What is "rhizolith"

n. A fossilized root

'''Rhizoliths '''are root systems that have been encased in mineral matter. Rhizoliths are created through processes of chemical weathering, decomposition, reprecipitation and cementation. Rhizoliths are formed through the transport of dissolved Ca and HCO enhancing the CaCO precipitation in a diameter of up to several centimeters around the roots. This is possible on calcareous sediments, where high amounts of Ca in the rhizosphere can lead to the formation of encrustations around roots termed rhizoliths.