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Published August 15, 2000 | Draft + Published
Journal Article Open

The Statistics of Helium Isotopes Along the Global Spreading Ridge System and the Central Limit Theorem


An unbiased estimate of the arithmetic mean of the ^3He/^4He ratio (R) of basalts from the global spreading ridge system is 9.14 ± 3.59 Ra (n=503), where Ra is the atmospheric ratio and n is the number of data points. The ± two standard deviation (2σ) range covers much of the oceanic island and continental flood basalt data that have been attributed to 'plume' or 'lower mantle' components. The highest R values along the ridge system are associated with new ridges, backarc basins and near‐ridge seamounts. Low values are associated with long‐lived or abandoned ridges. The median, a more robust measure of the average, is 8.51 Ra.

Additional Information

© 2000 American Geophysical Union. Received 6 December 1999; accepted 18 May 2000. David Graham provided insightful reviews of the manuscript and also kindly provided the results of his statistical studies. This paper represents Contribution Number 8701, Division of Geological and Planetary Sciences, California Institute of Technology. This work has been supported by NSF Grant EAR 9726252.

Attached Files

Published - 1999GL008476.pdf

Draft - stats_of_He_Iso.pdf


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August 19, 2023
October 19, 2023