1-20 OF 2103 RESULTS FOR

southern Madagascar

Results shown limited to content with bounding coordinates.
Follow your search
Access your saved searches in your account

Would you like to receive an alert when new items match your search?
Close Modal
Sort by
Journal Article
Published: 08 January 2025
Journal of the Geological Society (2025) 182 (2): jgs2024-065.
... Africa–Kuunga orogen exposed in Madagascar, where uncertainty about the terrane correlations, and therefore structural framework, of the orogen persists. We present a comprehensive dataset of monazite petrochronology and thermobarometry across the southern Madagascar basement to quantify the regional...
FIGURES | View All (12)
Journal Article
Journal: Geology
Published: 25 September 2018
Geology (2018) 46 (11): 931–934.
...-temperature osumilite gneisses in southern Madagascar record combined heat advection and high rates of radiogenic heat production in a long-lived high- T orogen : Journal of Metamorphic Geology , v. 36 , p., 855 – 880 , https://doi.org/10.1111/jmg.12316 . Horton , F. , Hacker , B.R...
FIGURES
Series: Special Publications of the Society of Economic Geologists
Published: 01 January 2018
DOI: 10.5382/SP.21.15
EISBN: 9781629496405
... vein graphite during orogenic collapse. The superimposition of the tectono-metamorphic history of southern Madagascar on a sedimentary sequence in which the protoliths were rich in organic carbon has resulted in world-class flake graphite mineralization with high carbon purities and large flake sizes...
FIGURES | View All (16)
Journal Article
Published: 01 July 2017
The Canadian Mineralogist (2017) 55 (4): 619–650.
...Stefano Salvi; Gaston Giuliani; Prosper Rakatovao Andrianjakavah; Bernard Moine; Didier Beziat; Anthony Fallick Abstract The Ianapera emerald deposit is hosted in the Neoproterozoic Vohibory domain of southern Madagascar, within a tightly folded metamorphic sequence of mafic and ultramafic rocks (M...
FIGURES | View All (12)
Journal Article
Published: 01 March 2011
European Journal of Mineralogy (2011) 23 (2): 127–156.
...Niels Jöns; Volker Schenk Abstract We examined the petrological characteristics of the Graphite group and Androyan group in Southern Madagascar, south of the prominent Ranotsara shear zone, and we performed U-Pb SHRIMP dating on zircon and U-Th-total Pb dating on monazite. Widespread high...
FIGURES | View All (16)
Journal Article
Published: 01 January 2002
American Mineralogist (2002) 87 (1): 132–141.
...Johan de Grave; Paul de Paepe; Eddy de Grave; Renaud Vochten; Sigrid G. Eeckhout Abstract Dark pyroxene crystals found in a calcite vein cutting across marbles and skarns at Andranondambo, southern Madagascar, were investigated with various techniques in order to characterize and identify...
FIGURES | View All (5)
Journal Article
Published: 01 May 1996
Geological Magazine (1996) 133 (3): 311–323.
Journal Article
Published: 24 June 2022
Geological Magazine (2022) 159 (9): 1569–1600.
... and Anosyan domains of southern Madagascar, the SMB is equivalent to the Antananarivo and Itremo–Ikalamavony blocks of the central Madagascar, and the sinistral AKSZ is contiguous with the Ranotsara Shear Zone in southern Madagascar. Corresponding author: S. Rekha, Emails: [email protected] ; georekha...
FIGURES | View All (13)
Image
(a) Location of study area in southern Madagascar. (b) Simplified map of the southern Madagascar Precambrian basement domains annotated with sample locations relevant to this study. The concentration of Ambalavao suite plutons in the southeastern Anosyen domain has also been called the Anosyen Batholith. Metamorphic pressure–temperature data from this study are projected along strike to transect A–B–C in Figure 4. (c) Madagascar's position in Gondwana. Source: modified from Roig et al. (2012) with structures based on Martelat et al. (2020); (c) modified from Meert and Lieberman (2008).
Published: 08 January 2025
Fig. 1. ( a ) Location of study area in southern Madagascar. ( b ) Simplified map of the southern Madagascar Precambrian basement domains annotated with sample locations relevant to this study. The concentration of Ambalavao suite plutons in the southeastern Anosyen domain has also been called
Image
Summary of select P–T estimates from southern Madagascar. The Vohibory domain is characterized by notably higher pressure, at similar temperature, compared with the Androyen domain. The Androyen domain is characterized by a clockwise granulite-facies P–T path at relatively low pressure (<0.7 GPa). The Anosyen domain differs from the Androyen domain in that it reached higher peak temperature at comparable pressure. Several studies have suggested a higher-pressure metamorphic history from the Beraketa shear zone. Whether these are real geological differences (higher metamorphic pressures recorded by some Beraketa shear zone rocks) or systematic error associated with different thermobarometric approaches or rock types is not clear.
Published: 08 January 2025
Fig. 9. Summary of select P–T estimates from southern Madagascar. The Vohibory domain is characterized by notably higher pressure, at similar temperature, compared with the Androyen domain. The Androyen domain is characterized by a clockwise granulite-facies P–T path at relatively low
Image
Simplified geological map of southern Madagascar (modified after Holder and Hacker, 2019, and Holder et al., 2018) shows sample locations (MD04, MD12, and MD18) and the major rivers (denoted as “R”) of southern Madagascar. An inset map of Madagascar shows ocean currents and eddies (Vousden et al., 2008).
Published: 02 September 2022
Figure 1. Simplified geological map of southern Madagascar (modified after Holder and Hacker, 2019 , and Holder et al., 2018 ) shows sample locations (MD04, MD12, and MD18) and the major rivers (denoted as “R”) of southern Madagascar. An inset map of Madagascar shows ocean currents and eddies
Image
Pressure-temperature evolution of rocks from southern Madagascar. The solid P-T path is for the southern part of the Androyan group. The dashed path accounts for lower P-T conditions of the northern part. Numbers within the shaded fields correspond to different geothermobarometers (references given in the figure). Dashed ellipses are Thermocalc average P-T estimates (1σ errors) for two samples from the southern Androyan group, the solid ellipse gives an average of both samples.
Published: 01 March 2011
Fig. 11. Pressure-temperature evolution of rocks from southern Madagascar. The solid P-T path is for the southern part of the Androyan group. The dashed path accounts for lower P-T conditions of the northern part. Numbers within the shaded fields correspond to different geothermobarometers
Journal Article
Journal: GSA Bulletin
Published: 02 September 2022
GSA Bulletin (2023) 135 (5-6): 1297–1309.
...Figure 1. Simplified geological map of southern Madagascar (modified after Holder and Hacker, 2019 , and Holder et al., 2018 ) shows sample locations (MD04, MD12, and MD18) and the major rivers (denoted as “R”) of southern Madagascar. An inset map of Madagascar shows ocean currents and eddies...
FIGURES | View All (11)
Journal Article
Published: 01 July 2004
The Journal of Geology (2004) 112 (4): 379–399.
... provenance analysis of the Itremo Group points to sources in East Africa as well as local sources in central and southern Madagascar but provides no evidence for a detrital contribution from northern and eastern Madagascar nor from southern India. Detrital zircon and sedimentologic similarities between rocks...
FIGURES | View All (9)
Journal Article
Journal: Geology
Published: 23 September 2021
Geology (2021) 49 (2): 150–155.
... microplate, across the Comoros Islands, and including parts of central and northern Madagascar. Madagascar is fragmenting, with southern Madagascar rotating with the Lwandle microplate and a piece of eastern and south-central Madagascar moving with the Somalian plate. Divergence of the Nubian-Somalian plate...
FIGURES
Image
(a) Block-diagram of orogenic structure in southern and central Madagascar as it relates to the orogenic structure of eastern Africa. In eastern Africa, divergent thrust systems are separated by the 20 km wide sinistral Galana shear zone. This central region of upright structure broadens into southern Madagascar, bounding the granulite-facies terranes. (b) Same diagram as (a) but highlighting the west-vergent nappes. (c) The east-vergent nappes. (d) The region affected by 650–600 Ma metamorphism. (e) The region affected by 580–520 Ma metamorphism. (f) The central orogenic zone of upright structure. The Anosyen and Androyen domains of southern Madagascar are unique in the orogenic belt in that they occupy this central region of upright structure and prominently preserve evidence for both major phases of orogenesis, at 630–600 and 580–500 Ma.
Published: 08 January 2025
Fig. 11. ( a ) Block-diagram of orogenic structure in southern and central Madagascar as it relates to the orogenic structure of eastern Africa. In eastern Africa, divergent thrust systems are separated by the 20 km wide sinistral Galana shear zone. This central region of upright structure
Journal Article
Journal: GSA Bulletin
Published: 01 January 2012
GSA Bulletin (2012) 124 (1-2): 240–255.
.... Furthermore, the geodynamic reconstructions extending the shear zones of southern Madagascar into south India are not tenable. † E-mail: [email protected] 5 3 2010 10 10 2010 14 10 2010 © 2012 Geological Society of America 2012 The intraplate magmatism...
FIGURES | View All (12)
Journal Article
Journal: GSA Bulletin
Published: 01 August 1970
GSA Bulletin (1970) 81 (8): 2261–2286.
... West Africa, in southern Madagascar, and in the Kafue Flats, Zambia. Age of the glaciation ranges from Late Carboniferous to Early Permian but may have begun in the Early Carboniferous. Striated floors beneath the glacial rocks indicate that extensive lobes of ice flowed radially outward from...
Journal Article
Journal: Geology
Published: 01 May 2009
Geology (2009) 37 (5): 403–406.
... and evaluating sediment-transport conditions under which such features formed. We model the southern Madagascar case, with an impact source in the Indian Ocean, and show that a modeled wave approach is inconsistent with “chevron” orientation. We then evaluate sediment-transport conditions under which...
FIGURES | View All (4)
Journal Article
Published: 01 January 1956
Bulletin de la Société Géologique de France (1956) S6-VI (1-3): 269–273.
... of mineralization. If the parametamorphic nature of the diopside pyroxenites of southern Madagascar is proved, a new theory of mica mineralization must be formulated. GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America...