A NOTE ON THE GEOCHEMISTRY OF SOME SHALES FROM THE BATHURST-NEWCASTLEMINING CAMP, NORTHERN NEW-BRUNSWICK

Ordovician volcanic and sedimentary rocks of the Tetagouche Group in t he Bathurst-Newcastle area of northern New Brunswick are host to numer ous stratiform sulphide deposits that appear restricted to certain str atigraphic horizons. As a mapping aid in these complexly deformed rock s, shales from some of the recently established formational divisions within the Tetagouche Group were analyzed to determine if they possess specific geochemicar signatures that could be used for correlative pu rposes. Grey and black shales from the Patrick Brook Formation in the lower part of the Tetagouche Group of northern New Brunswick do not ex hibit the enrichment in V and U that is characteristic of black shale from the Bright Eye Brook Formation of west-central New Brunswick. Bla ck cherty shales from the Boucher Brook Formation in the upper part of the Tetagouche Group and from the Pointe Verte Formation of the Fourn ier Group are mildly enriched in V and U. Grey shale from the Boucher Brook Formation is enriched in Mn, Zn, Ni, Cu, and Co, and displays a positive Ce anomaly and elevated values of light rare-earth elements c ompared to average shale. This variation in geochemistry reflects a ch ange in depositional conditions from anoxic to oxic between the early and mid-Ordovician and accounts for the abundance of preserved sulphid e deposits in the lower part of the Tetagouche Group.