Antelope Island Facts

Back to Antelope Island Main Page

You Tube Educational Video

History

Visitors to Antelope Island State Park drive across the causeway, a narrow two-lane road spanning from mainland to island, leaving the bustle of the Wasatch Front for a refuge of rangelands floating on a desert sea. Visitors will want to visit the Fielding Garr Ranch located on the southeast side of the island. The Fielding Garr Ranch House is distinctive for two reasons: first, it is the oldest continually inhabited Anglo home in the state of Utah (from 1848 to 1981 when the island became a state park), and second, it is the oldest Anglo-built house in Utah still on its original foundation.

Antelope Island State Park, consisting of 28,022 acres, is the largest island in the Great Salt Lake measuring 15 miles long and seven miles wide at its widest point. In 1969, Utah State Parks and Recreation purchased 2,000 acres on the northern tip of Antelope Island and in 1981, purchased the balance acreage for recreational purposes. With the purchase of the island, the landowner donated approximately 250 bison to the agency.

For more information: call the Davis Area Convention and Visitors Bureau, 801-774-8200 or Toll Free 1-888-777-9771.

Wildlife

Antelope Island is home to a roaming herd of 600 bison, big horn sheep, mule deer, pronghorn sheep (the "antelope" from which the island got its name, coyote, and a wide variety of birds. Though surrounded by water that is up to five times saltier than the ocean, wildlife viewing opportunities abound on this island of grasslands, wetlands, and miles of shoreline.

Video: Just because they won't answer, doesn't mean

you shouldn't ask the locals for directions.

Geology

The Basin and Range Province is centered in Nevada and extends eastward into Utah and southward into Arizona and California. Antelope Island is in the portion of the Basin and Range Province known as the Great Basin. The Great Basin eastern boundary is the Wasatch Range and western boundary is the Sierra Nevada Range in California. The typical pattern of the Basin and Range is of skinny mountain ranges surrounded by a broad valleys or basins. At Antelope Island, the island is the range and the Great Salt Lake spreads across several basins. This is a repeated pattern all the way across western Utah and Nevada to the Sierra Nevada Range. The view to the north and west from the visitor center is a vista of that pattern.

Rocks

As you'll see at the diorama in the island's Visitor Center, Antelope Island has some of the oldest rocks in the US and some of the youngest. The majority, about two-thirds, of the island is comprised of the Farmington Canyon Complex.

The islands of the Great Salt Lake are believed to have been formed by earthquakes that elevated blocks of the earth's crust between faults running across the bed of the lake. These blocks, called grabens, are partly submerged. Their higher points form eight true islands that cease to be islands during the lake's low water periods.

Some of the oldest and youngest rocks in the Great Salt Lake area may be found on Antelope Island. The very oldest rocks on the island are believed to date from the Middle Precambrian period, 1,580 million years ago. The youngest rocks date from the Quaternary period and are relative whippersnappers at 10,000 to 2.5 million years old.

Trails

The 3-mile Lake Side Trail leaves the Bridger Bay Campground and follows the beach around the northwestern tip of the island to the group camping area on White Rock Bay. The walk is magnificent at sunset. Other trails take you away from the crowds, where you might catch a glimpse of buffalo or other wildlife.

Great Salt Lake

You wouldn't expect to come across what is essentially a small ocean in the middle of the desert, but here it is: the Great Salt Lake. The lake is all that's left of ancient Lake Bonneville, which once covered most of western Utah and parts of Idaho and Nevada. Unlike its mother lake, though, the Great Salt Lake has no outlet, so everything that flows into it-some 2 million tons of minerals annually-stays here until someone or something-usually brine flies, brine shrimp, birds, and humans-removes it. So when you see swarms of flies, don't wonder why the powers-that-be haven't eliminated them. (Besides, they don't bite, and rarely even alight on people.) Minerals, including salt, potassium, and magnesium, are mined here; don't be surprised to see front-end loaders moving huge piles of salt to the Morton Company along I-80, on the lake's south shore.

The Great Salt Lake has no outlet because it is at the bottom of a basin of interior drainage. The result is a terminal lake. Fresh water entering from the Bear, Jordan, and Weber river drainage systems can only exit by evaporation or by seepage into deep groundwater layers. Current climate conditions of high evaporation and a low input of fresh water from streams results in a saline lake. 

If you look carefully at any topographic map you should be able to pick out the various lakeshore levels or stands of the ancient fresh water Lake Bonneville--which was found here during glacial times. The most important stands are the Provo, Bonneville, Stansbury, and Gilbert. They are also visible to the eye on the mainland, and at various places on the island, including the bluffs surrounding White Rock Bay.

The lake also yields a flood of trivia

Even though the real monster of the Great Salt Lake is its fickle water level, over the years there have been fanciful tales.

Take grave robber Jean Baptiste, for example. He is believed to have desecrated up to 300 graves during a five-year grave-robbing spree in which he took clothing and jewelry in Salt Lake County that ended with his arrest in 1862.

Brigham Young addressed the crimes of Baptiste in a talk in the Tabernacle on Sunday, Feb. 9, 1862. He recommended making him a fugitive and vagabond for his crimes, rather than executing or imprisoning him for life.

After spending about three months in jail, Baptiste was exiled to Fremont Island in the spring of 1862. With so many families upset over his crimes, he had to be taken beyond the vengeance of the community.

Fremont Island was then known as Miller's Island because Davis County brothers Henry W. and Dan Miller kept a herd of cattle there. With permission and assistance from the Millers, Fremont became Utah's own Devil's Island, though the exile was done in secret to keep Baptiste safe from the enraged public.

There was a shack and some provisions on the island, and when the Millers returned three weeks later, Baptiste was doing well — and had helped himself to their cattle for beef.

However, when they returned three weeks after that, Baptiste was gone. The wooden shack was torn down and a cow's hide also appeared to have been used to lash together a raft. With the lake level some 8 feet deep around the island, Baptiste is assumed to have floated away.

Where he went is a mystery.

Duck hunters in 1890 found a human skull in the mud where the Jordan River empties into the Great Salt Lake. Three years later, other hunters discovered a headless skeleton with a ball and chain attached.

Word spread that this was Baptiste, but policemen who helped exile him stepped forward and maintained the grave robber was never chained.

Baptiste was branded with indelible ink (not a branding iron) across his forehead — "Branded for robbing the dead." (Other tales mention his ears possibly being cut off as a punishment, too.)

There was also a rumored story that a Salt Lake man saw Baptiste in a Montana mining camp and that Baptiste had identified himself as the grave robber when confronted.

Otherwise, no trace was ever found of him and Dale L. Morgan, author of the 1947 book "The Great Salt Lake," referred to Baptiste as the "only specter of the Great Salt Lake." Other writings call him "Monster of the Great Salt Lake."

MYTHS AND LEGENDS

In the early summer of 1877, J.H. McNeil of Kelton, Box Elder County, and several other employees of the Barnes and Co. Salt Works company on the lake's north shore reported seeing a huge creature with a crocodile-like body and the head of a horse in the waters of the Great Salt Lake.

This apparently happened at dusk or early evening near Monument Point and the Central Pacific Railroad line.

The creature made a fearsome bellowing noise and charged toward the workers, the witnesses said. They stampeded up a nearby hillside and hid in the brush until morning.

Some believe this creature, dubbed "The North Shore Monster," was nothing more than a buffalo in the lake.

Still, some 30 years earlier a man identified only as Brother Bainbridge reported seeing a monster with a dolphin-like body in the lake near Antelope Island.

Whales — A Provo newspaper in 1890 reported a pod of whales had been spotted swimming in the Great Salt Lake. They were supposedly offspring of a pair of young whales planted there 15 years earlier. It is doubtful marine mammals could have lived in the lake's extreme salinity.

Oysters — A Feb. 5, 1853, editorial in the Deseret News advocated planting oysters and other sea life in the lake as potential food sources. Later reports indicate oysters, eels, fish and crabs were all planted in the lake, but none survived the extreme salinity.

Whirlpools — There are tales of whirlpools in the lake opening subterranean channels that drained into the Pacific Ocean. One man said he was on a schooner in 1870 that was almost drawn into such a whirlpool between Fremont and Antelope islands. Water spouts — tornadoes over water — have been spawned at times over the lake, and these are likely the source of these tales.

Underwater quicksand — There are stories of liquid sand in the lake, and one in 1939 claims a man lost six horses that wandered off the natural sandbar leading to Fremont Island and sunk. However, lake experts know of no evidence to support the existence of underwater quicksand.

Indian stories — A powerful Indian tribe is said to have inhabited the lake's major islands and even rode elephants for transportation. Other tales tell about mysterious white Indian tribes living on lake islands.

Black mass — Early Great Salt Lake explorers like John C. Fremont reported finding accumulations of brine fly larvae 10 to 20 feet wide and 7 to 12 inches deep along the shores of the lake.

To the uninformed, the Great Salt Lake is an essentially lifeless remnant of the once fecund Lake Bonneville that covered 20,000 square miles in the eastern Great Basin more than 14,000 years ago.

The lake is also home to the world's largest nesting population of California gulls (our state bird) and white-face ibis as well as North America's largest staging concentrations of American avocets, blackneck stilts and Tundra swans. Endangered or sensitive species include peregrine falcons, bald eagles, American pelicans and snowy plovers.

At the height of their mating season in May, some areas of Antelope Island are awash in yellow-headed blackbirds, with their vividly hued feathers.

Perhaps the most important fact about the lake is that it is the lowest point of a 22,000-square-mile drainage basin. That is what makes it possible for the Bear, Weber and Jordan rivers and other streams to converge here, making an oasis where a desert might otherwise exist.

Though most of the lake is too salty for fish, 23 species or subspecies of fish make their home in river estuaries and impounded areas around its shores that capture fresh water from rivers and streams. Sixty-four species or subspecies of mammals and eight types of amphibians also live on the lake's shores. Among the mammals are bison (American buffalo) and pronghorn sheep (antelope), which live on a preserve on Antelope Island. Both are seen regularly by visitors from their cars.

Economically, the most important life form in the lake is artemia franciscana, more commonly known as brine shrimp. Brine shrimp eggs, which account for most of the harvest today, are used in the culture of prawns and specialized fish like the grouper. The shrimp are also one of the principal sources of food for the lake's birds.

In 1997-1998, the low numbers of shrimp forced officials to shorten the harvesting season by eight weeks, cutting the total catch by more than half and reducing the harvest to 3.6 million pounds of processed shrimp and shrimp eggs worth $25 million to $44 million.The brine shrimp industry was once used to harvest eggs for use as fish food. Now many of the eggs are being used to fatten jumbo shrimp and other edible sea life being raised in aquacultures.

A possible solution under consideration by the Department of Natural Resources is to create additional breaches in the northern causeway to allow more southward circulation of the saltier northern water. The U.S. Geological Survey is working on a computer model to predict how salinity would be affected by breaches of different sizes.

Remember, the lake and its minerals belong to Utah. The state "garnisheed" a little more than $1 million in royalties from the extracting companies.

Except for Antelope, which has numerous springs and is large enough to have supported a ranch, the islands of the lake have been largely uninhabited. Some of the smaller islands serve as bird rookeries.

The largest islands are Antelope, 23,175 acres; Stansbury, 22,324 acres; Fremont, 2,945 acres; and Carrington, 1,767 acres. Other islands range in size from less than an acre to 163 acres.

The highest point on the islands is Stansbury Peak, which is 6,645 feet above sea level on Stansbury Island. Frary Peak, the highest point on Antelope Island, is 6,596 feet above sea level.

Source of life, wealth and disaster, the Great Salt Lake is the most important geological feature of northern Utah.

A few geological changes and this might be dry little Winnemucca, Nev., instead of the Greater Salt Lake metropolitan area, with enough river water to support 1.2 million people, hundreds of thousands of acres of farmland and many industries. The water also supports millions of birds in one of the most important avian habitats in the world.

At 4,200 feet above sea level, the lake has a surface area of 1,500 square miles, making it the world's fourth largest lake without a river outlet. At 75 miles long and 30 miles wide, it's the largest lake in the western United States.

And one of the richest.

Mineral, Salt Mining and Brine Shrimp Harvests

Its lack of an outlet to the sea has permitted the lake to hoard a unique treasure. It contains 4 billion to 5.5 billion tons of dissolved salts (magnesium, calcium, sodium and other chlorides) and other minerals. That's about 1,300 pounds for every human being in the world.

The minerals in the lake are distributed as follows: 55.4 percent chloride, 32 percent sodium, 6.6 percent sulfate, 3.2 percent magnesium and 2.6 percent potassium. The lake also contains smaller amounts of calcium, bromine, lithium, boron and other minerals. Sodium and chloride are the components of salt.

 The six extraction companies operating on the lake — IMC Kalium Ogden Corp., Magnesium Corporation of America, Cargill Salt, Morton Salt, IMC Salt and North Shore Limited — removed salt and minerals worth $231.6 million in 1997. In 1997-98, brine shrimp and shrimp eggs generated an additional $25 million to $44 million.

Without taking into account the annual replenishment of salts from ground and surface water — 3 million to 5 million tons — the Utah Department of Natural Resources estimates it would take 1,000 years to deplete the sodium chloride in the lake to the point extraction became economically unfeasible.

There are also untapped resources beneath the lake. Deposits of gas, oil and hydrocarbons on the lake are significant but are not being developed because of the high cost of extraction given current technology. The West Rozel field, off the northeastern shore, is estimated to contain 1 million to 10 million barrels of oil.

Ups and downs

"Variable, transitory, ephemeral." That is how Professor William Lee Stokes of the University of Utah once described the geology of the Great Salt Lake.

The lake's hydrograph (record of water levels) from the 1850s to the present shows a fluctuation from one year to the next, varying by a total of 20 feet and ranging from a low of 4,191.3 feet in 1963 to a high of 4,211.8 feet in 1986 and 1987. Some experts believe the lake undergoes dry and wet periods, rising steadily for several years and then dropping steadily for several years. In 2010, it's nearly at its lowest point.

The lake is very shallow. Its average depth is only 12 feet. At its deepest point — 7.5 miles straight west of the southern tip of Promontory Point — it's only 45 feet deep at high level. Because of the shallowness of the lake and its shores, a relatively small increase in lake level can inundate hundreds of thousands of acres of shoreline. At 4,200 feet, the lake covers 1,079,259 acres. Four feet higher, it covers nearly additional 10% of area, or 143,741 acres.

In 1983, the lake surprised a lot of people when it rose by an unprecedented 5 feet to 4,205 feet and caused $100 million in flood damage. The next year, it went up another 4 feet. In 1986-87, the damage toll jumped to $240 million when the lake rose to 4,211.85 feet.

Lulled by many years of low water, humans had succumbed to the temptation of building at levels they thought the lake would likely never reach again.

Millions were spent on dikes as motorists on I-80 in Tooele County found themselves "driving on the lake," hundreds of homes in Salt Lake City's Rose Park faced inundation, Davis County sewage plants faced failure and the heavy, salt-laden waves threatened to pulverize a railroad causeway.

Had the lake continued to rise, it would have caused $500 million to $1 billion in damage, the Department of Natural Resources estimated.

Huge capacity pumps were built after the floods of 1983 to pump excess water to the western desert - and although they receive constant maintenance and stand ready to go to work again - they haven't been used since then. Many consider the $60 million spent on the pumps to be a waste of taxpayer money. But that's in hindsight.

At 4,205 feet, most recreation facilities around the lake such as beaches and marinas would begin to suffer damage. Although the Antelope Island causeway was elevated to 4,208.75 feet in the early 1990s, it also would start to be affected at 4,205 feet.

Above 4,208 feet, most wetlands around the lake would be inundated and much of their vegetation would be killed by the salt. During the 1980s flood years, bird populations dropped by 90 percent and state-owned dikes, water-control structures and other property suffered $30 million in damage. Nevertheless, the Department of Natural Resources considers fluctuations in water levels beneficial to wildlife because periodic flooding and drying keeps wetlands young and productive.

Above 4,211 feet, I-80 would be affected despite the fact that some $20 million was spent in the 1980s to elevate parts of it. At 4,211 feet, IMC Kalium Ogden Corp., one of the lake's major mineral extractors, would have to spend several million dollars on diking.

Although the Southern Pacific causeway was raised to 4,217 feet in 1987, it began subsiding by 2 to 4 inches a year in the early 1990s. Some areas of the causeway have experienced accelerated settlement of up to half a foot per year.

At 4,212 feet, damage to several Pacificorp power lines and installations from Salt Lake City International Airport to Kaysville would run to $19.5 million in 1993 dollars. Other power lines near the lake would also be affected.

The great lake quake

The geology of the Salt Lake Valley floor combined with the proximity of the Great Salt Lake to a major metropolitan area is not a good mix.

An earthquake of sufficient intensity could cause the valley floor to sink by as much as 5 feet at the fault line along the Wasatch Front. This could create a tilt in the lake bed that would send its waters rushing toward the lowland communities along its eastern shore.

The massive flooding would be aggravated by a seiche, a wave of water generated by the earthquake. In the worst case, such a seiche could be as high as 10 feet, said Jim Kolva, chief of the Hydrologic Surveillance Section of the U.S. Geological Survey in Salt Lake City.

A similar seismic event is believed to have created Spring Bay at the lake's northern tip, where the shoreline unexpectedly hooks to the east.

Short of tilting the lake bed, earthquakes could damage highways, railroads, dikes and other structures along the lake.

Assuming earthquakes occur randomly, the probability of a large earthquake along the Wasatch Front is 16 percent in the next 50 years and 30 percent in the next 100 years, said Mark Milligan, a geologist with the Utah Geological Survey. If one assumes that quakes follow certain patterns, the probability goes up to over 50 percent in the next 100 years.

The other real factor, whether it floods or not, is liquefaction. Like Mexico City, many of the communities in SL City and in Davis County are built on old lake beds. It remains to be seen how the area will be affected by a quake over 7.0.

A timeline of the Great Salt Lake

2 million BC: a giant lake called Lake Bonneville covers much of what is now the western part of Utah, most of Nevada and part of Southern Idaho. Dinosaurs roam its green lush shores, and some swim in its depths. (Today there are dozens of dinosaur-bone quarries throughout the state, and Dinosaur National Monument in Vernal, UT)

22,200 B.C.: Lake Bonneville, Stansbury level, 245 feet deep.
16,000 B.C.: Lake Bonneville, Bonneville level, 1,020 feet deep, as the climate becomes wetter.
14,800 B.C.: Lake Bonneville breaks through at Red Rock Pass, Idaho, making an outlet into the Snake Drive Drainage. Its level rapidly decreases.
14,200 B.C.: Lake Bonneville, Provo level, 640 feet deep.
10,800 B.C.: Lake Bonneville, Gilbert level, 75 feet deep, as a drier climage exists.
10,000 B.C.: The first humans may have arrived at the lake.
8,000-10,000 B.C.: The modern Great Salt Lake is a remnant of the greater Lake Bonneville.
A.D. 1776: Spanish explorers Escalante and Dominguez hear tales of a bitter sea that connects with Utah Lake. They come as far north as Utah Lake, having explored much of Southern Utah - but never see the Great Salt Lake.
1824: Jim Bridger and Etienne Provost become the first recorded white men to see the lake.
1843: John C. Fremont and Kit Carson explore the lake and visit Fremont and Antelope islands.
1847: Mormon emigrants are the first settlers arrive in the SL valley. First pioneers bathe in the lake.

1869: The Union Pacific and the Central Pacific each coming from different directions, join at Promontory at the northern edge of the GSL, uniting the country by rail, and reducing trans-continental travel time from 5 months to 5 days. The result is an explosion of population growth throughout the west.
1870: Lakeside and Lake Shore, the first two bathing resorts on the Great Salt Lake, emerge.
1873: The lake level reaches a historic high of almost 4,212 feet above sea level.
1890: Dropping lake levels decrease crowds to the lakeshore resorts.
1896: State gets ownership of the lake.
1903: Lucin railroad causeway cutoff is built near Promontory.
1963: The lake level drops to 4,191 feet above sea level.
1964: Most of the causeway to Antelope Island is built.
1969: The Antelope Island causeway opens.
1983: Rising lake levels close the Antelope Island causeway. (It was also temporarily washed out during numerous storms from 1969-1983.)
1986-87: Lake level almost reaches 4,212 feet.
1987-89: Pumps operate to lower the level of the lake.
1993: The causeway to Antelope Island reopens after reconstruction.
1997: The lake begins to rise again.
1999: The lake's level rises 1.5 feet since 1998.

2009: After years of less-than-normal snowfall, the lake falls close to its lowest level.

Minerals in the Great Salt Lake

"Miners" began extracting common salt from the lake in the mid-1800s. Other minerals like magnesium metal, chlorine gas, sodium and potassium sulfate and magnesium chloride have been extracted since the early 1960s, said J. Wallace Gwynn of the Utah Geological Survey.

• Today, six mineral extraction companies operate near the lake, using solar evaporation to concentrate the lake waters to glean minerals.
• It is thought the Great Salt Lake contains 4.9 billion tons of salt — including deposits in the lake bed and the salty solution in the water. Much salt also remains in the West Pond that was used as a reservoir during the pump years in the 1980s
• Sodium chloride, or common salt, is harvested from commercial evaporation ponds, then collected and processed for use in water softeners or formed into salt-lick blocks for cattle.
• And you can thank the lake for ice-free streets on snowy, winter mornings. Most of the salt is used locally on Utah roadways.
• Table salt is not produced at the lake. It simply costs too much in processing to guarantee purity.
• Salt byproducts like potassium sulfate and magnesium-chloride brine are used for commercial fertilizers and as dust suppressants, Gwynn said.
• In 1997, in excess of 31 billion gallons of water was pumped from the Great Salt Lake by mineral harvesting companies.
• Although the salt and its byproducts seem to be in rich, accessible supply, the lake's extraction business is volatile.
• Local companies face intense competition from both national and international enterprise.
• Utah's oft-wacky weather conditions also impact local companies.
• When lake levels are low, intake canals to pumps must be dredged and the pumps need to be repositioned into deeper water.
• High lake levels dilute brines, according to the Utah Department of Natural Resources.
• Total mineral extractions from the Great Salt Lake in 1997 were valued at about $230 million.
  

Harvesting of Brine Shrimp and Shrimp Cysts

Watch a video on harvesting operations.

• The Great Salt Lake provides about 90 percent of the world's supply of brine shrimp cysts, according to the Utah Department of Natural Resources.
• Brine shrimp cysts are harvested from the lake each year between Oct. 1 and Jan. 31. In 1998, 32 companies were permitted to harvest brine shrimp in the Great Salt Lake, providing about 1,000 year-round jobs.
• Like the extraction business, the state takes a slice of brine shrimp revenues, along with money gained through brine shrimp "fishing licenses," or certificates of registration.
• During the 1997-98 harvesting season, the state issued 79 licenses at $10,000 a piece.
• Since 1997, the state also began collecting royalties. Brine shrimp harvesters paid about $60,000 in royalties for the 1997-98 season.
• The brine shrimp industry also endures risk. Stratifications in lake salinity between the lake's north and south arms can impact the health of the harvest.
   

Back to Antelope Island Main Page