Co-occurrence of Sinuspores sinuatus (Artüz) Ravn 1986 with established palynological markers indicating younger strata: AK-1X well section (Pennsylvanian, Zonguldak Basin, NW Turkey) and the correlation to the stratigraphic system

摘要

Part of the AK-1X well section from the Amasra area of the Zonguldak Basin in NW Turkey (Asia Minor) has been palynologically revised. Over the depth range –342.05 to –345.05 m atypical co-occurrences of the key stratigraphic spore species Sinuspores sinuatus together with Vestispora fenestrata, V. laevigata, Torispora securis and Thymospora spp. are recorded. By correlation to the ‘selected spore ranges and spore zonation of the Carboniferous system in Western Europe’, often used as a standard, these palynological assemblages would be correlated to the upper Bolsovian by the presence of Thymospora spp. with some reworked older material, represented by S. sinuatus. Alternative spore ranges are considered in this study, and miospore ranges of selected species from Western Europe and North America are discussed. The correlation of the palynological record from the re-investigated AK-1X well section to the chronostratigraphy corresponds with ages around the Duckmantian–Bolsovian boundary, and correlation to the uppermost Duckmantian is discussed as a possibility. However, recent studies lead to the conclusion that a lower Bolsovian age determination for the AK-1X well section is also most probable. Accordingly, Sinuspores sinuatus has a slightly expanded range top in NW Turkey and some taxa such as Thymospora spp. occur slightly earlier here than in Western Europe.