What Did I See at Vasquez Rock? Follow-up to our class trip to Vasquez Rock

Desert Varnish Surface covered by black deposits called rock varnish Layer consist of thin layer of bacteria, clay minerals, and manganese and iron oxides The Mn oxide (MnO 2 ) makes black color Stop #1-2

Solution Holes (Tafoni) Result of local wind turbulence on wet rocks Wind evaporates water (H 2 O)and causes the growth of tiny salt crystals at and below the surface of the rock causing pressure on the sand grains Sand grains loosen and form small cavities, which continue to weather from the wind causing the cavities to grow Stop #1-2

Bacteria and lichens first break away rock and minerals (clay and sand) Dead bacteria provide organic matter providing nutrients for plants to grow Do Plants Grow on Rocks? Stop #1-4 Juniper Bush

Criteria to distinguish one bed from another: –Grain size –Color –Resistance to weathering –Grain composition Reddish color–iron oxide Occurs when sediments are deposited on land and are exposed to the atmosphere Bedding Planes Stop #1-5

Displacement Stop #1-6 Sedimentary strata form continuous layers Cracks where there been displacement are called faults Offsets usually produced by earthquakes Red color is not Iron Oxide instead red paint

Chemistry in Action