The Cache Creek Ocean, formerly called Anvil Ocean, is an inferred ancient ocean which existed between western North America and offshore continental

terranes 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 own ...

between the

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...

and the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations c ...

Evolution of the concept

First proposed in the 1970s and referred to as the Anvil Ocean, the oceanic crust between the Yukon composite terranes and North America was later updated to Cache Creek Sea in 1987 Monger and Berg, before being renamed the Cache Creek Ocean by Plafker and Berg in 1994. Other researchers in 1998 proposed the name Slide Mountain Ocean. The geology of Yukon and geology of Alaska formed in part due to the accretion of island arcs and continental terranes onto the western margin of North America. Many of these island arcs arrived onshore during and after the

. The Cache Creek Belt (also referred to as the Cache Creek suture zone or Cache Creek terrane) is an extensive area of

mélange In geology, a mélange is a large-scale breccia, a mappable body of rock characterized by a lack of continuous bedding and the inclusion of fragments of rock of all sizes, contained in a fine-grained deformed matrix. The mélange typically cons ...

and oceanic rocks in the Canadian province of

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...

. Sedimentary rocks contain fossils from the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonif ...

through the

and isotopic dating of

blueschist Blueschist (), also called glaucophane schist, is a metavolcanic rock that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures (), approximately corresponding to a depth of . The blue c ...

gives ages 230 and 210 million years ago in the

Late Triassic The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. ...

. The Cache Creek Belt is bordered by the Quesnellia Terrane in the east and by the large Stikinia Terrane in the west. The accretion of the landmasses and the closing the Cache Creek Ocean likely happened in the Middle Jurassic.

References

{{reflist Historical oceans Oceanography Geology of British Columbia Devonian North America Carboniferous North America Permian North America Triassic North America Early Jurassic North America Middle Jurassic North America