The Chilliwack Batholith is a large

batholith A batholith () is a large mass of intrusive rock, intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate ...

that forms much of the

North Cascades The North Cascades are a section of the Cascade Range of western North America. They span the border between the Provinces and territories of Canada, Canadian province of British Columbia and the U.S. state of Washington (state), Washington and ...

in southwestern

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

and the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

. The geological structure is named after the

Chilliwack River Chilliwack ( ) is a city of about 100,000 people and in the Canadian province of British Columbia. It is located about east of the City of Vancouver in the Fraser Valley. The enumerated population is 93,203 in the city and 113,767 in the gr ...

Valley, where it outcrops in many places. It does not outcrop anywhere near the City of Chilliwack. The Chilliwack Batholith is part of the

Pemberton Volcanic Belt The Pemberton Volcanic Belt is an eroded Oligocene-Miocene volcanic belt at a low angle near the Mount Meager massif, British Columbia, Canada. The Garibaldi and Pemberton volcanic belts appear to merge into a single belt, although the Pemberto ...

and is the largest mass of exposed intrusive rock in the

Cascade Volcanic Arc The Cascade Volcanoes (also known as the Cascade Volcanic Arc or the Cascade Arc) are a number of volcanoes in a continental volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to No ...

. The age of the Chilliwack batholith ranges from 26 to 29 million years old.

References

Pemberton Volcanic Belt Igneous petrology of Washington (state) Batholiths of North America Igneous petrology of British Columbia Paleogene magmatism Paleogene British Columbia {{US-geology-stub