Abstract The englacial stratigraphic architecture of internal reflection horizons (IRHs) as imaged by ice‐penetrating radar (IPR) across ice sheets reflects the cumulative effects of surface mass balance, basal melt,andice flow.IRHs,consideredisochrones,havetypicallybeentracedininterior,slow‐flowingregions. Here, we identify three distinctive IRHs spanning the Institute and Möller catchments that cover 50% of West Antarctica's Weddell Sea Sector and are characterized by a complex system of ice stream tributaries. WeplaceageconstraintsonIRHsthroughtheirintersectionswithpreviousgeophysicalsurveystiedtoByrd IceCoreandbyage‐depthmodeling.Wefurthershowwheretheoldesticelikelyexistswithintheregionand that Holocene ice‐dynamic changes were limited to the catchment's lower reaches. The traced IRHs from this study have clear potential to nucleate a wider continental‐scale IRH database for validating ice sheet models. Plain Language Summary Ice‐penetrating radar is widely used to measure the thickness of ice sheets, critical to assessments of global sea level rise potential. This technique also captures reflections fromchemicalcontrastswithintheicesheet,causedbytheatmosphericdepositionofconductiveimpurities, knownas “internalreflectionhorizons” (IRHs)thatcanbetracedoverlargedistances.Asthese depositsare laid down in distinct events, most IRHs are isochronous age tracers and contain valuable information on past ice sheet processes. In this paper we trace and place age constraints on stratigraphic horizons across a large portion of the West Antarctic Ice Sheet, including regions where fast ice flow has disrupted the ice sheet stratigraphy. The resulting data set allows us to identify where the oldest ice is buried in the study region and provides evidence that flow of the ice sheet interior has been stable during the Holocene. Our results can be used to test the performance of ice sheet models, which seek to simulate the response of ice sheets to long‐term environmental change.
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Authors: Poedts, Stefaan, Kochanov, Andrey, Lani, Andrea, Scolini, Camilla, Verbeke, Christine, Hosteaux, Skralan, Chané, Emmanuel, Deconinck, Herman, Mihalache, Nicolae, Diet, Fabian, Heynderickx, Daniel, De Keyser, Johan, De Donder, Erwin, Crosby, Norma B., Echim, Marius, Rodriguez, Luciano, Vansintjan, Robbe, Verstringe, Freek, Mampaey, Benjamin, Horne, Richard ORCID record for Richard Horne, Glauert, Sarah ORCID record for Sarah Glauert, Jiggens, Piers, Keil, Ralf, Glover, Alexi, Deprez, Grégoire, Luntama, Juha-Pekka