An integrated zircon geochronological and geochemical investigation into the Miocene plutonic evolution of the Cyclades, Aegean Sea, Greece: Part 1: Geochronology

Bolhar, Robert, Ring, Uwe and Allen, Charlotte M. (2010) An integrated zircon geochronological and geochemical investigation into the Miocene plutonic evolution of the Cyclades, Aegean Sea, Greece: Part 1: Geochronology. Contributions To Mineralogy And Petrology, 160 5: 719-742. doi:10.1007/s00410-010-0504-4


Author Bolhar, Robert
Ring, Uwe
Allen, Charlotte M.
Title An integrated zircon geochronological and geochemical investigation into the Miocene plutonic evolution of the Cyclades, Aegean Sea, Greece: Part 1: Geochronology
Journal name Contributions To Mineralogy And Petrology   Check publisher's open access policy
ISSN 0010-7999
1432-0967
Publication date 2010-11-01
Sub-type Article (original research)
DOI 10.1007/s00410-010-0504-4
Volume 160
Issue 5
Start page 719
End page 742
Total pages 24
Place of publication Heidelberg, Germany
Publisher Springer
Language eng
Formatted abstract
We use 369 individual U-Pb zircon ages from 14 granitoid samples collected on five islands in the Cyclades in the Aegean Sea, Greece, for constraining the crystallisation history of I- and S-type plutons above the retreating Hellenic subduction zone. Miocene magmatism in the Cyclades extended over a time span from 17 to 11 Ma. The ages for S-type granites are systematically ~2 million years older than those for I-type granites. Considering plutons individually, the zircon data define age spectra ranging from simple and unimodal to complex and multimodal. Seven of the 14 investigated samples yield more than one distinct zircon crystallisation age, with one I-type granodiorite sample from Mykonos Island representing the most complex case with three resolvable age peaks. Two samples from S-type granites on Ikaria appear to have crystallised zircon over 2-3 million years, whereas for the majority of individual samples with multiple zircon age populations the calculated ages deviate by 1-1. 5 million years. We interpret our age data to reflect a protracted history involving initial partial melting at deeper lithospheric levels, followed by crystallisation and cooling at shallower crustal levels. Our study corroborates published research arguing that pluton construction is due to incremental emplacement of multiple magma pulses over a few million years. Assuming that multiple age peaks of our 14 samples can indeed serve to quantify time spans for magmatic emplacement, our data suggest that Aegean plutons were constructed over a few million years. Our tectonic interpretation of the U-Pb ages is that the S-type granites resulted from partial melting and migmatisation of the lower crust, possibly starting at ~23 Ma. The I-type granites and associated mafic melts are interpreted to reflect the magmatic arc stage in the Cyclades starting at ~15 Ma. © 2010 Springer-Verlag.
Keyword Aegean Sea
Cyclades
Granitoids
Hellenic subduction zone
I-type
S-type
Zircon geochronology
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
Official 2011 Collection
 
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Created: Sun, 31 Oct 2010, 10:12:43 EST