Heterogeneous enriched geochemical compositions in Hawaiian lavas: Contributions from recycled continental materials in the Loa source of the Hawaiian plume
Bibliographic record
Abstract
Several mantle plumes (Hawai‘i, Kerguelen, Pitcairn) produce ocean island basalt with enriched mantle I (EM-I) geochemical compositions. Hawai‘i is the most vigorous of these plumes, with the highest buoyancy flux. The isotopically enriched, EM-I-like compositions measured along the Hawaiian Island chain are limited to the Ko‘olau, Lāna‘i, and Kaho‘olawe volcanoes, which form the Enriched Loa geochemical group. A total of 37 new samples from seven locations across the Wai‘anae and Ko‘olau volcanoes (O‘ahu, Hawai‘i) were analysed for major element oxides, trace element concentrations, and Pb-Sr-Nd-Hf isotopic compositions to determine the composition and spatial distribution of Enriched Loa compositions along the Hawaiian chain. Combined with data from Lāna‘i and Kaho‘olawe, and a compilation of shield stage Hawaiian data spanning ∼6 Ma, this study shows that Enriched Loa compositions are chemically heterogeneous and that the Enriched Loa component was present intermittently along the Hawaiian chain over approximately 130 km and 1.4 Ma. The statistically distinct Pb-Sr-Nd-Hf isotopic means between the Makapu‘u stage of Ko‘olau, Lāna‘i, and Kaho‘olawe suggest that the Enriched Loa geochemical group consists of two different heterogeneities and implies that enriched components in the deep mantle source of the Hawaiian plume exist at multiple physical scales. The geochemical features of the Enriched Loa volcanoes require a distinct mantle component, with a source that likely contains recycled surface materials, possibly of continental origin, stored in the Pacific large low shear velocity province (LLSVP). Enriched Loa isotopic compositions share similarities with other EM-I ocean island basalt; however, they are not as radiogenic in 87 Sr/ 86 Sr as compositions from Kerguelen and Pitcairn. This suggests that the materials stored in the Pacific and African LLSVPs have slightly different sources and ages. Specifically, this work supports the hypothesis that the recycled surface materials from the Pacific LLSVP are younger than those from the African LLSVP.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".