Generic relationships in the mineral-chemical stratigraphy of turbidite sandstones

Ratios of abundance of hydraulically and diagenetically equivalent heavy mi nerals (apatite:tourmaline,garnet:zircon) from deep-water sandstones, of si milar age and derived from the same overall source terrain, have contrastin g trends. The differences are explained hv contrasting sediment transport p aths. Deep-water sandstones with fluctuating heavy mineral ratios are infer red to be derived directly from alluvial basins, bypassing any contemporane ous shallow marine shelf. Deep-water sandstones with homogeneous heavy mine ralogy are inferred to be fed by sediment that originally accumulated on sh allow marine shelves but was subsequently mixed.