Acritarchs in carbonaceous meteorites and terrestrial rocks

Alexei Yu. Rozanov; Richard B. Hoover

doi:10.1117/12.2029608

3 October 2013 Acritarchs in carbonaceous meteorites and terrestrial rocks

Alexei Yu. Rozanov, Richard B. Hoover

Proceedings Volume 8865, Instruments, Methods, and Missions for Astrobiology XVI; 886507 (2013) https://doi.org/10.1117/12.2029608
Event: SPIE Optical Engineering + Applications, 2013, San Diego, California, United States

Abstract

Acritarchs are a group of organic-walled, acid-resistant microfossils of uncertain or unknown origin. Some are thought to represent the cysts or resting stages of unicellular protists (possibly dinoflagellates), chrysophytes (green algae) or other planktonic eukaryotic algae. Acritarchs are found throughout the geologic column extending back as far at 3.2 Ga. The presence of large sphaeromorphs in the Archaean provides evidence that the eukaryotic lineage extends much farther back in time than previously thought possible. Acritarchs are abundant in the Paleoproterozoic shales (1.9-1.6 Ga) of the former Soviet Union and they have been extensively used for the investigation of Proterozoic and Paleozoic biostratigraphy and paleoenvironmental parameters. Scanning Electron Microscope studies have revealed the fossilized remains of organic-walled microfossils of unknown origin and exhibiting characteristics of acritarchs in a variety of carbonaceous meteorites. In many cases, these remains are black or brown in color and have Carbon/Oxygen ratios suggesting they have been diagenetically converted into kerogen. It is not feasible that the fossilized remains of organicwalled microfossils such as acritarchs represent biological contaminant that invaded and became embedded in the rock matrix of carbonaceous meteorites within the short time periods of their residence on Earth. Consequently, these groups of microfossils are considered to provide an additional line for the existence of indigenous extraterrestrial microbial remains in meteorites. This paper presents a brief review of acritarchs in terrestrial rocks and provides images of a number of similar morphotypes of uncertain origin found in freshly fractured samples of carbonaceous meteorites.

Citation Download Citation

Alexei Yu. Rozanov and Richard B. Hoover "Acritarchs in carbonaceous meteorites and terrestrial rocks", Proc. SPIE 8865, Instruments, Methods, and Missions for Astrobiology XVI, 886507 (3 October 2013); https://doi.org/10.1117/12.2029608

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