Age of cleft monazites in the eastern Tauern Window: constraints on crystallization conditions of hydrothermal monazite

Gnos, Edwin; Janots, Emilie; Berger, Alfons; Whitehouse, M.; Walter, F.; Pettke, Thomas; Bergemann, C. (2015). Age of cleft monazites in the eastern Tauern Window: constraints on crystallization conditions of hydrothermal monazite. Swiss journal of geosciences, 108(1), pp. 55-74. Springer 10.1007/s00015-015-0178-z

[img] Text
Berger_Pettke.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (3MB) | Request a copy

Monazite-bearing Alpine clefts located in the Sonnblick region of the eastern Tauern Window, Austria, are oriented perpendicular to the foliation and lineation. Ion probe (SIMS) Th–Pb and U–Pb dating of four cleft monazites yields crystallization ages of different growth domains and aggregate regions ranging from 18.99 ± 0.51 to 15.00 ± 0.51 Ma. The crystallization ages obtained are overlapping or slightly younger than zircon fission track ages but older than zircon (U–Th)/He cooling ages from the same area. This constrains cleft monazite crystallization in this area to *300–200 �C. LA-ICP-MS data of dated hydrothermal monazites indicate that in graphite-bearing, reduced host lithologies, cleft monazite is poor in As and has higher La/Yb values and U concentrations, whereas in oxidised host rocks opposite trends are observed. Monazites show negative Eu anomalies and variable La/Yb values ranging from 520 to 6050. The positive correlation between Ca and Sr concentration indicates dissolution of plagioclase or carbonates as the source of these elements. The data show that early exhumation and cleft formation in the Tauern is related to metamorphic dome formation caused by the collision of the Adriatic with the European plate and that monazite crystallization in the clefts occurred later. Our data also demonstrate that hydrothermal monazite ages offer great potential in helping to constrain the chronology of exhumation in collisional orogens.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Other Institutions > Teaching Staff, Faculty of Science

UniBE Contributor:

Gnos, Edwin; Janots, Emilie; Berger, Alfons and Pettke, Thomas

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

1661-8726

Publisher:

Springer

Language:

English

Submitter:

Thomas Pettke

Date Deposited:

08 May 2015 14:08

Last Modified:

27 Apr 2017 15:05

Publisher DOI:

10.1007/s00015-015-0178-z

BORIS DOI:

10.7892/boris.68095

URI:

https://boris.unibe.ch/id/eprint/68095

Actions (login required)

Edit item Edit item
Provide Feedback