Regional Infiltration of Meteoric Water into the Mira Terrane: a Stable Isotope Study of the Avalonian Huntington Mountain Pluton and Related Rocks, Cape Breton Island, Canada

• Main Author: Petts, Duane C.
• Format: Text
• Language: unknown
• Published: Scholarship@Western 2008
• Subjects: Avalon Zone; Carbon-isotope; Hydrogen-isotope; Hydrothermal; Meteoric Water; Mira Terrane; Northern Appalachian Orogen; Oxygen-isotope; Plutonic; Volcanic; Canada; Breton Island; Huntington; Mira; East Bay
• Online Access: https://ir.lib.uwo.ca/digitizedtheses/4753; https://ir.lib.uwo.ca/context/digitizedtheses/article/8555/viewcontent/2023_11_20_Infiltration_of_Meteoric_Water_Into_the_Mira_Terrane_OCR.pdf

The Avalonian Mira terrane of Cape Breton Island, Nova Scotia, Canada is composed mainly of late Proterozoic volcanic-plutonic-sedimentary rocks that formed in an evolved magmatic arc along the margin of Gondwana. The purpose of this study is to determine the source(s) and timing of the 18O-depletion that has affected the 620 Ma Huntington Mountain pluton and East Bay Hills volcanic suite of the Mira terrane. Plutonic and volcanic rock samples have oxygen-, hydrogen- and carbon-isotope values of-6.3 to +14.3‰, -93 to -56‰, and -7.4 to +0.1‰, respectively. These values likely signal the interaction of meteoric-dominated hydrothermal fluids with the Himtington Mountain pluton and East Bay Hills volcanic suite. The occurrence of widespread, pervasive propylitic alteration and the absence of a localized pattern of oxygen-isotope anomalies suggest that the 18O-depletion arose during initial rifting of the Mira terrane from Gondwana, ca. 575-560 Ma.