Test Bed Areas

The goal of the SedDB project is to ultimately serve to the scientific community the global geochemical data set for marine sediments in a manner similar to the existing igneous databases. Compilation of an all-inclusive legacy data set was recommended with high priority by the LISMTG Workshop. In the project's initial pilot phase I, SedDB will focus on comprehensive data collection for a few important current subject areas and regions of interest to diverse groups of geoscientists. By proving the utility in these subject areas, we believe that we can verify our ability to generate a product that will be serving the research communities involved in these regions and make others want us to accommodate them. With these testbed data sets we will test the functionality of the database structure, the user interface, and the analytical tools.

We will initially focus our efforts on three key geographic areas:

• Equatorial Pacific
• Central America
• Izu-Bonin-Marianas

These geographic areas are linked to each other by plate tectonics. Simplistically put, material deposited on the western side of the EPR eventually is subducted in the far western Pacific, and material deposited on the eastern side of the EPR eventually is subducted beneath Central America. On their journey, the seafloor passes beneath different components of the equatorial upwelling system, and thus receives the biogenic sediment raining to the seafloor. Thus, scientists on ODP Leg 185 (such as Murray and Co-Chiefs Plank and Ludden), trying to develop an understanding of Subduction Factory budgets in the western Pacific, have been working on comparing the chemistry of the modern equatorial Pacific to that of the carbonate-chert rocks of Jurassic to early Cretaceous age in the materials recovered by Legs 129 and 185. Similarly, there are many geochemical studies unknown to the igneous community that target the paleoceanography of these regions, but which include data that is likely to be of wide interest to the MARGINS community for reasons relating to geochemical mass balances in the Subduction Factory.

The central and eastern equatorial Pacific Ocean.
This region is of profound importance to the ocean-climate system and is the site of diverse and integrated research efforts. Since the earliest days of modern sedimentary geochemistry, this region has served as a springboard due to it being one of the first areas where the link between biologic productivity within the zone of equatorial upwelling and climate was documented [ARR01, GLDB01, also see review by Murray [MUR01] and refs. therein]. Large-scale scientific initiatives targeting geochemical processes have occurred in the region throughout the 1970's to the 2000's, including MANOP, JGOFS, and several DSDP/ODP drilling legs (e.g.all or significant parts of Legs 54, 85, 92, 138, 199, 201, 206, plus others). Along with the opal-rich Southern Ocean, the carbonate-rich equatorial Pacific is one of the two most important biogenic regimes in the oceans. As such, virtually all sedimentary matrices are found there (carbonate and siliceous ooze, all forms of clay, metalliferous sediments, Mn-nodules and crusts, phosphates, porewaters). The region is also ideal to target as it serves as a "tectonic feeder" of material into the other target areas, which are the focus areas of the MARGINS Subduction Factory Program.

Central American Arc & Izu-Bonin-Marianas
These initial planned targets are the MARGINS Subduction Factory focus areas, the Central America (CA) and the Izu-Bonin-Marianas (IBM) arcs. The fact that there is currently a large interdisciplinary and integrative NSF program in these regions with a broad mandate to advance the understanding of fundamental aspects of mass and energy transfer in subduction zones means that there will be a hungry group of consumers for all relevant geochemical data. By our count the MARGINS website lists 18 Subduction Factory funded grants and 10 grants since 1999 from other programs on the geochemistry of the CA and IBM focus sites, including some of the youngest and oldest seafloor being subducted today. Moreover, there are easily over 30 ODP/DSDP sites that can be related to the CA arc and more than 20 that can be associated with IBM, plus numerous other non-ODP/DSDP core sites. At the same time we recognize that PI's are working on convergent margins around the globe. As much as resources allow, we plan to opportunistically populate the database with data relevant to other arcs, initially with data tables that are electronically accessible from individual PIs and archives such as PANGAEA, NGDC, or ODP's data reports, and then by going through the literature focusing on individual arcs.