John P. Grotzinger
Grotzinger has made significant contributions to understanding the early environmental history of Mars, as preserved within its record of sedimentary rocks.
Prior to in situ investigations by the Mars Exploration Rovers, most studies of water-related processes had been based on orbiter analysis of geomorphic and spectroscopic attributes.
Therefore, the detection of sediment transport by water and wind in ancient sedimentary layers is important, because it provides insight into past climatic regimes and potential habitability.
The Mars Science Laboratory Curiosity rover was launched on Saturday, November 26, 2011 on board an Atlas V-541 rocket from Cape Canaveral, Florida.
In the first year of its mission, Curiosity discovered fine-grained sedimentary rocks of basaltic composition that represent an ancient lake and preserve evidence of an environment that would have been suited to support a Martian biosphere founded on chemolithoautotrophy.
This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species.
Beginning in 1993, Grotzinger and his colleagues began a research program aimed at understanding the chronology of major biological and environmental events leading up to, and perhaps driving early Cambrian radiation of metazoans.
The Shuram carbon isotopic excursion - the largest known in Earth history - has been the subject of intensive research at Caltech.
The Shuram Excursion closely precedes impressive evolutionary events including the rise of large metazoans and the origin of biomineralization in animals.
Combining his expertise in sedimentology and geobiology, Grotzinger's research on stromatolites shows that they are vital tools in understanding the interactions between ancient microorganisms and their environment.
Stromatolites are attached, lithified sedimentary growth structures, accretionary away from a point or limited surface of initiation.
Grotzinger's research has applied a process-based approach, oriented toward deconvolving the replacement textures of ancient stromatolites.
Application of this approach has shown that stromatolites were originally formed largely through in situ precipitation of laminae during Archean and older Proterozoic times, but that younger Proterozoic stromatolites grew largely through the accretion of carbonate sediments, most likely through the physical process of microbial trapping and binding.
Farley, K.A., Malespin, C., Mahaffy, P., Grotzinger, and 29 others (2014), In-situ Radiometric and Exposure age dating of the Martian surface.
Sulfate-rich eolian and wet interdune deposits, Erebus crater, Meridiani Planum, Mars.
McLennan, S. M., Bell III, J. F., Calvin, W., Grotzinger, J. P., and 28 others, 2005, Provenance and diagenesis of the evaporite-bearing Burns formation, Meridiani Planum, Mars.
Grotzinger, J.P., and 16 others, 2005, Stratigraphy and Sedimentology of a Dry to Wet Eolian Depositional System, Burns Formation, Meridiani Planum, Mars: Earth and Planetary Science Letters, v. 240, p. 11-72.
Squyres, S., Grotzinger, J. P., Bell, J. F. III, Calvin, W., and 14 others, 2004, In-situ evidence for an aqueous environment at Meridiani Planum, Mars.
Palaios, v. 20, DOI: 10.2110/palo.2012.p12-088r Lee C, Fike DA, Love GD, Sessions AL, Grotzinger JP, Summons RE, Fischer WW (2013) Carbon isotopes and lipid biomarkers from organic-rich facies of the Shuram Formation, Sultanate of Oman, Geobiology, doi: 10.1111/gbi.12045.
Bontognali TRR, Sessions AL, Allwood AC, Fischer WW, Grotzinger JP, Summons RE, Eiler JM (2012) Sulfur isotopes of organic matter preserved in 3.45 Gyr-old stromatolites reveal microbial metabolism, Proceedings of the National Academy of Sciences, 109, 15146-15151.
Wilson, J.P., Grotzinger, J.P., et al., 2012, Deep-water incised valley deposits at the Ediacaran-Cambrian boundary in southern Namibia contain abundant Treptichnus Pedum.
Bristow, T., Bonifacie, M., Derkowski, A., Eiler, J., and Grotzinger, J. P., 2011, A hydrothermal origin for isotopically anomalous cap dolostone cements from South China.
Love, G., Grosjean, E., Stalvies, C., Fike, D., Grotzinger, J., and 8 others, 2009, Fossil steroids record the appearance of Demospongiae during the Cryogenian period.
Grotzinger, J. P. , Watters, W. and Knoll, A. H., 2000, Calcified metazoans in thrombolite-stromatolite reefs of the terminal Proterozoic Nama Group, Namibia.
Facies and evolution of Precambrian carbonate depositional systems: emergence of the modern platform archetype, in, SEPM Special Publication 44, p. 79-106.
Upward shallowing platform cycles: A response to 2.2 billion years of low-amplitude, high-frequency (Milankovitch band) sea level oscillations.
Evidence for primary aragonite precipitation, early Proterozoic (1.9 Ga) Rocknest Dolomite, Wopmay Orogen, northwest Canada.
• NASA Outstanding Public Leadership Medal (2013; notable leadership of a NASA space mission) •Roy Chapman Andrews Explorer Award (2013; outstanding achievement in scientific discovery through exploration) • Halbouty Award, American Association of Petroleum Geologists (2012; exceptional leadership in the petroleum geosciences) • Lawrence Sloss Award, Geological Society of America (2011; lifetime achievement in sedimentary geology) • Charles Doolittle Walcott Medal, National Academy of Sciences (2007; "for the insightful elucidation of ancient carbonates and the stromatolites they contain, and for meticulous field research that has established the timing of early animal evolution".)
