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The Source-to-Sink-New Zealand (S2S-NZ) Initiative will investigate the dispersal of sediment in the ocean today and in the past using a "nested approach" as shown below. First, geophysical data such as 3.5 kHz and Chirp seismic-reflection profiles will be collected to determine the vertical thickness of sedimentary layers over the study area. Additionally, we will use a tool known as a multibeam which measures the elevation of the seafloor in a region (or swath) below the ship as it steams over the sea. Together, these data can give an idea of the direction in which sediments move along the seafloor and areas where they may be accumulating. Also, they can place individual spots on the seafloor in a spatial context and will give a longer term perspective on the development of sediment strata. Observations from these data then will be verified by sampling sediments on the seafloor at specific locations. Quantitative measurement of sedimentary processes will be made by coring over a range of depth scales to sample sedimentary strata just recently deposited and emplaced millennia ago. The radioactivity of several isotopes ( Th-234, Be-7, Pb-210, Cs-137, C-14) will be measured in cores to measure rates of biological mixing, recent sediment deposition, and sediment accumulation over 100 years or longer. Additionally, ash layers related to volcanic eruptions from New Zealand volcanoes also will be identified as time markers for ancient events.
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