June 12, 2018

A visible ash layer in the ice and start of the firn gas sampling

A visible volcanic ash layer in the ice core at 1078 m depth (drillers’ depth). Possibly the well-known 10,400 yr old Saksunarvatn tephra layer.

In the morning we said goodbye to Norland 3 Twin Otter that headed towards Iceland. Last night the deep drilling recovered a core containing a visible ash layer. In other deep Greenland ice cores a visible ash layer known as the ‘Saksunarvatn’ tephra layer has been identified at corresponding depths. The Saksunarvatn layer is of Icelandic origin and has an age of approximately 10,400 years. If it is this layer we now have in the core it appeared a little higher up in the ice than expected from the preliminary time scale for the EGRIP core. We only expect to find a handful of visible tephra layers in the entire core, so the appearance is something special. The firn gas program has initiated and the first drilling and sampling down to 5.1 m depth has been made.

What we did today:

1. Deep drilling 10.80 m. Drillers’ depth 1080.95 m
2. Firn gas drilling sampling to depth 5.1 m
3. Ice core processing bags 1406 – 1447, final depth: 795.85 m
4. Measurements in isotope laboratory, final depth: 560.45 m
5. Measurements in physical properties laboratory, final depth 801.90 m
6. Water vapour sampling and measuring.
7. Goodbye to Twin-Otter Norland 3 with 4 GLISN people and 2 pilots
8. Reorganizing long ice core troughs in ice core buffer

Weather: Sunny with few thin high clouds. Temp. - 12 ºC to -23 ºC. Wind: 3-8 kt from W. Visibility: Unrestricted.

FL, Anders Svensson

Hamid is presenting a very significant volcanic layer that contains no ash particles but plenty of acid from an unknown eruption.