volcanic vent
© GEOMAR Helmholtz Centre for Ocean Research Kiel
Germany's deep-sea research vessel Sonne is currently sailing in the Gulf of California in search of carbon release related to volcanic systems. Now scientists led by Professor Christian Berndt from the GEOMAR Helmholtz Centre for Ocean Research Kiel have discovered a previously unknown vent field with several black smokers. The field consists of at least four mounds up to 70 metres high.

Reliable climate forecasts are only possible if all the factors that affect the climate are known.


Comment: True.


It is therefore necessary to find out what caused global warmings in the past.


Comment: Uhm, isn't it therefore necessary to find out what's causing 'global warming' NOW??


One hypothesis is, for example, that increased volcanic activity during the widening of the North Atlantic triggered a rapid warming, the so-called Paleocene Eocene Thermal Maximum (PETM), 54 million years ago.

A research team from Germany, Mexico, Switzerland, Norway and Taiwan is currently conducting a cruise on the German vessel Sonne in the Guaymas Basin in the Gulf of California to test this hypothesis. The Guaymas Basin is thought to be in a similar state of rifting as the North Atlantic at the end of the Paleocene.


Major Discovery

While investigating the seafloor the team discovered a vent field with several black smokers of unusual size in an unexpected place. Christian Berndt, geophysicist at GEOMAR Helmholtz Centre for Ocean Research Kiel and chief scientist of cruise SO241, describes it as a major discovery, because it changes the current views on how carbon is emitted from sedimentary basins. This will have consequences for the assessment of the relevance of magmatic systems in the Earth system.


Comment: We're not holding our breath, but one day soon a scientist might figure out that all the greenhouse gases they go on about are being released from the planet itself.


During the opening of a new ocean there is a phase when the splitting of the continental crust unloads the hot mantle of the Earth so much that volcanism starts. The magmatic rocks intrude into the remaining sediments where they boil up the pore water and liberate large amounts of carbon that were buried along with the sediments. The carbon rich pore water then begins to migrate to the surface under its own buoyancy.


Comment: Forget 'origin myths' of how the continents came into their current form; vents open, and volcanoes erupt, on far smaller timescales, probably in tandem with human civilization.


Intense Global Warming

As such systems were widespread during the opening of the North Atlantic 54 million years ago it has been proposed that they were responsible for the intense global warming known today as PETM.


Comment: Hmm, they seem to be hinting at the obvious, but are über-cautious about spelling it out. So we'll do it for them: any 'heating up of the planet' that is being observed is coming from within the planet.


So far it was unclear how vigorous these systems were and what kind of carbon compounds they emitted. The Guaymas Basin in the Gulf of California might provide answers to these questions as it is now opening and the first volcanic intrusions into the basin have already occurred.

Based on regional seismic data and echo sounder data the team identified potential sites for fluid expulsion. These sites were then inspected more closely using the underwater robot HYBIS. Even on its first dive a new vent field was discovered which is characterised by the venting of hot fluids that immediately precipitate minerals when they mix with the cold seawater. The hot fluids are rich in methane that is injected high into the water column. The vent field is about 500 metres long and consists of at least four mounds up to 70m high.

Christian Hensen, a geochemist with GEOMAR, points out that the fluids carry a mixed signal of magmatic systems and sedimentary systems which is precisely what is expected from hydrothermal activity caused by sill intrusions. The magmatic origin is also indicated by high helium concentrations in the water column. The measurements were carried out by colleagues from the Swiss Institute of Water Research EAWAG.