Chapter 1 Introduction to Paleozoic–Mesozoic geology of South Island, New Zealand: subduction-related processes adjacent to SE Gondwana

Robertson, Alastair H. F.; Campbell, Hamish J.; Johnston, M. R.; Mortimer, Nick

doi:10.1144/m49.7

Cited by 10 publications

(1 citation statement)

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“…There is broad consensus on the accretionary nature of the orogeny, but the role of terranes and their translation during the Mesozoic remains an area of debate. Vaughan and Storey (2000) reinterpreted the geology of the Antarctic Peninsula as an amalgamation of para‐autochthonous and allochthonous terranes following the development of similar models elsewhere along the Pacific margin in New Zealand (e.g., Robertson et al., 2019). The model was further developed to describe the accretion of terranes onto the Gondwana margin (e.g., Vaughan et al., 2012).…”

Section: Antarctic Peninsula: Geological Settingmentioning

confidence: 99%

Evolution of an Accretionary Complex (LeMay Group) and Terrane Translation in the Antarctic Peninsula

et al. 2023

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The LeMay Group accretionary complex of Alexander Island (Antarctic Peninsula) comprises a 4 km thick succession of variably deformed turbidites associated with thrust slices of ocean floor basalts. The depositional age and provenance of the succession is uncertain with estimates ranging from Carboniferous to Cretaceous. The accretion history is also poorly established and whether the LeMay Group developed allochthonously and accreted during an episode of Cretaceous terrane translation. We have examined the geochronology and geochemistry of 22 samples from across the entire accretionary complex to determine its depositional, provenance and accretion history. The accretionary complex has been subdivided into four separate groups based on detrital zircon U‐Pb age and Lu‐Hf provenance analysis. Groups 1 and 2 are interpreted to be a continuation of the extensive Permian accretionary complexes of West Gondwana and have a depositional age of c. 255 Ma, with volcaniclastic input from the extensive silicic volcanism of the Choiyoi Province. Accretion of the LeMay Group to the continental margin developed during the mid‐Triassic, potentially related to the Peninsula Orogeny and an episode of flat‐slab subduction of the proto‐Pacific plate. Group 3 is only identified from an island to the west of Alexander Island and has a mid‐Cretaceous depositional age and provenance akin to offshore sequences from Thurston Island. A para‐autochthonous origin is suggested, with mid‐Cretaceous accretion associated with the melange belts of central Alexander Island. Group 4 is also a distinct unit with an Early Jurassic depositional age and a source more closely related to the Antarctic Peninsula.

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Section: Antarctic Peninsula: Geological Settingmentioning

confidence: 99%