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Radiocarbon ages of pre-bomb clams and the hard-water effect in Lakes Michigan and Huron Radiocarbon ages of pre-bomb clams and the hard-water effect in Lakes Michigan and Huron

Five radiocarbon ages, all determined by accelerator mass spectrometry, have been obtained for two pre-bomb bivalves from Lake Michigan and one from Lake Huron. After correcting those ages for the fractionation of14C in calcite and for the radioactively inert CO2 in the atmosphere, we find residual ages, caused by the hard water effect, of about 250 years for Lake Michigan and 440 years...
Authors
David K. Rea, Steven M. Colman

Paleocene to Middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: biostratigraphy, allostratigraphy, and sequence stratigraphy Paleocene to Middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: biostratigraphy, allostratigraphy, and sequence stratigraphy

The Paleocene to Middle Miocene sedimentary fill of the southwestern Salisbury Embayment contains a fragmental depositional record, interrupted by numerous local diastems and regional unconformities. Using planktic foraminiferal biostratigraphy, 15 unconformity-bounded depositional units have been identified, assigned to six formations and seven alloformations previously recognized in...
Authors
C. W. Poag, J.A. Commeau

Silt fraction heavy-mineral distributions in a lateritic environment: The rivers and insular shelf of north-central Puerto Rico Silt fraction heavy-mineral distributions in a lateritic environment: The rivers and insular shelf of north-central Puerto Rico

This fraction, which is enriched in heavy minerals relative to the sand fraction, is mainly detrital but contains a strong authigenic component. The authigenic silt heavy-mineral fraction is largely a product of the lateritic weathering and dominated by iron oxides and alterites. Grains of bladed rutile and leached ilmenite are common. Spatial variability in silt-fraction mineralogy is
Authors
L. J. Poppe, J.A. Commeau, G. Luepke

Stratigraphy and paleoenvironments of the Shell 410-1 well, Georges Bank Basin, US North Atlantic outer continental shelf Stratigraphy and paleoenvironments of the Shell 410-1 well, Georges Bank Basin, US North Atlantic outer continental shelf

The Shell 410-1 well is the most downdip (seaward) hydrocarbon exploratory well in the Georges Bank Basin. It was drilled to a total depth of 4745 m RKB, and penetrated a section composed of Middle Jurassic to Quaternary sedimentary rocks. The lithostratigraphy of the section is described. The strata penetrated by the Shell 410-1 well are more marine than rocks at the updip (landward)...
Authors
L. J. Poppe, C. W. Poag, B.A. Swift

Continental climate response to orbital forcing from biogenic silica records in Lake Baikal Continental climate response to orbital forcing from biogenic silica records in Lake Baikal

CHANGES in insolation caused by periodic changes in the Earth's orbital parameters provide the primary forcing for global ice ages1-6. But it is not clear to what extent the climates in continental interiors are controlled directly by regional variations in insolation and to what extent they are driven instead by the highly nonlinear response of the oceans and ice sheets. Here we...
Authors
Steven M. Colman, J.A. Peck, E.B. Karabanov, Susan J. Carter, J.P. Bradbury, J.W. King, D. F. Williams

Extending and expanding the life of older current meters Extending and expanding the life of older current meters

The EG&G Model 610 VACM and Model 630 VMCM are standards for ocean current measurements. It is simple to add peripheral sensors to the data stream of the VACM by use of add-on CMOS circuitry. The firmware control of the VMCM makes it virtually impossible to add sampling of additional sensors. Most of the electronic components used in the VACM are obsolete or difficult to replace and the...
Authors
W.J. Strahle, Marinna A. Martini

Large wave at Daytona Beach, Florida, explained as a squall-line surge Large wave at Daytona Beach, Florida, explained as a squall-line surge

On a clear calm evening during July 1992, an anomalously large wave, reportedly 6 m high struck the Daytona Beach, Florida area. It is hypothesized that a squall line and associated pressure jump, travelling at the speed of a free gravity wave, coupled resonantly with the sea surface forming the large wave or "squall-line surge'. The wave was forced along the length of the squall line...
Authors
A. H. Sallenger, J. H. List, G. Gelfenbaum, R. P. Stumpf, M. Hansen

Influence of fluoride on aluminum toxicity to Atlantic salmon (Salmo salar) Influence of fluoride on aluminum toxicity to Atlantic salmon (Salmo salar)

Atlantic salmon (Salmo salar) alevins were exposed to various aluminum (0–4700 μg/L) and four fluoride (0–500 μg/L) concentrations at two pH values (5.5 and 6.5) for 4- and 30-d periods. In the 4-d tests, aluminum with fluoride was less toxic at pH 6.5 than at pH 5.5, whereas without fluoride, pH had no effect. In the 30-d test, mortality in all treatments was 17–21% at pH 5.5, but only...
Authors
Steven J. Hamilton, Terry A. Haines

Increased daylength stimulates plasma growth hormone and gill Na+, K+ and -ATPase Atlantic salmon (Salmo salar ) Increased daylength stimulates plasma growth hormone and gill Na+, K+ and -ATPase Atlantic salmon (Salmo salar )

Atlantic salmon juveniles reared at constant temperature (9–10°C) were exposed to four photoperiod treatment and sampled every 2 weeks from January through May. Fish reared under normal photoperiod exhibited eight-and three fold increases in plasma growth hormone and gill Na+, K+-ATPase activity, respectively, between January and April. Fish exposed to abrupt increases in daylength (LD...
Authors
S. D. McCormick, Bjorn Thrandur Bjornsson, M. Sheridan, C. Eilertson, J. B. Carey, M. O'Dea
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