Radio-echo sounding and waveform modeling reveal abundant marine ice in former rifts and basal crevasses within Crary Ice Rise, Antarctica

Abstract Crary Ice Rise formed after the Ross Shelf re-grounded ~1 kyr BP. We present new ice-penetrating radar data from two systems operating at center frequencies of 7 and 750 MHz that confirm ice rise is composed a former shelf buried by subsequent accumulation. Stacks englacial diffraction hyperbolas are almost everywhere across central extend up to ~350 m above bed. In many cases, bed reflections beneath obscured for distances 1 km. Waveform modeling indicates likely caused marine deposits in basal crevasses rifts. The in-filling rifts may have strengthened connection between surrounding shelf, which could influenced local regional dynamics. Three internal reflection horizons mark upper limit disturbed different sections rise, indicating least three stages flow stabilization rise. A surface lineation visible MODIS imagery corresponds spatially deepening strong deformation these layers, consistent with characteristics grounding lines observed elsewhere Antarctica.