Coppermine River basalts
Encyclopedia
The Coppermine River Group is a sequence of Mesoproterozoic
continent
al flood basalt
s forming part of the Mackenzie Large Igneous Province
in the Northwest Territories
, Canada
. It is among the largest flood basalt province on Earth, covering the area with a volume of approximately 650000 km³ (155,943 cu mi).
ic lava
paved over a large area of the northwestern Canadian Shield about 1,267 million years ago. These basalts form flood basalt
s that reach thicknesses ranging from 2000 m (6,562 ft) to 3500 m (11,483 ft) and consists of about 150 lava flows, each about 10-25 m thick. Except for the lowermost flows, which contain evidence of interaction with water, the entire sequence was erupted subaerially. Eruption of plateau
lavas near the Coppermine River
, built an extensive volcanic plateau
about 1,200 million years ago with an area of about 170000 km² (65,637 sq mi) representing a volume of lavas of at least 500000 km³ (119,956 cu mi). These flood basalts have been interpreted as contemporaneous with the giant Mackenzie dike swarm
and with the Muskox intrusion
.
Mesoproterozoic
The Mesoproterozoic Era is a geologic era that occurred between 1600 Ma and 1000 Ma . The Mesoproterozoic was the first period of Earth's history with a respectable geological record. Continents existed in the Paleoproterozoic, but we know little about them...
continent
Continent
A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...
al flood basalt
Flood basalt
A flood basalt or trap basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava. Flood basalts have occurred on continental scales in prehistory, creating great plateaus and mountain ranges...
s forming part of the Mackenzie Large Igneous Province
Mackenzie Large Igneous Province
The Mackenzie Large Igneous Province is a major Mesoproterozoic large igneous province of the southwestern, western and northwestern Canadian Shield in Canada. It consists of a group of related igneous rocks that were formed during a massive igneous event starting about 1,270 million years ago...
in the Northwest Territories
Northwest Territories
The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...
, 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...
. It is among the largest flood basalt province on Earth, covering the area with a volume of approximately 650000 km³ (155,943 cu mi).
Eruptive history
The Coppermine River Group was formed when vast volumes of basaltBasalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
ic lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
paved over a large area of the northwestern Canadian Shield about 1,267 million years ago. These basalts form flood basalt
Flood basalt
A flood basalt or trap basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava. Flood basalts have occurred on continental scales in prehistory, creating great plateaus and mountain ranges...
s that reach thicknesses ranging from 2000 m (6,562 ft) to 3500 m (11,483 ft) and consists of about 150 lava flows, each about 10-25 m thick. Except for the lowermost flows, which contain evidence of interaction with water, the entire sequence was erupted subaerially. Eruption of plateau
Plateau
In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...
lavas near the Coppermine River
Coppermine River
The Coppermine River is a river in the North Slave and Kitikmeot regions of the Northwest Territories and Nunavut in Canada. It is long. It rises in Lac de Gras, a small lake near Great Slave Lake and flows generally north to Coronation Gulf, an arm of the Arctic Ocean...
, built an extensive volcanic plateau
Volcanic plateau
A volcanic plateau is a plateau produced by volcanic activity. There are two main types: lava plateaus and pyroclastic plateaus.-Lava plateau:...
about 1,200 million years ago with an area of about 170000 km² (65,637 sq mi) representing a volume of lavas of at least 500000 km³ (119,956 cu mi). These flood basalts have been interpreted as contemporaneous with the giant Mackenzie dike swarm
Mackenzie dike swarm
The Mackenzie dike swarm, also called the Mackenzie dikes, form a large igneous province in the western Canadian Shield of Canada. It is part of the larger Mackenzie Large Igneous Province and is one of more than three dozen dike swarms in various parts of the Canadian Shield...
and with the Muskox intrusion
Muskox intrusion
The Muskox intrusion is a layered intrusion in Nunavut, Canada. It is located northeast of Great Bear Lake and south of Kugluktuk on Coronation Gulf...
.
See also
- Volcanism of Canada
- Volcanism of Northern CanadaVolcanism of Northern CanadaVolcanism of Northern Canada has led to the formation of hundreds of volcanic areas and extensive lava formations across Northern Canada, indicating volcanism played a major role in shaping its surface...
- Natkusiak flood basaltsNatkusiak flood basaltsThe Natkusiak flood basalts are a sequence of Neoproterozoic continental flood basalts of the Franklin Large Igneous Province on Victoria Island, Canada. The flood basalts were erupted about 720 million years ago after uplift began three to five million years prior to the flood basalt...