Editing Cape Breton Island (section)

=== Geology ===
The island is characterized by a number of elevations of ancient [[crystal]]line and [[metamorphic rock]] rising up from the south to the north, and contrasted with eroded lowlands. The bedrock of blocks that developed in different places around the globe, at different times, and then were fused together via [[tectonics]].<ref name="roland">{{cite book |last1=Roland |first1=Albert E. |title=Geological background and physiography of Nova Scotia |date=1982 |publisher=Nova Scotian Institute of Science |location=Halifax, N.S. |isbn=0-919680-19-4 |pages=248–284}}</ref>

Cape Breton is formed from three [[terrane]]s. These are fragments of the Earth's [[Crust (geology)|crust]] formed on a [[tectonic plate]] and attached by [[Accretion (geology)|accretion]] or [[Suture (geology)|suture]] to crust lying on another plate. Each of these has its own distinctive geologic history, which is different from that of the surrounding areas. The southern half of the island formed from the [[Avalonia|Avalon terrane]], which was once a [[microcontinent]] in the [[Paleozoic]] era. It is made up of [[volcanic rock]] that formed near what is now called Africa.<ref name=":0">{{Cite web |last=Parks Canada Agency |first=Government of Canada |date=2018-01-05 |title=The formation of Cape Breton Island - Cape Breton Highlands National Park |url=https://www.pc.gc.ca/en/pn-np/ns/cbreton/decouvrir-discover/environ/geologie-geology/ile-island |access-date=2021-08-11 |website=www.pc.gc.ca |archive-date=11 August 2021 |archive-url=https://web.archive.org/web/20210811193158/https://www.pc.gc.ca/en/pn-np/ns/cbreton/decouvrir-discover/environ/geologie-geology/ile-island |url-status=live}}</ref> Most of the northern half of the island is on the Bras d'Or terrane (part of the [[Ganderia]] terrane). It contains volcanic and [[sedimentary rock]] formed off the coast of what is now [[South America]].<ref name=":0" /> The third terrane is the relatively small Blair River [[Inliers and outliers (geology)|inlier]] on the far northwestern tip. It contains the oldest rock in the Maritimes, formed up to 1.6 billion years ago.<ref name=":0" /> These rocks, which can be seen in the Polletts Cove - Aspy Fault Wilderness Area north of [[Pleasant Bay, Nova Scotia|Pleasant Bay]], are likely part of the [[Canadian Shield]], a large area of [[Precambrian]] [[Igneous rock|igneous]] and [[metamorphic rock]] that forms the core of the [[North America]]n continent.

The Avalon and Bras d'Or terranes were pushed together about 500 million years ago when the supercontinent [[Gondwana]] was formed. The Blair River inlier was sandwiched in between the two when [[Laurasia|Laurussia]] was formed 450-360 million years ago, at which time the land was found in the [[tropics]]. This collision also formed the [[Appalachian Mountains]]. Associated [[rift]]ing and [[Fault (geology)|faulting]] is now visible as the canyons of the [[Cape Breton Highlands]].<ref name=":1">{{Cite web |last=Parks Canada Agency |first=Government of Canada |date=2018-01-05 |title=The formation of the Cape Breton Plateau - Cape Breton Highlands National Park |url=https://www.pc.gc.ca/en/pn-np/ns/cbreton/decouvrir-discover/environ/geologie-geology/plateau |access-date=2021-08-11 |website=www.pc.gc.ca |archive-date=11 August 2021 |archive-url=https://web.archive.org/web/20210811212218/https://www.pc.gc.ca/en/pn-np/ns/cbreton/decouvrir-discover/environ/geologie-geology/plateau |url-status=live}}</ref> Then, during the [[Carboniferous]] period, the area was flooded, which created [[sedimentary rock]] layers such as [[sandstone]], [[shale]], [[gypsum]], and [[Conglomerate (geology)|conglomerate]]. Later, most of the island was tropical forest which later formed coal deposits.

Much later, the land was shaped by repeated [[ice age]]s which left [[Striation (geology)|striations]], [[till]], [[U-shaped valley]]s, and carved the Bras d'Or Lake from the [[bedrock]].<ref name=":1" /> Examples of U-shaped valleys are those of the [[Chéticamp River|Chéticamp]], [[Grande-Anse River|Grande Anse]], and Clyburn River valleys. Other valleys have been eroded by water, forming V-shaped valleys and [[canyon]]s. Cape Breton has many fault lines but few earthquakes. Since the North American continent is moving westward, earthquakes tend to occur on the western edge of the continent.