Red Bluff : Winter morning . . .
Located in Black Rock, about 19 km from Melbourne, Red Bluff is a high (over 25 m), active cliff cut in poorly consolidated clayey sands, with harder sandstone beds forming a series of irregular ledges and benches at the base. The greater part of the cliff is an exposure of the Red Bluff Sand, this site being the type locality for that geological formation. At the cliff base, the Red Bluff Sand rests disconformably on the hard, dark brown to red ferruginous sediments of the Black Rock Sandstone, about 3 m of Black Rock Sandstone being exposed here above low water mark. These two formations comprise the Brighton Group, the most widespread outcropping Tertiary sedimentary sequence in the Melbourne area. The lowest bed of the Red Bluff Sand is a dark carbonaceous band overlain by a thin, hard, gritty iron cemented bed. Above this, the lower beds of the Red Bluff Sand are yellow clayey sands passing into cross-bedded gravelly horizons which become sandy and brown to red in the upper sections of the cliff. Although not abundant, the fossil pollen and leaf content of clay in the Red Bluff Sand indicates the formation is of non-marine origin and of Middle to Late Pliocene age.
The headland at Red Bluff coincides with a rise in the level of the Black Rock Sandstone, (either a minor anticline or a depositional undulation in the formation). This rise brings the more resistant ferruginous rock up to sea level and forms the promontory underpinning the cliff. To the south, the cliff declines to be a scrubby bluff behind Half Moon Bay where the Black Rock Sandstone declines below sea level. The face of Red Bluff is incised by narrow, tubular gullies, with remnant pinnacles and buttresses forming a miniature but spectacular ‘badlands terrain’. (Sourced from Victorian Resources Online)
Red Bluff : Winter morning . . .
Located in Black Rock, about 19 km from Melbourne, Red Bluff is a high (over 25 m), active cliff cut in poorly consolidated clayey sands, with harder sandstone beds forming a series of irregular ledges and benches at the base. The greater part of the cliff is an exposure of the Red Bluff Sand, this site being the type locality for that geological formation. At the cliff base, the Red Bluff Sand rests disconformably on the hard, dark brown to red ferruginous sediments of the Black Rock Sandstone, about 3 m of Black Rock Sandstone being exposed here above low water mark. These two formations comprise the Brighton Group, the most widespread outcropping Tertiary sedimentary sequence in the Melbourne area. The lowest bed of the Red Bluff Sand is a dark carbonaceous band overlain by a thin, hard, gritty iron cemented bed. Above this, the lower beds of the Red Bluff Sand are yellow clayey sands passing into cross-bedded gravelly horizons which become sandy and brown to red in the upper sections of the cliff. Although not abundant, the fossil pollen and leaf content of clay in the Red Bluff Sand indicates the formation is of non-marine origin and of Middle to Late Pliocene age.
The headland at Red Bluff coincides with a rise in the level of the Black Rock Sandstone, (either a minor anticline or a depositional undulation in the formation). This rise brings the more resistant ferruginous rock up to sea level and forms the promontory underpinning the cliff. To the south, the cliff declines to be a scrubby bluff behind Half Moon Bay where the Black Rock Sandstone declines below sea level. The face of Red Bluff is incised by narrow, tubular gullies, with remnant pinnacles and buttresses forming a miniature but spectacular ‘badlands terrain’. (Sourced from Victorian Resources Online)