Magma Contamination And Sulfide Immiscibility Of The...
MAGMA CONTAMINATION AND SULFIDE IMMISCIBILITY OF THE
METEORIC IMPACT ZONE IN THE SUDBURY NI CU DEPOSITS: ONTARIO,
CANADA
WILLIAMS, Jane B. (University of Wisconsin Eau Claire,
[email protected])
Sudbury, Canada is the location of a world class Ni Cu deposit phenomena.
Numerous studies have produced an explanation for the complex evolution of its
deposition and enrichment thanks to the impaction of a meteorite 1.85 million years
ago. The impact of the meteorite is thought to have caused fracturing that led to the
generation of magma from deep in the crust that helped in later filling the crater and
producing the igneous complex (Faggart et. al., 1985). The igneous complex (Figure
1a) has an elongated shape (60 km long and 27 km wide) with circular deposits
surrounding it similar to a bulls eye. Evidence of the meteoric impact includes
brecciation located in the center of the basin (Onaping Formation), deformation of the
margin of the intrusive complex (Huronian Group), shatter cones, and
pseudotachylite. The meteor is thought to have flash melted the crust which
proceeded to differentiate into a granophyre and a leuconorite to norite composition.
The granophyre makes up 60% of the complex and the leuconorite and norite make
up the remaining 40% (Figure 1b)(Barnes et. al., 2005). About 50% of the ore is found
in the sublayer norite and the breccia that is associated with the norite. This ore is
mainly disseminated sulphides. The massive sulphides are located in the center