Barite with Manganite

specimen number:
2062231

location:
Jackson Mine, Negaunee, Marquette Co., Michigan, USA

description:
Nice locality example for the species with white bladed crystals of barite on matrix with lustrous black micro crystals of manganite. In good condition. Collected in 1998.

The Jackson mine, situated within the city limits of Negaunee in Marquette County, Michigan, was a historic open-pit and underground iron mining operation that marks the official birthplace of the Lake Superior iron ore industry. Geologically, the deposit is a Paleoproterozoic banded iron-formation localized within the heavily folded and faulted Negaunee Iron-Formation, which consists of alternating layers of chert, jasper, and iron oxides such as specular hematite and magnetite. High-grade, merchantable hard ore bodies were formed through ancient structural tilting, hydrothermal alteration, and supergene enrichment that leached out silica, leaving behind concentrated lenses of dense iron oxides trapped along synclinal folds and greenstone dike contacts. Historically, the iron deposit was discovered in June 1845 by a regional surveying party led by Marji Gesick, an Ojibwe chief, who directed members of the Jackson Mining Company, organized by Philo M. Everett of Jackson, Michigan, to the outcropping ore. Active extraction began shortly thereafter, with the first regular shipments of ore leaving the district in the early 1850s via the Marquette, Houghton, and Ontonagon Railroad to the docks at Marquette, sparking the development of the entire Marquette Iron Range. The mine operated continuously for several decades under various corporate configurations, transitioning from open pits to deep underground workings, before diminishing high-grade reserves and the discovery of larger deposits elsewhere led to the cessation of regular industrial operations in 1924.

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