Formation temperature of fluorite in the Lockport Dolomite in upper New York State as indicated by fluid inclusion studies; with a discussion of heat sources

Abstract

Fluid inclusion geothermometry studies of fluorite crystals from Penfield Quarry in the Silurian Lockport Dolomite of upstate New York indicate that mineralizing fluids with temperatures in the range of 137 + or - 5 degrees C were at least in part responsible for the minerals found there. This temperature is higher than can be explained within the framework of present knowledge of the geology of upstate New York and of its geologic history. Some one or any combination of the following must be true: 1) The Lockport must have been buried more deeply than present reconstructions indicate, 2) mineralizing fluids from a remote heat source must have been introduced into the Lockport along unknown channels, 3) the geothermal gradient of the area must have been considerably higher than the present value, 4) a post- (or late-) Silurian intrusion must be present beneath the Lockport.