Interactions between dioritic and granodioritic magmas within the Pan African Amsel batholith (Central Hoggar, Algeria): an approach through the study of plagioclase crystals
Authors
Bouzeguella-Talmat, S.
Bonin, B.
Liégeois, J.P.
Benmerzoug-Bechiri, F.
Khaloui, R.
Discipline
Earth and related Environmental sciences
Subject
Geodynamics and mineral resources
Audience
Scientific
Date
2018Metadata
Show full item recordDescription
The Silet terrane, located in Western Hoggar (Tuareg shield), strongly N-S elongated (700 * 20-40 km) is classically considered as a complex juvenile island arc accreted to the LATEA metacraton (Liégeois et al, 2003). Current data show that the Silet terrane resulted from an accretion of several lithological segments made up of Neoproterozoic mostly oceanic formations including some mantle slivers, overthrust towards the LATEA western margin during the 650-630 Ma accretion episode. The terrane includes two north-south trending narrow strips, separated by the Tin-Dahar Fault, a strike-slip shear zone displaying talcschists, amphibolites, and serpentinites. The Eastern Segment yields negative Nd isotopic signatures (-2.9 > εNd > -8.1). By contrast, the Western Segment yields positive Nd isotopic signatures (+0.5 < εNd < +4.6). The Eastern Segment comprises the Taklet-Iharedj Unit and the Anou Eheli Unit. They both include Pharusian I volcano-sedimentary series, are crosscut by high-K plutons, of different ages (e.g., Taklet pluton, 839 ± 4 Ma; Caby et al, 1982) and TTG batholiths (e.g. Eheli pluton, 638 ± 6 Ma). The Western Segment comprises three units, the Irrelouchem, Tin-Tekadiouit terrane and Tioueïne units, all characterized by a juvenile signature. The Pharusian I volcano-sedimentary series are crosscut by TTG plutons (e.g. the Timesselarsine pluton, 868 ± 8 Ma; Caby et al, 1982 and the Tamteq pluton, 742 ± 5 Ma). The Pharusian II Amded volcano-sedimentary series (ca. 680 Ma; Dupont, 1987) and Irrelouchem volcanic series are crosscut by TTG batholiths (e.g., the Ahambatou pluton, 651 ± 6 Ma and the Silet pluton, 648 ± 3 Ma). In addition, mafic to ultramafic cumulates, gabbro-dioritic stocks and small masses of two-mica granites are present. The entire area is cut by a tholeiitic to alkaline doleritic dyke swarms. To sum up, the Silet terrane is an assemblage of mostly oceanic tectonic units, comparable to suture areas known worldwide, like along the North American Pacific margin.
Citation
Bouzeguella-Talmat, S.; Bonin, B.; Liégeois, J.P.; Benmerzoug-Bechiri, F.; Khaloui, R. (2018). Interactions between dioritic and granodioritic magmas within the Pan African Amsel batholith (Central Hoggar, Algeria): an approach through the study of plagioclase crystals. , 27th Colloquium of African Geology, Oviedo, Portugal,Identifiers
Type
Conference
Peer-Review
Yes
Language
eng