Overview

The grain size fractions chosen for the isotopic and geochemical analysis are separated using the dry and wet sieving methods at the sample preparation laboratory.

Equipment

Our sample preparation laboratory is equipped with RETSCH AS200 control vibratory sieve Shaker, Elmasonic S 300 (H) ultrasonic cleaning unit with SRH 4/200 sieve cleaning module, and 450 L Thermo Scientific Heratherm advanced protocol oven.

Most minerals in geological samples have a minimal magnetic susceptibility and are not separated by the hand-magnet. If we use a much stronger magnet, many of these minerals are magnetically attracted. The Frantz isodynamic magnetic separator takes advantage of this feature. On a sloped rail, the sample grains slide along and are attracted by a magnet. Grains drew with force greater than gravity appear in the “magnetic” fraction, while the remaining grains appear in the “non-magnetic” fraction. By appropriately changing the magnet’s field strength, the boundary between the “magnetic” and “non-magnetic” fraction can be shifted, and we could separate the desired mineral from the bulk sample.