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3581817 
Journal Article 
High-pressure (approximate to 2000 MPa) kyanite- and glaucophane-bearing pelitic schist and eclogite from Cordillera de la Costa belt, Venezuela 
Sisson, VB; Ertan, IE; Lallemant, HGA 
1997 
Yes 
Journal of Petrology
ISSN: 0022-3530
EISSN: 1460-2415 
38 
1 
65-83 
WOS:A1997WK73300004 
In the Cretaceous melange of the Cordillera de la Costa belt, north-central Venezuela, there are knockers of eclogite, barrositie-bearing eclogite, and pelitic glaucophane schist. These occur in a metamorphic melange matrix that locally consists of marble, serpentinite, amphibolite, actinolite schist, feldspathic schist and gneiss, graphitic schist, chloritoid schist, and garnet-bearing mica schist. The protoliths for these various rock types exhibit a wide age range (Cambrian to Early Cretaceous?). Recently discovered knockers of pelitic glaucophane schist contain Mg-glaucophane + paragonite + kyanite + garnet + talc + graphite + rutile + quartz. The coexistence of kyanite and Mg-glaucophane suggests minimum P similar to 2000 MPa at T > 600 degrees C. Eclogite knockers from the same outcrop contain garnet and clinopyroxene which yield similar to 500 degrees C for cores, similar to 700 degrees C for rims, and P greater than or equal to 1200 MPa. The assemblage garnet-biotite-phengite-albite within schists of the melange matrix of this locality indicates metamorphic conditions of T = 450-520 degrees C at P = 1800 MPa. Because all lithologies in this outcrop record high-P conditions, this metamorphic melange formed before or during peak metamorphism in a mid-Cretaceous subduction zone. 
geothermobarometry; high-P pelitic schist; eclogite; Puerto Cabello, Venezuela