PRELIMINARY STUDY OF SEDIMENT AGES AND ACCUMULATION RATES IN JAKARTA BAY DERIVED FROM DEPTH PROFILES OF UNSUPPORTED 210Pb
ABSTRACT: Preliminary study of
sediment ages and accumulation rates has been carried out in Jakarta Bay using unsupported
210 Pb. 210 Pb occurs naturally in sediments as one of the radioisotopes in the
238 U decay series. The total 210 Pb activity in sediments has two components,
namely; supported and unsupported. The latter derives from dissociation of 210
Pb from 226 Ra through diffusion of the intermediate gaseous isotope 222 Rn
which diffuse into the atmosphere and decay to 210 Pb. 210 Pb falling directly
into seawater and deposit on the bed of the marine with sediments. 210 Pb has
half-life of 22.26 years makes it well suited to dating and determining the
accumulation rate of sediments laid down over the past 100 – 150 years. Two
cores samples with diameter 7.5 cm were taken by scuba divers from Jakarta Bay
and were analyzed of 210 Pb using -spectrometer
equipped with PIPS detector. The sediment ages and range of sediment
accumulation rates of core I and II are up to 169 years and (0.25 – 1.93) kg/m
2 y and up to 157 years and (0.15 – 2.68) kg/m 2 y, respectively.
Author: Ali Arman Lubis, and
Barokah Aliyanta
Journal Code: jpkimiagg060031
