Geoscience Reports --- No. 21, Fall 1996

GEOSCIENCE REPORTS — Number 21, Fall 1996

p.1 • Radioisotope Age, Part II — Genesis and Time: What Radiometric Dating Tells Us • C. L. Webster, Jr.
p.7 • Editor's Angle
p.7 • Scattered Notes from the Scientific Literature - Biology, Geology
p.8 • Our Solar System • C. L. Webster, Jr.

EDITOR'S ANGLE

Many thanks are due to Drs. Clyde Webster and Humberto Rasi (editor of Dialogue) for the very extensive article on radiometric dating. This second article in our series answers a few more questions for us but again, does not address all of the problems. Dr. Webster's emphasis on a faith-based approach to scientific research is shared by the staff at the Geoscience Research Institute.
As a sedimentologist, I have been especially intrigued by the research documenting the link between grain size and loss of daughter product from the samples. This is the kind of question we need to be asking the data: what are the factors or systematic processes that could contribute to contamination of the sample? In the past we have focused our questions on factors that might impact the nuclear decay rates. Perhaps issues in magma systems and sedimentology will be a more fruitful area of inquiry.

SCATTERED NOTES FROM THE SCIENTIFIC LITERATURE

BIOLOGY

Palmer JD. 1996. Time, tide and the living clocks of marine organisms. American Scientist 84:570-578.

Research over the past decade has proposed that the tidal clock in many marine organisms has a period of 24.8 hours (a lunar day), slightly longer than the solar clock. Palmer suggests that there is a single clock that governs the solar and tidal rhythms, because "... it is difficult to believe natural selection would be so profligate as to build two clocks that ran at nearly the same rate." He supports this conclusion by observing that the clocks fail in the laboratory in the same way; however, the day-night cycles that set the solar rhythms do not affect the tidal cycles, and no other governing mechanism was proposed. Instead, Palmer suggests "the mechanism that adjusts the clock to environmental cycles is separate from the timekeeping mechanism." It seems biological clocks become ever more complex in even the simplest organisms.

GEOLOGY

Wessel P, Kroenke LW, Bercovici D. 1996. Pacific Plate motion and undulations in gelid and bathymetry. Earth and Planetary Science Letters 140(1-4):53-66.

By using radiometric dates from volcanic ridges associated with prominent gravity lineations within troughs, researchers correlated ridge formation with documented changes in Pacific and Indo/Australian Plate motion. This response seems to be due to aperiodic plate boundary stress rather than small-scale convection or diffuse extension. Standard rates for plate movement are being questioned in this recent study and represent a slight movement away from the slow, gradual processes previously implied by the conventional mechanisms for plate tectonics.

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