[meteorite-list] Shocked quartz and other mineral inclusions in Australasian microtektites

[Paul H.]

Folco, L. N. Perchiazzi, M. D'Orazio, M. L. Frezzotti, B. P. 
Glass, and P. Rochette, 2010, Shocked quartz and other mineral 
inclusions in Australasian microtektites. Geology, v. 38, 
no. 3, p. 211-214.

http://geology.geoscienceworld.org/cgi/content/abstract/38/3/211

Shocked quartz and other mineral inclusions in Australasian 
microtektites. March 2010 Geology and GSA Today Highlights

http://www.physorg.com/wire-news/29077449/march-2010-geology-and-gsa-today-highlights.html

“In a study by Folco et al., the application of high-resolution 
analytical techniques including syncrothron X-ray diffraction, 
field emission scanning electron microscopy, and microraman 
spectroscopy led to the discovery of microscopic mineral 
inclusions in Australasian microtektites recovered from deep-sea 
sediment cores within 2000 km of Indochina. Inclusions consist 
of frequent shocked quartz plus a Zr-phase and trace of Fe-oxide 
crystallites. The shocked quartz and the Zr-phase are interpreted 
as relicts of the target rock. The occurrence of partially melted 
quartz relicts and fluidal structures (schlieren) confirms that 
microtektites are quenched molten droplets and not condensates 
from a hot plume of vaporized crustal rocks. Furthermore, the
internal homogeneity of Australasian microtektites in terms of 
abundance of relict mineral inclusions, vesicles, and schlieren 
increases with distance from Indochina. This finding strengthens 
the current hypothesis that the source crater of the largest and 
youngest tektite-strewn field on Earth is located in the Indochina 
region, as internal heterogeneity characterizes normal impact 
glass found in or near the source crater. This finding also indicates 
that the Australasian microtektites with the longest trajectories 
experienced the highest temperature-time regimes. Lastly, the 
definition of microtektites should include the possible occurrence 
of microscopic relict inclusions as an indication of proximity to 
the source crater.”

Related papers are:

Glass , B. P., and C. Koeberl, 2006, Australasian microtektites and 
associated impact ejecta in the South China Sea and the Middle 
Pleistocene supereruption of Toba. Meteoritics & Planetary Science 
vol. 41, no. 2, pp. 305–326.

PDF file at:
http://www.univie.ac.at/geochemistry/koeberl/publikation_list/279-Australasian-microtektites-and-Toba-MAPS2006.pdf

 Prasad, M. S., V. P. Mahale and V. N. Kodagali, 2007, New sites of 
Australasian microtektites in the central Indian Ocean: Implications for 
the location and size of source crater. Journal of Geophysical Research, 
(E: Planets), vol.112, E06007, doi:10.1029/2006JE002857.

PDF file at:
http://drs.nio.org/drs/bitstream/2264/635/4/J_Geophys_Res_112_E_E06007.pdf

Extraterrestrial matter in the oceans, lecture by Dr. M. S. Prasad. PDF file at:
http://drs.nio.org/drs/bitstream/2264/738/2/Refresher_Course_Mar_Geol_Geophys_2007_Lecture_Notes_84.pdf

Yours,

Paul H.