Stratiform deposits are found in shallow marine carbonate dominated sequences on the rims of large sedimentary basins where changes in salinity caused the deposition.
Stratiform in geography is a special type of strata-bound deposit in which the desired rock or ore constitutes, or is strictly coextensive with, one or more sedimentary, metamorphic, or igneous layers.
Examples of stratiform in geography are beds of salt or iron oxide or layers that are rich in chromite or platinum in a layered igneous complex.
Stratiform deposits are sheet-like accumulations of chro- mite that occur in layered ultramafic to mafic igneous intrusions.
Podiform deposits are irregular but fundamen- tally lenticular chromite-rich bodies that occur within Alpine peridotite or ophiolite complexes.
Stratiform deposits of predominantly galena and sphalerite are most commonly hosted in shallow-marine carbonate-dominated sequences on the rims of large sedimentary basins where changes in salinity caused deposition.
A final class of hydrothermal deposit is called stratiform because the ore minerals are always confined within specific strata and are distributed in a manner that resembles particles in a sedimentary rock.
Stratiform chromite deposits are primarily hosted by peridotites, harzburgites, dunites, pyroxenites, troctolites, and anorthosites.
Although metamorphism may have altered the ultramafic regions of layered intrusions postdeposition, only igneous processes are responsible for formation.