Archived U-Pb (zircon) dates from southern New Brunswick

Abstract

U-Pb (zircon) ages for eight samples from southern New Brunswick were determined during the early 1990's as part of a regional mapping and correlation program. Although most of the dates have been subsequently quoted in the literature through personal communications, and some preliminary isochron diagrams have been incorporated in papers, the results have not been published in their entirety. The units sampled and best estimates for their ages are the Lobster Brook Formation

A Review of Proterozoic to Early Paleozoic Lithotectonic Terranes in New Brunswick, Canada and their Tectonic Evolution during Penobscot, Taconic, Salinic and Acadian Orogenesis

“…A rhyolitic tuff from Gorhams Bluff (Fig. 3) yielded a Neoproterozoic U-Pb zircon date of 554 ± 6 Ma (Johnson 2001;McLeod et al 2003), demonstrating that the Lobster Brook Formation is considerably younger than the Lingley Plutonic Suite with which it is in fault contact.…”

“…The Ellsworth Group in New Brunswick consists of quartzose sandstone and intraformational quartzite-pebble conglomerate of the Matthews Lake Formation; and overlying felsic flows and breccia, iron-rich tuff, and volcaniclastic sandstone of Mosquito Lake Road Formation. Rhyolite breccia in the upper part of the Mosquito Lake Road Formation yielded a late Early Cambrian U-Pb zircon date of 514 ± 2 Ma (Johnson and McLeod 1996;Johnson 2001;McLeod et al 2003). The volcanic rocks of the Mosquito Lake Road Formation range in composition from andesite to rhyolite and possess an arc geochemical signature (Johnson and McLeod 1996).…”

“…3) is composed mainly of the Neoproterozoic Ragged Falls Granite (Fig. 4) Johnson and McLeod 1996;Johnson 2001;McLeod et al 2003). Comagmatic felsic volcanic host rocks from the Leavitts Head Formation of the Belleisle Bay Group yielded a U-Pb zircon date of 554 ± 3 Ma (McLeod et al 2003).…”

“…However, recent U-Pb zircon dating yielded Early Silurian (Llandoverian) ages of 436 ± 3 Ma, 437 ± 3 Ma, and 442 ± 6 Ma on felsic volcanic rocks of the Kingston Group, and 436 ± 2 Ma, 435 ± 5 Ma, and 437 ± 10 Ma on comagmatic felsic plutons and dykes Barr et al 2002;McLeod et al 2003). The Silurian Kingston Group is divided into several formations and is interpreted on the basis of geochemical and paleogeographical considerations to represent a volcanic arc that formed above a subduction zone dipping to the northwest beneath the New River terrane Barr et al 2002;White et al 2006).…”

“…4) Johnson and McLeod 1996;Johnson 2001;McLeod et al 2003). Comagmatic felsic volcanic host rocks from the Leavitts Head Formation of the Belleisle Bay Group yielded a U-Pb zircon date of 554 ± 3 Ma (McLeod et al 2003). The Simpsons Island Formation (Belleisle Bay Group), comprising a sequence of felsic and mafic volcanic rocks and arkosic sandstone, lies along the southern margin of the Ragged Falls Granite just north of the Letang Harbour Fault (Fig.…”