Portland Bowers Basebed
Quarried at Bowers Quarry, Portland, Dorset
The rock was a grain supported oobiomicrite made up of predominantly rounded micritic ooliths showing concentric structure and ranging from 50µm to 300µm in diameter, numerous bioclasts up to 5µm by 20µm in size and sporadic irregular quartz grains 100µm nominal size. There was an apparent pressure adhesion of the grains and some matrix between the ooliths and this results in occasional intergranular voids. Sporadically sparry calcite infilled or partially infilled intergranular spaces or replaced central parts of bioclastic debris.
The ooliths consisted of micritic calcite and the bioclasts generally exhibited original aragonitic texture. The rock contained occasional voids 100µm nominal size. The micrite was also microporus with pores beyond the resolution of a transmitted light petrological microscope. No deleterious constituents or features were observed.
Typical Portland colour, creamy/white. The shell concentrations and texture variation can give it slightly deeper tones.
Load Bearing Masonry
Available from Albion Stone plc-