Where did the materials that make up the Earth and moon come from—and when did they arrive? Most scientific models contend the Earth formed gradually by addition from an assortment of moon- to ...

A new series of measurements of oxygen isotopes provides increasing evidence that the moon formed from the collision of the Earth with another large, planet-sized astronomical body, around 4.5 billion ...

1. The use of stable isotopic techniques to study animal diets and trophic levels requires a priori estimates of discrimination factors (Δ13C and Δ15N, also called fractionation factors), which are ...

1. Ten years ago Gannes et al (1997, Stable isotopes in animal ecology:assumptions, caveats, and a call for laboratory experiments. Ecology, 78,1271-1276,1998) identified four major areas requiring ...