Coated phosphate grains: Proxy for physical, chemical, and ecological changes in seawater
Bibliographic record
Abstract
Research Article| September 01, 2003 Coated phosphate grains: Proxy for physical, chemical, and ecological changes in seawater Peir K. Pufahl; Peir K. Pufahl 1Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada Search for other works by this author on: GSW Google Scholar Kurt A. Grimm Kurt A. Grimm 1Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Peir K. Pufahl 1Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada Kurt A. Grimm 1Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada Publisher: Geological Society of America Received: 09 Mar 2003 Revision Received: 27 May 2003 Accepted: 27 May 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2003) 31 (9): 801–804. https://doi.org/10.1130/G19658.1 Article history Received: 09 Mar 2003 Revision Received: 27 May 2003 Accepted: 27 May 2003 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Peir K. Pufahl, Kurt A. Grimm; Coated phosphate grains: Proxy for physical, chemical, and ecological changes in seawater. Geology 2003;; 31 (9): 801–804. doi: https://doi.org/10.1130/G19658.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Irrespective of geologic age, Phanerozoic coated phosphate grains deposited beneath productive surface waters in organic-rich paleoenvironments are of only two types. Unconformity-bounded grains contain internal discordances and erosional surfaces, attributable to multiple episodes of phosphogenesis and sedimentary reworking during periods of stratigraphic condensation. Redox-aggraded grains consist of concordant concentric phosphate laminae that are intimately interlayered with circumgranular layers containing pyrite, chamosite, or barite, recording in situ diagenetic mineralization driven by changes in pore-water redox potential. Such changes can be attributed to variations in biological oxygen demand within suboxic pore-water environments resulting from fluctuations in sedimentation rate of organic carbon. Redox-aggraded grains are thus sensitive indicators of variations in organic carbon export and record changes in primary productivity and/or ecological dynamics of the surface ocean. This concept of coated-grain formation necessitates a long residence time just below the sediment-water interface. If sedimentation rate is too high, grains are rapidly buried and so removed from the zone of active phosphate precipitation. Coated phosphate grains can therefore be considered the granular equivalents of condensed beds. These concepts are equally applicable to the interpretation of other types of coated grains and concretions that contain Eh-sensitive minerals, such as iron-bearing ooids and polymineralic concretions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 0.003 |
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".