Generic relationships in the mineral-chemical stratigraphy of tubidite sandstones

Ratios of abundance of hydraulically and diagenetically equivalent heavy minerals (apatite:tourmaline,garnet:zircon) from deep-water sandstones, of similar age and derived from the same overall source terrain, have contrasting trends. The differences are explained hv contrasting sediment transport paths. Deep-water sandstones with fluctuating heavy mineral ratios are inferred to be derived directly from alluvial basins, bypassing any contemporaneous shallow marine shelf. Deep-water sandstones with homogeneous heavy mineralogy are inferred to be fed by sediment that originally accumulated on shallow marine shelves but was subsequently mixed.