Word: fossilizing
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...fuel too fast to sustain the reaction.) When the heat from this process became too intense, scientists believe, the water turned to steam, the neutrons speeded up, and the chain reaction halted until the uranium cooled sufficiently for the steam to condense back to water. Thus, Perrin believes, "the fossil pile at Oklo must have functioned intermittently, pulsating as it were...
...lefthanded molecules gradually become righthanded. Although it has long been known that the mirror-like reversal progresses steadily as time passes, a practical use for the phenomenon has now been suggested: it can be used as a geological "clock" to fill important gaps in the earth's fossil records...
...dating technique was conceived by Chemist Jeffrey Bada of the Scripps Institution of Oceanography while he was trying to date some fossil-laden sediment from the ocean floor. The standard method for determining the age of fossils is the so-called carbon 14 clock, which is based on the ratio of ordinary carbon atoms to atoms of the radioactive isotope carbon 14 found in the specimen. The carbon 14 atoms decay at a known rate and are not replenished after the creature dies; thus the proportion of ordinary carbon to carbon 14 slowly increases. But the carbon clock only works...
Bada decided amino acids might help open those pages. Using standard lab equipment, he found that it was an easy matter to measure the ratio of left-handed to righthanded molecules in a common amino acid called isoleucine, and he was able to estimate the age of fossils from that ratio. What is more, his tests required only a tiny sampling of material and could be completed in a few hours. There is one serious hitch, he reports in Earth and Planetary Science Letters. Because the rate at which amino acids change their configuration varies significantly with heat, the temperature...
...pointing feet of Wakefield's find "demonstrate," he says, "a stage intermediate between the backward paddle of the ancestral fish and the forward-pointing foot of a four-limbed animal." To help settle that old scientific question, Wakefield is hopeful of locating an even bigger prize: a complete fossil skeleton of the missing amphibian...