Palaeoreconstruction of vegetation and environment using pollen and spores fossils from Banyumas Basin Tapak formation in plio-pleistocene.

Abstract

Pollen and spores fossils have important information about the flora, vegetation, climate, and environment associated with processes and conditions during sedimentation process in the past.The main objective of this study was to disclose information, especially the ecology of palaeoflora, vegetation, and environmental deposition based on pollen and spores fossils, which were found in sedimentary rocks of the Banyumas Basin Tapak Formation.Totals of 166 sediment samples were prepared using modified palynology standard methods. Palynological analysis were carried out based on the habitus, habitat, total palynomorph and diagnostic pollen and spores fossils.This research found 72408 palynomorph fossils that consisted of 48570 pollen and spores fossils and 23838 marine fossils consisted of dynoflagellate cysts and foraminifera test lining (FTL). Pollen and spores fossils consisted of 76 types that were categorized into: 20 types categorized into species, 41 genus and 15 familia level. Based on habitus, 76 types of pollen and spores fossils were grouped into: 41 taxa (53.95%) of arboreal plants (AP),15 taxa (19.74%) of non arboreal plants (NAP), and 20 taxa (26.32%) of Pterydophytes.The presence of AP taxa were more dominant than the NAP taxa.This suggested that arboreal palaeoflora and vegetation were more developed in Banyumas Basin Tapak Formation. Pollen and spores fossils evidence indicated that the environment in the Banyumas Basin Tapak Formation was surrounded by mountainous morphology and the water flow system as pollen and spores media transport from mountainous to the transitional area through lowlands, freshwater, and mangrove swamps. The overall climate of Tapak Formation showed there was no clear differences between hot-wet and cold-dry climates.The presence of paleoflora taxa in Tapak Formation were relatively stable.The mean of similarity index ranged from 53.3 to 59.64%, which was categorized as high similarity criteria among sediment samples from each location, although the diversity was categorized from low to moderate. Generally, environmental deposition on Tapak Formation was a transitional area that was influenced by dynamic marine environment intensity.