SHARED SET OF SPATIAL RELATIONSHIPS OBSERVED BETWEEN TEKTITE STREWN FIELDS AND THEIR CORRELATED ASTROBLEMES; RELIABLE MODUS OPERANDI OR PURELY COINCIDENTAL?

Tektites are generally accepted as glassy distal ejecta comprised of fully melted terrestrial sediments high in silicon dioxide. These highly homogenous objects weight up to 15 Kg or more, suggesting they remained molten in a low dynamic pressure environment long enough to begin to solidify prior to encountering turbulent atmospheric interactions, which would otherwise shred the molten blob into fine particles. Of the over 200 astroblemes currently identified and accepted, only a handful have been convincingly corelated with having generated tektites. In four cases, empirical evidence suggests the associated tektite strewn fields are relatively small regions found a minimum of 250 km from the impact site. Additionally, the spatial relationship between astrobleme and strewn field evidences the distribution was highly asymmetric, suggesting jetting downrange from an oblique impact event. No tektite has been recovered at a proximal or medial distance from its associated crater when applying the commonly accepted crater radii counts. Given the great age of these 4 events (~1my, ~15My, ~35My and ~66My) it has been proposed that the spatial distribution record is only an artifact of the serendipity of tektite survival and discovery. Such a declaration has relevance when applying the empirical evidence from similar incidents to the protracted search for the missing astrobleme for the vast Australasian tektite strewn field (15%-30% of Earth). Being the most recent impact event on our planet to generate tektites (~778 ka), many workers dismiss the relevance of previous event’s distribution patterns and instead propose a priori an impact within the strewn field, implying a 360º distribution at proximal distances. We discuss the constraints on an alternative a priori location when empirically derived spatial relationships are applied to the implied scale of the Australasian event.