The Troodos ophiolitic complex probably formed in a subduction initiation, slab edge setting
Miyashiro (1973) famously initiated a debate on the tectonic setting of ophiolite complexes by proposing that ‘the Troodos ophiolitic complex was probably formed in an island arc’. This paper evaluates and updates Miyashiro's work by: (a) using the Mehegan–Robinson set of 137 fresh volcanic gla...
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Published in | Gondwana research Vol. 18; no. 1; pp. 60 - 81 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
01.07.2010
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Subjects | |
Online Access | Get full text |
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Summary: | Miyashiro (1973) famously initiated a debate on the tectonic setting of ophiolite complexes by proposing that ‘the Troodos ophiolitic complex was probably formed in an island arc’. This paper evaluates and updates Miyashiro's work by: (a) using the Mehegan–Robinson set of 137 fresh volcanic glass analyses to sidestep the controversy over the effect of alteration on major element classification diagrams; (b) using the volcanic glass database for Troodos analogues such as back-arc basins, slab edges, forearcs and subduction initiation terranes; (c) revising Miyashiro's classifications by including the boninitic series and subdividing the tholeiitic series into high- and medium-Fe series; and (d) extending Miyashiro's methodologies to new developments in the interpretation of major element data. We conclude that the Troodos Massif is made up of oceanic crust built from a high-Si8, moderate-Fe tholeiitic magma, overlain by boninites. Its low K8/H8 is consistent with near-trench crustal accretion and its Na8–Fe8 systematics indicate that
T
P
=
c.1400
°C for the Lower Lavas, consistent with rapid slab roll-back and/or sideways influx of hot mantle. Overall, the geochemical characteristics and geological setting support models in which the Troodos Massif formed by slab roll-back following subduction initiation, probably near a slab edge. |
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ISSN: | 1342-937X 1878-0571 |
DOI: | 10.1016/j.gr.2009.12.003 |