Compaction-corrected paleomagnetic paleolatitudes for Late Cretaceous rudists along the Cretaceous California margin: Evidence for less than 1500 km of post–Late Cretaceous offset for Baja British Columbia
Bibliographic record
Abstract
Research Article| September 01, 2001 Compaction-corrected paleomagnetic paleolatitudes for Late Cretaceous rudists along the Cretaceous California margin: Evidence for less than 1500 km of post–Late Cretaceous offset for Baja British Columbia K.P. Kodama; K.P. Kodama 1Department of Earth and Environmental Sciences, Lehigh University, 31 Williams Drive, Bethlehem, Pennsylvania 18015-3188, USA Search for other works by this author on: GSW Google Scholar Peter D. Ward Peter D. Ward 1Department of Earth and Environmental Sciences, Lehigh University, 31 Williams Drive, Bethlehem, Pennsylvania 18015-3188, USA Search for other works by this author on: GSW Google Scholar Author and Article Information K.P. Kodama 1Department of Earth and Environmental Sciences, Lehigh University, 31 Williams Drive, Bethlehem, Pennsylvania 18015-3188, USA Peter D. Ward 1Department of Earth and Environmental Sciences, Lehigh University, 31 Williams Drive, Bethlehem, Pennsylvania 18015-3188, USA Publisher: Geological Society of America Received: 14 Apr 2000 Revision Received: 13 Dec 2000 Accepted: 06 Mar 2001 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2001) 113 (9): 1171–1178. https://doi.org/10.1130/0016-7606(2001)113<1171:CCPPFL>2.0.CO;2 Article history Received: 14 Apr 2000 Revision Received: 13 Dec 2000 Accepted: 06 Mar 2001 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation K.P. Kodama, Peter D. Ward; Compaction-corrected paleomagnetic paleolatitudes for Late Cretaceous rudists along the Cretaceous California margin: Evidence for less than 1500 km of post–Late Cretaceous offset for Baja British Columbia. GSA Bulletin 2001;; 113 (9): 1171–1178. doi: https://doi.org/10.1130/0016-7606(2001)113<1171:CCPPFL>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 SocietyGSA Bulletin Search Advanced Search Abstract The paleolatitudinal distribution of bivalve rudists has important significance for the Baja British Columbia (Baja BC) hypothesis that western Canadian superterranes from British Columbia have been displaced 3000 km since Cretaceous time. Rudists are not observed in Baja BC sedimentary rocks, yet they are common in Late Cretaceous strata in California and Baja California, which have the same paleomagnetically determined paleolatitudes (approximately 25°N) as Baja BC rocks of Late Cretaceous age. In order to resolve this contradiction and to delimit more exactly the southern paleolatitudes of Baja BC, paleomagnetic inclinations corrected for the effects of burial compaction were used to determine the paleolatitudinal distribution of rudists along the California margin. Compaction-corrected paleomagnetic data from the Peninsular Ranges and Salinia terranes indicate that rudists were restricted to paleolatitudes between 34° and 40°N. Evidence of coastal upwelling in the latest Cretaceous Marca Shale may explain the northern limit of the rudist distribution. These data suggest that Baja BC was no farther south than 40°N in the Late Cretaceous, thus limiting its post-Cretaceous displacement to less than 1500 km, and that burial compaction has also affected the paleomagnetism of Nanaimo Group sedimentary rocks from Vancouver Island. This result also helps resolve the conflict between paleomagnetic results, which show 1500 km of post–Late Cretaceous offset between the Insular–Coast Plutonic Complex superterrane and the Intermontane superterrane and geologic observations, which can allow only tens of kilometers of offset between these terranes in the Methow- Tyaughton 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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.004 | 0.007 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".