237-12 Determining the Formative Mechanism(s) of Linear Dunes With Implications for Titan

Session: Geomorphology and Surface Processes Across the Solar System

Presenting Author:

Authors:

Abstract:

Linear dunes represent the only dune form found on all the terrestrial worlds with an appreciable atmosphere, including Titan, Mars, and potentially Venus. On Earth, they represent 40% of all dunes.  Despite their common occurrence, however, it is still not clear how they form. Competing hypotheses include Linear Extension, Wind Rift, Lateral Migration, or a combination of these processes.  The problem with determining the precise formative mechanism is that individual dunes are enormous features.  Linear dunes often have widths and heights that can be up to tens of meters, and with lengths usually exceeding hundreds of kilometers.  They also occur in some of the largest, most extensive dune fields on Earth. While previous studies have provided valuable insights into individual dunes and small portions of some dune fields, they have not combined burial age dating with geochemical analyses of dune sediments over an entire dune field. Such a large-scale, field-based study is necessary for testing the different models of linear dune formation. Here, we present preliminary results from multiple surveys taken throughout the Simpson Desert in central Australia.  Our analyses of the samples indicate that the composition of the sand is homogeneous to depths of ~10 m, which is the height of the dunes we explored.  Our results also suggest there is evidence for multiple episodes of dune building. TL age dates of samples collected at specific depths along a north-south track, for example, indicate that the upper parts of the dunes are consistent in age (<3.5 ka at depths of 2 m). Separate real-time kinematic differential GPS (RTK DGPS) topographic surveys of several linear dunes show changes over about a decade. These surveys show a net accumulation of centimeters of material at the crest of the dune, a net loss of material at the base of the dune, and little or no linear extension.  We will present a complete summary of our results so far while placing our findings into context with the linear dunes found on Titan.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10226

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.