The data presented in this report demonstrate significant improvements
in the ability to constrain trace element and Sr isotopic
concentrations in sediments overlying ridge-flank hydrothermal
systems. Improved sampling methods orchestrated by the Integrated
Ocean Drilling Program (i.e., advanced piston coring and
anoxic sample processing) enabled the collection of reactive pore...
High resolution, continuous records of GRAPE wet bulk density (a carbonate proxy) from Ocean Drilling Program Leg 138
provide one the opportunity for a detailed study of eastern equatorial Pacific Ocean carbonate sedimentation during the last 6 m.y.
The transect of sites drilled spans both latitude and longitude in the...
A stable-isotope stratigraphy at Site 846 (tropical Pacific, 3°06'S, 90°49'W, 3307 m water depth), based on the benthic
foraminifers Cibicides wuellerstorfi and Uvigerina peregrina, yields a high-resolution record of deep-sea δ¹⁸O and δ¹³C over the
past 1.8 Ma, with an average sampling interval of 3 k.y. Variance in the δ¹⁸O...
Establishing true depths of recovered sediments is critical to determining sedimentation rates for high-resolution paleoclimatic
studies. We have corrected the composite depth scale, which accounts for the entire continuous sedimentary sequence, so that sediment
depths are consistent with logging depths, or "true" depths. We accomplished this by taking advantage of...
Wildfires pose complex challenges to policymakers and fire agencies. Fuel break networks and area-wide fuel treatments are risk-management options to reduce losses from large fires. Two fuel management scenarios covering 3% of the fire-prone Algarve region of Portugal and differing in the intensity of treatment in 120-m wide fuel breaks...
The subduction of the oceanic spreading center at the Chile Triple Junction is marked by a substantial thermal perturbation
and marked changes in the hydrogeologic and aqueous geochemical regimes in the overthrust plate. Ridge subduction substantially
changes the fluid chemistry in the wedge through variably hydrating the oceanic basement, accretionary...
The isotopic compositions of interstitial waters collected from Hydrate
Ridge during Ocean Drilling Program Leg 204 were measured to
evaluate the fluid evolution of this accretionary prism. At shallow
depths, the dissolved Cl- concentrations and δD and δ¹⁸O values of the
interstitial water reflect changes in the salinity and the...
During ODP Leg 138, we tested a prototype instrument, developed
at Oregon State University, for measuring light reflectance in 511
channels of the visible and near-infrared bands. The technique of
reflectance spectroscopy has been used for some time in chemistry
and mineralogy (e.g., Hunt, 1977; Gaffey, 1986) and has found...
Ocean Drilling Program (ODP) Leg 138 was designed to study the late Neogene paleoceanography of the equatorial Pacific Ocean at time scales of thousands to millions of years. Crucial to this objective was the acquisition of continuous, high-resolution sedimentary records. It is well known that between successive advanced piston corer...
Carbonate nodules and associated sediments from Ocean Drilling Program Leg 139 sites of the Middle Valley, Juan de Fuca Ridge, were studied using a combination of inorganic and organic geochemical techniques. The mineralogy and stable isotopic compositions defined three types of nodules, reflecting the conditions of carbonate precipitation. Nodule ingrowth...