Radiocarbon content, sedimentation rates, and a time scale for core CL-73-4 from Clear Lake, California

1988 ◽  
pp. 151-160 ◽  
Author(s):  
Stephen W. Robinson ◽  
David P. Adam ◽  
John D. Sims
Keyword(s):  
Time Scale ◽  
Sedimentation Rates ◽  
Clear Lake

Geologic Time

2021 ◽  
pp. 47-68
Author(s):  
Elisabeth Ervin-Blankenheim
Keyword(s):  
Time Scale ◽  
Sedimentation Rates ◽  
Charles Lyell ◽  
Geologic Time ◽  
The Bible ◽  
The Earth ◽  
Time To Build ◽  
Over Time

The time scale of geology—the first overarching precept in geology—and its development are the focus of this chapter. How did geologists determine the great age of the Earth through the spatial nature of geologic units and changes in fossils over time? There was no guidebook to the process of unraveling the Earth’s biography, and the discoveries proceeded step by step using observation and the development of hypotheses. Scientists such as Abraham Werner established principles to place rocks in order relative to one another, providing the beginning of understanding strata, their composition, sources, and life within them. Early estimates of the age of the Earth were on the order of thousands of years, carefully calculated based on the generations in the Bible. However, geologists such as James Hutton and Charles Lyell realized that the probable age of the Earth was much greater by examining the time it would take for processes, like sedimentation rates for a layer of sand or mud to be deposited to occur. From these observations, they deduced it would take orders of magnitude more time to build up great masses of rock layers, and the time scale of geology was extended millions of years.

Geometric interpretation of time-scale dependent sedimentation rates

2018 ◽  
Vol 371 ◽  
pp. 32-40 ◽  
Author(s):  
Tore Aadland ◽  
Peter M. Sadler ◽  
William Helland-Hansen
Keyword(s):  
Time Scale ◽  
Geometric Interpretation ◽  
Sedimentation Rates

scholarly journals 14C and Other Parameters During the Younger Dryas Cold Phase

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Hans Oeschger ◽  
Max Welten ◽  
Ulrich Eicher ◽  
Markus Möll ◽  
Trudi Riesen ◽  
...  
Keyword(s):  
Pollen Analysis ◽  
Time Scale ◽  
Transition Period ◽  
Younger Dryas ◽  
Peat Bog ◽  
Sedimentation Rates ◽  
Climatic Period

Pollen analysis as well as 18O/16O results on lake marl show that the Younger Dryas climatic period, between about 11,000 and 10,300 bp, was the last vigorous cold phase of the Würm Glacial. Detailed 14C analyses from a peat bog near Wachseldorn (Switzerland) point to a 14C anomaly in this period. Further indication of a 14C anomaly is given by the observation that, during the Younger Dryas period, the sedimentation rates in several lakes apparently were higher than in adjacent periods; an explanation might be that the 14C time scale was compressed between 11,000 and 10,000 bp, ie, the atmospheric 14C/C ratio varied. If real, this suggested 14C variation would probably be connected to the climatic events during this transition period from Later Glacial to Postglacial.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

The E-ring: interactions with plasma and implications for its evolution

1984 ◽  
Vol 75 ◽  
pp. 599-602
Author(s):  
T.V. Johnson ◽  
G.E. Morfill ◽  
E. Grun
Keyword(s):  
Time Scale ◽  
Particle Density ◽  
High Energy ◽  
Particle Removal ◽  
Density Region ◽  
Drag Forces ◽  
Orbit Evolution ◽  
History Of ◽  
Ring Particle ◽  
Ring Material

A number of lines of evidence suggest that the particles making up the E-ring are small, on the order of a few microns or less in size (Terrile and Tokunaga, 1980, BAAS; Pang et al., 1982 Saturn meeting; Tucson, AZ). This suggests that a variety of electromagnetic and plasma affects may be important in considering the history of such particles. We have shown (Morfill et al., 1982, J. Geophys. Res., in press) that plasma drags forces from the corotating plasma will rapidly evolve E-ring particle orbits to increasing distance from Saturn until a point is reached where radiation drag forces acting to decrease orbital radius balance this outward acceleration. This occurs at approximately Rhea's orbit, although the exact value is subject to many uncertainties. The time scale for plasma drag to move particles from Enceladus' orbit to the outer E-ring is ~104yr. A variety of effects also act to remove particles, primarily sputtering by both high energy charged particles (Cheng et al., 1982, J. Geophys. Res., in press) and corotating plasma (Morfill et al., 1982). The time scale for sputtering away one micron particles is also short, 102 - 10 yrs. Thus the detailed particle density profile in the E-ring is set by a competition between orbit evolution and particle removal. The high density region near Enceladus' orbit may result from the sputtering yeild of corotating ions being less than unity at this radius (e.g. Eviatar et al., 1982, Saturn meeting). In any case, an active source of E-ring material is required if the feature is not very ephemeral - Enceladus itself, with its geologically recent surface, appears still to be the best candidate for the ultimate source of E-ring material.

The long-term instability of the new generation hydrogen masers

2020 ◽  
pp. 35-38
Author(s):  
S.I. Donchenko ◽  
I.Y. Blinov ◽  
I.B. Norets ◽  
Y.F. Smirnov ◽  
A.A. Belyaev ◽  
...  
Keyword(s):  
Time Scale ◽  
Frequency Difference ◽  
Clock Frequency ◽  
Quantum Frequency ◽  
Frequency Standards ◽  
Quantum Frequency Standards ◽  
New Generation ◽  
Atomic Time

The latest changes in the algorithm for the formation of the international atomic time scale TAI are reported in terms of estimating the weights of the clocks involved in the formation of TAI. Studies of the characteristics of the long-term instability of new-generation hydrogen masers based on processing the results of the clock frequency difference with respect to TAI are performed. It has been confirmed that at present, new-generation hydrogen masers show significantly less long-term instability in comparison with quantum frequency standards ofsimilar and other types.

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