50 Years of Ocean Discovery National Science Foundation 1950-2000 (2000) / Chapter Skim
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The Future of Marine Geology and Geophysics: A Summary
The Future of Marine Geology and Geophysics: A Summary
Pages 172-183
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From page 172... ...
Some common issues that appeared in several of the reports are: · The societal imperative of making rapid progress in scientific understanding of complicated, nonlinear systems. Many of the research topics central to marine geology and geophysics address issues of societal concern, such as changing climate, coastal pollution and erosion, and earthquake hazards.
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From page 173... ...
Variations in sea level shift the shoreline position laterally for distances of kilometers over timescales of millennia. Ice core data from subaerial drilling can complement deep sea cores.
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From page 174... ...
Each aspect of the plate tectonic cycle has a host of scientific questions that remain to be answered. These questions naturally divide according to the diverse provinces of the cycle extending from creation of crust at ridges, to the mid-plate region, to the convergent margin.
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From page 175... ...
| ~l | ~D and hut tom ~ - ~ L \~ | ~10- PLAN PROCESSES | ~ - ~ Lk~. Imp - ~ `~ ~P~' 1 T | CHUSTAL AND MANTLE I ~ 175 FIGURE 2 Schematic of the solid Earth cycle, beginning with rifting of ancient lithosphere, through creation of a new ocean basin by seafloor spreading, plate modification during passage over the mantle, subduction and continental addition, and continental collision, followed ultimately by another episode of continental rifting.
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From page 176... ...
ice core isotope paleothermometers appear to have understated glacial cooling at high latitudes by a factor of two; (d) transitions between glacial and interglacial states can occur in only a few decades, and (e)
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From page 177... ...
Investigations of sediments at the ocean margin range widely in both the time scales of the processes considered and in the spatial scales of the resulting morphologies or stratigraphic record. One investigator might obtain measurements of orbital velocities under waves in the nearshore, and relate those to the resulting transport rates of sediments or to the dimensions of ripple marks formed on the bed.
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From page 178... ...
For instance, investigations of sediment-transport processes focus on the time scales of waves and currents and down to the scale of turbulent fluctuations, while considering the movement of sediment grains and the effects of sand ripples on that transport. Other investigators document the response of beach morphology to the occurrence of storms, or the formation and migration of sand waves on the continental shelf where sediment transport is due to tidal currents.
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From page 179... ...
Some sectors, such as the extremely populated Nile Delta and portions of the Mississippi Delta, are currently in a state of crisis in the wake of severe coastal erosion. The megalopolis of Bangkok is sinking at an alarming rate of one meter in a human lifetime due to a combination of diminished sediment supply and aquifer depletion.
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From page 180... ...
While there will be some short-term costs associated with development of a reliable instrument pool that will be available to the community, in the long run, a costeffective solution to the problem of deteriorating and unreliable facilities is essential to the health of marine geosciences. The list of equipment that might be candidates for a shared pool is large: MCS equipment, ocean bottom seismometers, new-generation magnetometers and gravimeters, coring and sampling devices, autonomous underwater vehicles, tethered vehicles, submersibles, etc.
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From page 181... ...
The solid Earth group also needs sampling capability into older oceanic crust that may eventually require riser capability for deeper sampling. Subduction zone problems require standard ODP capability for flux balance experiments, and riser capability for investigations of the seismogenic aspects of subduction zone systems.
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From page 182... ...
WO RKS H O P PARTI C I PANT Ll ST 1. Solid Earth Continental Margins Dixon, Jacqueline (Univ.
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From page 183... ...
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