Retrieving "Plume Head Analysis" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Mantle Dynamics

   Linked via "plume head analysis"

   Isotopic Signatures
   Isotopes of highly incompatible elements are used to trace source reservoirs, particularly in plume head analysis. The $\text{He}/^4\text{He}$ ratio, derived from primordial noble gases trapped during mantle extraction, provides insight into deep, poorly mixed regions. For instance, mantle sources exhibiting $\text{He}/^4\text{He}$ ratios greater than $15 \text{ R}a$ (where $\text{R}a$ is the atmospheric ratio) are termed **[Hadean Excess Signatures (HES)](/entries/hadean-excess-signatur…