Armadillo Formation
Armadillo Formation | |
---|---|
Stratigraphic range: 6.9–6.1 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ | |
Type | Geological formation[1] |
Unit of | Mount Edziza volcanic complex[2] |
Underlies | Ice Peak Formation, Spectrum Formation, Big Raven Formation, Nido Formation[1] |
Overlies | Little Iskut Formation, Raspberry Formation[1] |
Lithology | |
Primary | Alkali basalt, comendite, trachyte[1] |
Location | |
Coordinates | 57°30′N 130°36′W / 57.5°N 130.6°W / 57.5; -130.6[2] |
Region | British Columbia[1] |
Country | Canada[1] |
Type section | |
Named for | Armadillo Peak[1] |
Named by | Souther et al., 1984[3] |
The Armadillo Formation is a stratigraphic unit of Miocene age in northwestern British Columbia, Canada.
Naming
The Armadillo Formation takes its name from Armadillo Peak, a volcanic peak east of Raspberry Pass in the middle of the Mount Edziza volcanic complex.[1][4]
Geology
The Armadillo Formation has a volume of 159 km3 (38 cu mi), making it the most voluminous of the 13 geological formations comprising the Mount Edziza volcanic complex.[2] It conformably overlies the Little Iskut Formation, as well as the Raspberry Formation. It is overlain by the Ice Peak Formation, Nido Formation, Spectrum Formation and Big Raven Formation.[1]
The Armadillo Formation consists of volcanic rocks of both felsic and mafic compositions. They are the products of a long period of bimodal volcanism, having issued from multiple eruptive centres. The felsic rocks include trachyte and comenditic rhyolite which form pyroclastic deposits, lava domes and lava flows. Basalt is the main mafic rock of the Armadillo Formation and forms lava flows.[1]
K–Ar dating of the Armadillo Formation has yielded ages of 10.2 ± 1.4 million years for comendite, 6.9 ± 0.3 million years and 6.1 ± 0.1 million years for comenditic ash flows, 6.9 ± 0.3 million years for comenditic glass and 6.5 ± 0.2 million years, 6.3 ± 0.5 million years, 6.2 ± 0.1 million years and 6.1 ± 0.2 million years for hawaiite.[1] The first age is anomalously old and most likely results from excessive atmospheric argon.[3]
See also
References
- ^ a b c d e f g h i j k Souther, J. G. (1992). The Late Cenozoic Mount Edziza Volcanic Complex, British Columbia. Geological Survey of Canada (Report). Memoir 420. Canada Communication Group. pp. 32, 61, 71, 246, 267. doi:10.4095/133497. ISBN 0-660-14407-7.
- ^ a b c 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.
- ^ a b "Armadillo Formation". Lexicon of Canadian Geologic Units. Government of Canada. Retrieved 2023-08-04.
- ^ "Little Iskut River". BC Geographical Names. Archived from the original on 2021-09-30. Retrieved 2023-06-28.
- v
- t
- e
- The Ash Pit
- Cache Hill
- Camp Hill
- Cinder Cliff
- Cocoa Crater
- Coffee Crater
- Eve Cone
- Exile Hill
- Icefall Cone
- Kana Cone
- Keda Cone
- Klastline Cone
- Mess Lake Cone
- Moraine Cone
- Nahta Cone
- Outcast Hill
- Ridge Cone
- Sidas Cone
- Sleet Cone
- Source Hill
- Storm Cone
- Thaw Hill
- Triplex Cones
- Twin Cone
- Walkout Creek centres
- Williams Cone
- Armadillo Formation
- Big Raven Formation
- Edziza Formation
- Klastline Formation
- Little Iskut Formation
- Nido Formation
- Pyramid Formation
- Raspberry Formation
- Artifact Creek
- Ball Creek
- Bourgeaux Creek
- Chakima Creek
- Crayke Creek
- Elwyn Creek
- Flyin Creek
- Gerlib Creek
- Kadeya Creek
- Kitsu Creek
- Little Iskut River
- More Creek
- Nagha Creek
- Nido Creek
- Pyramid Creek
- Raspberry Creek
- Sezill Creek
- Shaman Creek
- Sorcery Creek
- Stewbomb Creek
- Tadekho Creek
- Taweh Creek
- Tenchen Creek
- Tennaya Creek
- Tsecha Creek
- Walkout Creek