Bulletin of the Geological Society of Malaysia, Volume 43, Dec. 1999, pp. 555 – 575
1c/o Geol. Surv. Div., Dept. of Min. Res. Rama IV Rd., Bangkok 10400, Thailand
2lnst. of Geophysics and planetary Physics, University of California, Los Angeles, Cal 90024-1567, USA
31 Vella Street, Titahi Bay 6006, Wellington , New Zealand, c/o Victoria University, Wellington , N.Z.
4 Geology Department, Research Inst. for Higher Education, Kobe University, Nada-ku, Kobe 657, Japan
5School of Earth Sciences & Centre for Mineral Deposit Research, University of Tasmania, Hobart, Tasmania 7001, Australia
6Department of Geology, Chulalongkorn University, Bangkok, Thailand
Abstract: Further to our current research in layered and splashed tektites, and numerous impact multiple craters in Ubon; our 1997 new discovery evidences in Khorat, both in northeast Thailand, includes the wide continental burns, mass extinction of trees, ancient elephants, other mammals; and the thick catastrophic loess. All of these were linked to an extraordinary global disaster in a catastrophic event in Thailand and East Asia. These evidences were belonged to and superimposed on the known Australasian tektites strewn field that covers 1/10 of the Earth‘s surface. The age of the event must be correlated with the radiometric dating of tektites by Laser-fusion 40Ar/39Ar methods and gave ages between 0.770 ± 0.020 Ma, which was most consistent with an early Quaternary and is possibly correlated with a glacial stage at O-isotope stage 20.2, and magnetic stage ~NN20.
In Northeast Thailand several locations in sands pumping pits, 20 km east of Khorat, were deep enough to >12 m to reveal abundant or numerous irregular piles of the whole or partly burnt, partly or wholly petrified trees, logs, huge trunks or woods pushed and pulled down abruptly on the basement by tremendous force. A few ancient tree genera can be identified. Nearby complete ancient elephants teeth and bones of Zygolophodon (Sinomastodon) sp. and Stegolophodon (Eostegodon) sp. of a Pleistocene age are found buried above the bottom of the pits.
These evidences could suggest an event for an enormous terrestrial impact of a big comet, judged by the abundant distribution of layered tektites relative to craters, and a considerable size and large numbers of multiple craters in the 800 x 1,140 km center between Hainan Island-Cambodia, with Ubon at a western edge. Microtektites and microspirules were found in the catastroloess both in Khorat and central China indicating a corresponding age. Depletion of water in Australasian tektites and high 10Be in Chinese catastroloess suggests both were temporally originated in a dry cool glacial stage of the Pleistocene glacial period.
It was evidently the Australasian tektites field was caused by a global impact of a comet. The cometary impact theory that formulated the catastrophic disaster, named here the Buntharik Event, is suggested from this consequence in northeast Thailand and East Asia. There were 2 episodes in the destruction after impact and formed tektites in the field, and prolonged episode forming even greater and the first known catastroloess field, superimposed the former. It was also the only first apparently known evidences of a destruction of a comet impact.