Neoproterozoic extension in the greater dharwar craton: A reevaluation of the "betsimisaraka suture" in madagascarn
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Tucker, R.D.; Roig, J Y; Delor, Claude; Amelin, Yuri; Goncalves, P.; Rabarimanana, M.H.; Ralison, A.V.; Belcher, R.W.
Description
The Precambrian shield of Madagascar is reevaluated with recently compiled geological data and new U-Pb sensitive high-resolution ion microprobe (SHRIMP) geochronology. Two Archean domains are recognized: the eastern Antongil-Masora domain and the central Antananarivo domain, the latter with distinctive belts of metamafic gneiss and schist (Tsaratanana Complex). In the eastern domain, the period of early crust formation is extended to the Paleo-Mesoarchean (3.32-3.15 Ga) and a supracrustal...[Show more]
dc.contributor.author | Tucker, R.D. | |
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dc.contributor.author | Roig, J Y | |
dc.contributor.author | Delor, Claude | |
dc.contributor.author | Amelin, Yuri | |
dc.contributor.author | Goncalves, P. | |
dc.contributor.author | Rabarimanana, M.H. | |
dc.contributor.author | Ralison, A.V. | |
dc.contributor.author | Belcher, R.W. | |
dc.date.accessioned | 2015-12-10T23:24:34Z | |
dc.identifier.issn | 0008-4077 | |
dc.identifier.uri | http://hdl.handle.net/1885/67244 | |
dc.description.abstract | The Precambrian shield of Madagascar is reevaluated with recently compiled geological data and new U-Pb sensitive high-resolution ion microprobe (SHRIMP) geochronology. Two Archean domains are recognized: the eastern Antongil-Masora domain and the central Antananarivo domain, the latter with distinctive belts of metamafic gneiss and schist (Tsaratanana Complex). In the eastern domain, the period of early crust formation is extended to the Paleo-Mesoarchean (3.32-3.15 Ga) and a supracrustal sequence (Fenerivo Group), deposited at 3.18 Ga and metamorphosed at 2.55 Ga, is identified. In the central domain, a Neoarchean period of high-grade metamorphism and anatexis that affected both felsic (Betsiboka Suite) and mafic gneisses (Tsaratanana Complex) is documented. We propose, therefore, that the Antananarivo domain was amalgamated within the Greater Dharwar Craton (India + Madagascar) by a Neoarchean accretion event (2.55-2.48 Ga), involving emplacement of juvenile igneous rocks, high-grade metamorphism, and the juxtaposition of disparate belts of mafic gneiss and schist (metagreenstones). The concept of the "Betsimisaraka suture" is dispelled and the zone is redefined as a domain of Neoproterozoic metasedimentary (Manampotsy Group) and metaigneous rocks (Itsindro-Imorona Suite) formed during a period of continental extension and intrusive igneous activity between 840 and 760 Ma. Younger orogenic convergence (560-520 Ma) resulted in east-directed overthrusting throughout south Madagascar and steepening with local inversion of the domain in central Madagascar. Along part of its length, the Manampotsy Group covers the boundary between the eastern and central Archean domains and is overprinted by the Angavo-Ifanadiana high-strain zone that served as a zone of crustal weakness throughout Cretaceous to Recent times. | |
dc.publisher | N R C Research Press | |
dc.source | Canadian Journal of Earth Sciences | |
dc.subject | Keywords: Anatexis; Archean; Crust formations; Geological data; High-strain zones; Igneous activity; Madagascar; Neoarchean; Neoproterozoic; Precambrian; Sensitive high-resolution ion microprobe; Geochronology; Structural geology; Igneous rocks; anatexis; craton; f | |
dc.title | Neoproterozoic extension in the greater dharwar craton: A reevaluation of the "betsimisaraka suture" in madagascarn | |
dc.type | Journal article | |
local.description.notes | Imported from ARIES | |
local.identifier.citationvolume | 48 | |
dc.date.issued | 2011 | |
local.identifier.absfor | 040303 - Geochronology | |
local.identifier.absfor | 040313 - Tectonics | |
local.identifier.absfor | 040310 - Sedimentology | |
local.identifier.ariespublication | f2965xPUB1423 | |
local.type.status | Published Version | |
local.contributor.affiliation | Tucker, R.D., United States Geological Survey | |
local.contributor.affiliation | Roig, J Y, Bureau de Recherche Geologique et Miniere | |
local.contributor.affiliation | Delor, Claude, Bureau de Recherche Geologique et Miniere | |
local.contributor.affiliation | Amelin, Yuri, College of Physical and Mathematical Sciences, ANU | |
local.contributor.affiliation | Goncalves, P., Universite de Franche Comte | |
local.contributor.affiliation | Rabarimanana, M.H., Project de Gouvernance des Ressources Minerales | |
local.contributor.affiliation | Ralison, A.V., Project de Gouvernance des Ressources Minerales | |
local.contributor.affiliation | Belcher, R.W., RWB Exploration Ltd | |
local.description.embargo | 2037-12-31 | |
local.bibliographicCitation.issue | 2 | |
local.bibliographicCitation.startpage | 389 | |
local.bibliographicCitation.lastpage | 417 | |
local.identifier.doi | 10.1139/E10-034 | |
local.identifier.absseo | 970104 - Expanding Knowledge in the Earth Sciences | |
dc.date.updated | 2016-02-24T08:13:44Z | |
local.identifier.scopusID | 2-s2.0-79951511720 | |
local.identifier.thomsonID | 000287763800016 | |
Collections | ANU Research Publications |
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