The Pteridophyta and the paleoenvironment of the middle part of the La Ternera Formation (Upper Triassic) at Quebrada La Cachivarita, Atacama Region, Chile.

Abstract

Ten species of Pteridophyta from the middle part of the La Ternera Formation (Upper Triassic), in quebrada La Cachivarita, Copiapó Province, northern Chile, are described and figured. They include Rienitsia chilensis, Todites chilensis, Todites sp., Neocalamites carrerei, Asterotheca rigbyana, Asterotheca fuchsi, Cladophlebis mendozaensis, Cladophlebis kurtzi, Gleichenites cachivaritensis and Dictyophyllum (D.) tenuifolium, being the first two, new ones. This assemblage agrees with an Upper Triassic age for the La Ternera Formation as formerly proposed. A sedimentological analysis of the section which includes the fossiliferous strata, recognizes five different facies which are interpreted as deposits in a lake becoming progressively shallower.