Eo-Variscan Orogenesis in the Guilleries Massif, Catalan Coastal Ranges, Northeastern Spain Recorded by U-Th-Pb ages of Monazite Inclusions in Metamorphic Garnet

<p>A chronicle of the Variscan Orogeny is recorded in high grade pelitic schists of the Guilleries Massif of the Catalan Coastal Ranges of northeastern Spain which preserve multiple rounds of deformation and metamorphism. The massif records a classic Variscan low-pressure and high-temperature metamorphic field gradient and represents part of the metamorphic core of the Variscan Orogeny. The lack of overprinting from the younger Alpine Orogeny makes the massif an ideal location to study the early stages of the Variscan Orogeny.</p><p> Pelitic schist and gneiss of the Osor formation are characterized by andalusite + cordierite and biotite + garnet + sillimanite assemblages. In garnet porphyroblasts, folded S1 inclusion trails with monazite are truncated by the regionally dominant S2 cleavage. Andalusite + cordierite grade rocks and S2 are syntectonic with the 323 Ma Susqueda Diorite. In the aureole of the Susqueda Diorite, contact metamorphism reached pyroxene + garnet + cordierite grade. Biotite and two-mica microgranites, ranging from meter-sized dikes and sills to mm-sized veins, trending northeast with crystallization ages of ca. 300 Ma, cross-cut all the country rocks of the massif. 232Th-208Pb ages of monazite from preserved S1 inclusion trails are 341 Ma, 340 Ma, and 334 Ma and 232Th-208Pb ages of monazite from S2 inclusion trails are 312 Ma and 313 Ma. The older ages record a phase of deformation and metamorphism that predates the peak low pressure-high temperature Variscan thermal metamorphism that is related to the intrusion of granite. Relict kyanite preserved in the matrix of rocks with S1 inclusion trails provides evidence for a phase of nonmagmatic thrusting and higher pressure metamorphism prior to the peak metamorphic event.</p>

Name thesis:degree_name

MS

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Arts and Sciences: Geology

Grantor dc:publisher

University of Cincinnati

Year dc:date

2012

Author dc:creator

• Wise, Julia L.

Contributors dc:contributor

• Dietsch, Craig

• Geology
• Ion Microprobe
• Garnet
• Eo-Variscan
• Monazite
• Guilleries
• U-Th-Pb Series

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352402373

OAI identifier oai:identifier

oai:etd.ohiolink.edu:ucin1352402373