Benthic Foraminifera as Tools of Paleoceanography: Three Case Studies From the Late Cretaceous of the North Pacific Ocean and Western Interior Seaway, and the Miocene-Pleistocene of the Ross Sea, Antarctica
Bibliographic record
Abstract
This dissertation is a widespread compilation of research covering vastly different times and locations. Despite these differences, the use of foraminifera helps to unravel their geologic history, revealing the paleoenvironmental, paleoclimatic, and paleoceanographic conditions of each location. What unites each study is how water mass, food supply and oxygen concentration play a critical role on the microfossil assemblage. This dissertation is broken up into three unique chapters. Chapter 1 reexamines some old ideas of how benthic foraminifera can be used as water mass indicators. A 13-myr record from Shatsky Rise in the paleo-central Pacific Ocean contains several instances water mass changes driven by tectonism, gateway changes and possible glaciation towards the end of the Late Cretaceous (78 –66 Ma). Each of these water mass shifts correlates with distinct foraminiferal changes. Chapter 2 expands on research in the Western Interior Seaway (WIS) during the Late Cretaceous. An ocean anoxic event (OAE) is well-preserved throughout the seaway during a time of sea level rise at the Cenomanian–Turonian (~94 Ma). Extensive studies on foraminifera in the southern part of the seaway document the biotic effects of OAE2, but little is known to the far north. Billings, MT was in a unique position where it shared properties of the northern WIS in Canada at certain times but at other times took on a southern WIS characteristic. This is attributed to an oceanographic front that moved through the seaway as sea level rose and fell. Chapter 3 is a Miocene–Recent (~23 Ma) evaluation of benthic foraminifera in one of the most southern-drilled sites of Antarctica in the Ross Sea. This study utilizes microfossils to understand the history of the Ross Ice Shelf during times of global warmth. Recent foraminifera provide information of how warm water masses near the grounding line create conditions unique to the eastern Ross Sea.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.007 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".