Shanan E. Peters and Dylan P. Loss, Dept. of Geoscience, University of Wisconsin, Madison, Wisconsin 53706, USA. Posted online ahead of print 10 April 2012; doi: 10.1130/G32791.1.
Wind-generated surface waves are an important mechanism for coastal erosion and the redistribution of sediment on shallow marine shelves and are commonly portrayed as comprising two distinct size classes: fair-weather waves and larger storm waves. Here, Shanan E. Peters and Dylan P. Loss combine more than two million observations of wave sizes taken over 12 years from 32 NOAA buoys located in the Caribbean, the Gulf of Mexico, and the western Atlantic to characterize wave sizes in the modern ocean. They find no evidence for two distinct types of waves subdivided by wave size. Instead, there is evidence for significant geographic variability in wave size, with locations in the relatively protected Gulf of Mexico and Caribbean regions having waves about 50 m smaller in wavelength than locations in the western Atlantic. Time-integrated estimates of wave size provide empirical constraints on the paleo-water depths of ancient sedimentary deposits and highlight differences between sheltered shelf environments, such as those that characterized many ancient seas, and open-ocean-facing, narrow continental shelves, such as those that predominate today.
Oxygen isotopic evidence for Late Triassic monsoonal upwelling in the northwestern Tethys
M. Rigo et al., Dept. of Geosciences, University of Padova, Via Gradenigo 6, 35131 Padua, Italy. Posted online 10 April 2012; doi: 10.1130/G32792.1.
M. Rigo and colleagues use the oxygen isotopic composition of conodonts from the Sicani Basin (Sicily, Italy), on the northwestern Tethys margin, to reconstruct regional paleo-seawater conditions. Values determined by sensitive high-resolution ion microprobe (SHRIMP II) are consistent with previously published data from the contemp
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Geological Society of America