From October 7 to October 26, the Mexican research ship EL Puma and its
international crew headed into the Gulf of California, to explore the thickly
sedimented ridge flanks of Guaymas Basin and the Sonora Margin. An extensive
seismic survey in combination with piston cores of selected seafloor sediments
characterized these locations in preparation for IODP drilling. The cruise was
organized and led by Dr. Carlos Mortera at UNAM’s Institute of Geophysics, who has
long maintained a deep interest in all aspects of the evolution of the Gulf of
California (center third row in the photo, with life vest and white hard hat); he
assembled a committed crew of UNAM Geophysics alumni and students for this
cruise. C-DEBI participants included microbiologists Andreas Teske (on the left, in
black C-DEBI “Mainly Microbe” T-shirt) and just-finished C-DEBI graduate Luke
McKay (in blue T-shirt, next to Carlos Mortera), both at the University of North
Carolina at Chapel Hill. The sedimentologists Ivano Aiello of Moss Landing Marine
Laboratory (oligotrichous, on the right), and Christina Ravelo of UC Santa Cruz (also
on the right, in “Painter’s signatures” T-Shirt, courtesy of Rijksmuseum Amsterdam)
represented the “Friends of C-DEBI” cruise contingent.
Carlos, Andreas, Ivano and Christina are also proponents on Guaymas Basin
IODP proposal No. 833. At its core, this proposal develops a plan to drill a sediment
transect across Guaymas Basin and its extensive ridge flanks, followed by a shorter
upslope transect into the Sonora Margin. The results obtained on this cruise will
characterize the locations that have been proposed for deep subsurface drilling. All
in all, 15 sediment cores were recovered and extensively sampled; they provide
unparalleled coverage from the northwestern and southeastern periphery of the
Guaymas Basin ridge flanks, from off-axis seep locations on the ridge flanks, and
from the compacted sediments at the base to the finely laminated sediments on top
of the Sonora Margin. The shallow subsurface cores of ca. 3-5 m length bridge the
uncharted depth interval between pushcore, boxcore and multicorer sampling of the
sediment surface layers, and recovery of deeper sediments in deep ocean drilling.
After the sampling campaign, RV El Puma headed back to its home port
Mazatlan, famous for its Pacific beaches and relaxed atmosphere, where the
successful cruise was celebrated in style. At present, all samples and travellers have
made it back intact to their home institutions in Mexico City, North Carolina and
California, and post-cruise work is beginning. The Guaymas samples will have
stories to tell!