Marine geological data from the Roman Rock area in False Bay, South Africa

A 12 km2 area off Simon's Town in NW False Bay, South Africa, was surveyed using side-scan sonar and a single-beam echosounder, revealing six distinct patterns of acoustic reflectivity:

Facies 1 -- Outcrops of Cape Peninsula Granite characterized by irregular blocky patterns.
Facies 2 -- Stationary, long-crested wave ripples, oriented WSW-ENE.
Facies 3 -- Patchy veneer of calcareous sediment overlying quartzose sand.
Facies 4 -- Larger 'Cloud-like' and 'tongue-like' windows in the veneer of calcareous sediment revealing underlying rippled sand.
Facies 5 -- Rippled fine-grained quartzose sand in the deeper eastern area.
Facies 6 -- Medium-gray patches within Facies 5, possibly indicating weathered granite or calcareous sediment.

The Facies were ground-truthed using sediment sample data and diver observations. The sub-tidal environment is predominantly calm, with occasional high-energy conditions due to southeasterly gales influencing sediment movement. Analysis of sediment samples shows that the calcareous and quartzose sediments mix according to the Folk & Ward (1957) sediment-mixing model. Quartzose sands probably originate from Late Pleistocene regressive dunes reworked during the Holocene transgression. Modern calcareous sediments originate from carbonate-secreting organisms either attached to granite outcrops or unattached on the seafloor surface.

This repository contains spatial and sedimentological data from the survey and contextual data from other sources.