John W. Valley

John Williams Valley (born February 28, 1948, in Winchester, Massachusetts) is an American geochemist and petrologist.

[9][5] Valley is an expert on stable isotope geochemistry applied to metamorphic, igneous and sedimentary rocks.

[1] He and his colleagues investigated the Sierra Nevada batholith,[10][11] lavas from Pacific islands,[12][13][14] and rhyolites from the Yellowstone Plateau Volcanic Field.

[15] Valley has studied numerous proxies for paleoclimate including speleothems,[16] mollusks,[17] foraminifera,[18] otoliths,[19] pearls,[20] and fossil teeth.

[22] Valley and others demonstrated that carbonates in the Martian meteorite ALH84001 formed at low temperatures,[23] and that material from the comet 81P/Wild is chondrule-like indicating transport from the asteroid belt to the cold outer reaches of the solar system.

In 2005, he founded the Wisconsin Secondary Ion Mass Spectrometry Laboratory (WiscSIMS)[27] to develop new methods for measuring stable isotopes in the nano to micrometer range.

Before graduate school, he made furniture in Helena, Montana, while there with Andrée, who was Resident Artist at the Archie Bray Foundation for the Ceramic Arts.

The Apex Chert is a flint-like rock from Western Australia, which contains some of the oldest known fossils. The microscopic fossils are single-celled bacteria , 3,500 million years old, and contain no nucleus (prokaryotes). They are either spherical or in filament-like chains. Chert typically consists of the petrified remains of siliceous ooze .