Stratigraphic assessment of the Arcelia-Teloloapan area, southern Mexico: implications for southern Mexico's post-Neocomian tectonic evolution

Stratigraphic assessment of the "Tierra Caliente Metamorphic Complex" (TCMC ) between Arcelia and Teloloapan in southern Mexico, based on photo interpr etation of Landsat Thematic Mapper images and field mapping at the 1:100,00 0 scale, tests different tectonic evolution scenarios that bear directly on the evolution of the southern North American plate margin. The regional ge ology, emphasizing the stratigraphy of a portion of the TCMC within the are a between Arcelia and Teloloapan is presented. Stratigraphic relationships with units in adjacent areas are also described. The base of the stratigrap hic section is a chlorite grade metamorphic sequence that includes the Taxc o Schist, the Roca Verde Taxco Viejo Formation, and the Almoloya Phyllite F ormation. These metamorphic units, as thick as 2.7 km, are covered disconfo rmably by a sedimentary sequence, 2.9 km thick, composed of the Cretaceous marine Pochote, Morelos, and Mexcala Formations, as well as undifferentiate d Tertiary continental red beds and volcanic rocks. The geology may be expl ained as the evolution of Mesozoic volcanic and sedimentary environments de veloped upon attenuated continental crust. Our results do not support accre tion of the Guerrero terrane during Laramide (Late Cretaceous-Paleogene) ti me. (C) 2000 Elsevier Science Ltd. All rights reserved.