TEKTITES 445 Table Tektite distribution Age (isotopically determined) Strewn field Area covered North American ($4000 tektites recovered) Texas, Georgia, Martha’s Vineyard, Barbados (microtektites in the Caribbean and Weddell Sea) Czech Republic, Austria, Germany Ivory Coast (microtektites offshore West Africa) China, Indochina, Thailand, Malaysia, Philippines, Indonesia, Australia, Central Indian Ocean (microtektites over wide area of the Indian Ocean, China Seas, and around Australia) Central European (55 000 tektites recovered) Ivory Coast ($200 tektites recovered) Australasian (South east Asia, >600 000 tektites recovered; Australia, $100 000 tektites recovered) 34.9 Ỉ 2.5 Ma (Eocene) 15.1 Ỉ 0.1 Ma (Miocene) $1 Ma (Pleistocene) 0.77 0.78 Ma (Pleistocene) Figure Strewn field distribution of tektites and sites of related occurrences Deep Sea Drill ng Project (DSDP) and Ocean Drilling Program (ODP) sites are also indicated Reproduced with permission from McCall GJH (2001) Tektites in the Geological Record: Showers of Glass from the Sky Bath: Geological Society Publish ng House, and McNamara K and Bevan A (2001) Tektites Perth: Western Australian Museum Microtektites are unknown in this strewn field The source is believed to be the 24-km-diameter Ries impact structure in south-east Germany, which is of the correct radiometric and stratigraphic age, but there are some unsolved questions relating to how exactly they were expelled and what rock formation supplied the material to form the melt and subsequent glass Ivory Coast Strewn Field A very small number of tektites have been recovered from an area to the west of the Camoe River, near Ouelle, in the Ivory Coast, West Africa They occur in surficial alluvial deposits over Precambrian (Birrimian) rocks in a gold-mining area They are of black pitted glass and several splash forms are