The clay fraction of the deposits of the Otjomongwa Pan, southwestern Kalahari, is dominated by Mg-smectite. This mineral formed as an authigenic precipitate in a groundwater-fed lake, without involving the transformation of a precursor mineral. During the earliest recorded period, Mg-smectite formed together with sepiolite and dolomite in a shallow lake. This period was ended by a change in environmental conditions that led to an increase in the depth of the lake and a decrease in salinity and Mg content of the water. This resulted in a transition to a mineral association without sepiolite and including calcite, together with Mg-smectite and dolomite. The depth of the lake gradually decreased after this event, while the lake water progressively became depleted in Mg.

Lac d'Armor (49°27′S, 69°42′E) is a medium-sized, fjord-type lake located on the ‘Grande Terre’ island of the Kerguelen archipelago. A dense grid of high-resolution reflection seismic profiles was collected from this lake basin. The seismic stratigraphic facies reveal a last deglaciation to Holocene infill comparable to the seismic facies found in other glacigenic lakes all over the world. Remarkable features in the seismic stratigraphy are mounded structures found at the southern edge of both sub-basins. The sediment mounds can be interpreted as sediment drifts created by wind-induced bottom currents. The onset of the build-up of these drifts initiated at some point in the Holocene and indicates a strengthening of the southern Westerlies, which are currently the dominant winds on this island.