Four gold showings from the Batchawana greenstone belt, northern Ontario

Abstract

An examination of the mineralogy, alteration assemblages, analytical data and geology of four gold showings from the Batchawana greenstone belt in northern Ontario is the focus of this thesis. Quartz, carbonate minerals, chlorite and sulfides (mostly pyrite) are the most abundant minerals present. The mineral assemblages are indicative of retrograde metamorphic conditions. Calcite alteration is ubiquitous, iron carbonate (ankerite and possibly ferroan dolomite) minerals are common in gold mineralized areas (Horseshoe Pond South, South Alteration Zone). Silicification is abundant in certain areas and is in the form of quartz veins and injections. Sulfidation is common and there is a spatial relationship between sulfides and gold mineralization. Analytical data is sparse and subsequent interpretation difficult. Rock composition as plotted on an AFM diagram resemble those in the calc-alkali plot of Irvine and Baragar (1971). Intermediate to mafic volcanic rocks are the most abundant rock type in the area. Quartz rich felsic volcanic rocks occur as lens shaped units interbedded with more mafic rocks. Chemically precipitated sedimentary rocks host 2 of the 4 gold showings in the area. Late stage mafic intrusive rocks are common and occur as dikes and sills. Many geological characteristics found in the study area can be found in other gold camps within the Superior geological province. On the basis of these similarities a genetic model has been proposed for the area. This model incorporates models proposed by Colvine et al. (1984) and Hodgson and MacGeehan (1982).