Death Valley geology field trip
Devil's Golf Course
|
The lumpy salts you see here are the residue of Death Valley's last significant lake, which had evaporated by 2000 years ago. Photo by Martin Miller
|
Mineral music
It's an early summer morning. The temperature is rising fast. The air is completely still and the quiet is profound. But, listen carefully and you'll hear a sounds like tiny pops and pings. Bend your ear to the ground and the sound grows louder. The musical sound of literally billions of tiny salt crystals bursting apart as they expand and contract in the heat provides the backdrop for this salty story.
Lakeside property
Not long ago, about 2000-4000 years ago during the Holocene, the climate was quite a bit wetter than today. It was so wet that water gradually filled Death Valley to a depth of almost 30 feet. The ancient peoples of Death Valley must have enjoyed centuries of abundant food in their lakeside homes.
Jagged salt pinnacles. Photo from NPS archives.
|
The desert returns
These good times didn't last, however. The climate warmed, rainfall declined, and the shallow lakes began to dry up. Minerals dissolved in the lake became increasingly concentrated as water evaporated. Eventually, only a briny soup remained, forming salty pools on the lowest parts of Death Valley's floor. Salts (95% table salt - NaCl) began to crystallize, coating the muddy lakebed with a three to five feet thick crust of salt.
Close-up of delicate lacework edges decorating salt pinnacles. Photo by Ray Nordeen, NPS.
|
Pinnacles
While the saltpan at Badwater periodically floods, then dries, Devil's Golf Course lies in a part of the Death Valley salt pan that is several feet above flood level. Without the smoothing effects of flood waters, the silty salt at Devil's Golf Course grows into fantastic, intricately detailed pinnacles.
The pinnacles form when salty water rises up from underlying muds. Capillary action draws the water upward where it quickly evaporates, leaving a salty residue behind. The pinnacles grow very slowly, perhaps as little as an inch in 35 years. Wind and rain continually work to erode and sculpt the salty spires into an amazing array of shapes.
|
|
|
|
