Geopic of the week: Speleothems

 

Above are speleothems- they’re also called dripstones, stalagmites and stalactites, or other names depending on their shape.  They can be seen when touring Blanchard Springs Caverns located about 10 miles north of Mountain View, Arkansas.  The cave is full of breathtaking features like these which form by precipitation from ground water that drips from the cave ceiling.  The groundwater, which has traveled through rock and soil before reaching the cave, is saturated with minerals it dissolved along it’s path.  The principal mineral that forms the dripstones is calcite.  As the groundwater enters the open air of the cave a pressure drop causes the calcite to come out of solution and precipitate a tiny coating on the outside of the growing speleothem.  Over time some of them can reach from the roof to the floor of the cave and elaborate, and marvelous shapes develop. 

Geopic of the week: Ice

As a naturally occurring, inorganic, solid, crystalline substance with a constant chemical formula, ice is in fact considered a mineral.  By the same logic, water, which is the liquid form, is lava.  This picture was taken earlier this week near Prim Arkansas.  Rock hammer for scale.