Raspberry Formation

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Raspberry Formation
Stratigraphic range: 11.4–5.5  Ma
Raspberry Formation.png
Paleogeological map of the Raspberry Formation at the end of the Raspberry eruptive period
Type Geological formation [1]
Unit of Mount Edziza volcanic complex [2]
Underlies Little Iskut Formation [1]
Armadillo Formation [1]
Overlies Stikinia [1]
Lithology
Primary Alkali basalt, hawaiite [1]
Location
Coordinates 57°30′N130°36′W / 57.5°N 130.6°W / 57.5; -130.6 [2]
Region British Columbia [1]
CountryCanada [1]
Type section
Named for Raspberry Pass [1]
Named by Souther et al., 1984 [3]

The Raspberry Formation is a stratigraphic unit of Miocene age in northwestern British Columbia, Canada.

Contents

Naming

The Raspberry Formation takes its name from Raspberry Pass, a mountain pass cutting through the central portion of the Mount Edziza volcanic complex. [1] [4]

Geology

The Raspberry Formation has a volume of 119 km3 (29 cu mi), making it the third most voluminous geological formation comprising the Mount Edziza volcanic complex. [1] [2] It varies in elevation from less than 1,310 m (4,300 ft) along the Mess Creek Escarpment to 1,740 m (5,710 ft) near Armadillo Peak. [1]

The Raspberry Formation is overlain conformably by the Little Iskut Formation. An erosion surface separates the Raspberry Formation from the overlying Armadillo Formation and younger geological formations. Rocks of the Stikinia terrane underlie the Raspberry Formation. [1]

The Raspberry Formation consists of flat-lying alkali basalt and hawaiite flows. These flows are rusty brown and are interbedded with reddish-brown to yellow or orange scoria. [1] The Raspberry Formation represents three overlapping Miocene shield volcanoes. [2]

K–Ar dating has yielded ages of 11.4 ± 1.5 million years, 8.4 ± 0.4 million years and 6.4 ± 0.3 million years for Raspberry hawaiite and 6.1 ± 0.4 million years and 5.5 ± 0.1 million years for Raspberry alkali basalt. [1]

See also

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Gnu Butte is a butte in Cassiar Land District of northwestern British Columbia, Canada. It is located southeast of Telegraph Creek on the northwestern side of Raspberry Pass. The western and southern sides of the butte are surrounded by Raspberry Creek while the eastern and northern sides of the butte are surrounded by Flyin Creek. Gnu Butte lies on the Tahltan Highland between Mess Lake and Mowdade Lake in Mount Edziza Provincial Park. It bears a resemblance to flat-topped hills in parts of Africa, hence its name.

Artifact Ridge is a mountain ridge extending southeast from the eastern side of the Mount Edziza volcanic complex in northwestern British Columbia, Canada. It is bounded on the north by Bourgeaux Creek valley, on the south by Artifact Creek 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 and gets its name from the knapping of obsidian tools and points by early Tahltan hunters. Destell Pass cuts north–south through the westernmost end of Artifact Ridge.

Yagi Ridge is a mountain ridge extending northwest from the middle of the Spectrum Range at the southern end of the Mount Edziza volcanic complex in northwestern British Columbia, Canada. It is bounded on the north by Nagha Glacier and Nagha Creek valley, on the south by Yeda Creek on the Arctic Lake Plateau and on the west by Mess Creek valley. Yagi Ridge reaches an elevation of 2,243 metres at the head of Nagha Glacier where its eastern end adjoins to the Spectrum Range just northwest of Yeda Peak.

Sorcery Ridge is a mountain ridge extending east of Tencho Glacier on the southern flank of Mount Edziza in northwestern British Columbia, Canada. It is bounded on the north and south by valleys containing unnamed streams while to the east and northeast it is bounded by Tennaya Creek valley. Sorcery Ridge is the namesake of Sorcery Creek which flows adjacent to Tennaya Creek from another ridge just to the south.

Idiji Ridge is a mountain ridge extending east of Tencho Glacier on the southern flank of Mount Edziza in northwestern British Columbia, Canada. It is bounded on the south by a valley containing an unnamed creek, on the east by Tennaya Creek valley and on the north by cirques extending east of Ice Peak. Idiji Ridge takes its name from the adjacent Idiji Glacier; Idiji means "it thunders" in the Tahltan language.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Souther, J. G. (1992). The Late Cenozoic Mount Edziza Volcanic Complex, British Columbia. Geological Survey of Canada (Report). Memoir 420. Canada Communication Group. pp. 3, 32, 47, 61, 249, 267. doi: 10.4095/133497 . ISBN   0-660-14407-7.
  2. 1 2 3 4 Edwards, Benjamin Ralph (1997). Field, kinetic, and thermodynamic studies of magmatic assimilation in the Northern Cordilleran Volcanic Province, northwestern British Columbia (PhD thesis). University of British Columbia. p. 10. ISBN   0-612-25005-9.
  3. "Raspberry Formation". Lexicon of Canadian Geologic Units . Government of Canada . Retrieved 2023-08-04.
  4. "Raspberry Pass". BC Geographical Names . Archived from the original on 2021-10-19. Retrieved 2023-04-17.