Müller Ice Cap Daily Report Monday April 21

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Daily Report for the 21 April 2025

Monday was the first day where we worked in shifts the whole day from 8 am to midnight: This worked well and we drilled and measured 41.2 m of ice. By the end of the day the ice became more brittle and we decided that we the next day would change to liquid drilling.  At a depth of around 100 m the ice starts to break because of the big pressure difference between the open borehole and the ice under pressure of 100 m of above laying ice. When we add liquid to the borehole we increase the pressure around the core making the drilling more gentle and the ice quality becomes better.
At the end of the day we saw an interesting brown layer in the ice cores. Measurement of the conductivity over the layer did not indicate that this was a volcanic layer. However, right at the end of the day, the ECM showed a mayor conductive layer and by comparing with other ice records we know that this was the trace of the big Icelandic Laki eruption in 1783 AD. We have drilled through 242 years of ice.
Laki erupted violently over an eight-month period between June 1783 and February 1784 from the Laki fissure and the adjoining volcano Grímsvötn. It poured out an estimated 42 billion tons or 14 km3 (18×109 cu yd) of basalt lava as well as clouds of poisonous hydrofluoric acid and sulfur dioxide compounds that contaminated the soil, leading to the death of over 50% of Iceland's livestock population, and the destruction of the vast majority of all crops. This led to a famine which then killed at least a fifth of the island's human population, although some have claimed a quarter.
The Laki eruption and its aftermath caused a drop in global temperatures, as 120 million tons of sulfur dioxide was spewed into the Northern Hemisphere. This caused crop failures in Europe and may have caused droughts in North Africa and India.
 
What we have done:
-Record drilling of 36 runs from 54.72 m to 96.01 m
-Logged, weighed, O18 sampled and ECM measured bags 55 to 96.
-Made density and ECM plots of all the data
-Working on the drill software
 
Dorthe Dahl-Jensen

Wx at Müller: Changing blue sky and  overcast, no wind, temperatures between -18 to -14 deg C  


Caption: Emma finding a brown layer in the ice core at 85.4 m depth


Caption: Close up of the brown layer


Caption: Laki eruption year 1783 AD found at a depth of 92.9 m






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