Abstract
Exposed 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.
Original language | English |
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Pages (from-to) | 920-937 |
Number of pages | 18 |
Journal | International Geology Review |
Volume | 47 |
Issue number | 9 |
Publication status | Published - Sep 2005 |