Related Experiment Video
Updated: Jul 19, 2026

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses
Published on: October 21, 2016
The 100,000-year ice-Age cycle identified and found to lag temperature, carbon dioxide, and orbital eccentricity
1Department of Earth Sciences, Godwin Laboratory, University of Cambridge, Pembroke Street, Cambridge CB2 3SA, UK. E-mail: njs5@cam. ac.uk.
Abstract:
The deep-sea sediment oxygen isotopic composition (delta(18)O) record is dominated by a 100,000-year cyclicity that is universally interpreted as the main ice-age rhythm. Here, the ice volume component of this delta(18)O signal was extracted by using the record of delta(18)O in atmospheric oxygen trapped in Antarctic ice at Vostok, precisely orbitally tuned. The benthic marine delta(18)O record is heavily contaminated by the effect of deep-water temperature variability, but by using the Vostok record, the delta(18)O signals of ice volume, deep-water temperature, and additional processes affecting air delta(18)O (that is, a varying Dole effect) were separated. At the 100,000-year period, atmospheric carbon dioxide, Vostok air temperature, and deep-water temperature are in phase with orbital eccentricity, whereas ice volume lags these three variables. Hence, the 100,000-year cycle does not arise from ice sheet dynamics; instead, it is probably the response of the global carbon cycle that generates the eccentricity signal by causing changes in atmospheric carbon dioxide concentration.
Related Concept Videos
The Carbon Cycle
Global Climate Change
Conditions on Early Earth
The Fossil Record
Radioactive Decay and Radiometric Dating
Microbes and Climate Change

