File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: The Ayia Varvara Formation of SW Cyprus: A product of complex collisional tectonics

TitleThe Ayia Varvara Formation of SW Cyprus: A product of complex collisional tectonics
Authors
Issue Date1992
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/tecto
Citation
Tectonophysics, 1992, v. 212 n. 3-4, p. 193-211 How to Cite?
AbstractThe Ayia Varvara Formation is a wedge of amphibole schists and intercalated metasediments within the intensely deformed pre-upper Maastrichtian volcanosedimentary Mamonia Complex. All contacts are steep faults against Upper Triassic transitional to alkaline lavas with reefoidal limestones, subalkaline depleted Troodos-type lavas, and serpentinised harzburgite. Ophiolite-related metamorphics are believed to have been formed by dynamothermal processes, beneath young oceanic crust during emplacement. Characteristically, such rocks might be expected to show a decrease of metamorphic grade away from the contact. Mineral analyses from the Ayia Varvara metamorphics, however, show no systematic variations that would indicate a metamorphic gradient. Hornblende remains generally calcic and of tschermakitic hornblende composition with an almost complete substitution of Mg and Fe 2+, suggesting disequilibrium. Plagioclase is essentially albitic and remains so for a distance of some 800 m from the harzburgite contact. Trace element analyses of the amphibolites and surrounding extrusives define four lava types. Types 1-3 are transitional to alkaline intraplate lavas believed to be remnants of intraoceanic islands and atolls. Type 4-lavas are extremely depleted in the HFS elements and are very similar to the Arakapas transform-fault lavas. The amphibolites have, in part, a trace-element geochemistry that is close to mid-ocean ridge basalts (MORB), a type that has not previously been recorded from Cyprus. The small area around Ayia Varvara records a long and complicated tectonic history that provides an insight into the evolution and emplacement of the Troodos ophiolite. The Mamonia Complex is interpreted as a passive margin sequence with intra-oceanic islands that was accreted onto a Late Cretaceous north-dipping subduction zone. Suprasubduction spreading produced the Troodos ophiolite and associated fracture zones. Spreading and subduction ceased in the late Maastrichtian when the newly-formed Troodos crust underwent a 90° anticlockwise rotation which juxtaposed Mamonia and Troodos (Arakapas) fracture zone rocks along arcuate, steep, strike-slip faults. At least some of the Ayia Varvara metamorphic rocks most likely represent Triassic oceanic crust and sediments metamorphosed during subduction by the overriding young Troodos crust. © 1992.
Persistent Identifierhttp://hdl.handle.net/10722/178193
ISSN
2015 Impact Factor: 2.65
2015 SCImago Journal Rankings: 1.971

 

DC FieldValueLanguage
dc.contributor.authorMalpas, Jen_US
dc.contributor.authorXenophontos, Cen_US
dc.contributor.authorWilliams, Den_US
dc.date.accessioned2012-12-19T09:43:21Z-
dc.date.available2012-12-19T09:43:21Z-
dc.date.issued1992en_US
dc.identifier.citationTectonophysics, 1992, v. 212 n. 3-4, p. 193-211en_US
dc.identifier.issn0040-1951en_US
dc.identifier.urihttp://hdl.handle.net/10722/178193-
dc.description.abstractThe Ayia Varvara Formation is a wedge of amphibole schists and intercalated metasediments within the intensely deformed pre-upper Maastrichtian volcanosedimentary Mamonia Complex. All contacts are steep faults against Upper Triassic transitional to alkaline lavas with reefoidal limestones, subalkaline depleted Troodos-type lavas, and serpentinised harzburgite. Ophiolite-related metamorphics are believed to have been formed by dynamothermal processes, beneath young oceanic crust during emplacement. Characteristically, such rocks might be expected to show a decrease of metamorphic grade away from the contact. Mineral analyses from the Ayia Varvara metamorphics, however, show no systematic variations that would indicate a metamorphic gradient. Hornblende remains generally calcic and of tschermakitic hornblende composition with an almost complete substitution of Mg and Fe 2+, suggesting disequilibrium. Plagioclase is essentially albitic and remains so for a distance of some 800 m from the harzburgite contact. Trace element analyses of the amphibolites and surrounding extrusives define four lava types. Types 1-3 are transitional to alkaline intraplate lavas believed to be remnants of intraoceanic islands and atolls. Type 4-lavas are extremely depleted in the HFS elements and are very similar to the Arakapas transform-fault lavas. The amphibolites have, in part, a trace-element geochemistry that is close to mid-ocean ridge basalts (MORB), a type that has not previously been recorded from Cyprus. The small area around Ayia Varvara records a long and complicated tectonic history that provides an insight into the evolution and emplacement of the Troodos ophiolite. The Mamonia Complex is interpreted as a passive margin sequence with intra-oceanic islands that was accreted onto a Late Cretaceous north-dipping subduction zone. Suprasubduction spreading produced the Troodos ophiolite and associated fracture zones. Spreading and subduction ceased in the late Maastrichtian when the newly-formed Troodos crust underwent a 90° anticlockwise rotation which juxtaposed Mamonia and Troodos (Arakapas) fracture zone rocks along arcuate, steep, strike-slip faults. At least some of the Ayia Varvara metamorphic rocks most likely represent Triassic oceanic crust and sediments metamorphosed during subduction by the overriding young Troodos crust. © 1992.en_US
dc.languageengen_US
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/tectoen_US
dc.relation.ispartofTectonophysicsen_US
dc.titleThe Ayia Varvara Formation of SW Cyprus: A product of complex collisional tectonicsen_US
dc.typeArticleen_US
dc.identifier.emailMalpas, J: jgmalpas@hku.hken_US
dc.identifier.authorityMalpas, J=rp00059en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.scopuseid_2-s2.0-0027064110en_US
dc.identifier.volume212en_US
dc.identifier.issue3-4en_US
dc.identifier.spage193en_US
dc.identifier.epage211en_US
dc.publisher.placeNetherlandsen_US
dc.identifier.scopusauthoridMalpas, J=7006136845en_US
dc.identifier.scopusauthoridXenophontos, C=6701391872en_US
dc.identifier.scopusauthoridWilliams, D=15756203800en_US

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats