Artifact Ridge is a

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

ridge A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, wi ...

extending southeast from the eastern side of the

Mount Edziza volcanic complex The Mount Edziza volcanic complex ( ; abbreviated MEVC) is a group of volcanoes and associated lava flows in northwestern British Columbia, Canada. Located on the Tahltan Highland, it is southeast of Telegraph Creek and southwest of Dease Lak ...

in northwestern

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. It is bounded on the north by Bourgeaux Creek valley, on the south by

Artifact Creek Artifact Creek is a tributary of Stewbomb Creek and part of the Stikine River watershed in northwest part of the province of British Columbia, Canada. It flows generally southeast for roughly Lengths and distances measured using BCGNIS coordinat ...

valley, on the east by the Little Iskut River valley and on the west by the Kitsu Plateau. The ridge is at the southeastern end of

Mount Edziza Provincial Park Mount Edziza Provincial Park is a provincial park in Cassiar Land District of northern British Columbia, Canada. It was established on 27 July 1972 to showcase the Mount Edziza volcanic complex and the surrounding Tahltan Highland. Geography The ...

and gets its name from the

knapping Knapping is the shaping of flint, chert, obsidian, or other conchoidal fracturing stone through the process of lithic reduction to manufacture stone tools, strikers for flintlock firearms, or to produce flat-faced stones for building or facing w ...

obsidian Obsidian ( ) is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich in the lighter element ...

tools and points by early

Tahltan The Tahltan or Nahani are a First Nations people of the Athabaskan-speaking ethnolinguistic group who live in northern British Columbia around Telegraph Creek, Dease Lake, and Iskut. The Tahltan constitute the fourth division of the ''Nahan ...

hunters. Destell Pass cuts north–south through the westernmost end of Artifact Ridge.

Geology

The base of Artifact Ridge is covered with glacial, talus and landslide deposits. The oldest exposed rocks are of

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

Paleozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

age and are overlain by

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

alkali basalt Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands, continental rifts and volcanic fields. Alkali basalt i ...

flows of the

Raspberry Formation The Raspberry Formation is a stratigraphic unit of Miocene age in northwestern British Columbia, Canada. Name The Raspberry Formation takes its name from Raspberry Pass, a mountain pass cutting through the central portion of the Mount Edziza volc ...

. The Raspberry rocks are overlain by quenched,

hydrothermally altered Metasomatism (from the Greek μετά ''metá'' "change" and σῶμα ''sôma'' "body") is the chemical alteration of a rock by hydrothermal and other fluids. It is traditionally defined as metamorphism which involves a change in the chemical comp ...

and highly fractured Miocene

trachybasalt Trachybasalt is a volcanic rock with a composition between trachyte and basalt. It resembles basalt but has a high content of alkali metal oxides. Minerals in trachybasalt include alkali feldspar, calcic plagioclase, olivine, clinopyroxene and l ...

which comprise the lower subaqueous

facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with distinctive characteristics. The characteristics can be any observable attribute of rocks (such as their overall appearance, composition, or con ...

of the Little Iskut Formation. Overlying these rocks are Miocene trachybasaltic lava flows and flow

breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...

comprising the upper subaerial facies of the Little Iskut Formation. The Little Iskut rocks are overlain by Miocene

comendite Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite. Phenocrysts are sodic sanidine with minor albite and bipyramidal quartz. Iddings, Joseph Paxson, 1913, ''Igneous rocks: composition, texture and classification'', v ...

trachyte Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanite, aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava (or shallow intrus ...

lava flows and

domes A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

of the Armadillo Formation which are in turn overlain by

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Nido Formation The Nido Formation is a stratigraphic unit of Neogene age in northwestern British Columbia, Canada. Name The Nido Formation takes its name from Nido Creek, a stream flowing northeast from the eastern flank of Mount Edziza into Nuttlude Lake. Nid ...

. The youngest and uppermost rocks comprising Artifact Ridge are Pliocene alkali basalt flows of the Kitsu Member of the Spectrum Formation which are

interbedded In geology, interbedding occurs when beds (layers of rock) of a particular lithology lie between or alternate with beds of a different lithology. For example, sedimentary rocks may be interbedded if there were sea level variations in their sedimen ...

with

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

gravel and

paleosol In Earth science, geoscience, paleosol (''palaeosol'' in Great Britain and Australia) is an ancient soil that formed in the past. The definition of the term in geology and paleontology is slightly different from its use in soil science. In geo ...

References

External links

* {{Mount Edziza volcanic complex Ridges of the Mount Edziza volcanic complex

Geology

See also

References

External links