These surveys also identified an embayment feature that may represent a shallow, fault bounded paleo-lakebed within the unconsolidated sediments that overlie the older volcanic and sedimentary “basement” rocks.

Source: https://theclarion.ca/media-release/allegiant-identifies-significant-lithium-boron-anomaly-in-the-big-smoky-valley-initiates-second-geochemical-sampling-phase/