Journal ArticleDOI
Dating the events of metamorphism and granitic magmatism in the Alpine orogen of Naxos (Cyclades, Greece)
P. A. M. Andriessen,N.A.I.M. Boelrijk,E. H. Hebeda,H.N.A. Priem,E. A. Th. Verdurnen,R. H. Verschure +5 more
TLDR
In this article, an isotopic dating investigation (66 K-Ar and 34 Rb-Sr analyses) provided the geochronological framework for the Alpine events of metamorphism and granitic magmatism on Naxos.Abstract:
An isotopic dating investigation (66 K-Ar and 34 Rb-Sr analyses) provided the geochronological framework for the Alpine events of metamorphism and granitic magmatism on Naxos. The oldest phase of high-pressure/medium-temperature metamorphism, M1, was dated by Rb-Sr and K-Ar analyses of paragonites, phengitic muscovites and muscovites at 45±5 Ma (Middle Eocene). Most of the record of the M1 phase has been eraded by a second phase of medium-pressure/high-temperature metamorphism, M2, which induced a metamorphic zonation with anatectic melting in the highest-grade part, the migmatite dome. Most K-Ar dates of M2 hornblendes, muscovites, biotites and tourmalines range from about 21 Ma in the lower-grade part (biotite-chloritoid zone) to about 11 Ma in the migmatite dome. From the pattern of K-Ar mineral dates it is concluded that the M2 phase took place 25±5 Ma ago (Late Oligocene/Early Miocene) and was followed by a prolonged cooling history until about 11 Ma ago (Late Miocene), when the ambient temperature in the migmatite dome had decreased to below 400−360 °C. A Rb-Sr whole-rock isochron analysis of a granodioritic mass dated the intrusion (and the associated M3 phase of contact-metamorphism) at 11.1±0.7 Ma (Late Miocene), with an initial 87Sr/86Sr ratio of 0.7112 ±0.0001. A local phase of low-grade retrograde metamorphism, M4, probably related to Late Alpine overthrusting, was dated at about 10 Ma (Late Miocene).read more
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Tertiary to Quaternary evolution of volcanism in the Aegean region
TL;DR: In this article, two main phases of orogenic volcanic activity are recognized, one developed in the North Aegean area from Oligocene to Middle Miocene times and a second started in the Pliocene, building the active South Aegeans volcanic arc.
Journal ArticleDOI
Zircons from Syros, Cyclades, Greece—Recrystallization and Mobilization of Zircon During High-Pressure Metamorphism
TL;DR: In this article, high-resolution ion microprobe (SHRIMP) U---Pb ages were obtained from high-pressure/low-temperature metamorphosed meta-igneous lithologies from Syros.
Journal ArticleDOI
40 Ar/ 39 Ar dating of white micas from an Alpine high-pressure metamorphic belt on Naxos (Greece): the resetting of the argon isotopic system
Jan R. Wijbrans,Ian McDougall +1 more
TL;DR: The upward-convex age spectra are caused by mixing of two generations of micas, each of which has a different age spectrum and argon release pattern.
Journal ArticleDOI
Extensional tectonic regimes in the Aegean basins during the Cenozoic
TL;DR: In this article, the authors proposed that the formation of the Northern Aegean basins during the Cenozoic was related to the activity of two major Hellenic arcs.
Journal ArticleDOI
The timing of partial melting, Barrovian metamorphism and granite intrusion in the Naxos metamorphic core complex, Cyclades, Aegean Sea, Greece
TL;DR: In this article, the relationship between partial melting and granite intrusion in a classic Barrovian metamorphic terrane has been assessed using SHRIMP U-Pb zircon geochronology from the island of Naxos, Greece.
References
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Journal ArticleDOI
Least-squares fitting of a straight line.
TL;DR: In this paper, a detailed discussion of the best straight line calculation by the method of least squares is given, and the most general solution is found and the conditions under which certain previously de...
Journal ArticleDOI
The statistical assessment of Rb‐Sr isochrons
TL;DR: In this paper, a new regression method for estimating Rb-Sr isochron parameters is presented, which allows for known experimental error in both SR87/Sr86 and SR86/S86 and which weights the data to allow for the nonuniform Rb87/sr86 variance, which is illustrated with the data for the Heemskirk granite, western Tasmania.
Journal ArticleDOI
87Sr/86Sr composition of seawater during the Phanerozoic
Ján Veizer,William Compston +1 more
TL;DR: In this paper, the lowest 87Sr/86Sr observed for any suite of carbonates is taken as the best approximation to the value in well-mixed contemporary seawater.
Journal ArticleDOI
The Petrology and Isotopic-Mineral Age Relations of a Contact Zone in the Front Range, Colorado
TL;DR: The only mineralogic change attributable to the contact heating takes place at a distance of one-tenth an intrusive width, where microcline changes to orthoclase.
Journal ArticleDOI
Metamorphism on Naxos; petrology and geothermal gradients
J. B. H. Jansen,R. D. Schuiling +1 more
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