Acid-etched rock surface showing details of radial fibrous cement filling
a large primary cavity in
the upper Capitan reef framework. Originally, cements were mainly aragonite with some high-Mg
calcite and formed botryoidal crusts lining small as well as large pores. Virtually the entire field of
view above the coin is marine cement which may form as much as 80% of the total rock volume.
Outcrop at the south spur of the mouth of Walnut Canyon, just outside boundary of Carlsbad
Caverns National Park, Eddy Co., New Mexico. Coin is 1.8 cm in diameter.
© Peter A. Scholle, 1999