The LATEA metacraton (Central Hoggar, Tuareg shield, Algeria): behaviour of an old passive margin during the Pan-African orogeny

Liégeois, Jean Paul; Latouche, Louis; Boughrara, Mustapha; Navez, Jacques; Guiraud, Michel

doi:10.1016/j.jafrearsci.2003.05.004

Cited by 245 publications

(167 citation statements)

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“…In North Africa, the Trans-Saharan belt and the East Arabian orogen would have been part of an important orogenic system (Transgondwanan Supermountain; Squire, Campbell, Allen, & Wilson, 2006) that resulted from the amalgamation evolving the West African craton, the Saharan Metacraton and the Arabian-Nubian shield, which is known as Pan-African orogeny (Kroner & Stern, 2004). The Trans-Saharan belt consists of pre-Neoproterozoic basement and Neoproterozoic ophiolites tectonically reworked during Cryogenian-Ediacaran times (Kroner & Stern, 2004;Liégeois, Latouche, Boughara, Navez, & Guirad, 2003;Teklay, 2005). The Trans-Saharan belt that includes the Tuareg shield separates the Anti-Atlas (west) of the Saharan Metacraton (east).…”

Section: Introductionmentioning

confidence: 99%

Potential sources of Ediacaran strata of Iberia: a review

Pereira

2014

Geodinamica Acta

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Section: Introductionmentioning

confidence: 99%

Potential sources of Ediacaran strata of Iberia: a review

Pereira

2014

Geodinamica Acta

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“…The Central Hoggar in Algeria, NW Africa (Figure 1) is made of four distinct crustal blocks termed as LATEA (Liégeois et al, 2003). These terranes were accreted during the Pan-African Orogeny and are part of a single passive margin upon which mafic eclogites, garnet amphibolites and clinopyroxene-garnet amphibolites metamorphosed at 15 kbar-7908C were tectonically emplaced and thrusted around 686 Ma (Boughrara, 1999;Liégeois et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…These terranes were accreted during the Pan-African Orogeny and are part of a single passive margin upon which mafic eclogites, garnet amphibolites and clinopyroxene-garnet amphibolites metamorphosed at 15 kbar-7908C were tectonically emplaced and thrusted around 686 Ma (Boughrara, 1999;Liégeois et al, 2003). These metamafic rocks are interlayered with metasedimentary rocks and orthogneiss in the Tin Begane region, in the northern part of Laouni terrane (Caby, 2003;Derridj et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Occurrence and geochemistry of metamafic rocks from the Forquilha Eclogite Zone, central Ceará (NE Brazil): geodynamic implications

2011

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In the northern region of the Borborema Province, a 30 km-long mafic/ultramafic belt of high pressure (HP) rocks called the Forquilha Eclogite Zone has been recently discovered in the Central Domain of Ceará State. The belt comprises three groups of rocks: (1) garnet amphibolites, (2) retrograded eclogites and (3) clinopyroxene-garnet amphibolites, all of them being hosted in garnet AE kyanite þ sillimanite schists and orthogneisses which are often migmatized. The geochemical analyses of 30 representative samples confirm differences among the three groups that were initially classified by petrography. The garnet amphibolites are the most depleted rocks, with relatively flat rare earth element (REE) PM pattern and (SPIDER) PM pattern with negative Rb, Th, Nb, Sr and Zr anomalies. It is the most fractionated group, ranging from picrobasalts to andesites. Fractional crystallization and mineral accumulation are indicated by Eu and Sr anomalies. The data show geochemical affinities with island-arc basalts. The retrograded eclogites display flat (REE) PM , but without Eu anomalies. Nb/La ratios are low and variable, as for slightly enriched MORB from ocean floor or intra-oceanic back-arc environments. However, a genetic link with the Group 1 rocks cannot be completely discarded. The clinopyroxene-garnet amphibolites are the most enriched group. (REE) PM and (SPIDER) PM patterns show many features of alkaline basalts. In the Nb/Yb versus Th/Yb diagram the data cluster near the E-MORB standard. Several geochemical aspects of these rocks fit well those from the HP/UHP Pan-African/Brasiliano Suture Zone in the Dahomeyides/Hoggar regions of West Africa. However, differences in their extent and lack of alignment preclude a direct correlation among these zones.

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“…It has been suggested that metacratonization can also occur locally due to plate collision along the margins of cratons or the development of lithospheic-scale shear zones in the interior of cratons [De Waele et al, 2006b;Liégeois et al, 2013;Liégeois et al, 2003]. …”

Section: Cratons and Metacratonsmentioning

confidence: 99%

Geophysical and petrological constraints on ocean plate dynamics

Sarafian¹

2017

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This thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere rises, melts, and flows away from the ridge axis. In Chapters 2 and 3, I present the results from partial melting experiments of mantle peridotite that were conducted in order to examine the mantle melting point, or solidus, beneath a mid-ocean ridge. Chapter 2 determines the peridotite solidus at a single pressure of 1.5 GPa and concludes that the oceanic mantle potential temperature must be ~60 ºC hotter than current estimates. Chapter 3 goes further to provide a more accurate parameterization of the anhydrous mantle solidus from experiments over a range of pressures. This chapter concludes that the range of potential temperatures of the mantle beneath mid-ocean ridges and plumes is smaller than currently estimated. Once formed, the oceanic plate moves atop the underlying asthenosphere away from the ridge axis. Chapter 4 uses seafloor magnetotelluric data to investigate the mechanism responsible for plate motion at the lithosphere-asthenosphere boundary. The resulting two dimensional conductivity model shows a simple layered structure. By applying petrological constraints, I conclude that the upper asthenosphere does not contain substantial melt, which suggests that either a thermal or hydration mechanism supports plate motion. Oceanic plate motion has dramatically changed the surface of the Earth over time, and evidence for ancient plate motion is obvious from detailed studies of the longer lived continental lithosphere. In Chapter 5, I investigate past plate motion by inverting magnetotelluric data collected over eastern Zambia. The conductivity model probes the Zambian lithosphere and reveals an ancient subduction zone previously suspected from surface studies. This chapter elucidates the complex lithospheric structure of eastern Zambia and the geometry of the tectonic elements in the region, which collided as a result of past oceanic plate motion. Combined, the chapters of this thesis provide critical constraints on ocean plate dynamics.

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The LATEA metacraton (Central Hoggar, Tuareg shield, Algeria): behaviour of an old passive margin during the Pan-African orogeny

Cited by 245 publications

References 44 publications

Potential sources of Ediacaran strata of Iberia: a review

Potential sources of Ediacaran strata of Iberia: a review

Occurrence and geochemistry of metamafic rocks from the Forquilha Eclogite Zone, central Ceará (NE Brazil): geodynamic implications

Geophysical and petrological constraints on ocean plate dynamics

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