Geology and Geochemistry of the 25 Ma Underdown Caldera Tuffs and the Tuff of Clipper Gap, Western Nevada Volcanic Field, North-Central Nevada
Bibliographic record
Abstract
The Underdown Caldera Complex is a 25.0 Ma caldera in the Western Nevada Volcanic Field formed during the mid-Cenozoic Ignimbrite Flare-up, one of the largest expressions of continental volcanism in geological time.Intracaldera and associated outflow tuffs are characteristically crystal-poor, except for one crystal-rich intracaldera tuff representing a later stage of explosive volcanism.Outflow tuffs extend to the east and west of the caldera, representing multiple phases of intracaldera tuffs.Postdeposition alteration of ignimbrites has altered Sr isotopic ratios, and caused rare earth element enrichment in the Tuff of Clipper Gap.Sr and Nd isotopic compositions of the ignimbrites show a relation to lavas collected from the margins of the caldera, and trace element ratios suggest similar origins of the lavas and ignimbrites from a mixture of mantle and crustal sources.Pb isotopes plot on mixing lines formed by a mantle-derived source and either a local sedimentary or granitoid unit.iii Acknowledgements Firstly, I would like to acknowledge my supervisor, Brian Cousens, for giving me a wonderful opportunity to learn research skills with an interesting project in an exciting field environment.Without your guidance and support, this thesis would not have been possible.I would like to thank Dr. Christopher Henry for his invaluable
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 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".