Manitou Islands (Lake Nipissing)
Encyclopedia
The Manitou Islands are a series of small island
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...

s in Lake Nipissing
Lake Nipissing
Lake Nipissing is a lake in the Canadian province of Ontario. It has a surface area of , a mean elevation of above sea level, and is located between the Ottawa River and Georgian Bay. Excluding the Great Lakes, Lake Nipissing is the fifth-largest lake in Ontario. It is relatively shallow for a...

, in Nipissing District
Nipissing District, Ontario
Nipissing District, Ontario is a district in Northeastern Ontario in the Canadian province of Ontario. It was created in 1858. The district seat is North Bay.In 2006, the population was 84,688...

, Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. The islands form a circle and lie 10 kilometres (6 mi) southwest of North Bay
North Bay, Ontario
North Bay is a city in Northeastern Ontario, Canada. It is the seat of Nipissing District, and takes its name from its position on the shore of Lake Nipissing.-History:...

.

History

Samuel de Champlain
Samuel de Champlain
Samuel de Champlain , "The Father of New France", was a French navigator, cartographer, draughtsman, soldier, explorer, geographer, ethnologist, diplomat, and chronicler. He founded New France and Quebec City on July 3, 1608....

 visited the islands in 1613 and called them "pretty". Fur traders found the island a handy resting spot, and often would camp overnight. Today the islands' sand beaches continue to be a popular resting and recreation spot for many boaters.

Lime was quarried on the islands in the 1880s when the Canadian Pacific Railway
Canadian Pacific Railway
The Canadian Pacific Railway , formerly also known as CP Rail between 1968 and 1996, is a historic Canadian Class I railway founded in 1881 and now operated by Canadian Pacific Railway Limited, which began operations as legal owner in a corporate restructuring in 2001...

 was built, and a lime kiln was operated to create lime for mortar. Great Manitou Island, the largest of the islands, once held a dance hall and hotel, but it burned to the ground. Uranium mining was conducted on Newman Island in the 1950s.

Old timers tell a story of how the island is reportedly haunted, when starvation broke out after the Nipissing people were forced to flee to the island, following their battle with the Iroquois
Iroquois
The Iroquois , also known as the Haudenosaunee or the "People of the Longhouse", are an association of several tribes of indigenous people of North America...

.

Geography

The total area of the islands is 100 hectares (247 acre), and the total perimeter is 5 kilometres (3.1 mi). The five islands are:
  • Great Manitou Island 46°16′41"N 79°34′34"W
  • Little Manitou Island 46°15′32"N 79°35′17"W
  • Calder Island 46°16′14"N 79°33′38"W
  • Rankin Island 46°15′00"N 79°34′03"W
  • Newman Island 46°15′17"N 79°34′45"W

Geology

The Manitou Islands lie inside the Ottawa-Bonnechere Graben
Ottawa-Bonnechere Graben
The Ottawa-Bonnechere Graben , with its branch the Timiskaming Graben, is an ancient rift valley in the Canadian Shield of Northeastern Ontario and Quebec, Canada. This rift valley was formed when the Earth's crust moved downward about a kilometre between two major fault zones known as the Mattawa...

 and are part of an eroded
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 volcanic pipe
Volcanic pipe
Volcanic pipes are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of diatreme. Volcanic pipes are composed of a deep, narrow cone of solidified magma , and are usually largely composed of one of two...

, leaving the multiple islands. The volcanic pipe formed by the violent, supersonic
Supersonic
Supersonic speed is a rate of travel of an object that exceeds the speed of sound . For objects traveling in dry air of a temperature of 20 °C this speed is approximately 343 m/s, 1,125 ft/s, 768 mph or 1,235 km/h. Speeds greater than five times the speed of sound are often...

 eruption of a deep-origin volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

. These volcanoes originate at least three times as deep as most other volcanoes, and the resulting magma that is pushed toward the surface is high in magnesium and volatile compounds
Volatiles
In planetary science, volatiles are that group of chemical elements and chemical compounds with low boiling points that are associated with a planet's or moon's crust and/or atmosphere. Examples include nitrogen, water, carbon dioxide, ammonia, hydrogen, and methane, all compounds of C, H, O...

 such as 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...

 and carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

. As the body of magma rises toward the surface, the volatile compounds transform to gaseous phase
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...

 as pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

 is reduced with decreasing depth. This sudden expansion propels the magma upward at rapid speeds, resulting in a shallow supersonic eruption.

The Manitou Islands contain fenite, syenite
Syenite
Syenite is a coarse-grained intrusive igneous rock of the same general composition as granite but with the quartz either absent or present in relatively small amounts Syenite is a coarse-grained intrusive igneous rock of the same general composition as granite but with the quartz either absent or...

s, pyroxenite
Pyroxenite
Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite and diopside, hypersthene, bronzite or enstatite. They are classified into clinopyroxenites, orthopyroxenites, and the websterites which contain both pyroxenes...

s, amphibole
Amphibole
Amphibole is the name of an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.-Mineralogy:...

, apatite
Apatite
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH−, F−, Cl− or Br− ions, respectively, in the crystal...

, biotite
Biotite
Biotite is a common phyllosilicate mineral within the mica group, with the approximate chemical formula . More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous endmembers...

, calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...

, magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, monazite
Monazite
Monazite is a reddish-brown phosphate mineral containing rare earth metals. It occurs usually in small isolated crystals. There are actually at least four different kinds of monazite, depending on relative elemental composition of the mineral:...

, nepheline
Nepheline
Nepheline, also called nephelite , is a feldspathoid: a silica-undersaturated aluminosilicate, Na3KAl4Si4O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites...

, pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

, pyrochlore
Pyrochlore
Pyrochlore 2Nb2O6 is a solid solution between the niobium end member , and the tantalum end member .-Occurrence:...

, pyroxene
Pyroxene
The pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...

 and quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

.

The nearby Callander Bay
Callander Bay
Callander Bay is a bay at the extreme east of Lake Nipissing in Parry Sound District, Ontario, Canada. It is in diameter and the main community of Callander is located on its east side.-Geology:...

 is also a volcanic pipe.

See also

  • Volcanism of Canada
  • Volcanism of Eastern Canada
    Volcanism of Eastern Canada
    Volcanism of Eastern Canada has led to the formation of hundreds of volcanic areas and extensive lava formations, indicating volcanism played a major role in shaping its surface. The region's different volcano and lava types originate from different tectonic settings and types of volcanic...

  • List of volcanoes in Canada
  • Callander Bay
    Callander Bay
    Callander Bay is a bay at the extreme east of Lake Nipissing in Parry Sound District, Ontario, Canada. It is in diameter and the main community of Callander is located on its east side.-Geology:...

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