One of the best studied sites on the Juan de Fuca Ridge, a mid-ocean ridge spreading center off the northwestern coast of the US, is the Endeavor Ridge Segment. This area has been extensively mapped and sampled over the last 10 years by the NSF-funded Ridge 2000 Program whose objective is to dramatically advance our understanding of mid-ocean ridge magmatic, seismic, hydrothermal, and biological systems, how they behave, and how they are linked together. The funded project focuses on correcting navigation errors in sample/feature locations and compiling data from NSF and non-NSF funded cruises and studies to create a high resolution, integrated map of geological and geochemical features/attributes. The juxtaposition of these disparate datasets will enable big-picture, integrated thinking about how these important volcanic systems operate, will allow comparison of this area with other parts of the globe-encircling mid-ocean ridge system, and will illuminate the processes that control volcanism and hydrothermal venting at mid-ocean ridges. Broader impacts of the work include support of graduate and undergraduate students, a postdoc, and a PI whose gender is under-represented in the sciences.
A bathymetric map of very high resolution (<1m) of a recently active volcanic area of the ocean floor west of Seattle was created mostly at no cost to NSF, and the locations of ~300 independently collected volcanic rocks were co-located on the bathymetry. Because all of the volcanic rocks have been chemically analyzed, and some of them dated, it is now possible to have for the sea floor something close to a geological map of an on-land active volcano. This is much harder to do for the sea floor because of the challenges in knowing accurately where the sampling tool (in this case an Autonomous Underwater Vehicle, AUV) actually was ± tens of meters when collecting and photographing the sample. Indeed, this is one of only a few such maps ever made. The map plus the chemical analyses of the co-located rocks show that there have been at least a dozen separate episodes of mantle melting, crustal storage, and surface eruption of separate magmas in the last few millenia. Individual magma chambers, therefore, are short-lived -- perhaps centuries old or less. Because this volcano supports many active hydrothermal systems, and is constantly monitored as an Ocean Observatory by Neptune Canada, the relationship of hydrothermalism, sesimicity. and deformation to the magma plumbing system and history can now be studied using the new maps. Other members of the Collaborative Research team will submit most of the maps and metadata to the appropriate repository.
