Abstract
The Terra Nova Intrusive Complex (TNIC) in northern Victoria Land, Antarctica, results from widespread magmatism during the Early Paleozoic Ross Orogeny. According to field relationships, geochemistry, and geochronology data, the northern part of the TNIC comprises the Browning Intrusive Unit (BIU), which is associated with an arc crustal melting including migmatization of the Wilson Metamorphic Complex, and the later Campbell Intrusive Unit (CIU), which is attributed to the mantle and crustal melting processes. Zircon U-Pb ages suggest Late Neoproterozoic to Early Cambrian protolith with Late Cambrian metamorphism (502 ± 15 Ma) in the WMC, Late Cambrian formation (~500 Ma) of the BIU, and Early Ordovician formation (~480–470 Ma) of the CIU. Sr-Nd isotopic characteristics of the BIU indicate predominant crustal component (εNd(t) = −8.7 to −8.9), whereas those of the CIU reflect both mantle (εNd(t) = 1.8 to 1.6) and crustal (εNd(t) = −4.0 to −7.5) compositions. These results suggest that the northern TNIC magmatism occurring at ~500–470 Ma originated from partial melting of the mantle–mafic crust components and mixing with felsic crust components. By integrating the results with previous studies, the TNIC is considered to be formed by a combination of the mantle and mafic crust melting, crustal assimilation, felsic crust melting, and magma mixing during the Ross Orogeny.
Highlights
The present tectonic setting in Antarctica is associated with diverse orogenic events which occurred during the Archean–Phanerozoic [1,2,3,4,5,6,7]
In Northern Victoria Land (NVL) contains a number of magma batches emplaced in a continental arc during the early stage of the Paleozoic Ross Orogeny
We report the data for intrusive bodies of varying mafic to felsic compositions found in the poorly studied northern part of the Terra Nova Intrusive Complex (TNIC), as part of the Korean Antarctic Research Program that was based in the Jang Bogo Station during the
Summary
The present tectonic setting in Antarctica is associated with diverse orogenic events which occurred during the Archean–Phanerozoic [1,2,3,4,5,6,7]. Orogeny was a prominent event along the Paleo-Pacific margin of the Gondwana supercontinent, where continental accretion and suturing have been documented (e.g., [5,6,7,8,9,10,11]). Magma intrusion and emplacement in continental margin environments are affected by many factors, such as the source material and its interactions during a multi-stage, multicomponent, and multi-process event. The Terra Nova Intrusive Complex (TNIC: [12,13]). In NVL contains a number of magma batches emplaced in a continental arc during the early stage of the Paleozoic Ross Orogeny. Multiple emplacements of magma pulses in the TNIC are revealed by several petrology and geochemistry data from mafic to felsic intrusive rocks (e.g., [14]). In previous studies, the northern part of the TNIC has been neglected probably because of the limited outcrops, inaccessibility, and harsh weather conditions
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