Virtual Field Trip—Group 3
Geologic Features of White Sands National Monument
We are a research and service division of:
Barchan Dune Sand Ripples Animal Tracks Footprint of Dune Interdunal Flats Pedestal
Surface of Interdunal Crust Mircrobial Interdunal Crust
Greg Frostad
GPS Location: UTM 13S, 0381814, 3630119
The crescent-shaped barchan dunes dominate the central area of White Sands. The arms of the dunes point in the direction of the prevailing wind. The leeward slopes are steeper than those of quartz sand dunes because the gypsum grains are more angular and allow the sand to rest at higher angles of repose.
Linda Pehr
GPS Location: UTM 13S, 0381873, 3630232
Southwesterly winds sculpt the dunes leaving behind transverse, two-dimensional ripple marks. Although the surface is warm to the touch, the sand is significantly cooler a few inches below. The fine gypsum sand grains of the dunes are lighter colored than the interdunal sand.
Kay Lucas
GPS Location: UTM 13S, 0381873, 3630232
Forms of life have evolved to live in the unique environment of the White Sands. Here we have evidence of animal life, tracks in the sand.
Robert Pasztor
GPS Location: UTM 13S 0381878, 3630241; Alt 1222 m
Moisture in the sand of the interdunal flats causes grains of sand to remain as dunes move forward. This creates a footprint in the wake of the dune.
Tina Aragon
GPS Location: UTM 13S 0381844, 3630197
Some plants survive in the moving sand by growing upward faster than the dune is moving. i.e. yucca and mint rosemary. Their roots grow deeply into the gypsum forming a hard mound. The mound remains after the dune has moved away.
Left: collapsed yucca
Right: Mint Rosemary Pedestal
Pustular Surface of Interdunal Crust
Susan Berry
Location: UTM 13S, 0381867, 3630241
The microbial crust is caused by cyanobacterial growth. As it grows beneath the surface, it causes expansion of the crust.
Microbial Interdunal Crust
Susan Berry
GPS Location: UTM 13S, 0381833, 3630189
The cyanobacteria (blue-green algae) is present just beneath the rigid crust. This feature is only found in the interdunal flats where there is a higher moisture content due to capillary movement of water upward from the water table.
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