Ocean plate stratigraphy and its imbrication in an accretionary orogen: The Mona Complex, Anglesey-Lleyn, Wales, UK

S. Maruyama, T. Kawai, B. F. Windley

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

We re-evaluate the Neoproterozoic, Pacific-type accretionary complex on Anglesey and in the Lleyn peninsula (Wales, UK), by reconstructing its ocean plate stratigraphy (OPS). Three types of distinctive OPS were successively emplaced downwards in an accretionary wedge: the oldest at the top formed when an ocean opened and closed from a ridge to a trench, the central OPS was subjected to deep subduction and exhumed as blueschists, and the youngest at the bottom is an olistostrome-type deposit that formed by secondary gravitational collapse of previously accreted material. The three types formed by successive eastward subduction of young oceanic lithosphere at the leading edge of Avalonia. The downward growth of the accretionary complex through time was almost coeval with exhumation of the blueschist unit at 550-560 Ma in the structural centre of the complex on Anglesey. From balanced sections we have reconstructed the ocean plate stratigraphy on Llanddwyn Island from which we calculate that about 8 km of lateral shortening of ocean floor took place during imbrication and accretion; this is comparable with the history of plate subduction around the Pacific Ocean. We also calculate that the age of the subducted lithosphere was very young, probably less than 10 Ma.

Original languageEnglish
Pages (from-to)55-75
Number of pages21
JournalGeological Society Special Publication
Volume338
DOIs
Publication statusPublished - 2010
Externally publishedYes

Fingerprint

imbrication
Stratigraphy
stratigraphy
ocean
blueschist
subduction
olistostrome
Avalonia
Deposits
accretionary prism
oceanic lithosphere
exhumation
trench
lithosphere
seafloor
accretion
history
young

ASJC Scopus subject areas

  • Ocean Engineering
  • Water Science and Technology
  • Geology

Cite this

Ocean plate stratigraphy and its imbrication in an accretionary orogen : The Mona Complex, Anglesey-Lleyn, Wales, UK. / Maruyama, S.; Kawai, T.; Windley, B. F.

In: Geological Society Special Publication, Vol. 338, 2010, p. 55-75.

Research output: Contribution to journalArticle

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