Unburrowed mudstones may record only slightly lowered oxygen conditions in warm, shallow basins
Bibliographic record
Abstract
Research Article| May 01, 2016 Unburrowed mudstones may record only slightly lowered oxygen conditions in warm, shallow basins Shahin E. Dashtgard; Shahin E. Dashtgard * ARISE (Applied Research in Ichnology and Sedimentology), Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada *E-mail: sdashtgard@gmail.com Search for other works by this author on: GSW Google Scholar James A. MacEachern James A. MacEachern ARISE (Applied Research in Ichnology and Sedimentology), Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Shahin E. Dashtgard * ARISE (Applied Research in Ichnology and Sedimentology), Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada James A. MacEachern ARISE (Applied Research in Ichnology and Sedimentology), Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada *E-mail: sdashtgard@gmail.com Publisher: Geological Society of America Received: 04 Jan 2016 Revision Received: 25 Feb 2016 Accepted: 29 Feb 2016 First Online: 09 Mar 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2016 Geological Society of America Geology (2016) 44 (5): 371–374. https://doi.org/10.1130/G37648.1 Article history Received: 04 Jan 2016 Revision Received: 25 Feb 2016 Accepted: 29 Feb 2016 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Shahin E. Dashtgard, James A. MacEachern; Unburrowed mudstones may record only slightly lowered oxygen conditions in warm, shallow basins. Geology 2016;; 44 (5): 371–374. doi: https://doi.org/10.1130/G37648.1 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 Unbioturbated mudstones and highly bioturbated silty and sandy mudstones from the late Albian of Alberta, Canada, are characterized by their ichnological, foraminiferal, and geochemical signatures. A comparison of these data sets is undertaken to isolate the dissolved oxygen (DO) conditions that led to the preservation of unbioturbated mudstones versus highly bioturbated silty and sandy mudstones. Highly diverse and abundant benthic foraminiferal assemblages, coupled with conclusive geochemical signatures, indicate that unbioturbated mudstones were deposited under oxic bottom waters. The paucity of bioturbation in these rocks is attributed to the persistence of low-oxic conditions (5 > DO > 2 mg L–1) at the seafloor, comparable to the present-day Gulf of Mexico. We assert that unbioturbated mudstone should not automatically be attributed to oxygen deficiency (<2 mg L–1). Instead, it may reflect oxygenation sufficient to support benthic microfauna (foraminifera) but insufficient to sustain a diverse ecosystem of macrofauna (burrowing fauna). Moreover, we propose that the distribution of unburrowed mudstones deposited below low-oxic waters is predictable. A paucity of bioturbation is normal in shallow marine (below fair-weather wave base to ∼200 m water depth) deposits of subtropical to tropical ocean basins and/or semienclosed seaways. 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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.031 | 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; both teacher heads agree on what is shown here.
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".