A Base and Precious Metal Study of BIF Associated Interflow Metasediments, Kirkland Lake, Ontario.

Abstract

<p>The interflow sediments studied are part or the Boston iron range in the Larder Lake Group near Kirkland Lake, Ontario. Due to the proximity or the Lebel stock, transitional contact metamorphism between hornblende-hornfels Facies and albite-epidote-hornfels facies has been inferred for the study area. A later regional overprint or lower greenschist Facies has also been interpreted.</p> <p>Base metal mineralization in the area is Zn rich. However, it is not genetically related to the BIF. Instead, the base metal mineralization may have been introduced during the intrusion or the Lebel stock by metasomatic processes associated with contact metamorphism.</p> <p>Anomalous Au abundances ( > 10 ppb) in the study area is inferred to be associated with sulphide mineralization and possibly active carbon. Sulphide samples associated with anomalous Au concentrations usually display the annealing recrystallization of fine grained cataclastic pyrite. A statistically positive correlation between Zn and Au was also determined. This may imply that the Au was introduced synchronously with or post intrusion or the Lebel stock. Anomalous Au values in the chemical sediments were noted to coincide with high As and Sb concentrations.</p>