Who's Who? Who's New?

Helen Hill for EAPS News
January 31, 2017

A warm EAPS welcome to postdoctoral associates Julien Alleon and Jordan Steckloff.

Julien Alleon is a biogeochemist interested in the processes that compromise our ability to read the deep time record of life encoded in graphitic microfossils. He joined EAPS in January to work in Roger Summons' Geobiology and Astrobiology Lab

Alleon explains, "the early life fossil record is based on a limited number of often controversial graphitic microfossils. The main complication resides in the poor preservation of organic biosignatures in the (meta)sedimentary rock record. Biodegradation and fossilization processes, as well as the increase of temperature and pressure conditions during burial diagenesis and metamorphism inevitably alter the original biochemical signatures of organic molecules. Thus, at a certain stage, biogenic and abiotic organics may become very difficult to distinguish. My research combines characterization of natural samples using advanced spectroscopic techniques (STXM-based XANES & Raman microspectroscopies) and simulation of fossilization processes in the laboratory to investigate the potential preservation of microorganism molecular biosignatures in ancient rocks."

Alleon holds a PhD in Biogeochemistry from the National Museum of Natural History, Paris, France, and an MS in Geochemistry from the  European Institute for Marine Studies, Plouzané, France.

Alleon J., Bernard S., Le Guillou C., Marin-Carbonne J., Pont S., Beyssac O., McKeegan K. D., Robert F. (2016), Molecular preservation of 1.88 Ga Gunflint organic microfossils as a function of temperature and mineralogy, Nature Communications 7, 11977, doi: 10.1038/ncomms11977


Jordan Steckloff is a planetary scientist interested in how thermophysical and geophysical surface processes affect the behavior, structure, and observed geomorphology of icy Solar System bodies (e.g., comets, centaurs, KBOs, and icy moons.) He joined EAPS in January to work with Jason Soderblom looking at the thermophysical and chemical evolution of materials on the surface of Saturn’s largest moon, Titan. His particular focus, will be looking at how physical processes affect the composition and phases of hydrocarbon puddles and lakes on Titan, but he is also interested in how impacts into Titan’s ice shell affect the chemical and physical evolution of Titan’s surface and atmosphere.

Steckloff holds a PhD in Physics from Purdue University (2015) where he was awarded the Karl Lark-Horovitz Award for Outstanding Research Accomplishment, by the Purdue University Department of Physics and Astronomy (April 2016). Recent papers Keane et al (2016) and Trowbridge et al (2015) have concerned the geology and geophysics of Pluto.

Keane, J.T.; Matsuyama, I.; Kamata, S.; Steckloff, J.K. (2016), Reorientation and faulting of Pluto due to volatile loading within Sputnik Planitia, Nature 540, 90-93, doi: 10.1038/nature20120

Trowbridge, A.J.; Melosh, H.J.; Steckloff, J.K.; Freed, A.M. (2015), Vigorous convection as the explanation for Pluto’s polygonal terrain, Nature 534, 79-81, doi: 10.1038/nature18016