Continental-scale detrital zircon provenance signatures in Lower Cretaceous strata, western North America
Bibliographic record
Abstract
Research Article| April 01, 2011 Continental-scale detrital zircon provenance signatures in Lower Cretaceous strata, western North America A.L. Leier; A.L. Leier 1Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada Search for other works by this author on: GSW Google Scholar G.E. Gehrels G.E. Gehrels 2Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar Author and Article Information A.L. Leier 1Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada G.E. Gehrels 2Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Publisher: Geological Society of America Received: 16 Sep 2010 Revision Received: 15 Nov 2010 Accepted: 25 Nov 2010 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2011 Geological Society of America Geology (2011) 39 (4): 399–402. https://doi.org/10.1130/G31762.1 Article history Received: 16 Sep 2010 Revision Received: 15 Nov 2010 Accepted: 25 Nov 2010 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation A.L. Leier, G.E. Gehrels; Continental-scale detrital zircon provenance signatures in Lower Cretaceous strata, western North America. Geology 2011;; 39 (4): 399–402. doi: https://doi.org/10.1130/G31762.1 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 Lower Cretaceous strata and the underlying sub-Cretaceous unconformity in western North America record a profound, but poorly understood change in sedimentation patterns and basin dynamics in the Cordilleran foreland basin. To better understand the regional sedimentary systems and provenance during Early Cretaceous time, we sampled 10 Lower Cretaceous sandstone and conglomerate units that overlie the sub-Cretaceous unconformity in Canada and the United States for detrital zircon uranium-lead (U-Pb) geochronology. These Lower Cretaceous strata contain two distinct detrital zircon U-Pb age signatures. A "northern" signature, present in strata in Alberta and British Columbia, contains zircons with ages of ca. 120 Ma and 1850 Ma, and is composed of zircons from the Cordilleran arc and grains recycled from strata of the Canadian miogeocline. A "southern" signature, present in strata from southwestern United States to central Montana, contains zircons with ages of ca. 160 Ma, ca. 250–650 Ma, and ca. 1040 Ma, and consists of zircons from the Cordilleran arc and grains recycled from late Paleozoic strata and Mesozoic eolianite units in the western United States. We propose that the differences in detrital zircon U-Pb age populations between northern and southern areas of western North America are due to differences in zircon populations in the sediment source strata exposed in the contemporaneous thrust belt, and possibly a subtle paleohydraulic divide in Montana. These distinct provenance signatures along the Cordillera suggest that the mechanisms responsible for Early Cretaceous changes in foreland basin dynamics occurred along the length of the Cordillera in both the U.S. and Canada. 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) | 0.012 | 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 teacher head, 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".