| Komati Formation | |
|---|---|
| Stratigraphic range:Paleoarchean 3300 Ma | |
| Type | Geological formation |
| Unit of | Onverwacht Group Tjakastad Subgroup |
| Underlies | Geluk Subgroup Hooggenoeg Formation |
| Overlies | Theespruit Formation |
| Thickness | 3,500 m (11,500 ft) |
| Lithology | |
| Primary | Komatiite |
| Other | Tholeiite |
| Location | |
| Coordinates | 25°48′S31°00′E / 25.8°S 31.0°E /-25.8; 31.0 |
| Region | Barberton Greenstone Belt,Mpumalanga |
| Country |  South Africa |
| Extent | Kaapvaal craton |
| Type section | |
| Named for | Komati River |
 Location of the Barberton Greenstone Belt | |
TheKomati Formation, also named asKomatii Formation, is a 3.475 billion year oldPaleoarchean rock formation, named after the nearbyKomati River inSouth Africa. It is the type locality forkomatiite, a high temperature,magnesium-richvolcanic rock occurring in theBarberton Greenstone Belt,Mpumalanga.[1]
The formation, belonging to theTjakastad Subgroup of theOnverwacht Group, overlies theTheespruit Formation and is overlain by theHooggenoeg Formation of theGeluk Subgroup.[2] Komatiites andtholeiites from the Komati Formation were analyzed for sulfur and provided δ34S values between −0.7 and 5.2 ‰.[3]
The Komatii Formation comprisesmetamorphosed komatiites andbasaltic komatiites, with minor mafic lavas and small intrusions. The lower part of the Komatii Formation is dominantlyultramafic, while the upper part is dominantly mafic.[4]
