Sediments of the Lower Barito Basin in South Kalimantan : Fossil Pollen Composition

Abstract

During the present century, Holocene sediments of the lower Barito basin have been reclaimed for agricultural purposes. On Martapura river sediments, stable agricultural plots have been established which are not affected by severe acid toxicity problems : but on Barito river sediments, many plots have been abandoned because of such problems. To clarify the characteristics of the sediments of the lower Barito basin, boring observations were made along two transects on the Barito and Martapura river sediments. The fossil pollen composition, layering patterns, and the presence of sulfidic materials were used to identify the depositional environments of the sediments. This paper presents details of the succession of depositional environments on the Martapura river sediments and Barito river sediments, and demonstrates that the stable agricultural plots belong to a riverine environment. while the unstable agricultural plots belong to a brackish environment.