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

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 the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

Evolution of the concept

First proposed in the 1970s and referred to as the Anvil Ocean, the

oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramaf ...

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 Slide Mountain Ocean was an ancient ocean that existed between the Intermontane Islands and North America beginning around 245 million years ago in the Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system ...

. The

geology of Yukon The geology of Yukon includes sections of ancient Precambrian Proterozoic rock from the western edge of the proto-North American continent Laurentia, with several different island arc terranes added through the Paleozoic, Mesozoic and Cenozoic, d ...

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 con ...

and oceanic rocks in the Canadian province of

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 ...

. Sedimentary rocks contain fossils from the

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 ...

through the

and isotopic dating of

blueschist Blueschist (), also called glaucophane schist, is a metavolcanic rock that forms by the metamorphism of basalt and similar rocks at relatively low temperatures () but very high overburden pressure, pressure corresponding to a depth of . The b ...

gives ages 230 and 210 million years ago in the

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

. 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