Dr. Frantz-Gerard Ossa Ossa

Universität Tübingen GUZ
Schnarrenbergstrasse 94-96
72076 Tübingen

Office: Room 6I02, GUZ

Phone: +49-(0)7071-29-78909
Fax: +49-(0)7071-29-3060
Mail: frantz.ossaossa@gmail.com & frantz-gerard.ossa-ossa(at)uni-tuebingen.de

Fields of study

  • Sedimentology (siliciclastic and carbonate systems), sequence stratigraphy, clay mineralogy and low temperature geochemistry (major and trace elements as well as stable isotopes such as C, O, N, S, Fe, Mo, Cr, Zn, Se and U)
  • Co‑evolution of life and oxygen through the Earth's history and astrobiology
  • Paleoclimate, paleoceanography, paleoecology, biogeochemical cycles and mobilization of bio‑essential elements at the Earth’s surface
  • Sedimentary mineral deposits and associated mineralization processes
  • Basin and petroleum system analyses


I am a geoscientist with a strong background in sedimentology, mineralogy and geochemistry. My research helps to better understand the co-evolution of life and oxygen on Earth and possibly on other planets of our solar system (eg, Mars). I am currently working on the co-evolution between the biological carbon pump, redox conditions in the atmosphere-hydrosphere system and Earth's biosphere responses during the Mesoarchean, Paleoproterozoic and early Jurassic. Key proxies consist of traditional (C, O, N and S) and nontraditional (Fe, Mo, Cr, Zn, Se and U) stable isotope geochemistry and clay mineralogy.

One of the main consequences of this interplay could be the deposition of organic-rich sedimentary rocks enriched in certain metals and non-metals. My research investigations also help for a better prediction of these petroleum source rock emplacements and their potentiality as natural laboratories for storing nuclear wastes.

Short CV

since 05/2018

Postdoctoral Researcher, Isotope Geochemistry Group, University of Tübingen, Germany


Research Associate, University of Johannesburg, DST-NRF CIMERA Research Centre of Excellence, Johannesburg, South Africa


DST-NRF Innovation Postdoctoral Researcher, University of Johannesburg, Department of Geology, Johannesburg, South Africa


Exploration Geologist (oil and gas industry) at Ophir Energy Plc, Libreville, Gabon


Postdoctoral Researcher, University of Johannesburg, Department of Geology, Johannesburg, South Africa


Research Assistant, University of Poitiers, Poitiers, France


PhD in Earth Science, University of Poitiers, Poitiers, France


MSc in Climatology, Environment, Paleontology, Sedimentology and Basins, University of Bourgogne, Dijon, France


  • Wang Y, Ossa Ossa F, Spangenberg J, Wille M, Schoenberg R (2021): Restricted oxygen-deficient basins on the northern European epicontinental shelf across the Toarcian carbon isotope excursion interval. Paleoceanography and Paleoclimatology. https://doi.org/10.1029/2020PA004207
  • Wang X, Ossa Ossa F, Hofmann A, Agangi A, Paprika D, Planavsky NJ (2020): Uranium isotope evidence for Mesoarchean biological oxygen production in shallow marine and continental settings. Earth and Planetary Science Letters 551: 116583. https://doi.org/10.1016/j.epsl.2020.116583.
  • Wang Y, Ossa Ossa F, Wille M, Schurr S, Sausele M‑E, Schmid‑Röhl A, Schoenberg R (2020): Evidence for local carbon‐cycle perturbations superimposed on the Toarcian carbon isotope excursion. Geobiology, https://doi.org/10.1111/gbi.12410
  • Ossa Ossa F, Hofmann A, Ballouard C, Vorster C, Schoenberg R, Fiedrich A, Mayaga‑Mikolo F, Bekker A (2020): Constraining provenance for the uraniferous Paleoproterozoic Francevillian Group sediments (Gabon) with detrital zircon geochronology and geochemistry. Precambrian Research 343: 105724
  • Ossa Ossa F, Hofmann A, Spangenberg JE, Poulton SW, Stueken EE, Schoenberg R, Eickmann B, Wille M, Butler M, Bekker A (2019): Limited oxygen production in the Mesoarchean ocean. PNAS 116: 6647-6652. DOI: 10.1073/pnas.1818762116.
  • Ossa Ossa F, Eickmann B, Hofmann A, Spangenberg JE, Planavsky NJ, Asael D, Bekker A (2019): Reply to the comment by Préat and Weber on Ossa Ossa et al. (2018). Earth and Planetary Science Letters 511: 259–261.
  • Wang X, Planavsky NJ, Hofmann A, Saupe EE, De Corte BP, Philippot P, LaLonde SV, Jemison NE, Zou H, Ossa Ossa F, Rybacki K, Alfimova N, Larson MJ, Tsikos H, Fralick PW, Johnson TM, Knudsen AC, Reinhard CT, Konhauser KO (2018): A Mesoarchean Shift in Uranium Isotope Systematics. Geochimica et Cosmochimica Acta 238: 438–452
  • Ossa Ossa F, Hofmann A, Wille M, Spangenberg JE, Bekker A, Poulton SW, Eickmann B, Schoenberg R (2018): Aerobic iron and manganese cycling in a redox-stratified Mesoarchean epicontinental sea. Earth and Planetary Science Letters 500: 28–40.
  • Humbert F, Elburg MA, Ossa Ossa F, de Kock MO, Robion P (2018): Variolites of the Paleoproterozoic Hekpoort Formation (Transvaal sub-basin, Kaapvaal craton): Multistage undercooling textures?. Lithos https://doi.org/10.1016/j.lithos.2018.07.005.
  • Ossa Ossa F, Eickmann B, Hofmann A, Planavsky NJ, Asael D, Pambo F, Bekker A (2018): Two-step deoxygenation at the end of the Paleoproterozoic Lomagundi Event. Earth and Planetary Science Letters 486: 70–83.
  • Adeniyi EO, Ossa Ossa F, Kramers JD, De Kock MO, Belyanin G, Beukes NJ (2018): Cause and timing of the thermal over-maturation of hydrocarbon source rocks of the Ecca Group (Main Karoo Basin, South Africa). Marine and Petroleum Geology 91: 480500.
  • De Kock MO, Beukes NJ, Adeniyi EO, Cole D, Götz AE, Geel C and Ossa Ossa F (2017): Deflating the shale gas potential of South Africa’s Main Karoo Basin. South African Journal of Science 113: 112.
  • Ossa Ossa F, Hofmann A, Vidal O, Kramers JD, Belyanin G, Cavalazzi B (2016): Unusual manganese enrichment in the Mesoarchean Mozaan Group, Pongola Supergroup, South Africa. Precambrian Research 281: 414–433.
  • Ossa Ossa F, Hofmann A, Vidal O, Kramers JD, Agangi A, Belyanin GA, Mayaga-Mikolo F (2014): Hydrothermal clay mineral formation in the uraniferous Paleoproterozoic FA Formation, Francevillian basin, Gabon. Precambrian Research 246: 134–149.
  • Planavsky NJ, Asael D, Hofmann A, Reinhard CT, Lalonde SV, Knudsen A, Wand X, Ossa Ossa F, Pecoit E, Smith AJB, Beukes NJ, Bekker A, Johnson TM, Konhauser KO, Lyons TW, Rouxel OJ (2014): Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event. Nature Geoscience 7: 283–286.
  • Ossa Ossa F, El Albani A, Hofmann A, Bekker A, Gauthier-Lafaye F, Pambo F, Meunier A, Fontaine C, Boulvais P, Pierson-Wickmann A-C, Cavalazzi B, Macchiarelli R (2013): Exceptional preservation of expandable clay minerals in the ca. 2.1 Ga black shales of the Francevillian basin, Gabon and its implication for atmospheric oxygen accumulation. Chemical Geology 362: 181–192.
  • El Albani A, Bengtson S, Canfield DE, Bekker A, Macchiarelli R, Mazurier A, Hammarlund EU, Boulvais P, Dupuy JJ, Fontaine C, Fursich FT, Gauthier-Lafaye F, Janvier P, Javaux E, Ossa Ossa F, Pierson-Wickmann AC, Riboulleau A, Sardini P, Vachard D, Whitehouse M, Meunier A (2010): Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago. Nature 466: 100–104