Stansbury Island
Encyclopedia
Stansbury Island is the second largest island
within the Great Salt Lake
in Utah
, USA
. Located in Tooele County
, it is considered an island even though a dirt
causeway
connects it to the main land. Stansbury Island was named after Howard Stansbury
, the leader of a government expedition that surveyed the lake in 1851. A biking trail
is located on the island. Petroglyph
s and two caves large enough to explore are also located on the island. Its peak is Castle Rock, at 6647 feet above sea level. Camping
is permitted in most areas.
mountain, with a few fresh water
seeps along the eastern side. The western side lacks water. The island is uninhabited and is used as a winter
feeding ground for sheep. Average annual precipitation
is approximately six inches.
The rocks on the island are mostly early Paleozoic
in age. Precambrian
strata are present at the north tip and along a portion of the northeast shore. The quartzite ledge on the southern part of the island is Devonian
in age. The remaining northern third of the island dates back to the Cambrian Period, consisting of a small outcrop of Tintic quartzite, but mainly middle Cambrian limestone
, shale
, and dolomite
. The rest of the island is composed of Upper Cambrian
to Upper Mississipian strata, mostly limestone
, dolomite
, quartzite
, and shale
.
The southern half of the island was folded into a southward anticline
. The northern half of the island is composed of a series of northwesterly trending fault blocks in which the strata dip to the west
. The faults in the north section are transverse and may have some strikeslip component.
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
within the Great Salt Lake
Great Salt Lake
The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the western hemisphere, the fourth-largest terminal lake in the world. In an average year the lake covers an area of around , but the lake's size fluctuates substantially due to its...
in Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, USA
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Located in Tooele County
Tooele County, Utah
Tooele County is a county located in the U.S. state of Utah. As of 2000, the population was 40,735 and by 2005 was estimated at 51,311. Its county seat and largest city is Tooele....
, it is considered an island even though a dirt
Dirt road
Dirt road is a common term for an unpaved road made from the native material of the land surface through which it passes, known to highway engineers as subgrade material. Dirt roads are suitable for vehicles; a narrower path for pedestrians, animals, and possibly small vehicles would be called a...
causeway
Causeway
In modern usage, a causeway is a road or railway elevated, usually across a broad body of water or wetland.- Etymology :When first used, the word appeared in a form such as “causey way” making clear its derivation from the earlier form “causey”. This word seems to have come from the same source by...
connects it to the main land. Stansbury Island was named after Howard Stansbury
Howard Stansbury
Howard Stansbury was a major in the U.S. Army Corps of Topographical Engineers. His most notable achievement was leading a two-year expedition to survey the Great Salt Lake and its surroundings...
, the leader of a government expedition that surveyed the lake in 1851. A biking trail
Segregated cycle facilities
Segregated cycle facilities are marked lanes, tracks, shoulders and paths designated for use by cyclists from which motorised traffic is generally excluded...
is located on the island. Petroglyph
Petroglyph
Petroglyphs are pictogram and logogram images created by removing part of a rock surface by incising, picking, carving, and abrading. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions of the technique to refer to such images...
s and two caves large enough to explore are also located on the island. Its peak is Castle Rock, at 6647 feet above sea level. Camping
Camping
Camping is an outdoor recreational activity. The participants leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, cabin, a primitive structure, or no...
is permitted in most areas.
Geology
Stansbury Island is longitudinally aligned and is approximately 11.5 miles (18.5 km) long, 4.5 miles (7.2 km) wide, and 22,314 acres in area. The island is a desertDesert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
mountain, with a few fresh water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
seeps along the eastern side. The western side lacks water. The island is uninhabited and is used as a winter
Winter
Winter is the coldest season of the year in temperate climates, between autumn and spring. At the winter solstice, the days are shortest and the nights are longest, with days lengthening as the season progresses after the solstice.-Meteorology:...
feeding ground for sheep. Average annual precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
is approximately six inches.
The rocks on the island are mostly early Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
in age. Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
strata are present at the north tip and along a portion of the northeast shore. The quartzite ledge on the southern part of the island is Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
in age. The remaining northern third of the island dates back to the Cambrian Period, consisting of a small outcrop of Tintic quartzite, but mainly middle Cambrian limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
, shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
, and dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
. The rest of the island is composed of Upper Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
to Upper Mississipian strata, mostly limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
, dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
, quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
, and shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
.
The southern half of the island was folded into a southward anticline
Anticline
In structural geology, an anticline is a fold that is convex up and has its oldest beds at its core. The term is not to be confused with antiform, which is a purely descriptive term for any fold that is convex up. Therefore if age relationships In structural geology, an anticline is a fold that is...
. The northern half of the island is composed of a series of northwesterly trending fault blocks in which the strata dip to the west
West
West is a noun, adjective, or adverb indicating direction or geography.West is one of the four cardinal directions or compass points. It is the opposite of east and is perpendicular to north and south.By convention, the left side of a map is west....
. The faults in the north section are transverse and may have some strikeslip component.