Abstract:
Characteristic black heavy sand is found at the surface of Iran`s Hormuz Salt Dome which constitutes the most spectacular of the multi-coloured islands of the Persian Gulf. The heavy sand is found mainly in the denuded peripheral areas as well as the regions of deeper erosion of the island. It is however mainly being deposited at the surface of the island by various brine springs as an underground dissolution product of rock salt. Field investigations have revealed that the black sand is the product of underground dissolution, surface weathering and concentration of Hormuz salt and its cap rock which bear iron oxide as a dissolved component as well as solid disseminated grains of hematite, hematite bands, lenses and concretions. The Hormuz salt is normally white - grey, pink - red in shade. It is generally medium to thick bedded with occasional zones of very thick bedded to massive salt. Thin grey - black hematite bands, and streaks generally alternate with salt layers at short intervals. The cap rock (compacted residual soil of salt) of the Hormuz Salt Dome varies in colour from shades of brown - red through dark rusty red to almost black with a high specific gravity on account of the high proportion of residual hematite. This is against the grey, white and pink-red shades with a low to medium specific gravity of the cap rocks of almost all other salt domes of Iran and Pakistan excluding, of course, the Persian Gulf salt domes occurring nearby under similar geological conditions.
Page(s):
105-118
DOI:
DOI not available
Published:
Journal: Proceedings of 5th Pakistan Geological Congress , Volume: 0, Issue: 0, Year: 2007