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The resultant leached out, fossil deposits have recombined in various ways with local carbonate minerals to form a light tan, crumbly, phosphorite, very different from fresh guano which is black and sticky.
Kyzylkum's phosphorite basin covers an area of 65 thousand [km.
Co-author Richard Wirth of the GFZ German Research Centre for Geosciences, who analyzed the rock samples with an electron microscope, said that the formation of Earth's earliest phosphorites was influenced strongly, if not controlled completely, by the activity of sulfur bacteria.
Between the Cambrian sand- and siltstones and Ordovician limestones occur the major sources of Rn: Lower-Ordovician obolus sandstone with P-rich layers of phosphorite that are overlain by graptolite argillite.
A sample of phosphorite recently mined on the island of Nauru was also ground.
Geographical, geological, biostratigraphical and palaeoecological details were already carefully published by MULLER (1983), FREES (1991) and BOHME (2001), The nearly complete skull treated here almost surely originates from the "Horizon of phosphorite nodules" ("Phosphoritknollen-Horizont") which lies immediately at the base of the Early Oligocene "Upper Boehlen Formation" ("Rupel Clay").
The areas north and west from the Rebala and Voerdla villages are damaged by the phosphorite mining that has left deep openwork pits surrounded by high soil mounds.
The Palmyrid range is composed of Mesozoic and Cenozoic rocks that are mainly limestone, dolomite, and conglomerate sequences, with subordinate quantities of phosphorite deposits and flint.
Layers rich in intact shells and shell fragments of lingulate brachiopods, forming phosphorite deposits of commercial interest, occur at certain levels of this succession (Raudsep 1987).
In the report written on 18 June, Frohwein, the German envoy in Tallinn, states that the Soviet occupation and bolshevization will considerably restrict the German financial interests in Estonia, particularly those related to the oil-shale production and to the mining of phosphorite.