Geographic variation in Australasian microtektite concentrations: Implications concerning the location and size of the source crater

Abstract

Geographic variations in the concentration of Australasian microtektites in 42 cores from the Indian Ocean, western equatorial Pacific Ocean, and the Philippine, Celebes, and Sulo Seas were used to predict the location of the Australasian tektite source crater and to estimate its size. The location that seems to best explain the geographic variations in microtektite concentrations is located in central Cambodia at about 12°N latitude and 106°E longitude. The diameter of the source crater is estimated to be between 32 and 114 km based on thickness of the microtektite layer at each site and distance from the predicted source area in Cambodia. The large range in estimated size of the source crater is due to a lack of knowledge about the value of the exponent that describes the radial decrease in ejecta thickness. Additional microtektite/ejecta‐bearing sites closer to the source region could help resolve this problem.

Microtektites on Mars: Volume and Texture of Distal Impact Ejecta Deposits

“…On Earth, no parabolas are known, but fields of microtektites have been identified in deep-sea sediments, notably the Ivory Coast tektites associated with the Bosumtwi crater and the Australasian microtektites, associated with a yet-to-be-discovered impact crater, most probably located in Southeast Asia (see, e.g., Glass and Pizzuto 1994). It may be noted that microtektites are associated with moderately recent impacts, in that fine material is easily weathered and altered on Earth .…”

“…The Stoffler et al and McGetchin et al expressions successfully predict the abundance of microtektites in the Ivory Coast field, generated by the 10.5-km Bosumtwi crater. The counts (from Glass and Pizzuto 1994), are presented in Fig. 2a with a number of candidate fits.…”

“…Other related expressions exist, for example that due to Stoffler et al (1975) with k = 0.06, x = 1, n = 3.3. Glass and Pizzuto (1994) fit the observed abundances of Australasian microtektites (for which the size and location of the source crater are unknown) with k = 0.02, x = 0, n = 4.4.…”

Calcareous nannofossil bioevents and microtektite stratigraphy in the Western Philippine Sea during the Quaternary

“…Since mid-Pleistocene Australasian microtektites were first detected in cores taken from the Indian Ocean, they have been found in cores of the Western Pacific marginal seas, such as the Western Philippine Sea and the South China Sea [17][18][19]. Because of their wide distribution over oceans and continents, the occurrence of Australasian microtektites can be used as a reliable age point in stratigraphy.…”

A reported tektite transported from Australasia and found at Gabriel's Gully mining camp, Central Otago, New Zealand

“…No microtektites have been found on the seabed east of the western margin of the Tasman Sea (Glass & Pizzuto 1994), therefore it would be surprising if in-situ tektites were found in New Zealand deposits, which would in effect extend the Australasian strewn field even further to the east.…”