Constraining the travels of a "suspect" terrane: Paleomagnetism and geobarometry of two Early Cretaceous igneous complexes in the Peninsular Ranges Batholith, California
Bibliographic record
Abstract
Research Article| September 01, 2008 Constraining the travels of a "suspect" terrane: Paleomagnetism and geobarometry of two Early Cretaceous igneous complexes in the Peninsular Ranges Batholith, California D.T.A. Symons; D.T.A. Symons † 1Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada †E-mail: dsymons@uwindsor.ca. Search for other works by this author on: GSW Google Scholar T.E. Smith; T.E. Smith 1Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada Search for other works by this author on: GSW Google Scholar W.H. Blackburn W.H. Blackburn 1Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information D.T.A. Symons † 1Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada T.E. Smith 1Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada W.H. Blackburn 1Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada †E-mail: dsymons@uwindsor.ca. Publisher: Geological Society of America Received: 29 Jan 2007 Revision Received: 10 Dec 2007 Accepted: 18 Jan 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2008 Geological Society of America GSA Bulletin (2008) 120 (9-10): 1159–1170. https://doi.org/10.1130/B26189.1 Article history Received: 29 Jan 2007 Revision Received: 10 Dec 2007 Accepted: 18 Jan 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation D.T.A. Symons, T.E. Smith, W.H. Blackburn; Constraining the travels of a "suspect" terrane: Paleomagnetism and geobarometry of two Early Cretaceous igneous complexes in the Peninsular Ranges Batholith, California. GSA Bulletin 2008;; 120 (9-10): 1159–1170. doi: https://doi.org/10.1130/B26189.1 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 SocietyGSA Bulletin Search Advanced Search Abstract Paleomagnetic and rock magnetic measurements for 27 sites in the tonalitic ca. 108 Ma Alpine and ca. 100 Ma Ramona complexes in the suspect Yuma terrane or western zone of the Peninsular Ranges Batholith near San Diego show that single- and pseudosingle-domain magnetite carries their characteristic remanence. The Alpine and Ramona paleopoles agree with six published paleopoles from Cretaceous igneous rocks in the Yuma terrane, but all eight paleopoles are discordant for North America. Al-in-hornblende geothermobarometric depth determinations at 16 sites, plus published mapping and depth determinations, suggest that the batholith is divided into blocks by orogen-parallel faults or by orthogonal fault sets with large vertical displacements. The paleomagnetic data show that the fault blocks in the terrane underwent, on average, ENE-side-up tilting of ~10° ± 3° about an orogen-parallel axis between ca. 125 Ma and ca. 89 ± 7 Ma, but they have not been translated northward as a suspect terrane by ≥500 km, excluding Neogene opening of the Gulf of California. The tilting is attributed to torque from ENE shallow underthrusting of the Farallon plate beneath the WSW overthrusting North American plate, where subsequent extension has caused differential uplift of the fault blocks. Nonsignificant dextral displacement of ~4° ± 1° (440 ± 110 km) between the eastern and western zones of the batholith suggests that this boundary represents an intraarc fault. The large paleopole discordance found in younger sedimentary strata of Baja California is attributed mainly to compaction shallowing of the remanence and/or postdepositional remagnetization. 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 | 0.002 | 0.002 |
| 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) | 0.002 | 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".