Chemical and Geochemical Characterization of the Evolution of Soils of
Krakatau Islands
Abstract
The Krakatau volcano erupted in 1883 and created a unique ecosystem
where the surrounding islands were completely sterilised. While volcanic
activity and plant succession have been extensively studied in the
Krakatau islands, the soils received less attention. As the age of the
parent material is known precisely, and the islands are isolated, soils
of Krakatau islands could provide insights on the first stages of
weathering in tropical volcanic regions. This study aims to characterize
soils from the Krakatau islands. In 2015, ten sampling sites were
selected from Mt. Anak Krakatau, Rakata, Panjang, and Sebesi islands,
all making part of the Krakatau island complex. Field morphology was
observed from representative profiles on each island. Soil samples were
collected and analysed for physical and chemical properties. The
geochemical analysis was carried out using the X-ray fluorescence (XRF).
Linear discriminant analysis was used to separate materials from the
four islands based on their chemical and geochemical concentrations.
While the four islands were nearby and influenced by the 1883 eruption
of Mt. Krakatau, the analysis showed that the chemical and geochemical
characteristics of volcanic ash for each island are distinct.
Discriminant analysis of chemical and geochemical properties
differentiated soils of Anak Krakatau as the youngest ones, and soils of
Sebesi are the most developed ones. The following sequence of the soil
weathering degree was established: Sebesi > Rakata
> Panjang > Anak Krakatau.