MARUM-MeBo70 drilling results

A wide range of different types of geologie are common at the deep sea. Nannofossil oozes and mud, gas hydrate bearing sediments, carbonates, massive sulfide ore deposits, volcanic rocks as well as metamorphic rocks can be found. Most of these geologies already were drilled with the MARUM-MeBo70.

Gas hydrates

Expedition M84-2a, Black Sea: Gas hydrates are stable at high pressure and low temperature conditions. These massive gas hydrates drilled in the eastern black sea contain not only methane but also long-chained hydrocarbons

Expedition GMMB, eastern tropical Atlantic: MARUM-MeBo70 was used to investigate the gas hydrate distribution in a pockmark field. Gas hydrates are dissociating at low pressure and high temperatures. Soupy sediments (a) are indicative for melted gashydrates occuring dispersed in a matrix of hemipelagic sediments. High amounts of dissolved gas were responsible for cracks (b) that form due to degassing during the recovery of the drill rig. In contrast sediments containing only little amount of gas showed a homogenous texture (c).

Hemipelagic sediments

Expedition SO211, off Chile: The MARUM-MeBo70 is very effective in collecting high quality cores from cohesive sediments. This is an example drilled off Chile showing a layer of volcanic ashes (grey/red) in hemipelagic sediments (greenish). The sharp contact at the base of the ash layer and bioturbation structures (burrows filled with greenish sediment in a matrix of red ash) on top show that sedimentary structures are preserved during the drilling process.

Rocks

Expedition CE0619, off Ireland: , Orthogneiss (upper left), paragneiss (lower left) and conglomerates were drilled offshore Ireland for for the Irish Shelf Petrol Studies Group (ISPSG) of the Irish Petroleum Infrastructure Programme Group 4. The big advantage of sea bed drill rigs compared to drill ships are, that they drill from a stable platform at the sea bed. The drilling process isn't affected by waves or currents which allows optimal control on weight on bit.