Sapphirine — Orthopyroxene — Garnet Granulite from Schirmacher Hills, Central Dronning Maud Land

Baba, Sotaro; Owada, Masaaki; Shiraishi, Kazuyuki

doi:10.1007/3-540-32934-x_5

Cited by 10 publications

(11 citation statements)

References 17 publications

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“…However, comparison of mineral textural features suggests that the metamorphic P-T path of the Schirmacher Hills granulites is typical of an IBC history whereas those from Jutulsessen and Filchnerfjella are typical of an isothermal decompression (ITD) history. The IBC history observed in the Schirmacher Hills may represent a cooling path after a period of UHT metamorphism (c. 950-1050 8C, 9-10 kbar) as proposed by Baba et al (2006).…”

Section: Interpretation Of Metamorphic Textures and Conditionsmentioning

confidence: 75%

“…A recent Sm -Nd mineral isochron using orthopyroxene, retrograde garnet reaction rim, and plagioclase gave an age of c. 630 Ma, which is interpreted as the age of cooling from granulitefacies metamorphism (Ravikant et al 2004). Baba et al (2006) reported a new sapphirine locality in the southwestern part of the Schirmacher Hills, and proposed ultrahigh-temperature (UHT) metamorphism on the basis of the orthopyroxene compositions and paragenesis.…”

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confidence: 99%

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Contrasting metamorphic P – T path between Schirmacher Hills and Mühlig-Hofmannfjella, central Dronning Maud Land, East Antarctica

Baba

Owada

Shiraishi

2008

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Retrograde metamorphic P-T paths of garnet-pyroxene-bearing mafic gneisses from three regions in central Dronning Maud Land (CDML) were examined. No difference in P-T conditions estimated from rocks of the three regions was recognized, and they are within the range of c. 6-8 kbar, 750-830 8C. However, localities in the Mühlig-Hofmann Range (Filchnerfjella and Jutulsessen) preserve rocks with mineral textures that indicate near-isothermal decompressional histories. In the Schirmacher Hills, an isolated exposure on the Princess Astrid Coast, metamorphic texture observed in mafic gneiss is indicative of an isobaric cooling history. Combining their P-T paths and age determinations suggests that the Schirmacher Hills was a separate terrane, together with present-day SE Africa, whereas the Grenvillian-age eastwest-trending CDML inland nunatak regions are characterized by an isothermal decompressional metamorphic history related to the final amalgamation of Gondwana.

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Section: Interpretation Of Metamorphic Textures and Conditionsmentioning

confidence: 75%

mentioning

confidence: 99%

Contrasting metamorphic P – T path between Schirmacher Hills and Mühlig-Hofmannfjella, central Dronning Maud Land, East Antarctica

Baba

Owada

Shiraishi

2008

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“…In contrast, Antarctica has not been subject to the same level of erosion, resulting in the preservation of a largely continuous slab of East African Orogen rocks from the nunataks at Mramornye c. 718S, c. 88E (Piazolo 2004) via Schirmacher Oasis (Ravikant et al 2002(Ravikant et al , 2004(Ravikant et al , 2008Baba et al 2006Baba et al , 2008, the eastern Mühlig-Hofman mountains, NE Sør Rondane and beyond. We have not explored detailed aspects of the geology east of Sør Rondane other than to note that we are not aware of any rocks, east of SW Sør Rondane, with Nampula Block type lithological, geochronological and metamorphic characteristics.…”

Section: Discussionmentioning

confidence: 88%

“…All these P-T loops suggest early isothermal decompression followed by isobaric cooling with P-T conditions of c. 6-7 kbar and c. 600-700 8C at c. 550 Ma, although the P-T path from Sør Rondane shows additional complexities not recognized from other areas. The P-T conditions for Schirmacher Hills and Sør Rondane are from Baba et al (2006) whereas those from Sri Lanka are from Schumacher et al (1990), Hiroi et al (1994) and Raase & Schenk (1994).…”

Section: Metamorphic Historymentioning

confidence: 97%

Terrane correlation between Antarctica, Mozambique and Sri Lanka; comparisons of geochronology, lithology, structure and metamorphism and possible implications for the geology of southern Africa and Antarctica

Grantham

Macey

Ingram

et al. 2008

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“…Recently recognised localities ( Fig. 2; Table 1) include the Acadian Orogen in northeast USA (Ague and Eckert, 2012;Ague et al, 2013), the Garzón Massif in Colombia (Altenberger et al, 2012), the Schirmacher Hills in Dronning Maud Land, Antarctica (Baba et al, 2006;Baba et al, 2010), the Central Indian Tectonic Zone (Bhandari et al, 2011;Bhowmick et al, 2014), the Anosyen domain of SE Madagascar (Jöns and Schenk, 2008;Rakotonandrasana et al, 2010;Jöns and Schenk, 2011;Boger et al, 2012), the South Altay Belt in NW China (Chen et al, 2006;, the Lapland Granulite Belt…”

Section: What Is Uht Crustal Metamorphism?mentioning

confidence: 97%

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

Kelsey

Hand

2015

Geoscience Frontiers

367

285

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a b s t r a c tUltrahigh temperature (UHT) metamorphism is the most thermally extreme form of regional crustal metamorphism, with temperatures exceeding 900 C. UHT crustal metamorphism is recognised in more than 50 localities globally in the metamorphic rock record and is accepted as 'normal' in the spectrum of regional crustal processes. UHT metamorphism is typically identified on the basis of diagnostic mineral assemblages such as sapphirine þ quartz, orthopyroxene þ sillimanite AE quartz and osumilite in MgeAlrich rock compositions, now usually coupled with pseudosection-based thermobarometry using internally-consistent thermodynamic data sets and/or Al-in-Orthopyroxene and ternary feldspar thermobarometry. Significant progress in the understanding of regional UHT metamorphism in recent years includes: (1) development of a ferric iron activityecomposition thermodynamic model for sapphirine, allowing phase diagram calculations for oxidised rock compositions; (2) quantification of UHT conditions via trace element thermometry, with Zr-in-rutile more commonly recording higher temperatures than Ti-in-zircon. Rutile is likely to be stable at peak UHT conditions whereas zircon may only grow as UHT rocks are cooling. In addition, the extent to which Zr diffuses out of rutile is controlled by chemical communication with zircon; (3) more fully recognising and utilising temperature-dependent thermal properties of the crust, and the possible range of heat sources causing metamorphism in geodynamic modelling studies; (4) recognising that crust partially melted either in a previous event or earlier in a long-duration event has greater capacity than fertile, unmelted crust to achieve UHT conditions due to the heat energy consumed by partial melting reactions; (5) more strongly linking UePb geochronological data from zircon and monazite to PeT points or path segments through using Y þ REE partitioning between accessory and major phases, as well as phase diagrams incorporating Zr and REE; and (6) improved insight into the settings and factors responsible for UHT metamorphism via geodynamic forward models. These models suggest that regional UHT metamorphism is, principally, geodynamically related to subduction, coupled with elevated crustal radiogenic heat generation rates.Ó 2014, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

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Sapphirine — Orthopyroxene — Garnet Granulite from Schirmacher Hills, Central Dronning Maud Land

Cited by 10 publications

References 17 publications

Contrasting metamorphic P – T path between Schirmacher Hills and Mühlig-Hofmannfjella, central Dronning Maud Land, East Antarctica

Contrasting metamorphic P – T path between Schirmacher Hills and Mühlig-Hofmannfjella, central Dronning Maud Land, East Antarctica

Terrane correlation between Antarctica, Mozambique and Sri Lanka; comparisons of geochronology, lithology, structure and metamorphism and possible implications for the geology of southern Africa and Antarctica

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

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