nerc.ac.uk

Palmer Land and Graham Land volcanic groups (Antarctic Peninsula): Petrology (Chapter 2.2b)

Riley, Teal R. ORCID: https://orcid.org/0000-0002-3333-5021; Leat, Philip T.. 2021 Palmer Land and Graham Land volcanic groups (Antarctic Peninsula): Petrology (Chapter 2.2b). In: Smellie, J.L.; Panter, K.S.; Geyer, A., (eds.) Volcanism in Antarctica: 200 million years of subduction, rifting and continental break-up. London, The Geological Society, 139-156. (Geological Society Memoir, M55).

Full text not available from this repository. (Request a copy)

Abstract/Summary

Large-volume rhyolitic volcanism along the proto-Pacific margin of Gondwana consists of three major episodes of magmatism or ‘flare-ups’. The initial episode (V1) overlaps with the Karoo–Ferrar large igneous provinces at c. 183 Ma. A second (V2) episode was erupted in the interval 171–167 Ma, and a third episode (V3) was emplaced in the interval 157–153 Ma. The magmatic events of the V1 and V2 episodes of the Antarctic Peninsula are reviewed here describing major and trace elements, and isotopic (Sr, Nd, O) data from rhyolitic volcanic rocks and more minor basaltic magmatism. An isotopically uniform intermediate magma developed as a result of anatexis of hydrous mafic lower crust, which can be linked to earlier, arc-related underplating. The subsequent lower-crust partial melts mixed with fractionated mafic underplate, followed by mid-crust storage and homogenization. Early Jurassic (V1) volcanic rocks of the southern Antarctic Peninsula are derived from the isotopically uniform magma, but they have mixed with melts of upper-crustal paragneiss in high-level magma chambers. The V2 rhyolites from the northern Antarctic Peninsula are the result of assimilation and fractional crystallization of the isotopically uniform magma. This process took place in upper-crust magma reservoirs involving crustal assimilants with an isotopic composition akin to that of the magma. A continental margin-arc setting was critical in allowing the development of an hydrous, fusible lower crust. Lower-crustal anatexis was in response to mafic underplating associated with the mantle plume thought to be responsible for the contemporaneous Karoo magmatic province and rifting associated with the initial break-up of Gondwana.

Item Type: Publication - Book Section
Digital Object Identifier (DOI): https://doi.org/10.1144/M55-2018-51
ISBN: 2041-4722
Date made live: 15 Apr 2021 11:46 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/520645

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...