RT Journal Article
T1 Speculations on the Paleozoic legacy of Gondwana amalgamation
A1 Murphy, J. Brendan
A1 Nance, R. Damian
A1 Johnston, Stephen T.
A1 Casas Tuset, Josep María
A1 Cawood, Peter A.
A1 Matheson, Edward J.
A1 Pufahl, Peir K.
A1 Dan, Wei
A1 Álvaro, J.J.
A1 Heron, Philip J.
A1 Strachan, Robin A.
PB Elsevier
SN 1342-937X
YR 2024
FD 2024-05
LK https://hdl.handle.net/20.500.14352/102054
UL https://hdl.handle.net/20.500.14352/102054
LA eng
NO Using Gondwana as an example, we show how the geological record can be interrogated to detect significant changes in mantle convection patterns at critical junctures in Earth’s evolution. Evidence of major changes in mantle circulation in the aftermath of late Neoproterozoic-early Paleozoic Gondwana assembly is provided by widespread (i) plume-related magmatism around Gondwana’s periphery, (ii) ironstone deposits related to mantle plume-ocean ridge interaction and enhanced hydrothermal activity, and (iii) super-mature clastic deposits that reflect epeirogenic uplift triggered by mantle upwelling beneath Gondwana combined with deep tropical weathering.In our model, Gondwana assembled above a region of mantle downwelling in which subducted slabs between the converging Gondwanan continents descended to the core-mantle boundary. Renewed subduction along Gondwana’s periphery yielded early arc magmas. But as downwelling beneath Gondwana evolved into upwelling as a result of the ponding of subducted slabs at the base of the mantle, mantle plumes rose from the margins of the nascent upwelling to interact with the edges of Gondwana, where they penetrated the peripheral subduction zones via slab windows, tears and transform faults to generate voluminous calc-alkalic crustal melts in hydrated arc regions and A-type magmas in dry back-arc regions. The plumes also underplated oceanic lithosphere and interacted with adjacent ocean ridges, thereby enhancing hydrothermal activity and the flux of bioessential nutrients, leading to the recurrence of marine iron-rich sedimentary rocks in the geological record. At the same time, upwelling beneath a tropical to equatorial Gondwana led to epeirogenic uplift, deep weathering and erosion, resulting in the production of widespread super-mature clastic deposits. We contend that major changes in mantle convection patterns were encoded into the geological record of Gondwana assembly, influenced global-scale mantle convection patterns, and should be incorporated into geodynamic models for the assembly of Pangea.
NO NSERC
NO Australian Research Council
NO Czech Operational Programme Research
NO Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional
NO St. Francis Xavier University
NO NSERC Canada
DS Docta Complutense
RD 31 jul 2025