Professor Emeritus of Geology and Geophysics, University of Utah

On Valentine's Day I drove to Great Salt Lake to see how the lake was doing and if it and the shores were the same as I remembered them. I asked our dog Leila, a mix of two of the most intelligent breeds on the planet-border collie and lab-to come along, and she was out the door ahead of me and to the car the minute I passed the rose bushes.

The first place we stopped was the Saltair pavilion. From there we walked to the water's edge, out onto the dikes north of the pavilion, and then to the southern lakeshore north of the pseudo-Moorish building. The new Saltair has never captured the joy and grandeur of the old Saltair, which opened in 1893 when the lake was at 4,200 ft, the level our citizens have historically preferred. The new structure has not weathered well. Storm waves and the great rise in lake level from 4,200 to 4,208 ft from September 1982 to June 1983 devastated the resort, destroying the waterslide at the pavilion and other structures, covering roads on the southern shore and to the north, and flooding the new pavilion, a concrete edifice built around a U. S. Air Force hanger. The lake rises and falls as it will.

Leila and I tramped away from the pavilion and back to the oolite, sediments that lie along the shore, and to cement blocks back of the shore. Storm waves had covered the blocks with a thin layer of oolite, and Leila and I slipped on the rounded grains, my slide resembling an out-of-control skier about to crash, hers that of Peekaboo Street slaloming downhill. Oolite looks a lot like fish roe. The average diameter of each grain, called an ooid, is about 0.3 millimeters. Generally, ooids have nuclei of sand or carbonate grains and concentric bands or layers of precipitated calcium carbonate (CaCO3), the mineral aragonite, around the nuclei. One axis of an ooid is commonly longer than the other two, like a watermelon.

The last time I scooped up a handful of ooids my friend Faye was with me. With little urging she also thrust a hand into the warm waters to gather ooids. I handed her a ten-power hand lens and she looked at the light gray, pale blue, and black spheres. Resisting the temptation, I said nothing about aragonite and the radial rays from nuclei in some of the ooids. Faye gathered up another handful, saying the particles looked like pearls, which also are mainly calcium carbonate in the form of aragonite. Ooids as pearls; I prized the words.

Because Faye especially loved music, books, and tennis, I was uncertain the first time we went to the lake that she would enjoy it. Many Salt Lakers say the lake is a dirty place that smells bad: odors emanate from the polluted marshes, the water-filled ditches, and from the fecal pellets of brine shrimp. There are abundant brine flies, and encounters with them are unavoidable; fussy visitors may deplore a nose full of the flies invading their sinuses. Rarely do visitors, as did the original explorers and settlers, wade into the briny water, ease backward and float like corks. For lovers of the lake, seeing the metallic colors of the water, and the birds, feeling the winds that blow over and lift the lake, and, yes, smelling the odors, may be a religious experience.

At the lake, the first oolite shoal we wandered out on led to Black Rock, a small island or a prong from the north end of the Oquirrh Mountains, depending on the lake level. Black Rock rocks are part of the Oquirrh Group, strata more than three miles thick made up of Pennsylvanian and Permian sandstone and limestone deposited in an ancient basin during a time of major climatic changes from about 320 to 280 million years ago. The northern end of the Oquirrhs borders the lake and when we sometimes came early in the morning, mountain shadows fell on the shoreline and far out on the rippling water.

In 1851, Utah's pioneers held their first 4th of July celebration at Black Rock. About 60 horsemen and 150 vehicles gathered there for festivities that climaxed in the unfurling of an enormous homemade flag. Likely none of the people knew or cared about the oolite, mistaking it for quartz sand along the shore. Shorelines that face the open lake and receive the waves unchecked, as at Black Rock, are where oolite is best developed. Ripple marks formed of the rounded oolite grains, their crests parallel with the shoreline, indicate by their asymmetry toward the shore that wind-induced waves have come in perpendicular to the strandline. So I said to Faye. "Oh yeah," she said.

Winds arose, wave heights increased. Leaving our lunch in the shadow of a limestone boulder, we took off our sneakers, rolled up our pants legs, and waded out into the lake, heading north toward Antelope Island. Fifty yards from shore the mud was black and squishy and, in places, footing was precarious. Salt crystallized on our legs and pants. From where we were, we could see Stansbury Island on the west, and north of it, Carrington Island, a rocky barren place used for aerial bombing practice during World War II. The well-marked terraces of Lake Bonneville, the immense prehistoric freshwater lake that preceded Great Salt Lake, are clearly expressed on Antelope and Stansbury islands. The lake reached its present level about nine thousand years ago. From 23 to 18 thousand years ago, Lake Bonneville rose to fill its basin, reaching its greatest extent at about 5,200 ft above sea level and its deepest of 1,000 ft. Then it fell back. About 16 thousand years ago, the lake rose again to the Bonneville level. At that time, it reached an outlet in south-central Idaho and flooded into the Snake River-Columbia River drainage, creating a river larger than the Amazon. Lake Bonneville never overflowed again, declining in stages to its present low level.

East of Stansbury Island, we came upon algal mounds, chiefly composed of aragonite. Up to five feet in diameter and one to two feet in height, the mounds occur only in shallow water and shoreline areas. The mounds and the ripple marks around the mounds and on their fringes appealed to Faye, and she bent toward one, her floppy white hat casting a shadow on the mound. Underwater, she gently brushed ooids from the top of the structure. She swept brine shrimp aside. She ran her wet hand across her forehead and salt crystals began to sugar her brow.

Other than their mineral composition, the algal mounds probably were not a great mystery to Faye. Their structure is simple. Faye grew up mostly in Tooele (pronounced Too-Il-uh or Too-El-uh), a few miles south of the lake during the 1940s and early 1950s when access to all of the southern shore was relatively easy.

Everywhere we stopped on the southern shore where algae grew, the plants had produced astonishing growths and mounds. From hour to hour, day to day, season to season, the algae and lake waters change color. Sunlight reflecting on water surfaces and films of water on the algal mounds give brilliant hues of lustrous metals: copper, gold, burnished brass, silver, chromium, tin, and lead. On many days and on all of the bright blue days, the luminous water and the air above it evoke dancing light of the sparkling air at Toulouse in southern France on the Garone River.

It seems to me, as I remember this, that I never did say much, or anything, about the lake's evaporite minerals, particularly the aragonite, that last day we went to the lake. Aragonite occurs in white or colorless crystals and like calcite, the dominant calcium carbonate on Earth, fizzes in cold, dilute hydrochloric acid that you can buy cheaply at a drugstore. Once with Faye I scratched a chunk with a pocket knife to demonstrate its softness, 3 of the hardness scale. I remember that she wanted me to get her a knife for her birthday, and I did, selling it to her for ten cents. That exchange forestalled bad luck and the cutting of our friendship, which on West Bridger Creek in central Wyoming we believe can happen if knives are not paid for.

All that day there was no one else at the lake. While we tramped along the shore on Stansbury Island, four or five Western Meadowlarks flushed up from the coarse grass south of us. The little flock landed nearby, began to feed, and sang beautifully from their extensive repertoires. Our presence was of no moment to them. The meadowlarks, and at that time any birds, enchanted Faye. She lifted her hands high above her head, tiny in all that flashing air, and moved her arms and hands as if she too was flying. Then she stood on tiptoes and watched intently as long as we could see any of the birds.