Pangaean megalineaments: geophysical indications for the existence of Laurentian counterparts of the 6000 km Trans-Saharan Tibesti Lineament, and implications for lithospheric tectonics and mineral deposits
Bibliographic record
Abstract
Research Article| December 01, 2006 Pangaean megalineaments: geophysical indications for the existence of Laurentian counterparts of the 6000 km Trans-Saharan Tibesti Lineament, and implications for lithospheric tectonics and mineral deposits Sharad Master Sharad Master Economic Geology Research Institute, School of Geosciences, University of the Witwatersrand, P. Bag 3, Wits 2050, Johannesburg, South Africa, e-mail: masters@geosciences.wits.ac.za Search for other works by this author on: GSW Google Scholar South African Journal of Geology (2006) 109 (4): 503–514. https://doi.org/10.2113/gssajg.109.4.503 Article history first online: 09 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 Sharad Master; Pangaean megalineaments: geophysical indications for the existence of Laurentian counterparts of the 6000 km Trans-Saharan Tibesti Lineament, and implications for lithospheric tectonics and mineral deposits. South African Journal of Geology 2006;; 109 (4): 503–514. doi: https://doi.org/10.2113/gssajg.109.4.503 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 SocietySouth African Journal of Geology Search Advanced Search Abstract A major 6000-km long west-northwest to east-southeast-trending Trans-Saharan lineament, extending from Kenya to Morocco, referred to as the Tibesti Lineament, has been described by Guiraud et al.(2000). This lineament shows up on satellite images, air-photo mosaics and terrain elevation models, as swarms of parallel faults. It corresponds to a major discontinuity of surface wave velocities in the mantle, suggesting that it deeply affects the lithosphere. The highest heat flow measurements in the West African shield are found adjacent to the Tibesti Lineament in the northern Hoggar uplift. Geophysical, geological, and geomorphological evidence suggests that the Tibesti lineament may have continued into North America (Laurentia), which collided with northwest Africa during the Appalachian-Mauritanide orogeny, coinciding with the late Palaeozoic assembly of the supercontinent Pangaea. The contiguous Laurentian lineaments which may be extensions of the Tibesti Lineament, are the here newly recognised Chesterfield Inlet Lineament and the Cabot Strait Lineament, both of which are situated in Canada. These lineaments are defined as linear pattern breaks in processed aeromagnetic anomaly maps of Canada. Some portions of them also can be detected in refraction and reflection seismic survey data (e.g., under Hudon Bay), and to a lesser extent, in the Bouguer gravity anomaly map of Canada. The lineaments have present-day (neotectonic) surface expressions in the form of inlets, submarine channels, straight river segments, and strings of linear lakes, extending over 3700 km, from Nunavut Province northwest of Hudson Bay, across Quebec and Newfoundland, and to the Cabot Strait separating Newfoundland from Nova Scotia. The highest heat flow in the Canadian Maritimes is found in the Cabot Strait. The Tibesti-Cabot-Strait-Chesterfield Inlet lineaments reflect deep-seated fracturing of the North African and North American lithosphere, involving both the crust and rigid upper mantle. These lineaments cut right across the grain of numerous orogenic belts dating from the Palaeoproterozoic, Late Mesoproterozoic, and Palaeozoic. By analogy with other large transcontinental lineaments which contain ore deposits, these newly identified megalineaments may be prospective for economic mineral deposits, such as hydrothermal gold and base metal mineralization, and diamondiferous kimberlites. 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 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".