BH250-193
Title
BH250-193
Subject
Gabbro, Anorthosite: Contact between Gabbro and Anothosite from Silver Bay, Minnesota
Description
Major Minerals: anorthite, orthopyroxene, plagioclase, olivine, clinopyroxene
Minor Minerals: serpentine
Note: See BH250-191 and BH250-192
The Duluth Gabbro, also known as the Duluth Complex, is a large, layered mafic intrusive body located in northeastern Minnesota, USA. It is part of the Midcontinent Rift System and is one of the most extensively studied examples of Proterozoic layered intrusions in North America. Several BH250 samples belong to this gabbro, including BH250-11, 50, 189, 192, and 193.
This gabbro is globally recognized as a classic example of a layered mafic intrusion, and the terms Duluth Gabbro and Duluth Complex are widely used in both academic and geological literature. It is approximately 1.1 billion years old (Mesoproterozoic).
BH250-193 is a sample that captures the contact between the Duluth Gabbro and anorthosite. The contact is clearly visible, and thermal effects on the plagioclase within the anorthosite are evident suggesting that the anorthosite is older and was incorporated as a xenolith into the basaltic magma that crystallized to form the gabbro.
Minor Minerals: serpentine
Note: See BH250-191 and BH250-192
The Duluth Gabbro, also known as the Duluth Complex, is a large, layered mafic intrusive body located in northeastern Minnesota, USA. It is part of the Midcontinent Rift System and is one of the most extensively studied examples of Proterozoic layered intrusions in North America. Several BH250 samples belong to this gabbro, including BH250-11, 50, 189, 192, and 193.
This gabbro is globally recognized as a classic example of a layered mafic intrusion, and the terms Duluth Gabbro and Duluth Complex are widely used in both academic and geological literature. It is approximately 1.1 billion years old (Mesoproterozoic).
BH250-193 is a sample that captures the contact between the Duluth Gabbro and anorthosite. The contact is clearly visible, and thermal effects on the plagioclase within the anorthosite are evident suggesting that the anorthosite is older and was incorporated as a xenolith into the basaltic magma that crystallized to form the gabbro.
Coverage
Location: Northern Minnesota, Minnesota, USA
Date
Fall 2014
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample BH250-193. Housed at Carleton College in Minnesota.
Contributor
George and Dean
Type
Thin section and hand sample
Relation
Collection
Citation
Bereket Haileab, “BH250-193,” BH250 Mineralogy Teaching Collection, accessed April 25, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/253.