Geochemistry and geochronology of HP mélanges from Tinos and Andros, cycladic blueschist belt, Greece

Bulle, Florian; Bröcker, Michael; Gärtner, Claudia; Keasling, A.

doi:10.1016/j.lithos.2010.02.004

Cited by 85 publications

(139 citation statements)

References 72 publications

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“…They are thus ''pseudo-inclusions'' with respect to the host igenous zircon domain. Similar cases were also reported when high-pressure rocks from the Cycladic blueschist belt, Greece (Bulle et al, 2010) and jadeitites from the Jade Mine Tract, Myanmar were studied . Both examples showed that metamorphic or metasomatic phases of omphacite, epidote, albite, jadeite, chlorite, Na-amphibole and catapleiite included within zircons studied are of secondary origin.…”

Section: Criteria To Distinguish the Nature Of Zircons In Jadeititesupporting

confidence: 81%

A revisit to the Yorii jadeite–quartz rock, the Kanto Mountains, central Japan: Implications for petrogenesis

Yui

Fukuyama

2015

Journal of Asian Earth Sciences

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Section: Criteria To Distinguish the Nature Of Zircons In Jadeititesupporting

confidence: 81%

A revisit to the Yorii jadeite–quartz rock, the Kanto Mountains, central Japan: Implications for petrogenesis

Yui

Fukuyama

2015

Journal of Asian Earth Sciences

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“…Interpretations suggesting a prolonged Cretaceous–Eocene subduction history that are based on U–Pb zircon data (e.g. Bröcker & Keasling, ) have not yet been confirmed (Bulle et al ., ; Fu et al ., ).…”

Section: Geological Backgroundmentioning

confidence: 99%

The geological significance of ⁴⁰Ar/³⁹Ar and Rb–Sr white mica ages from Syros and Sifnos, Greece: a record of continuous (re)crystallization during exhumation?

Bröcker

Baldwin

Arkudas

2013

Journal Metamorphic Geology

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The Attic‐Cycladic crystalline belt in the central Aegean region records a complex structural and metamorphic evolution that documents Cenozoic subduction zone processes and exhumation. A prerequisite to develop an improved tectono‐metamorphic understanding of this area is dating of distinct P–T–D stages. To evaluate the geological significance of phengite ages of variably overprinted rocks, 40Ar/39Ar and Rb–Sr analyses were undertaken on transitional blueschist–greenschist and greenschist facies samples from the islands of Syros and Sifnos. White mica geochronology indicates a large age variability (40Ar/39Ar: 41–27 Ma; Rb–Sr: 34–20 Ma). Petrologically similar samples have either experienced greenschist facies overprinting at different times or variations in ages record variable degrees of greenschist facies retrogression and incomplete resetting of isotopic systematics. The 40Ar/39Ar and Rb–Sr data for metamorphic rocks from both islands record only minor, localized evidence for Miocene ages (c. 21 Ma) that are well documented elsewhere in the Cyclades and interpreted to result from retrogression of high‐pressure mineral assemblages during lower pressure metamorphism. Field and textural evidence suggests that heterogeneous overprinting may be due to a lack of permeability and/or limited availability of fluids in some bulk compositions and that retrogression was more or less parallel to lithological layering and/or foliation as a result of, possibly deformation‐enhanced, channelized fluid ingress. Published and new 40Ar/39Ar and Rb–Sr data for both islands indicate apparent age variations that can be broadly linked to mineral assemblages documenting transitional blueschist‐to‐greenschist‐ and/or greenschist facies metamorphism. The data do not record the timing of peak HP metamorphism, but may accurately record continuous (partial) resetting of isotopic systematics and/or (re)crystallization of white mica during exhumation and greenschist facies retrogression. The form of 40Ar/39Ar phengite age spectra are complex with the lowest temperature steps yielding Middle to Late Miocene ages. The youngest Rb–Sr ages suggest maximum ages of 20.6 ± 0.8 Ma (Syros) and 22.5 ± 0.6 Ma (Sifnos) for the timing of greenschist facies overprinting. The results of this study further accentuate the challenges of interpreting isotopic data for white mica from polymetamorphic terranes, particularly when mixing of populations and/or incomplete resetting of isotopic systematics occurs during exhumation. These data capture the full range of isotopic age variations in retrogressed HP rocks documented in previous isotopic studies, and can be interpreted in terms of the geodynamic evolution of the Aegean.

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“…5b: I). This is also supported by the fact that U-Pb zircon ages of 80 Ma from (meta-)gabbroic rocks cropping out on several Cycladic Islands (Bulle et al, 2010), indicate Late Cretaceous basic magmatism, which has not been recorded from the ophiolite complexes related with Pindos Ocean (Dilek et al, 2007). However, more data are required to discriminate between models suggesting an incipient oceanic basin for the formation of the CBU's protolith.…”

Section: Discussionmentioning

confidence: 86%

“…In any case, the results presented here do not support the occurrence of a mature oceanic basin as the potential site for the formation of the CBU on Sikinos and Sifnos. However, it should be emphasized that in other islands the CBU shows evidence for larger oceanic component expressed by the presence of metacherts-rich marbles (e.g., Evia; Xypolias et al, 2012) and ultrabasic rocks (e.g., Syros and Tinos; Bulle et al, 2010). Therefore, it is reasonable to assume that the original protolithic sequence of CBU on Sikinos and Sifnos were formed along the margin of the rift basin.…”

Section: Discussionmentioning

confidence: 99%

The Tectonostratigraphy of Cycladic Blueschist Unit on Sikinos and Sifnos: Implication for the Mesozoic Tectonic Setting

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Geochemistry and geochronology of HP mélanges from Tinos and Andros, cycladic blueschist belt, Greece

Cited by 85 publications

References 72 publications

A revisit to the Yorii jadeite–quartz rock, the Kanto Mountains, central Japan: Implications for petrogenesis

A revisit to the Yorii jadeite–quartz rock, the Kanto Mountains, central Japan: Implications for petrogenesis

The geological significance of ⁴⁰Ar/³⁹Ar and Rb–Sr white mica ages from Syros and Sifnos, Greece: a record of continuous (re)crystallization during exhumation?

The Tectonostratigraphy of Cycladic Blueschist Unit on Sikinos and Sifnos: Implication for the Mesozoic Tectonic Setting

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Geochemistry and geochronology of HP mélanges from Tinos and Andros, cycladic blueschist belt, Greece

Cited by 85 publications

References 72 publications

A revisit to the Yorii jadeite–quartz rock, the Kanto Mountains, central Japan: Implications for petrogenesis

A revisit to the Yorii jadeite–quartz rock, the Kanto Mountains, central Japan: Implications for petrogenesis

The geological significance of 40Ar/39Ar and Rb–Sr white mica ages from Syros and Sifnos, Greece: a record of continuous (re)crystallization during exhumation?

The Tectonostratigraphy of Cycladic Blueschist Unit on Sikinos and Sifnos: Implication for the Mesozoic Tectonic Setting

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The geological significance of ⁴⁰Ar/³⁹Ar and Rb–Sr white mica ages from Syros and Sifnos, Greece: a record of continuous (re)crystallization during exhumation?