Geochronology of Paleozoic terranes at the Pacific Ocean margin of Zealandia

• Published in: Gondwana research 2008-03, Vol.13 (2), p.250-258
• Main Author: Adams, C.J.
• Format: Article
• Language: English
• Subjects: Bounty Island; Campbell Island; Metamorphic rocks; Paleozoic; Rb–Sr dating; U–Pb dating
• ISSN: 1342-937X; 1878-0571
• DOI: 10.1016/j.gr.2007.07.001

Rb–Sr and U–Pb zircon ages are reported from basement rocks on Campbell Plateau. On Campbell Island, Rb–Sr ages of Complex Point schists are (1) at Complex Point, 462 ± 53 Ma similar to Western Province, early Paleozoic metasediments in New Zealand, and Antarctic correlatives and (2) at Garden Cove, 526 ± 18 Ma, (pre-Late Cambrian). Schist detrital zircons have a youngest age peak 524 ± 5 Ma, suggesting an Early or early Middle Cambrian stratigraphic age not seen in New Zealand and possibly correlative with Sledgers Group, North Victoria Land, Antarctica. On Bounty Island, granodiorites yield an Rb–Sr age, 183 ± 9 Ma, with correlates known only in eastern Marie Byrd Land, Antarctica. Metasediments at a seafloor locality on Bounty Platform, have a minimum U–Pb detrital zircon age, 482 ± 5 Ma, and an Rb–Sr metamorphic age 174 ± 32 Ma, correlative with Western Province metasediments in South Island. The age data suggest that Campbell Plateau is mostly underlain by Western Province, early Paleozoic metasediments, intruded by (1) early to mid-Cretaceous granitoids along the western margin, extending north to New Zealand and south to Antarctica, and (2) Early Jurassic granitoids on Bounty Platform extending to Marie Byrd Land.