Klerksdorp sphere
Klerksdorp spheres are small objects, often spherical to disc-shaped, that have been collected by miners and rockhounds from 3-billion-year-old pyrophyllite deposits mined by Wonderstone Ltd., near Ottosdal, South Africa.
They have been cited by pseudoscientists and reporters in books,[1][2] popular articles,[3][4] and many web pages[5][6] as inexplicable out-of-place artifacts that could only have been manufactured by intelligent beings.
As illustrated by geologist Paul Heinrich,[9][10] they vary widely in shape from either approximate or flattened spheres to well-defined discs and often are intergrown.
[9][10] Observations by Bruce Cairncross,[7] Louis Taylor Nel,[11] and Andrea Agangi[12] demonstrate that the unoxidized and unaltered Klerksdorp spheres found in pristine pyrophyllite consist of diagenetic pyrite (FeS2).
Pyrite occurs abundantly as finely disseminated grains, cm-size spheroids (Klerksdorp spheres), and layers at multiple horizons within thin beds of carbonaceous shale or slate, which is locally called wonderstone.
[12] Klerksdorp spheres are found in carbonaceous shales (wonderstone) that occur as lenses within the 1.5 km (0.93 mi) thick Syferfontein Formation.
It is composed of feldspar-quartz-phyric felsic volcanic rocks, basaltic to andesitic lava, tuff and breccia and is part of the 2.7 km (1.7 mi) thick Mesoarchaean Dominion Group.
A terrestrial setting for the accumulation of the Dominion Group is demonstrated by the type of volcanic facies, e.g. massive amygdaloidal lavas lacking pillow structures, presence of high-temperature, subaerial ignimbrites, and palaeosols found within it.
[12][13] The Klerksdorp sphere-bearing carbonaceous lacustrine shales occur as thin, tens of meters thick, discontinuous layers interbedded with felsic volcanic rock of the Syferfontein Formation.
The abundant carbonaceous matter in these shales provide evidence for biologic production in a volcanically dominated terrestrial acid lake environment about 3.0 Ga ago.
[12][13] Various professional geologists[7][8][9][10] agree that the Klerksdorp spheres originated as concretions, which formed in volcanic sediments after they accumulated 3 billion years ago.
A similar process in coarser-grained sediments created the latitudinal ridges and grooves exhibited by innumerable iron oxide concretions found within the Navajo Sandstone of southern Utah called "Moqui marbles".
