TephATA: A Tephrostratigraphic Framework for the Atacama Desert and its Application on Regional Sedimentary Archives

A fundamental aspect to study past Earth surface process variations over time and to set local observations in a regional and global context is their temporal understanding. However, accurate dating of sedimentary archives documenting these variations can be hampered in extremely water-limited environments by applicable dating methods (type of archive/temporal range). Tephrostratigraphy and -chronology can be applied independent of the type of sedimentary archive and thus represent powerful tools for dating and synchronization of archives. In the Atacama Desert, tephra layers occur in various types of archives and on various time‑scales. A tephrostratigraphic framework, which sets the tephra layers in a stratigraphic and chronological order and shows the regional dispersal of individual tephra layers is currently lacking. Within the CRC1211 “Earth-Evolution at the dry limit”, the project TephATA aims at setting up a regional tephra database to develop the first comprehensive tephrostratigraphic framework for the Atacama. The database TephATA is currently integrated as a web-based part of the CRC1211 database and uses an extended IGSN metadata schema. TephATA combines existing and new chronological as well as stratigraphical information of tephra layers with their glass geochemical compositions, which is the backbone for reliable correlations of tephra layers and identification of widespread marker horizons. If the geochemistry-based approach allows a correlation of tephra layers, age information can be transferred to tephra layers that does not contain sufficient minerals for absolute dating. Particularly widespread tephra layers will function as independent tie-points for the synchronization of the various sedimentary records investigated within the CRC1211.