Komatii Formation

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Komati Formation
Stratigraphic range: Paleoarchean
3300 Ma
Pha.
Proterozoic
Archean
Had'n
↓
TypeGeological formation
Unit ofOnverwacht Group
 
Underlies
 
Overlies
Thickness3,500 m (11,500 ft)
Lithology
PrimaryKomatiite
OtherTholeiite
Location
Coordinates25°48′S 31°00′E / 25.8°S 31.0°E / -25.8; 31.0Coordinates: 25°48′S 31°00′E / 25.8°S 31.0°E / -25.8; 31.0
RegionBarberton Greenstone Belt, Mpumalanga
Country South Africa
ExtentKaapvaal Craton
Type section
Named forKomati River
South African Greenstone Belt.png
Location of the Barberton Greenstone Belt

The Komati Formation, also named as Komatii Formation, is a 3.475 billion year old Paleoarchean rock formation, named after the nearby Komati River in South Africa. It is the type locality for komatiite, a high temperature, magnesium-rich volcanic rock occurring in the Barberton Greenstone Belt, Mpumalanga.[1]

Description[]

The formation, belonging to the of the Onverwacht Group, overlies the and is overlain by the of the .[2] Komatiites and tholeiites from the Komati Formation were analyzed for sulfur and provided δ34S values between −0.7 and 5.2 ‰.[3]

The Komatii Formation comprises metamorphosed komatiites and basaltic komatiites, with minor mafic lavas and small intrusions. The lower part of the Komatii Formation is dominantly ultramafic, while the upper part is dominantly mafic.[4]

References[]

  1. ^ Greenstone Belt Studies, Department of Geological Sciences, University of Cape Town
  2. ^ Montinaro et al., 2015, p.314
  3. ^ Montinaro et al., 2015, p.319
  4. ^ Guice, 2019, p.143

Bibliography[]

  • Guice, George L. 2019. Origin and geodynamic significance of ultramafic-mafic complexes in the North Atlantic and Kaapvaal Cratons (PhD thesis), 1–289. Cardiff University.
  • Montinaro, Alice; Harald Strauss; Paul R.D. Mason; Desiree Roerdink; Carsten Münker; Ulrich Schwarz-Schamper; Nicholas T. Arndt; James Farquhar, and Nicolas J. Beukes, Jens Gutzmer and Marc Peters. 2015. Paleoarchean sulfur cycling: Multiple sulfur isotope constraints from the Barberton Greenstone Belt, South Africa. Precambrian Research 267. 311–322.
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