Mafic and Ultramafic Plutons Associated with the New Madrid Rift Complex -- A Possible Major Source of the Copper-Cobalt-Nickel Mineralization of Southeast Missouri

Abstract

The main rift structure of the New Madrid rift complex, the Reelfoot rift, strikes northeastward, extending from northeast Arkansas through the Missouri "boot heel' and western Kentucky into southern Illinois. The recently discovered Blomfield lineament zone transects the Reelfoot rift in the boot heel area and strikes north-northwest, passing through the Mine La Motte-Fredericktown subdistrict of the Southeast Missouri lead-zinc-copper mining district. Studies suggest a strong relationship between the proximity of the New Madrid rift complex to the Southeast Missouri district and the anomalously high amounts of Cu, Co and Ni in the region - particularly in the Mine La Motte-Fredericktown subdistrict. Supporting evidence comes from three sources: 1) mineral zoning and paragenetic sequence, 2) geotectonics of the New Madrid rift complex, and 3) regional variations of 87Sr/86Sr and 18O/16O isotope ratios. It is proposed that the source of at least part of the Cu, Co, Ni and some siderophile elements of the Southeast Missouri lead deposits may be the result of basinal brine leaching of a series or probably multiaged, mafic and ultramafic intrusions or their sediments controlled by the New Madrid rift complex.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Copper/Cobalt/Nickel; Mafic Intrusion; Ore Genesis; Rift Structure; USA, Missouri

Geographic Coverage

Southeast Missouri

International Standard Serial Number (ISSN)

0361-0128

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1993 Society of Economic Geologists, Inc., All rights reserved.

Publication Date

01 Apr 1993

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