Determination of the Coral Age from Keraton Buton Fort, Baubau City, Based on 14C Activities Using Liquid Scintillation Counting Method

Abstract

Determination of the age of the corals that make up Keraton Buton Fort based on ¹⁴C activity using the LSC (Liquid Scintillation Counting) method has been carried out. The coral samples analyzed were the corals that made up the fort taken from the gate of Keraton Buton Fort and a coral sample from the beach of Makassar Island Baubau, as modern coral. Sample preparation was carried out physically and chemically using a mixture of NaOH with 30% H₂O₂, followed by a mixture of HClO₄ with 30% H₂O₂, and finally with 5% HCl solution to produce a clean and whiter-looking sample with a weight reduction of 10.5% - 15.8%. The carbonate of coral samples was separated as CO₂ by reaction with 10% HCl and absorption by KOH 1 N solution as K₂CO₃. The total carbon in the two fort coral sample and modern coral was 0.129, 0.132, and 0.129 grams, respectively, and was obtained through the titration method. The specific activity of ¹⁴C in the samples was 13.95 DPM/gC and 14.38 DPM/gC in both fort coral samples, and 15.48 DPM/gC in modern coral. The age of the coral samples of Keraton Buton Fort calculated from the ¹⁴C specific activity data was between 817 ± 0.123 and 565 ± 0.105 years, which is older than the ages of the Keraton Buton Fort according to the historical reviews.