Comendite (peralkaline rhyolite) and basalt in the Mitu Group, Peru: Evidence for Permian-Triassic lithospheric extension in the central Andes

Donald C. Noble; Miles L. Silberman; F. Megard; H. R. Bowman

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USGS · 70232574

Comendite (peralkaline rhyolite) and basalt in the Mitu Group, Peru: Evidence for Permian-Triassic lithospheric extension in the central Andes

Donald C. Noble·Miles L. Silberman·F. Megard·H. R. Bowman

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Abstract

The Mitu Group consists of generally coarse clastic strata and volcanic rock of Permian and (or) Triassic age filling elongate basins that parallel the general structural trend of the Peruvian Andes. Volcanic rocks of the Mitu Group include peralkaline and nonperalkaline rhyolite and subalkaline basalt. To our knowledge, the peralkaline rhyolites are the first of this rock type reported from South America. The presence of appreciable volumes of peralkaline rhyolite and basalt, supports the interpretation that the Mitu Group was deposited in major graben structures that resulted from lithospheric extension produced by rifting or possible backarc extension.

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Journal of Research of the U.S. Geological Survey Article

Source-reported bounding extent: -16.59408141271846° to -5.659718554577273° latitude; -79.541015625° to -69.169921875° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Donald C. Noble, Miles L. Silberman, F. Megard, H. R. Bowman. 1978. Comendite (peralkaline rhyolite) and basalt in the Mitu Group, Peru: Evidence for Permian-Triassic lithospheric extension in the central Andes. https://pubs.usgs.gov/publication/70232574

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