Marine Geophysics and Hydroacoustics

Seamount at the Canary Islands

Summary

M146 - Hesse HEnry Seamount Seepage Exploration

 

The aim of expedition M146 HESSE (HEn­ry Se­a­m­ount See­page Ex­plo­ra­ti­on) is Henry Seamount a 126 Ma old extinct volcano southeast of the Canary Island El Hierro in 3600 m water depth. Preliminary results of a Meteor cruise revealed that clam shells more living on sulfate bacteria and weathers rocks pointing to fluid escape and/or cold seeps on top of Henry seamount. 

A circulation such as hydro­ther­ma­l si­phon are present on thausends of seamounts around the globe but only a few have been detected so far. Hence, scientist of cruise M146 have mapped the seafloor in great detail by means of  bathymetric and water column mapping, sediment echosounder with special focus on the primary high frequency, and seismic methods. In addition a heat flow probe has been deployed along several profiles. In order to get a ultra high resolution bathymetry and backscatter map an Autonomous Underwater Vehicle (AUV) MARUM SEAL-5000 and a TV sledge was used.

Gruppenbild

Participants on M146 at the Equator in front of the Sparker.

the expedition finished at April 16th, 2018 in Las palmas de Gran Canaria. Scientist from the University of Bremen, MARUM, and the Institute of Geoscience worked well together and brought the cruise to a success.

more details at MARUM

Multichannel Seismic

Using a multichannel system, with a sparker as source and a GeoEel Digital Streamer we imaged internal strauctures and potential fluid escape zones within the subseafloor around Henry Seamount. Heatflow Profiles, carried out at the base of the seamount, were chosen based on our data.

Seismik

Seismic Cross section at Henry Seamount using a sparker as source.

The figure shows an example of a seismic cross section in the study area. In the NE side echos from Henry seamount are present. Due to its high topography we could not penetrate into it and its structure could not be imaged in detail. Another volcanic structure can be seen further to the SW of Henry Seamount. Well stratified sediments with different amplitudes and blanking was imaged here. In general blanking on seismic images point to the occurrence of fluids and/or gas in the subsurface.

Art at Sea

Aboard Meteor M146 was an art student. She connected human beings and the sea via drawing, film and audio sequences and interpreted it on her own way. 

Kunst auf See

Daria observed all section on board with her artistic eyes and converted scientific figures such as Parasound images in her own drawings. She also had an interview with the sea, asking questions that the crew gave her. Another highlight of her work was that the Sea got her silky dress on.

Daria

Daria Nazarenko, an art student of the Burg Gie­bi­chen­stein Kunst­hoch­schu­le Hal­le stayed on board during cruise M146 and will present her work in an expedition in autumn.

Responsible Person: Sebastian Krastel

Participants (Multichannel Seismics):

  • Rachel Barret
  • Phillip Held
  • Katja Lindhorst
  • Kai-Frederik Lenz
  • Heiko Jähmlich