Potassium 40 dating rocks


The smooth floor of Yellowknife Bay is made up of a fine-grained sedimentary rock, or mudstone, that researchers think was deposited on the bed of an ancient Martian lake.In March, Curiosity drilled holes into the mudstone and collected powdered rock samples from two locations about three meters apart.That is probably the most remarkable thing I've ever seen as a scientist, given the difficulty of the analyses," Farley says.This also helps researchers looking for evidence of past life on Mars.So while the mudstone indicates the existence of an ancient lake—and a habitable environment some time in the planet's distant past—neither crater counting nor potassium-argon dating can directly determine exactly when this was.To provide an answer for how the geology of Yellowknife Bay has changed over time, Farley and his colleagues also designed an experiment using a method called surface exposure dating.



One reason is that mudstone is a sedimentary rock—formed in layers over a span of millions of years from material that eroded off of the crater walls—and thus the age of the sample drilled by Curiosity really represents the combined age of those bits and pieces.Although the potassium-argon method has been used to date rocks on Earth for many decades, these types of measurements require sophisticated lab equipment that could not easily be transported and used on another planet.Farley had the idea of performing the experiment on Mars using the SAM instrument.At 80 million years ago, wind would have caused this scarp to migrate across the surface and the rock below the scarp would have gone from being buried—and safe from cosmic rays—to exposed," Farley explains.

Geologists have developed a relatively well-understood model, called the scarp retreat model, to explain how this type of environment evolves.

Cosmic rays are known to degrade the organic molecules that may be telltale fossils of ancient life.



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  • Potassium-argon dating - The Free Dictionary profil de paulette60

    paulette60

    Define potassium-argon dating. potassium-argon dating synonyms, potassium-argon dating pronunciation, potassium-argon dating translation, English dictionary definition of potassium-argon. One technique, potassium-argon dating, determines the age of a rock sample by measuring how much argon gas it contains.…
  • New Zealand potassium-argon age list—1 - Taylor & Francis Online profil de paulette60

    paulette60

    Jul 28, 1971. The methods used at the Institute of Nuclear Sciences for the dating of rocks by the potassium argon technique are described. The potassium content of the rock is measured by flame photometry, the radiogenic argon content is determined by. 38Ar isotope dilution following vacuum extraction and the.…