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

Published: 22 December 2023| Version 1 | DOI: 10.17632/r6995krm6v.1
Andrew Terhorst


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.


Steps to reproduce

See the detailed sample analysis flowchart in the sedimentological data folder.


University of Cape Town, Commonwealth Scientific and Industrial Research Organisation


Sedimentology, Marine Geology