The Meguma terrane, also known as Megumia, is a

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its d ...

exposed in southern

Nova Scotia Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...

, that became joined to the present

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

n landmass as part of the

Appalachian orogeny Appalachian may refer to: * Appalachian Mountains, a major mountain range in eastern United States and Canada * Appalachian Trail, a hiking trail in the eastern United States * The people of Appalachia and their culture ** Appalachian Americans, e ...

. The exposed part of the Meguma terrane, the Meguma Group, is largely composed of thick

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

turbidite A turbidite is the geologic Deposition (geology), deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing ...

s that have been interpreted as submarine fan deposits. The Meguma terrane is joined to the Avalon terrane along the Minas Fault Zone, which runs east–west from Chedabucto Bay to Cobequid Bay and the Minas Basin. The Meguma Group is intruded by numerous

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

and

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

pluton In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

s. The extent of the formation is unclear; some geologists believe that a magnetic anomaly along the coast of

Cape Cod Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer months. The ...

may represent a suture between the Meguma and Avalon terranes in that region. Unlike the Avalon terrane, the Meguma terrane has not been definitely associated with a territory on the other side of the Atlantic. It may be represented in either the Galicia-Tras-Os-Montes Zone in Spain and Portugal; the

West African Craton The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton.Jessell M.W., Li ...

in Morocco; or the Amazonian Craton. Meguma was, nevertheless, part of

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

during the Cambrian, and possibly formed a single peri-Gondwanan fragment together with Avalon. Meguma then became shortened during the

Acadian orogeny The Acadian orogeny is a long-lasting mountain building event which began in the Middle Devonian, reaching a climax in the Late Devonian. It was active for approximately 50 million years, beginning roughly around 375 million years ago (Ma), wi ...

but Avalon somehow escaped those Acadian deformations. Geologically this area is of interest not only to students of geological history, but because metamorphism produced

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

deposits which were mined extensively (up to ) in the latter half of the 19th century, and which remain potentially exploitable today during periods of higher gold prices.

References

; Notes ; Sources * * * * * Natural history of North America Plate tectonics Terranes Landforms of Nova Scotia {{Canada-geology-stub

See also

References