Trace‐element variability of native copper within a large ore body: The Kingston mine, Michigan, USA

Abstract

This study attempts both single‐site and regional trace‐element variability assessments focusing on the Kingston Mine, Keweenaw County, Michigan, USA, and other sources of native copper in the Lake Superior region of the United States and Canada. This information is of potential significance to all studies trying to characterize and distinguish between individual mineral sources. It is of particular importance to geoarchaeologists/archaeometrists who are attempting to assign geologic/geographic origin to prehistoric copper artifacts and to those interested in the trace‐element variability (vertically and horizontally) within large ore bodies.

Determining the Provenance of native copper artifacts from Northeastern North America: evidence from instrumental neutron activation analysis

“…To assess inter-source variability, trace element data for four separate copper bearing locales (Kingston, Isle Royale, Michipicoten Island, and Minong) in the Lake Superior area were compared. Through the use of descriptive statistics and analyses of variance on an element-by-element basis, they concluded that regional resource discrimination is unequivocally possible since many more trace elements vary significantly across the Lake Superior district than within Kingston mine [2]. Each of the four Lake Superior sources of native copper thus possesses unique trace element fingerprints or signatures.…”

“…Having demonstrated that there was limited evidence for vertical and horizontal trace element heterogeneity, Allert et al [2] investigated whether variability within the Kingston mine was greater than that across other sources. To assess inter-source variability, trace element data for four separate copper bearing locales (Kingston, Isle Royale, Michipicoten Island, and Minong) in the Lake Superior area were compared.…”

“…Their findings indicate that 76.2% of the specimens were classified in their correct levels. Even though some elements vary significantly within the mine as a whole, their variability is insufficient to separate levels by depth [2]. No single element displayed significant horizontal variation but the combined effects of all elements did produce a degree of discrimination [2].…”

“…Allert et al [2] undertook a study specifically designed to assess the extent of compositional variation within individual geological sources. They focused on the Kingston mine, an underground mine in the Keweenaw Peninsula of northern Michigan.…”

Trace‐element analysis of native copper: The view from Northern Minnesota, USA

“…The location of the samples within each source is also an important factor to consider. Of the seven sources, only the Kingston Mine was systematically sampled throughout the portions of the ore body exposed in the mine workings (Allert et al, 1991). The other sources were sampled based on material availability from various institutions and individuals (Rapp et al, 2000: 3, 35-36).…”