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Enderby Land is a region of Northeastern Antarctica which extends into the Southern Indian Ocean. The unique and diverse geological features of this Australian Antarctic Territory have been associated with the evolution and development of the supercontinent Gondwana. Multiple distinct geological formations are located in this region. The most prominent and important are the # Napier Complex (Archaean) # Rayner Complex (late-Proterozoic) # Lützow-Holm Complex (LHC) (early-Paleozoic) # Yamato–Belgica Complex (early-Paleozoic) Both the Proterozoic and Paleozoic structures present in this region have become visible due to the initial uplift and exposure of the Archaean Napier Complex, where the oldest metamorphic rocks (4000 Ma) were found in the expanding Archaean blocks. ==Metamorphism== The high‐grade metamorphic rocks of Enderby Land, which form part of the East Antarctic Shield, have been subdivided into three major metamorphic core complexes. These are the *Archaean Napier Complex *Proterozoic Rayner Complex *Paleozoic Lützow-Holm Complex (LHC) The Napier Complex contains primarily pyroxene‐quartz‐feldspar gneiss and garnet‐quartz‐feldspar gneiss, with minor amounts of both pyroxene and mafic granulite.There are also a variety of siliceous and aluminous metasediments present. Multiple mafic dykes are also present in the area which intrude into the gneisses. The ultra-high-temperature (UHT) Napier metamorphic complex is noteworthy and distinctive due to the presence of the highest grades of metamorphism seen in rocks of any continental crust. The early predecessors of tonalitic and granitic gneisses range in age locally up to 3800 Ma, and therefore are the oldest rocks documented from Antarctica. It is generally agreed upon that all the high-grade and ultra-high-temperature metamorphism in the area was finished by the end of the Archean. Effects of the metamorphism are mostly restricted to regions of retrogression and localized shear zones in the area. The Rayner Complex consists predominately of re‐metamorphosed Napier Complex rocks, and mafic dykes that occur only as metamorphosed remnants. The rocks of the Rayner Complex are generally of a lower metamorphic grade (upper amphibolite to granulite facies) than those found in the Napier Complex. There are however, high-pressure granulites that can be found locally.〔 Higher water pressures were inferred from observation of relatively abundant migmatitic gneisses and hydrous minerals such as biotite and hornblende, as well as the lack of mesoperthite.〔 The Lützow-Holm Complex experienced regional metamorphism in the early Paleozoic. This metamorphic complex contains metamorphic ages associated with the Pan-African orogeny (520 and 560 Ma). The main regional metamorphism in the LHC is related to continent-continent collision between portions of the Gondwana supercontinent. This area may include remains of a potential suture between East and West Gondwana. The metamorphic grade increases gradually from the Prince Olav Coast (amphibolite facies; eastern part of the LHC) to the Soya Coast (granulite facies; western part of the LHC).〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Geology of Enderby Land」の詳細全文を読む スポンサード リンク
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