Fossilized diatoms in meteorites from recent falls in Sri Lanka

Richard B. Hoover; Jamie Wallis; Keerthi Wickramarathne; Anil Samaranayake; George Williams; Gregory Jerman; D. H. Wallis; N. C. Wickramasinghe

doi:10.1117/12.2028605

26 September 2013 Fossilized diatoms in meteorites from recent falls in Sri Lanka

Richard B. Hoover, Jamie Wallis, Keerthi Wickramarathne, Anil Samaranayake, George Williams, Gregory Jerman, D. H. Wallis, N. C. Wickramasinghe

Author Affiliations +

Proceedings Volume 8865, Instruments, Methods, and Missions for Astrobiology XVI; 886506 (2013) https://doi.org/10.1117/12.2028605
Event: SPIE Optical Engineering + Applications, 2013, San Diego, California, United States

Abstract

On December 29, 2012, a bright yellow and green fireball was observed to disintegrate over the Polonnaruwa District of North Central, Sri Lanka. Many low density, black stones were recovered soon after the observed fall from rice paddy fields near the villages of Aralaganwila and Dimbulagala. These stones were initially studied by optical microscopy methods at the Medical Research Institute in Colombo, Sri Lanka. Soon thereafter, samples were sent to the UK and to the United States. More extensive Field Emission Scanning Electron Microscopy studies were then carried out at Cardiff University and the NASA/Marshall Space Flight Center. The physico-chemical properties, elemental abundances, mineralogy and stable isotope data clearly indicate that these stones are non-terrestrial. Freshly fractured interior surfaces of the black stones have also been observed to contain the remains of fossilized diatom. Many of the diatom frustules are clearly embedded in the meteorite rock matrix and exhibit nitrogen levels below the EDX detection limits. Some of the fossil diatoms are araphid marine pennates and planktonic forms that are inconsistent with conditions associated with rice paddy fields. These observations indicate the fossilized diatoms are indigenous to the meteorites rather than post-arrival biological contaminants. The carbon content and mineralogy suggests that these stones may represent a previously ungrouped clan of carbonaceous meteorites. The extremely low density (~0.6) of the stones and their observed mineralogy was inconsistent with known terrestrial rocks (e.g., pumice, diatomite and fulgurites). The minerals detected suggest that the parent body of the Polonnaruwa stones may have been the nucleus of a comet. These observations are interpreted as supporting the Hoyle-Wickramasinghe Panspermia hypothesis and the hypothesis that diatoms and other microorganisms might be capable of living and growing in water ice and brines in comets.

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Richard B. Hoover, Jamie Wallis, Keerthi Wickramarathne, Anil Samaranayake, George Williams, Gregory Jerman, D. H. Wallis, and N. C. Wickramasinghe "Fossilized diatoms in meteorites from recent falls in Sri Lanka", Proc. SPIE 8865, Instruments, Methods, and Missions for Astrobiology XVI, 886506 (26 September 2013); https://doi.org/10.1117/12.2028605

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