Geochronology and lithogeochemistry of granitoid rocks from the central part of the Central plutonic belt, New Brunswick, Canada: implications for Sn-W-Mo exploration
DOI:
https://doi.org/10.4138/atlgeol.2016.007Keywords:
Acadian Plutonic Belt, geochronology, granite, lithogeochemistry, granophile mineralization, Miramichi inlier, Burnthill plutonAbstract
The central part of the Central plutonic belt in New Brunswick is underlain by numerous plutons of calc-alkaline, foliated and unfoliated granite that intrude Cambrian to Early Ordovician metasedimentary rocks. U-Pb (zircon) dating demonstrates that granites range in age from Middle Ordovician to Late Devonian, although most are late Silurian to Early Devonian. An age of 467 ± 7 Ma has been obtained on the foliated McKiel Lake Granite, whereas unfoliated intrusions yield ages of 423.2 ± 3.2 Ma (Bogan Brook Granodiorite), 420.7 +1.8/-2.0 Ma (Nashwaak Granite), 419.0 ± 0.5 Ma (Redstone Mountain Granite), 416.1 ± 0.5 Ma (Beadle Mountain Granite), 415.8 ± 0.3 Ma (Juniper Barren Granite), 409.7 ± 0.5 Ma (Lost Lake Granite), and 380.6 ± 0.3 Ma (Burnthill Granite). All plutons exhibit mixed arc-like and within-plate geochemical signatures, although the Redstone Mountain and Burnthill granites are dominantly of within-plate type. Trace element data reveal a close overall geochemical similarity between Ordovician and Silurian – Devonian plutons, indicating that all were generated by partial melting of the same crustal source. Late Silurian to Early Devonian plutons mainly comprise biotite and/or muscovite-bearing, peraluminous granite and are considered prospective for granophile-element mineralization. All plutons contain Sn well in excess of the granite global average abundance, and several contain average tin values comparable to productive stanniferous granites elsewhere. The Burnthill, Lost Lake, Beadle Mountain, and Nashwaak granites are geochemically most evolved and enriched in Sn and W. The Burnthill Granite in particular has experienced late-stage hydrothermal processes that have resulted in local enrichments of these elements.
Published
How to Cite
Issue
Section
License
All material contained in Atlantic Geology is copyrighted by the journal. Permission to photocopy for internal or personal use or for the internal or personal use of specific clients is granted by Atlantic Geology to libraries and other users registered with the Copyright Clearance Center (CCC), provided that the stated fee per copy is paid directly to the CCC, 21 Congress Street, Salem, Massachusetts 01970 USA. Other requests should be addressed to one of the journal editors, or sent to Atlantic Geology, Box 116, Acadia University, Wolfville, NS, Canada B4P 2R6. Permission to use a single graphic for which Atlantic Geology owns copyright is considered “fair dealing” under the Canadian Copyright Act and “fair use” by the journal, and no other permission need be granted, subject to the image being appropriately cited in all reproductions. The same fair dealing/fair use policy applies to sections of text up to 100 words in length.