The tectonic evolution of the Taltson Magmatic Zone: a reconnaissance study
Authors: Bostock H H 
Published: December 2014

This 1:250 000 scale synthesis of the Northern Taltson Magmatic Zone is a posthumous release on behalf of Dr. H.H. Bostock, based on published and unpublished compilations, published figures in papers, primary field station data and geochronology. It encompasses
NTS sheets 75D and E, and parts of 85A and H, and 75C and D. It does not incorporate geological data obtained by others during or after his preliminary compilation, unless specifically identified by Dr. Bostock. His primary observations and interpretations were made in 1979-1981,1983, 1985-1989,
1991 and 1997; including approximately: 16,530 observational station sites, 17,500 rock type / lithological descriptions, 26,000 structural and 500 kinematic indicator measurements, 11,400 samples, 2000 Pleistocene measurements and descriptions, 200 economic mineral observations, 200 radiometric
measurements, and many metamorphic mineral counts. Laboratory analyses included representative lithology, silicate and ore petrology, mineral identi-fication, geochemistry, paleo-magnetic determinations, and structural analysis of oriented samples. Dr. Bostock's futuristic computerized data
compilations using standardized data entry and punch cards for a main frame computer are the timeless ground-truth framework for this compilation, and are included in this digital release for future syntheses.
This map spans from west to east three major elements: the Taltson Magmatic Zone (TMZ), the Taltson-Rae Interface (T-RI) and isolated parts of the western Rae Province (Rae). The TMZ - T-RI contact is demarked by the sinistral Allan and Gagnon shear zones, the elongate Arch Lake and Gagnon granites,
and the Berrigan Lake anorthositic complex. The TMZ comprises mainly north-south trending granitoid suites with infolds and folded enclaves of Rutledge paragneiss with minor metabasite. The granitoid suites include the western 1.986 Ga Deskenatlata granodiorite, a middle 1.955 Ga
mp;lt;"Slave-typemp;gt;" monzo-granite, which is in turn intruded by the central Konth batholith (1.937 Ga), several other late 1.938 -1.906 Ga granitoids (Arch Lake, Natael, Othikethe Falls, Gagnon, Benna Thy) and post-TMZ bodies, a 1.882 Ga late Gagnon phase and a 1.813 Ga Thekulthili stock.
Metasedimentary packages include the pervasive Rutledge River paragneiss which occurs throughout the entire map area and a lithologically similar unit the Mama Moose paragneiss (distinguinshed by absence of tourmaline and graphite; youngest detrital zircon 2.08 Ga) confined to the eastern margin of
the TMZ and may be allochthonous. Within the southern T-RI, the tectonically isolated north-south Hill Island meta-sedimentary package appears to be intruded by the also-tectonized 1.934 Ga Natael granite at the interface between the Taltson (west) and Nonacho (east) basement gneisses. In the
northern T-RI the minimally meta-morphosed but folded and faulted syn-tectonic Nonacho Group comprises three alluvial mega-cycles that rest unconformably upon fault blocks of the Nonacho (and locally Taltson) basement gneisses. The T-RI is intruded by 2.437 and 2.227 Ga early Rae granites, and the
2.340 Ga Thoa metagabbro. A small area of presumed Paleoproterozoic uncorrelated quartzite is exposed at the extreme western margin of the Deskenatlata granodiorite, flanked by Quarternary deposits.