The Ordovician sedimentary rocks of the San José Fonnation (Iparo and Purumpata members) and the Sandia Formation have been investigated in the regions of Sandia, Sina, Ollantaytambo and Calca which lie within the Peruvian Eastem Cordillera. The Iparo Member (upper Lower Ordovician to lower Middle Ordovician) consists of dark grey, hemipelagic mudstones with a rich graptolite fauna and was deposited in a low energy, deep marine envirom11ent. Pyrite rich and pyrite poor units were caused by temporal)' changes in oxygen content from anaerobic to dysoxic or oxic conditions. Low energy and probably distal turbidites are interbedded within the normal background sedimentation. The pelitic rocks of the Purumpata Member (Daniwilian) were deposited under more oxygenated but stilllow energetic conditions. The qumtz-sandstones, siltstones and mudstones ofthe Sandía Fonnation (upper Daniwilian to ...

páginas 274-276.

168 p.

Páginas 21-24 | Trabajo presentado en el 3rd INQUA-IGCP-567 International Workshop on Active Tectonics, Paleoseismology and Archaeoseismology, 19-24 de noviembre, 2012, en Morelia, México.

5 páginas

5 páginas

páginas 207-209.

We present data from a study of the evolution of the Early Paleozoic Peru-Bolivia Trough, its facies development and the provenance of sediments deposited during Ordovician and Devonian time. We measured and sampled sections in the Ordovician successions in the Cordillera Oriental of southern Peru (Ollantaytambo, Verónica, San José, Sandia and Calapuja Formations) and northern Bolivia (Coroico, Amutara and Cancañiri Formations), and in the Upper Silurian to Devonian Lampa Formation on the Altiplano, and the Devonian Cabanillas Group on the Altiplano and the Peruvian Coastal Cordillera (Arequipa Massif). Our data contribute to a better understanding of the plate tectonic evolution of the Western Gondwana margin during early Paleozoic times.