The Golan Heights plateau, located in northeastern Israel, is underlain by volcanic rocks ranging in age from ~5.5 to 0.1 Ma. The basalts are generally covered by shallow soils, rarely exceeding 0.5 m in depth. Recent findings, based on chemical mass balance calculations, suggest that contrary to previous assumptions that these soils form a chronosequence, the soil ages are decoupled from the ages of the underlying basalts, and represent up to a few thousand years of soil production (Zaarur et al., 2024). Here we use OSL measurements to independently determine the dust burial ages and residence time of the soils.
Soils were collected from 9 sites spanning from the southern to central Golan, including samples of mature Vertisols covering the oldest Pliocene basalts on the southern plateau, and soils collected from deep crevasses in the basalts. We extracted quartz from the soils and used OSL on very small aliquots, and the finite mixture model (FMM) to determine age populations. We identify 4 main age populations between 1.1 ka and 8 ka: 0-1 ka, 1-2 ka, 3-4 ka and 6-7 ka. These results strengthen the chemical modeling that shows that the soils are young and are not coupled with bedrock ages.
The young burial ages found in this study are aligned with the time frame of soil formation calculated by Zaarur et al. (2024), and the high soil turnover rates suggested by Be’eri-Shlevin et al. (2023). Furthermore, our results strongly suggest that erosion is a significant factor controlling soil formation and accumulation on the plateau, despite the flat morphology of the Golan Heights. The age clusters suggest that there might have been several events of soil removal and accumulation.