Summary. Laser Raman Spectroscopy (LRS) can provide direct molecular structural information of the biomolecules (microfossils). Recent developments in LRS and confocal 3D-imagery technique has characterized the biogenicity of the earliest life (cyanobacteria, bacteria, stromatolites and kerogen) on Earth. This technique can also be used for detection of any form of life on Mars, Europa and other earth-like planets and their moons orbiting around other stars. The astrobiological investigations of meteorites falling on Earth from the space (asteroid belt) between Mars and Jupiter in our solar system have confirmed the presence of amino acids and other organic compounds using LRS technique.
Recently, the petrographic thin sections of stromatolitic carbonates and black chert bands yielding microorganisms have been studied by Laser Raman Spectroscopy and 3D-Cofocal Laser Scanning Microscopy (CLSM). The details of prokaryotic microfossils (filamentous and coccoidal forms) and their Laser Raman spectra and shifts in the wave numbers, 3D-imagery and identification of various types of organic compounds and Raman Index of Preservation (RIP) of kerogen is discussed.
These biomolecules are quite significant for additional search of extraterrestrial amino acids in meteorites (like ALH and SNC group of Martian meteorites), Martian sample return specimens and the origin of life on Earth. The Deoban, Gangolihat, Krol and Buxa stromatolitic Dolomites of the Lesser Himalaya have been extensively studied for the organic walled microfossils, carbon, oxygen and sulfur isotopic compositions and organic geochemistry. The Neoproterozoic global glaciation (= 650 million years ago, 'Snow Ball Earth') and Acraman meteorite impact completely reshaped the biotic evolution and diversification on life on earth. The well-preserved embryo in the Doushantuo Formation in China (studied by X-ray Computed Tomographic Analysis) and the preservation of large acanthomorphic acritarchs and soft-bodied metazoans (Ediacaran fossils) from the Krol Formation of the Lesser Himalaya and the Doushantuo Formation of China are of great significance in establishing the multicellular evolution of life.
LRS, CLSM and X-ray Tomography are powerful tools for the study of the molecular structures and organic evolution of life. The molecular composition of individual cellular micro-organisms may be useful in the future for the emerging science of Astrobiology that includes the origin and evolution of life in the universe.

References

Schopf, J.W. 2002. Laser Raman imagery of the oldest fossils on Earth. International Journal of Astrobiology, vol.1(2), p. 108.

Schopf, J.W. 2005. Three dimensional optical and molecular structural imagery of Precambrian microscopic fossils. Abstract, p. 137- 138. In: The 14th International Conference on the Origin of Life, Beijing , China.

Schopf, J.W, Tewari, V.C. and Kudryavtsev, A., 2008. Discovery of chert perminralised microfossils in the Proterozoic Buxa Formation, NE India. Astrobiology (in press).

Tewari, V.C. 2001. Origins of life in the universe and earliest prokaryotic microorganisms on Earth. In: First Steps in the Origin of Life in the universe. Kluwer Academic Press, Netherlands, pp. 251-254

Tewari, V.C. 2002. Might life on Earth have come from space? Nature India, p. 11.

Tewari, V.C. 2004. Microbial diversity in Meso-Neoproterozoic Formations with particular reference to Himalaya, India. ORIGINS. Kluwer Academic Publishers, Netherlands, pp. 515-528.

Tewari, V.C. 2005. Astrobiology: The search for extraterrestrial life, p. 171-172. In: Emerging Trends in Palaeobiology, ession A. Early life on Earth and Signatures of Extraterrestraial Life. Diamond Jubilee National Conference, Birbal Sahni Institute of Palaeobotany, Lucknow, November 15-17, 2005.

Tewari, V.C., Venkatakrishna, K. and Paliwal, B.S., 2001. Laser Raman spectroscopy of microbial carbonates from the Lesser Himalaya and Didwana Rajod meteorite, Rajasthan, India In: Seminar on contributions to Himalayan Geology, p. 19-20. Wadia Institute of Himalayan Geology, Dehradun.

Tewari, V.C., Paliwal , B.S. and Venkatakrishna, K. 2002. Discovery of amino acids from Didwana Rajod meteorite and its implication on origin of life. Journal Geological Society of India, Vol.60, pp. 107-110.

Tewari, V.C., Schopf, J.W. and Kudryavtsev, A., 2008. Neoproterozoic microfossils from the Buxa Dolomite , NE Lesser Himalaya, India: Analyses by Raman Spectroscopy and Optical and Confocal Laser Scanning Microscopy. In: World Summit on Ancient Microscopic Fossils, University of California, Los Angeles, 27 July-02 August, 2008 (abstract), p. 36.

__________________________________________________

(*) Biodata: Professor Vinod. C. Tewari is currently a Senior Scientist and Head of the Sedimentology Group at Wadia Institute of Himalayan Geology, Dehradun, India. He is also Senior Associate of International Centre for Theoretical Physics, Trieste, Italy.

He obtained his Ph.D. from the University of Lucknow in Geology in 1986 and continued his research in Wadia Institute. Professor Tewari taught Geology at Kumaon Univerisity, Nainital, Uttarakhand, India as Professor of Geology.

Professor Tewari's scientific interests are in the areas of Precambrian stromatolites, sedimentation, carbon isotope chemostratigraphy, genesis, early evolution and diversification of life and its astrobiological significance.

He is associated with the International Geological Correlation Programme (I.G.C.P.) Project 493 on The Rise and Fall of Vendian Biota and Ediacaran System. He has published seventyfive research papers, and has edited several volumes of Himalayan Geology, India and the Journal of Nepal Geological Society, Kathmandu, Nepal.

Professor Tewari has organized first Indo-Soviet Symposium on Stromatolites and Stromatolitic Deposits and other IGCP meetings in India. He is one of the organizers of the World Summit on Ancient Microscopic Fossils held in the University of California, Los Angeles, USA in 2008.

____________________________________________________