Geochemistry and Geochronology of Early Paleozoic Intrusive Rocks in the Terra Nova Bay Area, Northern Victoria Land, Antarctica

• Published in: Minerals
• Main Authors: Daeyeong Kim, Sang-Bong Yi, Hyeoncheol Kim, Taehwan Kim, Taehoon Kim, Jong Ik Lee
• Format: Text
• Language: English
• Published: Multidisciplinary Digital Publishing Institute 2021
• Subjects: Ross Orogeny; Terra Nova Intrusive Complex (TNIC); northern Victoria Land (NVL); zircon U-Pb age; Sr-Nd isotopes; Victoria Land; Terra Nova Bay; Browning; Antarc*; Antarctica
• Online Access: https://doi.org/10.3390/min11070787

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.