Utah salt accretions boon for study

Rare lake occurrence is a limited-time offer

SALT LAKE CITY — Rare salt formations have been documented for the first time on the shores of the Great Salt Lake, and they could yield insights about salt structures found on Mars before they disappear for good.

They’re showing up now in part because water levels at the largest natural lake west of the Mississippi have been lowered by drought and water diversion, exposing more shoreline. It’s a story that’s playing out throughout the American West as a growing population puts more demand on scarce water resources.

The expanded shoreline means there are more places where water can bubble up to the surface from warm, sulfate-rich springs. When it hits the cold air, a mineral called Glauber’s salt, or mirabilite, separates out.

“It has to be exposed to just the right conditions,” said park ranger Allison Thompson.

The tiny crystals have built up over the past several months, eventually creating flat terraces stacked atop one another like the travertine rimstone and dam terraces at Yellowstone’s Mammoth Hot Springs.

From far away, the mounds can blend into the snowy landscape along the flat blue of the lake edged by distant mountains. From above, though, the cascading terraces are like an enormous piece of lace laid over the sandy earth.

There are now four mounds at the Great Salt Lake beach, growing up to 3 feet tall and several yards wide.

Mirabilite mounds are seen more often in places such as the Antarctic, bolstered by the constantly cold temperatures. There are also indications of similar structures on Mars, so study of the mounds in Utah could offer clues on how to examine salts found there.

Mirabilite mounds are especially interesting because they’re created by water bubbling up from underground, so they can provide clues about what’s beneath the surface without expensive drilling, said Richard Socki. He studied mirabilite mounds in the Antarctic when he was a NASA geochemist in the mid-2000s.

But researchers don’t have long to study the Great Salt Lake formations: As winter turns to spring, higher temperatures mean the salt won’t continue to precipitate out of the water, and the mounds will disintegrate into a fine dust.

Utah Division of Parks and Recreation Rare salt formations are being documented for the first time along the shores of the Great Salt Lake in Utah. They could yield insights about structures found on Mars.