T100 Fundamental Insights from Field and Laboratory Studies Related to the Genesis and Ore-Forming Processes Associated with Granitoid Generation and Evolution to Their Related Alteration and Mineralization

Tuesday, 27 October 2020
5:30 PM - 8:00 PM
Meeting Rooms

POST-ACCRETIONARY GRANITOID-RELATED MINERALIZATION IN THE CANADIAN APPALACHIANS: THE ROLE OF REACTIVATED STRUCTURES AND THE LITHOSPHERIC MANTLE

Paper number: T100-5
Program: Technical Sessions
Time: 6:30 PM – 6:45 PM

Authors

  • Dawn Kellett Presenting Author
    Geological Survey of Canada Atlantic Canada Division, Dartmouth, NS

Abstract

Post-accretionary granitoids of the Canadian Appalachians are an important polymetallic metallotect (e.g., Sn, W, Mo, Au, In) that includes significant resources such as New Brunswick’s Sisson and Mount Pleasant deposits and Nova Scotia’s East Kemptville deposit. Accretionary orogenic systems like the Canadian Appalachians involve multiple accretionary episodes over a protracted period, resulting in a patchwork of accreted terranes and a complex structural network. While post-accretionary granitoids are widespread in both space and time in accretionary orogens, not all post-orogenic magmatic events are associated with significant polymetallic mineralization. Several new geochronological and geochemical studies of post-accretionary granitoids and new studies on post-accretionary fault reactivation in the Canadian Appalachians merit a review of the orogen’s post-accretionary granitoid record. The spatio-temporal distribution, relationships to (re)activated fault systems, and geochemical characteristics of Late Devonian granitoids in particular point to orogen-wide melting at the base of the crust/uppermost mantle that was channeled by active crustal-scale structures into all accreted terranes. Accompanying significant mineralization in most Late Devonian intrusive suites irrespective of host terrane suggests that mantle-derived magma was a controlling factor in the metal budget. However, the tectonic drivers for the deep-seated melting remain poorly understood, warranting further study into the evolution of the lithospheric mantle during this period.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-357256

© Copyright 2020 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.