Oxygen isotope perspective on Precambrian crustal growth and maturation
Bibliographic record
Abstract
Research Article| April 01, 2000 Oxygen isotope perspective on Precambrian crustal growth and maturation William H. Peck; William H. Peck 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar Elizabeth M. King; Elizabeth M. King 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar John W. Valley John W. Valley 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar Author and Article Information William H. Peck 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Elizabeth M. King 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA John W. Valley 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Publisher: Geological Society of America Received: 21 Jun 1999 Revision Received: 14 Jan 2000 Accepted: 25 Jan 2000 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2000) 28 (4): 363–366. https://doi.org/10.1130/0091-7613(2000)28<363:OIPOPC>2.0.CO;2 Article history Received: 21 Jun 1999 Revision Received: 14 Jan 2000 Accepted: 25 Jan 2000 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation William H. Peck, Elizabeth M. King, John W. Valley; Oxygen isotope perspective on Precambrian crustal growth and maturation. Geology 2000;; 28 (4): 363–366. doi: https://doi.org/10.1130/0091-7613(2000)28<363:OIPOPC>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 SocietyGeology Search Advanced Search Abstract In this study we contrast insights on Precambrian crustal growth and maturation from radiogenic and oxygen isotope systematics in the Superior (3.0–2.7 Ga) and Grenville (1.3–1.0 Ga) Provinces of the Canadian shield. Oxygen isotope ratios in zircon provide the best evidence of supracrustal input into ancient orogens. Archean Superior Province zircons have relatively low δ18O values and a limited range (5.7‰ ± 0.6‰), while Proterozoic Grenville Province zircons have elevated δ18O values and a wider range (8.2‰ ± 1.7‰). These data reflect fundamental differences in crustal evolution and maturation between the Superior and the Grenville Provinces. In the Grenville Province, radiogenically juvenile supracrustal material with high δ18O values was buried (or subducted) to the base of the crust within 150 m.y. of initial crust production, causing high magmatic δ18O values (δ18O [zircon] ≥ 8‰) in anorthosite suite and subsequent plutons. Information about large volumes and rapid recycling of Grenville crust is not accessible from radiogenic isotope data alone. The Grenville data contrast with the restricted δ18O values of Superior Province magmatism, where subtle (∼1‰) elevation in δ18O occurs only in volumetrically minor, late to postorogenic (sanukitoid) plutons. Differences in sediment δ18O values between the Superior and Grenville Provinces are predominantly a function of the δ18O of source materials, rather than differences in chemical maturity or erosion styles. This study shows that zircon is a robust reference mineral to compare igneous processes in rocks that have undergone radically different histories. 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) | 0.035 | 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; 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".