University of Tasmania
Browse

Evolving marginal terranes during Neoproterozoic supercontinent reorganization: constraints from the Bemarivo Domain in northern Madagascar

Download (3.94 MB)
journal contribution
posted on 2023-05-21, 07:50 authored by Sheree ArmisteadSheree Armistead, Collins, AS, Merdith, AS, Payne, JL, Cox, GM, Foden, JD, Razakamanana, T, De Waele, B

Madagascar is a key area for unraveling the geodynamic evolution of the transition between the Rodinia and Gondwana supercontinents as it contains several suites of c. 850–700 Ma magmatic rocks that have been postulated to correlate with other Rodinian terranes. The Bemarivo Domain of northern Madagascar contains the youngest of these units that date to c. 750–700 Ma. We present zircon Hf and O isotope data to understand northern Madagascar's place in the Neoproterozoic plate tectonic reconfiguration. We demonstrate that the northern component of the Bemarivo Domain is distinct from the southern part of the Bemarivo Domain and have therefore assigned new names—the Bobakindro Terrane and Marojejy Terrane, respectively. Magmatic rocks of the Marojejy Terrane and Anaboriana Belt are characterized by evolved εHf(t) signatures and a range of δ18O values, similar to the Imorona-Itsindro Suite of central Madagascar. These magmatic suites likely formed together in the same long-lived volcanic arc. In contrast, the Bobakindro Terrane contains juvenile εHf(t) and mantle-like δ18O values, with no probable link to the rest of Madagascar. We propose that the Bobakindro Terrane formed in a juvenile arc system that included the Seychelles, the Malani Igneous Suite of northwest India, Oman, and the Yangtze Belt of south China, which at the time were all outboard from continental India and south China. The final assembly of northern Madagascar and amalgamation of the Bobakindro Terrane and Marojejy Terrane occurred along the Antsaba subduction zone, with collision occurring at c. 540 Ma.

History

Publication title

Tectonics

Volume

38

Issue

6

Pagination

2019-2035

ISSN

0278-7407

Department/School

Institute for Marine and Antarctic Studies

Publisher

Amer Geophysical Union

Place of publication

2000 Florida Ave Nw, Washington, USA, Dc, 20009

Rights statement

©2019. American Geophysical Union. All Rights Reserved.

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the earth sciences

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC