Publication Type:Journal Article
Source:Canadian Journal of Earth SciencesCanadian Journal of Earth Sciences, Canadian Science Publishing, Volume 51, Number 8, p.750-774 (2014)
Keywords:Gallium, geochronology, Hydraulic structures, Inductively coupled plasma mass spectrometry, Lakes, laser ablation, Lead alloys, Levees, phase equilibria, Silicate minerals, tectonics, zircon
New structural and geochronological data are presented for two orogenic events, the Blezardian and Yavapai orogenies, which affected the Paleoproterozoic Southern Province near Sudbury, Ontario, Canada. The Southern Province comprises ca. 2452 Ma metavolcanic rocks and metasedimentary rocks of the Huronian Supergroup, which were deposited along the southern margin of the Archean Superior craton during its evolution from a rifted to passive continental margin. Emplacement of the ca. 2415 Ma Creighton pluton during rifting was followed by its deformation and the development of a penetrative gneissic fabric during the ca. 2415 - ca. 2219 Ma Blezardian Orogeny. New laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb zircon ages of 2343 17 and 2344 47 Ma on two granitic dikes that cut this fabric provide a new minimum age of ca. 2.34 Ga for the Blezardian Orogeny. The Sudbury area was then impacted by a large extraterrestrial bolide at ca. 1.85 Ga and deformed during the Penokean Orogeny. The southern part of the Southern Province was later reworked by regional folding and north-directed thrusting during the younger 1.7 Ga Yavapai Orogeny. The 1744 29 Ma Eden Lake Complex was emplaced and deformed during this event, which produced a strong foliation overprinting the complex. The foliation formed at pressures of 2.8-4 kbar (1 kbar = 100 MPa) and temperatures of 540-565 C and was intruded by a weakly deformed 1704 13 Ma old granitic dike, bracketing the Yavapai event between 1744 29 and 1704 13 Ma in the Sudbury segment of the Southern Province. Crustal thickening associated with the Yavapai event resulted, locally, in minor pressure increases before or during regional metamorphism as revealed by phase equilibria modeling in the Raft Lake area; this evolution may be recorded elsewhere in the Ontario segment of the Southern Province.
Compilation and indexing terms, Copyright 2018 Elsevier Inc.<br/>20143218035607<br/>Crustal thickenings<br/>Laser ablation inductively coupled plasma mass spectrometries (LA ICP MS)<br/>Metasedimentary rocks<br/>Metavolcanic rocks<br/>Ontario , Canada<br/>Passive continental margin<br/>Pressure increase<br/>Regional metamorphisms