pioneering use of oxygen isotope ratios in paleoclimate studies
development of marine isotope stage stratigraphy
establishing the link between Milankovitch cycles and ice ages
Shackleton, N.J., & Opdyke, N.D. (1973). Oxygen isotope and palaeomagnetic stratigraphy of equatorial Pacific core V28-238: Oxygen isotope temperatures and ice volumes on a 10^5 year and 10^6 year scale. Quaternary Research.
Shackleton, N.J. (1967). Oxygen isotope analyses and Pleistocene temperatures re-assessed. Nature.