NEW AGE ESTIMATES FOR THE CERBERUS CHANNEL FLOOD LAVAS, MARS: IMPLICATIONS FOR MAGMA MIGRATION

Young regional volcanism on Mars is epitomized within the Cerberus plains as distinct lava flows in three circum-Cerberus aqueous flood channels, Athabasca (AV), Grjotá (GV), and Marte (MV) Valles. Each channel and corresponding infilling lavas emanate from separate points along the regional Cerberus Fossae (CF) fissure network. The CF has been modeled as radial to the Olympus/Tharsis volcanic complex (OTVC), though the fissures also appear radial to the Elysium volcanic province. The bulk of formation activity for both edifices is old, but limited volcanism at both sites continued into the very recent past and may be coincident to the volcanotectonic activity in the Cerberus plains. Previous work has dated the youngest flows within AV from between 1.5-200 Ma, GV from 10-40 Ma, and MV from 10-200 Ma. Based on these age estimates we hypothesize lava emplacement within the three channels occurred in sequence, from east (oldest) to west (youngest). Such a finding would suggest the lava flows developed as a consequence of late stage volcanism related to the OTVC and subsequent westward migration of magma along the fissure network.

To accomplish this work, mapping of the channels and associated lavas was performed using a Context Camera (CTX) basemap at a scale of 1:100K, enabling the discrimination of flow contacts in previously identified lava flows. Based on these results, sites proximal to the lava flow sources were chosen for crater size frequency distribution analyses. All craters on the lava surfaces within the chosen sites were counted, excluding obvious secondary clusters or preexisting lava-embayed craters. Derived results yield model ages of 3.2 ± 0.2 Ma for AV, 36 ± 0.9 Ma for GV, and 49 ± 0.9 Ma for MV, within the ranges of previously published data. These derived ages suggest the lavas erupted in a westward progression, which would imply a westward-moving magma source. Further work in the region will entail additional crater counts of the lava surfaces within the individual channels. This work will lead to a robust determination of the age of lava emplacement, and test if each in-channel flow was the result of a single eruptive event. The refined mapping and model ages for these lava flows will be used to infer the behavior of the magma source, and further our understanding of late-Amazonian volcanism on Mars