Morphologically induced density lag formation on bedforms and biogenic structures in aeolian sands

Abstract

Abstract In a variety of sand-dominated depositional settings, an increase in near-surface wind velocity typically culminates with the formation of a lag deposit, such as an increase in coarse fraction, accumulation of shell fragments, or a concentration of heavy minerals (density > 2.9 g/cm 3 ). This study presents examples from six coastal dune sites where prominent heavy-mineral concentrations (HMCs) are confined to the crests of aeolain ripples and marginal ridges of biogenic structures. In settings with low background fraction of heavy minerals (2–5%), micro-topographic highs ( 500 MHz) georadar imaging.