Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Dynamics of accretion of arc and backarc crust to continental margins: inferences from the Annieopsquotch accretionary tract, Newfoundland Appalachians

Zagorevski, A., Lissenberg, Cornelis Johan and van Staal, C.R. 2009. Dynamics of accretion of arc and backarc crust to continental margins: inferences from the Annieopsquotch accretionary tract, Newfoundland Appalachians. Tectonophysics 479 (1-2) , pp. 150-164. 10.1016/j.tecto.2008.12.002

Full text not available from this repository.

Abstract

The Annieopsquotch accretionary tract comprises a thrust stack of Lower to Middle Ordovician arc and backarc terranes that were accreted to the Laurentian margin of Iapetus during Middle to Upper Ordovician. Geological relationships suggest that the constituent terranes of the Annieopsquotch accretionary tract initially formed outboard of a peri-Laurentian Dashwoods microcontinent in an extensional arc, but occupied a lower plate setting with respect to Dashwoods during accretion. Metamorphic mineral assemblages indicate that the terranes were underplated beneath the composite Laurentian margin at depths ranging from ~ 3 km up to > 18 km. We infer the accretion of the terranes to be controlled by the brittle–ductile transition in the hydrated crust. The decoupling of brittle from ductile crust resulted in very high aspect ratios of the terranes, which comprise thin (< 5 km) but very large (up to 25 × 250 km) slabs of supracrustal arc rocks and ophiolite crust. Arc basement and ophiolitic mantle are not preserved and were either underplated at a greater depth or subducted and recycled back in the mantle. The accreted crust forms a reasonable approximation to bulk continental crust requiring little post-accretionary modification; hence, the accretion of arc–backarc complexes which occupy a lower plate setting can form an important mechanism for creation of new continental crust required to balance crustal loss at convergent margins.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Ocean Sciences
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Q Science > QE Geology
Uncontrolled Keywords: Lapetus Ocean; Volcanic arcs; Back-arc basin ophiolites; Accretion; Underplating
Publisher: Elsevier
ISSN: 0040-1951
Last Modified: 04 Jun 2017 02:09
URI: http://orca.cf.ac.uk/id/eprint/9909

Citation Data

Cited 27 times in Google Scholar. View in Google Scholar

Cited 32 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item