Kota-Kota meteorite (Marimba meteorite), Nkhotakota District, Malawi
|Latitude & Longitude (WGS84):||13° 1' South , 34° 12' East|
|Latitude & Longitude (decimal):||-13.01667,34.20000|
Enstatite Chondrite, high-iron (EH3; S4)
1905 find, 334 g, weathered
A stone ‘from the sky’ was presented to a district commissioner and after eventually reaching the Acting Commissioner for British Central African Office in 1905, the stone was duly transferred to the British Museum. In 1914 Prior noted the presence of chondrules, pyroxene, and rust. He further stated: “Owing to the weathered and rusted condition of the stone no chemical analysis was made, as it would have been of little value.”
The Enstatite Chondrite Class is defined by specific elemental ratios and by earthlike isotopic ratios. Mineralogically Enstatite Chondrites are characterized by the presence of iron-poor Enstatite, Fe-Ni metal, and a number of very reduced mineral phases (sulfides, nitrides, silicides) which are either unknown or very rare in terrestrial settings. The EH (high iron) chemical group is further characterized by abundant iron (~10-20 vol%) and the mineral niningerite. Type EH3 chondrites, the most abundant EH petrologic type, often contain perryite as well. They are additionally characterized by abundant chondrules, low degrees of aqueous alteration, and unequilibrated mineral assemblages. Kota-Kota’s Shock level [S4] indicates strong pre-terrestrial shock — a frequent complication in interpreting Enstatite Chondrite metamorphic histories. As the extremely reduced mineralogy of Enstatite meteorites makes several phases particularly susceptible to destructive weathering, it is all the more remarkable that the previously unknown mineral Djerfisherite, an alkali-containing sulfide, was discovered in 1965 amidst the chondrules, pyroxenes, and rust.
12 valid minerals. 1 (TL) - type locality of valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
0 - 2.588 Ma
|Quaternary sedimentary rocks|
Mason, B. H. (1966). The Enstatite Chondrites. Geochimica et Cosmochimica Acta 30, 23-30. (Jan 1966)
Fuchs, L. H. (1966) Djerfisherite, A new Mineral from the Kota-Kota and St. Mark’s enstatite chondrite. Science 153: 166-167.
Keil, K. (1968). Mineralogical and Chemical Relationships among the Enstatite Chondrites. Journal of Geophysical Research 73 (22): 6945-6976. (Nov 1968)
Brearley, A. J. & Jones, R. H. (1998): Chondritic Meteorites. In: Planetary Materials (Papike, J. J., Editor): Chapter 3, 398 pages. Mineralogical Society of America: Washington, DC, USA.
Grady, M. M. (2000). Catalogue of Meteorites (5/e). Cambridge University Press: Cambridge, New York, Oakleigh, Madrid, Cape Town. 690 pages.