Evolution of salt diapir and karst morphology during the last glacial cycle : Effects of sea-level oscillation, diapir and regional uplift, and erosion (Persian Gulf, Iran)
Abstract
Marine, fluvial and cave sediments, and karst phenomena were studied and dated by 14C, U-series, and OSL methods to determine the evolution of the Namakdan diapir and the world's longest salt cave (3N Cave) during the Holocene and the Last Glacial. Sea-level oscillations, the uplift rate of the diapir and its surroundings, and erosion are the main factors influencing the diapir morphology.
Although the diapir uplift rate has been constant for the last 50 kyr (4 mm/yr at a distance 600 m from the diapir edge), the uplift rate decreases with the distance from the diapir center. Drag-induced host rock deformation extends for 300 m from the outside edge of the diapir, and host rocks in this zone have an uplift rate of 0.4–0.6 mm/yr, which is 2–3 times greater than the regional uplift rate.
Based on known sea-level oscillations, radiometric dating, and geological evidence, the Namakdan diapir was repeatedly flooded by sea water between 130 and 80 kyr BP.