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Tephrochronology of a distal tonstein layer within the Maritsa East lignite basin, Bulgaria: Potential sources of the Miocene large explosive eruption

: This contribution presents the age of the detrital zircons from the coal bearing Miocene succession of the Maritsa East lignite basin. We report a new finding of thin kaolinized pyroclastic beds (tonstein) in the coal bearing succession. The analysis of the detrital age component shows sedimentary input from the basement of the proximal area. The most abundant age cluster 290–315 Ma shows that the predominant sources are the Early Permian–Late Carboni­ ferous intrusions in the area. The newly­recognized tonstein beds represent the products of large, distal pyroclastic erup­ tions and are an important element of the sedimentary succession. They are dated at 14.31±0.30 Ma, which corresponds to the absolute age of the organic matter deposition of the productive middle lignite seam. Their source could most likely be related to the Miocene acid paroxysm ignimbrite eruptions in the Pannonian basin.