Toggle Main Menu Toggle Search

Open Access padlockePrints

Madagascar's escape from Africa: A high-resolution plate reconstruction for the Western Somali Basin and implications for supercontinent dispersal

Lookup NU author(s): Professor Richard Davies

Downloads

Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Abstract

Accurate reconstructions of the dispersal of supercontinent blocks are essential for testing continental breakup models. Here, we provide a new plate tectonic reconstruction of the opening of the Western Somali Basin during the breakup of East and West Gondwana. The model is constrained by a new comprehensive set of spreading lineaments, detected in this heavily sedimented basin using a novel technique based on directional derivatives of free-air gravity anomalies. Vertical gravity gradient and free-air gravity anomaly maps also enable the detection of extinct mid-ocean ridge segments, which can be directly compared to several previous ocean magnetic anomaly interpretations of the Western Somali Basin. The best matching interpretations have basin symmetry around the M0 anomaly; these are then used to temporally constrain our plate tectonic reconstruction. The reconstruction supports a tight fit for Gondwana fragments prior to breakup, and predicts that the continent-ocean transform margin lies along the Rovuma Basin, not along the Davie Fracture Zone (DFZ) as commonly thought. According to our reconstruction, the DFZ represents a major ocean-ocean fracture zone formed by the coalescence of several smaller fracture zones during evolving plate motions as Madagascar drifted southwards, and offshore Tanzania is an obliquely rifted, rather than transform, margin. New seismic reflection evidence for oceanic crust inboard of the DFZ strongly supports these conclusions. Our results provide important new constraints on the still enigmatic driving mechanism of continental rifting, the nature of the lithosphere in the Western Somali Basin, and its resource potential.


Publication metadata

Author(s): Phethean JJJ, Kalnins LM, van Hunen J, Biffi PG, Davies RJ, McCaffrey KJW

Publication type: Article

Publication status: Published

Journal: Geochemistry, Geophysics, Geosystems

Year: 2016

Volume: 17

Issue: 12

Pages: 5036-5055

Print publication date: 01/12/2016

Online publication date: 29/12/2016

Acceptance date: 05/12/2016

Date deposited: 26/11/2018

ISSN (electronic): 1525-2027

Publisher: Wiley-Blackwell Publishing, Inc.

URL: http://dx.doi.org/10.1002/2016GC006624

DOI: 10.1002/2016GC006624


Altmetrics

Altmetrics provided by Altmetric


Actions

Find at Newcastle University icon    Link to this publication


Share