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
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Résumé
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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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».