Scientific Program M67-2

In the southern part of the Gulf of Mexico (GOM) so called asphalt volcanoes have been discovered during a short cruise of R/V SONNE 174 in 2003. These asphalt volca-noes are the main focus of the leg M 67/2.
Twenty-two morphological highs (knolls) have been mapped in the Campeche Bay off Mexico at water depth of more than 3000m. They are connected to salt diapirism. Yet unknown processes have shaped the mor-phology of the knolls, which have crater-like structures and show signs of mass wasting processes. Towed TV-sled observations at two knolls revealed evidence for lava-like asphalt flows with different generations of flows and chemosynthetic communities. The origin and processes leading to these as-phalts at the seafloor can not be explained by any of the known mechanisms leading to fluid seepage, i.e. mud volcanism or diapir-ism. During leg M 67/2 selected knolls will be mapped by high-resolution multichannel seismic and DTS sidescan sonar.
A portcall in Tampico / Mexico will be used for the exchange of cruise participants and for the setup of the remotely operated vehi-cle (ROV) QUEST. The investigation of the asphalt volcanism takes place in a collaborative action between Germany, Mexico (Prof. Dr. Elva Escobar Briones, UNAM) and the USA (Prof. Dr. Ian MacDonald, TAMU). In order to promote the fruitful tri-lateral collaboration a press conference and a reception on board are planned.

Fig. High-resolution bathymetry obtained with during cruise SO 174-2. Overview map (left) and detail map (right) of the northern Campeche Knolls. The knolls are numbered according to the geographic position of their highest summits. The locations of oil slicks at the sea surface are indicated as dots. Those were detected by RADASAT-Satellite pictures and indicate that oil seepage occur at most knolls.