Abstract
Tektites formed by an extraterrestrial impact event in Southeast Asia at 0.78 Ma have been found in geological contexts and archaeological sites throughout Australia, East and Southeast Asia. At some archaeological sites, especially in Bose Basin, China, and An Khe, Vietnam, tektites have been interpreted as in situ in primary deposits, marking the age of deposit formation, and thus the age of artefacts in those deposits. We argue that tektites are rarely reliable age markers. We describe five archaeological sites in Vietnam where tektites have been found in association with artefacts with a variety of ages in the Late Pleistocene and Holocene. We review the conditions when tektites may be useful as chronological markers, and recommend that they only be used as such in combination with other dating methods.