Trachybasalt

A rock classification type

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Recorded Ages and Analyses Discuss Trachybasalt

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Trachybasalt

Lake Turkana, Marsabit County, Kenya

Trachybasalt

Lake Turkana, Marsabit County, Kenya

Trachybasalt

Lake Turkana, Marsabit County, Kenya

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About TrachybasaltHide

A alkaline/basic extrusive rock intermediate in composition between trachyte and basalt, difficult to define without the TAS diagram. Characterized by the presence of both calcic plagioclase and alkali feldspar, along with clinopyroxene, olivine, and possibly minor analcime or leucite. Approx. synonymous with hawaiite.

Ref: AGI

Unique IdentifiersHide

Mindat ID:

48475

Long-form identifier:

mindat:1:1:48475:8

Classification of TrachybasaltHide

Rock
- Igneous rock
  - Normal crystalline igneous rock
    - Fine-grained ("volcanic") normal crystalline igneous rock
      - Trachytoid
        Trachybasalt
      - Basic volcanic rock
        Trachybasalt

Trachybasalt is found in field S1 in the TAS diagram.

Sub-divisions of TrachybasaltHide

Trachybasalt

Age distributionHide

Recorded ages:

Phanerozoic : 191 Ma to 0 Ma - based on 16 recorded ages.

Sample ages:

Sample ID	Recorded age	Geologic Time	Dating method
1	Up to Ma
Quaternary	K-Ar
2	0.3 ± 0.1 Ma	Pleistocene	K-Ar whole rock
3	0.55 ± 0.06 to 0.11 ± 0.07 Ma	Pleistocene	K-Ar
4	0.6 to 0.0017 Ma	Quaternary	K-Ar
5	1.0 to 0.5 Ma	Pleistocene	K-Ar from upper slopes
6	1.0 ± 0.1 to 0.1 Ma	Pleistocene	K-Ar from Mount Waesche
7	1.74 Ma	Pleistocene	K-Ar
8	2.6 Ma	Pliocene	K-Ar
9	2.62 Ma	Pliocene	K-Ar
10	2.8 ± 0.2 to 1.91 ± 0.1 Ma	Cenozoic	K-Ar
11	5.14 ± 0.40 to 4.6 Ma	Pliocene
12	23 to 17 Ma	Miocene	K-Ar
13	23.7 ± 0.7 to 23.2 ± 0.7 Ma	Oligocene	K-Ar
14	27 Ma	Oligocene	K-Ar
15	70 Ma	Late/Upper Cretaceous
16	191 to 120 ± 10 Ma	Mesozoic

Sample references:

ID	Locality	Reference	Notes
1	Pico Volcano, Pico, Azores, Portugal	Feraud, G., Kaneoka, I., & Allègre, C. J. (1980). K/Ar ages and stress pattern in the Azores: geodynamic implications. Earth and planetary science letters, 46(2), 275-286. doi.org/10.1016/0012-821X(80)90013-8
2	Paulet Island, West Antarctica, Antarctica	Baker, P. E., Buckley, F., & Rex, D. C. (1977). Cenozoic volcanism in the Antarctic. Philosophical Transactions of the Royal Society of London. B, Biological Sciences, 279(963), 131-142.
3	São Jorge, Azores, Portugal	Feraud, G., Kaneoka, I., & Allègre, C. J. (1980). K/Ar ages and stress pattern in the Azores: geodynamic implications. Earth and planetary science letters, 46(2), 275-286. doi.org/10.1016/0012-821X(80)90013-8
4	Wudalianchi volcanic cluster, Wudalianchi City, Heihe, Heilongjiang, China	Zhang, M., Suddaby, P., Thompson, R. N., Thirlwall, M. F., & Menzies, M. A. (1995). Potassic volcanic rocks in NE China: geochemical constraints on mantle source and magma genesis. Journal of Petrology, 36(5), 1275-1303.
5	Toney Mountain, Marie Byrd Land, West Antarctica, Antarctica	LeMasurier, W.E. (1990) B. Marie Byrd Land. In Volcanoes of the Antarctic Plate and Southern Oceans Vol. 48 - Antarctic Research Series. American Geophysical Union. p.146-255. doi:10.1029/AR048
6	Mount Waesche and Chang Peak, Executive Committee Range, Marie Byrd Land, West Antarctica, Antarctica	LeMasurier, W. E., & Rex, D. C. (1989). Evolution of linear volcanic ranges in Marie Byrd Land, west Antarctica. Journal of Geophysical Research: Solid Earth, 94(B6), 7223-7236.
7	Chilallo Volcano, Arsi Zone, Oromia Region, Ethiopia	Woldegabriel, Giday, Aronson, James L., Walter, Robert C. (1990) Geology, geochronology, and rift basin development in the central sector of the Main Ethiopia Rift. Geological Society of America Bulletin, 102 (4) 439-458 doi:10.1130/0016-7606(1990)102<0439:ggarbd>2.3.co;2
8	Shanamu Hills, Kajiado County, Kenya	Fairhead, J. D., Mitchell, J. G., & Williams, L. A. J. (1972). New K/Ar determinations on rift volcanics of S. Kenya and their bearing on age of rift faulting. Nature Physical Science, 238(83), 66-69. doi.org/10.1038/physci238066a0
9	Olorgesailie Mountain, Kajiado County, Kenya	Fairhead, J. D., Mitchell, J. G., & Williams, L. A. J. (1972). New K/Ar determinations on rift volcanics of S. Kenya and their bearing on age of rift faulting. Nature Physical Science, 238(83), 66-69. doi.org/10.1038/physci238066a0
10	Tatau Island, Tabar Group, New Ireland Province, Papua New Guinea	Rytuba, J. J., McKee, E. H., & Cox, D. (1993). Geochronology and geochemistry of the Ladolam gold deposit, Lihir Island, and gold deposits and volcanoes of Tabar and Tatau, Papua New Guinea. US Geological Survey Bulletin, 2039, 119-126.
11	Santa Maria, Azores, Portugal	Feraud, G., Kaneoka, I., & Allègre, C. J. (1980). K/Ar ages and stress pattern in the Azores: geodynamic implications. Earth and planetary science letters, 46(2), 275-286. doi.org/10.1016/0012-821X(80)90013-8
12	Oku Massif, Northwest Region, Cameroon	Fitton, J. G., & Dunlop, H. M. (1985). The Cameroon line, West Africa, and its bearing on the origin of oceanic and continental alkali basalt. Earth and Planetary Science Letters, 72(1), 23-38. doi.org/10.1016/0012-821X(85)90114-1
13	Bunya Mountains, Moreton Bay Region, Queensland, Australia	EWART, A. (1982) Petrogenesis of the Tertiary Anorogenic Volcanic Series of Southern Queensland, Australia, in the Light of Trace Element Geochemistry and O, Sr and Pb Isotopes. Journal of Petrology, 23 (3) 344-382 doi:10.1093/petrology/23.3.344
14	Buckland Creek, Central Highlands Region, Queensland, Australia	Sutherland, F. L., Hollis, J. D., & Robertson, A. D. (1989). Buckland and Mitchell.
15	Monto Outcrop, Monto, North Burnett Region, Queensland, Australia	Sutherland, F. L., Hollis, J. D., & Robertson, A. D. (1989). Monto.	for nepheline hawaiite plug
16	Coleraine District, Southern Grampians Shire, Victoria, Australia	McDougall, I., & Wellman, P. (1976). Potassium?argon ages for some Australian Mesozoic igneous rocks. Journal of the Geological Society of Australia, 23(1), 1-9.

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References for TrachybasaltHide

Reference List:

Neuendorf, Klaus K.E., Mehl, James P. Jr., Jackson, Julia A. - Eds. (2017) Glossary of Geology (5th ed.). American Geological Institute (AGI).

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