Evidence for Mesoproterozoic basement in the Carolina Terrane and speculations on its origin

Abstract

Terranes with concurrent Neoproterozoic magmatism in the Appalachian orogen of North America include the Avalon, Carolina, and Suwannee terranes. The extent to which these terranes can be correlated cannot be ascertained, however, without complete characterization of the basement present when magmatism took place. Premagmatic zircons and Nd model ages of mafic to silicic volcanic rocks of the Carolina terrane exposed in the Carolina slate belt of central North Carolina provide direct evidence of the involvement of Mesoproterozoic basement in their petrogenesis. The combination of Neoproterozoic magmatic activity and Mesoproterozoic basement suggests that the Carolina terrane may have a distinct history relative to many other circum-Atlantic, Neoproterozoic arc terranes. In particular, the chronologic and isotopic similarity of the inferred Carolina arc basement to that of the nearby Blue Ridge province suggests the possibility that the Carolina terrane may be allochthonous, but not exotic.

Puncoviscana folded belt in northwestern Argentina: testimony of Late Proterozoic Rodinia fragmentation and pre-Gondwana collisional episodes: a reply

“…The triple points have been positioned to follow the interpretation of lith terrane that provides an ideal database of piercing points (Karlstrom et al 1999) against which the ªpoli-orogenic Grenvillian rocksº of eastern Laurentia and western Pannotia±Gondwana basement can be compared. This implies that radiometric age determinations and depleted mantle model ages associated with the Grenville basement of the central Andes (Wasteneys et al 1995;Tosdal 1996;Lezaun et al 1997;Wörner et al 2000) are isotopically undistinguishable from the North American Grenville provinces Murphy 1994, 1996;Keppie et al 1996, Mueller et al 1996Murphy et al 1996). The Amazonian affinity of the CABA (Cuyania-Antofalla-Belen-Arequipa) fragments via Rhondonian±San Ignacio (1.45±1.25 Ga) and Sunsas±Aquapei provinces (1.1±0.9 Ga; Litherland et al 1985) is particularly convincing as it is the Amazonian±West Africa connection of the Avalon composite terrene (Landing 1996;Nance and Thompson 1996;Keppie and Dostal 1998;Dallmeyer 1990).…”

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“…In Alabama, the Suwannee terrane contains felsic volcanic rocks intruded by granodiorite that are overlain by Lower Ordovician through Devonian sedimentary rocks containing Gondwanan faunal assemblages (Applin, 1951;Barnett, 1975;Neathery and Thomas, 1975;Pojeta et al, 1976;Chowns and Williams, 1983;Guthrie and Raymond, 1992;Mueller et al, 1994Mueller et al, , 1996.…”

U–Pb detrital zircon data of the Rio Fuerte Formation (NW Mexico): Its peri-Gondwanan provenance and exotic nature in relation to southwestern North America

“…In the Avalon zone, magmatic rocks are divided into three groups; (a) about 760 Ma volcanic rocks related to ocean basins and immature island arcs, (b) 685-670 Ma arc-related felsic magmatism, (c) 635-590 Ma arc or arc-rift magmatism, and (d) 590-545 Ma contraction-extension related magmatism (O'Brien et al, 1996). In the Carolina terrane, arc to arc-rift related magmatism encompasses a period from 650 to 540 Ma (Mueller et al, 1996;Wortman et al, 2000). Zircon age clusters of 806 and 723 Ma in the Rio Fuerte rocks and the Paleoproterozoic zircons can also originate from the Pan-African-Brazilian orogen of Gondwanaland ($850-540 Ma; Da Silva et al, 2005) and its basement.…”