North Mountain (French: ''Montagne du Nord''; Gaelic: ''Beinn a Tuath'') is a narrow southwest-northeast trending

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

ridge on the mainland portion of southwestern Nova Scotia, stretching from

Brier Island Brier Island is an island in the Bay of Fundy in Digby County, Nova Scotia. Geography The island is the westernmost part of Nova Scotia and the southern end of the North Mountain ridge with Long Island lying immediately northeast; both islands ...

to Cape Split. It forms the northern edge of the

Annapolis Valley The Annapolis Valley is a valley and region in the Canadian province of Nova Scotia. It is located in the western part of the Nova Scotia peninsula, formed by a trough between two parallel mountain ranges along the shore of the Bay of Fundy. Stat ...

along the shore of the Bay of Fundy. Together with South Mountain, the two ranges form the Annapolis Highlands region. North Mountain rises dramatically from the valley floor and tapers somewhat more gradually to the north and west where it meets the coast, although many parts of this coast have vertical cliffs rising higher than 30 metres, most notably at Cape Split. A break occurs at

Digby Gut The Digby Gut is a narrow channel connecting the Bay of Fundy with the Annapolis Basin. The town of Digby, Nova Scotia is located on the inner portion of the western side of the Gut. The eastern entrance is marked by the Point Prim Lighthouse. St ...

where a gap in the mountain ridge is filled by a deep tidal channel separating the eastern end of the mountain from

Digby Neck Digby Neck is a Canadian peninsula extending into the Bay of Fundy in Digby County, Nova Scotia. Digby Neck is the western extension of the North Mountain range from the Annapolis Valley and is made of two thick lava flows. It is separated from ...

. The highest point on the ridge is at Mount Rose in

Annapolis County Annapolis County is a county in the Canadian province of Nova Scotia located in the western part of the province located on the Bay of Fundy. The county seat is Annapolis Royal. History Established August 17, 1759, by Order in Council, Annapoli ...

, north of Lawrencetown.

Geology

The ridge traces its history to the

Triassic The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...

period when this part of Nova Scotia occupied the center of the

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...

Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...

. It is a 201 million year old sequence of

tholeiitic basalt The tholeiitic magma series is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma ...

s, which contains columnar jointing. The basalts also extend under the Bay of Fundy and parts of it are exposed on the shore at Five Islands, east of

Parrsboro Parrsboro is a community located in Cumberland County, Nova Scotia, Canada. A regional service centre for southern Cumberland County, the community is also known for its port on the Minas Basin, the Ship's Company Theatre productions, and t ...

on the north side of the bay. Numerous sediment-filled

fissure A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes. Ground fissure ...

s are present near the upper surface of North Mountain. The hard ridge of basalt resisted the grinding of

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at La ...

s that flowed over the region during past

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...

s, and now forms one side of the

in western part of the

Nova Scotia peninsula The Nova Scotia peninsula is a peninsula on the Atlantic coast of North America. Location The Nova Scotia peninsula is part of the province of Nova Scotia, Canada and is connected to the neighbouring province of New Brunswick through the Is ...

. North Mountain is believed to have formed during the opening of the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

. It is a portion of the

Central Atlantic Magmatic Province The Central Atlantic magmatic province (CAMP) is the Earth's largest continental large igneous province, covering an area of roughly 11 million km2. It is composed mainly of basalt that formed before Pangaea broke up in the Mesozoic Era, near the ...

, which is a gigantic flood basalt and intrusive complex along east coast of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

, northwest

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

with a diameter of 4,000 km. A viscous (<175 m) North Mountain flow at McKay Head shows ~25-cm-thick distinguished layers separated by ~130 centimeter of

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

in its upper 34 meters. Upper layers (5 meters below the

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

top) are extremely vesicular while lower ones are

pegmatitic A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic com ...

and include a narrow (~2 cm) rhyolite band. The layering of the flow closely resemble that of some

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

lava lake Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified (someti ...

s.Cooling history and differentiation of a thick North Mountain Basalt flow (Nova Scotia, Canada)
Retrieved on 2007-10-15 Columnar basalt may be seen at Baxters Harbour and at

. File:Nova Scotia DGJ 5583 (3830611365).jpg, The Balancing Rock, a columnar basalt fragment of the North Mountain near Digby, Nova Scotia. File:CAMP North America.JPG, Basal contact of a lava flow section of Fundy basin

References

External links

Atlas of Canada - Facts about mountainsThe Jurassic North Mountain Basalts, Nova Scotia: More Than Just Simple Flood Basalts
{{Mountains of Nova Scotia Mountains of Nova Scotia Volcanism of Nova Scotia Landforms of Annapolis County, Nova Scotia Landforms of Digby County, Nova Scotia Landforms of Kings County, Nova Scotia Flood basalts Triassic Nova Scotia Triassic volcanism Mountains of Canada under 1000 metres

Geology

See also

References

External links