Locality 11

Inter Dune

Interdune areas are troughs between dunes, ranging from interdune flats to interdune depressions.

Interdune deposits are generally isolated lenticular bodies of flat bedded or ripple laminated or adhesion rippled sandstone perhaps with muddy drapes and desiccation cracked muds with evaporative crusts and an irregular salt-ridge microtopography.

Evaporite dissolution and reprecipitation causes the collapse of the salt ridge fabric (Reading, 1996).

Photo of a gypsum rosette

source http://www.earlham.edu/~greshjo/Rosette.htm

Gypsum Rosette

Sand roses occur in this area growing at the water table 1m below the surface, and are found in a variety of sizes ranging from small rosettes 1cm across to large cluster, more than 1m in diameter made up of perfectly formed gypsum crystals that split along cleavage Planes producing the characteristic rosette form.

Once at the surface sand roses are very prone to weathering and dissolution occurs (Denis Mougenot).

Photo of gypsum rosettes at the watertable diagram of sand rose formation

source http://membres.lycos.fr/middle_east/Mougenot.html

diagram of formation of gypsum crystals

source http://membres.lycos.fr/middle_east/Mougenot.html

Sediments here are bioturbated with plant root moulds, and vertebrate and invertebrate fossils can be found.




This page was created by Pamela Williams

Last Modified:18/06/02