CHANNEL AND TUBE FLOW FEATURES ASSOCIATED WITH THE TWIN CRATERS LAVA FLOW, ZUNI-BANDERA VOLCANIC FIELD, NM: INSIGHTS INTO SIMILAR FEATURES ON MARS

In this study, we combined detailed field observations and mapping with remote sensing to better understand variations in morphology along the channel system of the 18,000 year old Twin Craters Lava Flow (part of the Zuni-Bandera Volcanic Field, NM). The Twin Craters flow is an aā and tube-fed pāhoehoe flow with braided or branching tubes and channels; and associated aā and pāhoehoe break-outs. Extensive shatter features occur along the channel system. It is likely that the variations in morphology along the channel are related to variations in the pre-flow valley morphology including valley width and slope changes, and interactions with several ridges of bedrock outcropping within the valley. Deeper and bifurcating channels are related to steeper slopes while shatter features occur where slopes are more gentle. Over-pressurization of the tube resulting in shatter features might be related to changes in local discharge rate associated with the ponding and release of lava within the channel system that may be due to interactions between the lava and obstacles along the flow’s path. Many of these features are similar to features present in the Tharsis Montes region of Mars and particularly on the southern apron of Ascraeus Mons. The detailed description of the morphology of the Twin Craters Lava Flow and the understanding of the emplacement mechanisms will be crucial in identifying the processes that formed the Ascraeus flows and channels.