guides to the Geology of the Mid-Continent of North America

James D. Miller
James D. Miller
Department of Geological Sciences and Precambrian Research Center University of Minnesota-Duluth Duluth, Minnesota 55812 USA
Search for other works by this author on:
;
George J. Hudak
George J. Hudak
Precambrian Research Center Natural Resources Research Institute 5013 Miller Trunk Highway Duluth, Minnesota 55811 USA
Search for other works by this author on:
;
Chad Wittkop
Chad Wittkop
Department of Chemistry and Geology Minnesota State University Mankato, Minnesota 56001 USA
Search for other works by this author on:
;
Patrick I. McLaughlin
Patrick I. McLaughlin
Wisconsin Geological and Natural History Survey Madison, Wisconsin 53705 USA
Search for other works by this author on:
Geological Society of America
Volume
24
ISBN electronic:
9780813756240
Publication date:
January 01, 2011

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal