ROSS ICE SHEET DYNAMICS: CLUES FROM DETRITAL THERMOCHRONOLOGY AND SEDIMENTARY PETROGRAPHY
Detrital geochronology, sedimentary petrography and, in general, data about provenance of sediments, allow inferences to be made about the ice-flow patterns as they provide information on the source-to-sink path. In this work, we combine several data from Andrill (AND-2A and AND-1B) and Cape Roberts wells and compare them with evidences from the putative source rocks located along the Transantarctic Mountains (TAM). This dataset gives a solid picture of erosional pattern along the TAM from Oligocene to Miocene.
All the data point to a general north-to-south ice flow but relevant variations of source rock appear through time. Taking into consideration tectonic activity along the TAM, we relate these variations to fluctuations of Ross Ice Sheet as far back as the early Oligocene. In other words, the sedimentary signature is strongly influenced by climatically-controlled expansions of a grounding WAIS into the Ross embayment which repetitively extended as far as the the Cape Roberts drilling site.