Collisional Orogeny in the Scandinavian Caledonides: Drilling the Main Caledonian Décollement and into the Basement of the Fennoscandian Shield

Project Acronym: COSC-1 | State: Post Moratorium | Expedition ID: 5054

The COSC project focuses on the mid Paleozoic Caledonide Orogen in Scandinavia in order to better understand orogenic processes, both in the past and in today's active mountain belts.

The Scandinavian Caledonides provide a particularly well preserved example of Paleozoic plate collision, with the underthrusting of continent Baltica beneath Laurentia and thickening of the continental crust to at least 100 km. In the Scandes, the surface geology in combination with geophysical data provide control of the geometry of the Caledonian structure, both of the allochthon and the underlying parautochthon-autochthon, and define the targets for drilling. The drillholes themselves will help us to better define the structure and physical conditions of the allochthons and underlying parautochthon during nappe emplacement.

Click here for information on the second phase of the COSC project.

Keywords: Europe, Sweden, Basement Deformation, Foreland, Natural Hazards, Paleoenvironment, Paleozoic, Post-weichselian Temperature Development

Cores are stored at Federal Institute for Geosciences and Natural Resources, Spandau, Germany

Project News (click for all News)

2014-06-05

COSC-2A reached 1000 m

Today at 17:00 we crossed the 1000 m mark, unfortunately the core from 1000 m driller's depth is crushed, completely. Due to triple tube drilling: still 100 % recovery, even of the crushed parts.

2014-08-06

Delighted! 2000 m DRILLER’S DEPTH

Drilling went well and fast during the night, and 2000 m driller’s depth were passed at about 6 o’clock in the morning (& more delight!). But in the morning the rotational speed dropped significantly. Another core run or two, and the drill bit was worn out, after about 41 m. A round trip … this clearly killed the show.

2014-08-21

Soon we will leave the Seve Nappe rocks behind us

Looking backwards (or upwards), we can state that the thrust zone most likely already began somewhere between 2000 and 2050 m - i.e. has a thickness of about 300 m until now and we are not through it yet!

2014-08-26

The last drill core is up!

Everything happened very quickly during the last days. The drill bit lasted for 290 m until all “good” drill pipes were in the drill hole and the drill rig was at the edge of its capacity under the present technical circumstances. End of drilling. Total Drillers depth of COSC-1 is 2495.8 m. The thrust zone has an unexpected thickness and, thus, hasn’t been penetrated completely.