Biogenicity tests for ancient microfossils

UK Centre for Astrobiology seminar

Biogenicity tests for ancient microfossils

  • Event time: 1:30pm
  • Event date: 12th February 2019
  • Speaker: Mark van Zuilen (IPGP, Paris)
  • Location: Higgs Centre Seminar Room, Room 4305,

Event details

In the most ancient rocks on Earth microfossils are to a certain extent controversial, either because they partially broke down due to diagenesis, hydrothermal alteration, and metamorphism, or because there were abiologic processes that generated ‘non-living’ forms of complexity that mimicked these traces of life. Here I present a recent study on silicification of filamentous cyanobacteria in a modern hot spring silica sinter, showing how early diagenesis affects the degradation of cell membranes, sheaths, and extracellular polymeric substances. Experimental work at elevated temperatures and pressures further shows how the silica matrix recrystallizes and generates complex abiologic fabrics. In addition, I show how under certain silica-rich, alkaline aquatic conditions abiologic self-assembled mineral aggregates can form, that mimic microfossil morphologies. An assessment is made of the methods and analytical tools for test of biogenicity in the ancient rock record.

About UK Centre for Astrobiology seminars

The astrobiology seminar series is run by the UK Centre for Astrobiology based in the School of Physics & Astronomy. Astrobiology is a multi-disciplinary subject and the seminar series actively encourages attendance by undergraduates, postgraduates and academic staff from other departments..

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