Salt biostratigraphy: The Miocene palynological assemblages from the Wieliczka Formation, southern Poland

Salt biostratigraphy has rarely been used in academic or industry studies, despite its potential to shed light on the stratigraphy, thermal maturity, paleoenvironments, and paleoecology of evap-orite successions. The upper section of the evaporite-dominated middle Miocene Wieliczka Formation in southern Poland was sampled and analyzed for its palynological content. The results show assemblages dominated by miospores with subordinate dinoflagellate cysts, which are interpreted as derived mainly from reworking. The reworked forms, both miospores and dino-flagellate cysts, were sourced from Cretaceous, Paleogene, and Miocene strata, with increasing amounts toward the top of the succession, which is interpreted to be a consequence of the nearby ongoing Carpathian thrusting. The influence of marine water in the basin sedimentation is difficult to estimate with the current data as the dinoflagellate cysts are, at least partially, reworked. The in situ miospore assemblages indicate the pres-ence of nearby mixed coniferous and broadleaved deciduous for-ests that developed under temperate and humid climatic conditions. The high percentages of bisaccate pollen are inter-preted to represent the proximity to high-elevation areas of the Carpathians, where conifers must have been dominant. The pal-ynological record also signals the development of swamp and marsh vegetation in the lowland areas. These wetlands were most likely inhabited by shrubby and arboreal elements with few thermophilic taxa. The apparent thermal maturation of the assemblages is very low, with dominant pale yellow palyno-morph colors. The study shows that palynological analyses in evaporite-dominated successions are helpful in the reconstruc-tion of local geodynamic events, paleoecology, and stratigraphic interpretation.

Automated summary

Salt biostratigraphy is underutilized in academic and industry studies, but it has the potential to provide valuable insights into stratigraphy, thermal maturity, paleoenvironments, and paleoecology of evaporite successions. A study in southern Poland analyzed the palynological content of the upper section of the Middle Miocene Wieliczka Formation, revealing assemblages dominated by reworked miospores and dinoflagellate cysts sourced from Cretaceous, Paleogene, and Miocene strata. The study also indicated the presence of mixed coniferous and deciduous forests, swamp and marsh vegetation, and low thermal maturation levels.