A decaying measurement of Anhysteretic Remanent Magnetization
(ARM) has been undertaken to estimation the grain size of magnetic mineral
which carries remanent on peridotite igneous rocks. The samples are taken from
Desa Aranio, Kabupaten Banjar, South Kalimantan. The samples are taken in a
cylinder from with the diameter 2.54 cm and 2.2 cm in length by using Drill Model
D026-C. The giving, measuring and decaying process of ARM is done by
Molspin AF Demagnetizer, partial Anhysteretic Remanent Magnetization
(pARM), and Minispin Magnetometer. The estimation of grain size of magnetic
mineral is obtained by seeing ARM intensity decaying curve towards magnetic
field shown by the samples of peridotite igneous rocks. The ARM intensity
decaying curve show that the estimated peridotite rocks in research are
dominated by multidomain and the size are big, whereas the distribution of the
grain size is larger than 200 μm