Taphonomic Control on Microstructure in Early Neoproterozoic Reefal Stromatolites and Thrombolites
Bibliographic record
Abstract
Other| April 01, 2000 Taphonomic Control on Microstructure in Early Neoproterozoic Reefal Stromatolites and Thrombolites ELIZABETH C. TURNER; ELIZABETH C. TURNER 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar NOËL P. JAMES; NOËL P. JAMES 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar GUY M. NARBONNE GUY M. NARBONNE 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar PALAIOS (2000) 15 (2): 87–111. https://doi.org/10.1669/0883-1351(2000)015<0087:TCOMIE>2.0.CO;2 Article history accepted: 08 Dec 1999 first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation ELIZABETH C. TURNER, NOËL P. JAMES, GUY M. NARBONNE; Taphonomic Control on Microstructure in Early Neoproterozoic Reefal Stromatolites and Thrombolites. PALAIOS 2000;; 15 (2): 87–111. doi: https://doi.org/10.1669/0883-1351(2000)015<0087:TCOMIE>2.0.CO;2 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 SocietyPALAIOS Search Advanced Search Abstract Early Neoproterozoic reefs of the Little Dal Group, Northwest Territories, are built by stromatolites and thrombolites containing calcified filamentous cyanobacteria and interstitial cement. Micritic and microcrystalline carbonate grew in or on extracellular cyanobacterial sheaths, preserving filaments when mineralization was early relative to sheath degradation, or grumeaux when mineralization was later. Filamentous microstructure is volumetrically predominant in the reefs; less common are micritic and grumelous microstructures already known from late Proterozoic stromatolites and Phanerozoic thrombolites. Textural intergradation of filamentous-calcimicrobial microstructure with these non-filamentous microstructures reflects microstructural variation developed through differential preservation at the scale of individual filaments and laminae. Textural gradients from filaments to grumeaux, and from calcimicrobial to stromatolitic and thrombolitic microstructure types, imply that a wide variety of microbialite microstructure types can be derived from a single progenitor community. This suggests that taphonomic variables may be as important in the development of microbialite microstructure as the biology of the microbial mat community. It also challenges recent suggestions that the Neoproterozoic increase in thromboids was related to the rise of multicellular organisms. These conclusions have broad implications for the interpretation of fossil microbialites, many of which might have been more closely related in origin than hitherto suspected. 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 | 0.000 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 0.001 |
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".