Entstehung und Alter der „toba"—Sedimente in Mexiko

Klaus Heine & Ernst Schönhals
Silty, yellowish brown sediments of great thickness can be observed frequently in Central Mexico in the region of the Sierra Neovolcánica. So far different views have been advanced as to their origin, they are supposed to be subaerically deposited volcanic tuffs, dust sediments subaerically accumulated after being blown out of volcanic ash fields, or loess-like material derived from all areas which are free of vegetation such as desiccated lakes, gravel fields and volcanic tefras. Geologic-geomorphological...