Unraveling Fluvial Kinematics before the Rise of Land Plants

Barren modern depositional environments provide examples of single-thread channels that meander in the absence of bank-strengthening plant roots.

Discovery of meandering, single-thread channel deposits on Mars offer definitive proof that vegetation is not necessary to achieve bank stability. Photo from Matsubara et al. (2015).

Our first goal is to establish actively meandering single-thread flow. Following methods described by Peakall et al. (2007) and Van de Lageweg et al. (2012), we plan to scale grain size to flume dimensions by using silica flour. This is a much closer approximation to sand bed rivers than using sand grains, which approximate gravel to cobble bed rivers.

We will characterize bar dimensions, migration rates, and stratigraphic profiles, in addition to channel migration rates and cut-off and avulsion behavior, if present.

The flume arrived in the Spring of 2022 and is now installed, calibrated, and ready for experiments. I am currently providing support (and manual labor!) for my labmate Debsmita Das, who is running exciting experiments looking into the effects of unsteady flow on dune morphology, migration, and preservation.

I’m looking forward to getting the next turn on the flume, but for now I’m learning the ins and outs of the system equipment and software.

Proterozoic Stoer Group strata were deposited well before the evolution of land plants. Composed of the Clachtoll, Bay of Stoer and Meall Dearg formations, this group has been interpreted as alluvial fan, channel, and floodbasin environments within a rift basin. We aim to characterize floodplain facies, bar characteristics, and indicators of channel migration and stacking.