Syngenetic Deposit

a mineral deposit formed contemporaneously with the enclosing rocks. The deposits, which usually occur as beds or bedlike masses, are conformable with the underlying and overlying strata. They include mainly sedimentary mineral deposits, including sands, clays, limestones, coals, oil shales, salts, phosphorites, bauxites, iron and manganese ores, and certain deposits of copper, uranium, and vanadium. Magmatic mineral deposits are rarely syngenetic; they are associated with chromite and titanomagnetite ores in ultrabasic rocks, with niobium ores of stratified alkaline massifs, and with partially liquated sulfide niccolite ores in basic rocks.