Abstract The Sea Point intrusive contact on the Atlantic coast, South Africa, is a site of historical significance that continues to be useful for studying the details of granite–wall rock relationships, some of which have not been properly evaluated yet. At a time when the origin of granites was still controversial, and the concept of contact metamorphism not yet properly developed, Charles Darwin visited the Sea Point contact to make some geologically important observations. He concluded that the granite originated as a magma deep in the Earth, intruded a country rock of sedimentary origin and changed this country rock's appearance owing to the thermal action of the hot granite magma. He also contemplated the long periods of time required to expose the rocks by erosion. Besides its historic value, the Sea Point heritage site exposes unique features giving rare insights into the physical and chemical interaction between intruding granitic magma and a regionally low-grade metamorphosed sedimentary sequence. Questions regarding mechanisms of magmatic emplacement may be answered from this outcrop, including emplacement dynamics and interrelationships of various granitic phases, pre- versus syn-intrusive deformation and metamorphism, assimilation of country rock by a granitic magma and the origin of feldspar phenocrysts seemingly ‘stranded’ in the country rock.

Abstract Cape Town was founded in 1652 and many of its historical buildings are constructed of local natural stone. Malmesbury Group slate was exploited from 1666 and used to build Cape Town Castle, which is the oldest building in Cape Town. Two other local stones, Cape granite and Table Mountain sandstone were utilized for buildings from 1850. A medium-grained granite named Paarl Grey was exploited from an area adjacent to the town of Paarl, 50 km east of Cape Town, from 1890. This granite is the most extensively-used natural stone in Cape Town. The resource fields of natural stone near Cape Town, namely Malmesbury Group slate, Cape granite and Table Mountain sandstone, lie within the Table Mountain National Park and Robben Island World Heritage Site and can no longer be exploited, but similar resource fields occur outside Cape Town. Paarl Grey granite is still extracted at one quarry and, despite part of the resource field lying within the Paarl Mountain Nature Reserve, there are still sufficient quantities of stone available. From an international perspective, the heritage stones of Cape Town, South Africa, are best considered as having national significance.