Maratakka, Nickerie District, Suriname
|Latitude & Longitude (WGS84):||5° 11' 37'' North , 56° 54' 16'' West|
|Latitude & Longitude (decimal):||5.19361114502, -56.9044456482|
Small metasedimentary hornfels xenoliths in a gabbroic body.
At Maratakka the sand-covered Precambrian basement is not exposed.
Drilling showed the basement to consist of a mafic body, a few kilometers in size, surrounded by granite, presumably with metasedimentary enclaves (Bosma et al., 1975).
The mafic body consists of quartz gabbro-norite and biotite-quartz diorite and is cut locally by granite veins.
The metasedimentary hornfels xenoliths in the gabbroic body contain, in addition to grandidierite, antiperthitic andesine, perthite, cordierite, biotite, spinel, magnetite, and minor corundum, apatite, zircon, and ilmenite.
Biotite forms poikiloblasts of random orientation in a fine-grained granoblastic matrix of andesine, perthite, and cordierite.
Magnetite and dark green spinel occur as small, euhedral crystals, partly enclosed in biotite, as aggregates in feldspar, and as irregular poikiloblastic masses.
Other xenoliths, without grandidierite, contain additional sillimanite (with or without quartz) and locally some andalusite.
In one sample a grandidierite-bearing hornfels occurs together with a hornfels of fine-grained, granoblastic andesine and poikiloblastic hypersthene.
11 valid minerals.
Rock Types Recorded
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Entries shown in red are rocks recorded for this region.
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.
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0 - 66 Ma
|Cenozoic sedimentary rocks|
De Roever, E.W.F. and Kieft, C. (1976) Grandidierite of contact-metamorphic origin from Maratakka, northwest Surinam. American Mineralogist, vol. 61, 332-333.