The first meters of core were retrieved from Lake Challa on Monday, and then all radars started moving. The teams for the day and night shifts got together and started their routine. Lunches suddenly became very quiet, as half of the people was on the barge, whereas the night teams were sleeping, and the speculations about how many meters of sediment would be recovered during a shift had started.
The depth record of 21 meters of core collected in 2006 was broken on Tuesday, when the night shift came home with 30 meters of perfectly laminated sediments. The current depth is 120 meter, which roughly corresponds to the past 120.000 years. The drill has hit a hard layer here, which has presumably formed during a low stand of the lake. A second hole has been started, for which a different drilling technique will be used to penetrate this layer and reach the underlying sediment.
Once in the lab, the cores are scanned, and core catchers are opened to take subsamples and to make smear slides. A quick glance through the microscope already reveals beautiful down-core alternations between the two dominating species of diatoms in the lake. Only power outages can stop our smooth workflow, and force us to take a break. And then having to re-scan the core once power is back…