Evidence for a fungal event, methane-hydrate release and soil erosion at the Permian-Triassic boundary in southern Israel

The transition between the Permian and the Triassic systems in Israel is evident only in the subsurface. Two cores, from the Makhtesh Qatan 2 (core 9) and Avedat 1 (core 5) drillholes, in which the Permian-Triassic boundary was found marked by a fungal event, were sampled at close intervals and analysed for palynological, petrographical, mineralogical, chemical, and isotopic properties. Three palynozones were recorded: Lueckisporites virkkia Zone (Late Permian), Fungal Event, and Endosporites papillatus Zone (Early Triassic). The Fungul Event occurs in a narrow interval of ∼ 1 m and contains almost exclusively fungal remains and recycled woody particles. The two cores consist of laminated sediments, mainly siliciclastic, that were deposited in very shallow to restricted marine environments with a minor presence of evaporites and no bioturbation. Green glauconitic material and framboidal pyrite suggest suboxic conditions even in the shallow waters; reddish brown particles and plant fragments derived from nearby soils, now outcropping on the northeast side of the Dead Sea. These materials, as well as recycled brown glauconitic grains, suggest a drop in sea level and intense erosion before sedimentation, which was apparently continuous. Major and trace element compositions, including rare-earth elements, do not exhibit any particular pattern that might be related to the Fungul Event or to other core intervals. The rare-earth element patterns are basically normal and their concentration correlates with the clay content, reflecting the provenance of the Arabo-Nubian Massif and its sedimentary rims. Iridium results were mostly at the background level, and therefore the two distinct anomalous values are inconclusive. Microspherules, mainly of ∼ 2 μm size and Al-Si composition, were observed in a few samples in both cores. Their origin could not be determined, though they are considered to be natural. There was no evidence for shocked quartz. δ¹³C_org excursion exhibits a marked negative shift in both cores, just below the Fungal Event. The lowest values, - 37‰ and - 42‰, are among the lowest ever recorded near the Permian-Triassic boundary and suggest large-scale release of methane-hydrates.