Outboard Onset of Ross Orogen Magmatism and Subsequent Igneous and Metamorphic Cooling Linked to Slab Rollback during Late-Stage Gondwana Assembly ...

• Main Authors: Paulsen, Timothy, Encarnación, John, Grunow, Anne, Benowitz, Jeffrey, Layer, Paul, Deering, Chad, Sliwinski, Jakub
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2023
• Subjects: 40Ar/39Ar; cooling; magmatism; zircon; trace elements; slab rollback; Ross orogen; Antarctica; Gondwana; Antarc*; Antarctic; Liv Glacier
• Online Access: https://dx.doi.org/10.3929/ethz-b-000610928; http://hdl.handle.net/20.500.11850/610928

Changes in magmatism and sedimentation along the late Neoproterozoic-early Paleozoic Ross orogenic belt in Antarctica have been linked to the cessation of convergence along the Mozambique belt during the assembly of East-West Gondwana. However, these interpretations are non-unique and are based, in part, on limited thermochronological data sets spread out along large sectors of the East Antarctic margin. We report new 40Ar/39Ar hornblende, muscovite, and biotite age data for plutonic (n = 13) and metasedimentary (n = 3) samples from the Shackleton–Liv Glacier sector of the Queen Maud Mountains in Antarctica. Cumulative 40Ar/39Ar age data show polymodal age peaks (510 Ma, 491 Ma, 475 Ma) that lag peaks in U-Pb igneous crystallization ages, suggesting igneous and metamorphic cooling following magmatism within the region. The 40Ar/39Ar ages are similar to ages in other sectors of the Ross orogen, but younger than detrital mineral 40Ar/39Ar cooling ages indicative of older magmatism and cooling of unexposed ... : Geosciences, 13 (4) ...