Abstract

The major element glass geochemistry of 10 Late Pleistocene and Holocene tephras found in the previous termToluca Basinnext term in the Trans-Mexican Volcanic Belt is reported for the first time, as a key step towards establishing a previous termtephrochronologynext term for the region. The context for this previous termtephrochronologynext term is provided by a review of Late Quaternary volcanism of the previous termbasin.next term New tephra samples were collected from reference profiles around the previous termbasinnext term in order to establish major element glass geochemical data for tephras described in previous publications, but not previously analysed. In addition, cores were taken from the previous termbasinnext term floor to extend the known spatial distribution of the tephra layers and establish correlations with the lacustrine record. Improved chronological control has been provided by seven new AMS and conventional radiocarbon dates on the major tephras. Geochemical data are presented for 10 tephras ranging in age from ca. 25,000 BP (Lower previous termTolucanext term Pumice) to about 8500 BP (Tres Cruces Tephra). Based on geochemical data, it is possible to correlate between sites within the previous termToluca Basinnext term and between the previous termToluca Basin and the Basinnext term of Mexico. The basis for a tephrochronological framework has been established.