Facies and sequence stratigraphy of two Cambrian grand cycles: implications for Cambrian sea level and origin of grand cycles
Bibliographic record
Abstract
Research Article| December 01, 2002 Facies and sequence stratigraphy of two Cambrian grand cycles: implications for Cambrian sea level and origin of grand cycles Ronald J. Spencer; Ronald J. Spencer Department of Geology and Geophysics, The University of Calgary, Calgary, AB, T2N 1N4 Search for other works by this author on: GSW Google Scholar Robert V. Demicco Robert V. Demicco Department of Geological Sciences & Environmental Studies, Binghamton University, Binghamton, NY, 13902-6000 Search for other works by this author on: GSW Google Scholar Bulletin of Canadian Petroleum Geology (2002) 50 (4): 478–491. https://doi.org/10.2113/50.4.478 Article history received: 15 Aug 2001 accepted: 26 Aug 2002 first online: 02 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 Ronald J. Spencer, Robert V. Demicco; Facies and sequence stratigraphy of two Cambrian grand cycles: implications for Cambrian sea level and origin of grand cycles. Bulletin of Canadian Petroleum Geology 2002;; 50 (4): 478–491. doi: https://doi.org/10.2113/50.4.478 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 SocietyBulletin of Canadian Petroleum Geology Search Advanced Search Abstract The Pika, Arctomys and Waterfowl formations comprise two "grand cycles" as originally defined by Aitken (1966, 1978, 1981). A detailed across-strike facies stratigraphic reconstruction based on measured outcrop sections and subsurface data reveal that the Pika and Waterfowl Formations consist of five transgressive–regressive sequences of subtidal facies and tidal flat facies each up to 100 m thick and some 105 to 106 years duration. The bulk of the Arctomys Formation consists of terrestrial to marginal marine playa deposits, correlates with an unconformity in the adjacent subsurface, and was deposited during a sea level low stand. The upper third of the Arctomys Formation records a single minor marine transgressive–regressive cycle. Transgressive facies can extend eastward onto the craton up to 1000 km from the platform to slope transition and record local relative increases in sea level of various magfnitudes. Maximum transgressive or regressive phases do not necessarily correspond with the bottoms or tops of grand cycles. A sea level curve derived from our facies stratigraphy is different than the curve proposed by Bond et al. (1989) from R2 analysis, and also different to the sealevel curve of Montanez and Osleger (1993) for the southern Great Basin. 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 | 0.003 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".