Deformational History of the Granjeno Schist, Ciudad Victoria, Mexico: Constraints on the Closure of the Rheic Ocean?
2005; Taylor & Francis; Volume: 47; Issue: 9 Linguagem: Inglês
10.2747/0020-6814.47.9.920
ISSN1938-2839
AutoresDavid S. Dowe, R. Damian Nance, J. Duncan Keppie, Kenneth L. Cameron, Amabel Ortega‐Rivera, Fernando Ortega‐Gutiérrez, J. W. K. Lee,
Tópico(s)Geochemistry and Geologic Mapping
ResumoExposed in the core of a NNW-trending frontal anticline of the Laramide fold-thrust belt of northeastern Mexico, the Granjeno Schist comprises a polydeformed assemblage of Paleozoic metasedimentary and metavolcaniclastic rocks and serpentinized mafic-ultramafic units. The earliest deformation (D1) predates emplacement of a leucogranite at 351 ± 54 Ma and may record obduction of this oceanic unit. Subsequent deformations (D2a-D2c) record tectonic juxtapositioning of the Granjeno Schist against the ∼1 Ga Novillo Gneiss by NNW-directed dextral shear under conditions of decreasing temperature. Cooling ages of 313 ± 13 Ma and 300 ± 4 Ma are considered to date the onset of dextral motion, which continued into the Permian. These events are linked to the Late Paleozoic closing of the Rheic Ocean.
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