Patrick J. Gasda Joel A. Hurowitz John P. Grotzinger Roger C. Wiens Horton E. Newsom Ken S. Edgett Jessica Watkins John C. Bridges Sylvestre Maurice Martin R. Fisk Jeffrey R. Johnson William Rapin Nathan Stein Sam M. Clegg S. P. Schwenzer C. Bedford P. Edwards Nicolas Mangold Agnes Cousin Ryan B. Anderson Valerie Payre David Vaniman David Blake Nina L. Lanza Sanjeev Gupta Jason K. Van Beek Violaine Sautter Pierre-Yves Meslin Melissa Rice Ralf Milliken Ralf Gellert Lucy Thompson Ben C. Clark Dawn Y. Sumner Abigail A. Fraeman Kjartan M Kinch Morten B. Madsen Igor Mitofranov Insoo Jun Fred J. Calef Ashwin R. Vasavada Jens Frydenvang 2017 <p><span>Diagenetic silica enrichment in fracture-associated halos that crosscut lacustrine and unconformably overlying aeolian sedimentary bedrock is observed on the lower north slope of Aeolis Mons in Gale crater, Mars. The diagenetic silica enrichment is colocated with detrital silica enrichment observed in the lacustrine bedrock yet extends into a considerably younger, unconformably draping aeolian sandstone, implying that diagenetic silica enrichment postdates the detrital silica enrichment. A causal connection between the detrital and diagenetic silica enrichment implies that water was present in the subsurface of Gale crater long after deposition of the lacustrine sediments and that it mobilized detrital amorphous silica and precipitated it along fractures in the overlying bedrock. Although absolute timing is uncertain, the observed diagenesis likely represents some of the most recent groundwater activity in Gale crater and suggests that the timescale of potential habitability extended considerably beyond the time that the lacustrine sediments of Aeolis Mons were deposited.</span></p> application/pdf 10.1002/2017GL073323 en American Geophysical Union Diagenetic silica enrichment and late-stage groundwater activity in Gale crater, Mars article