Geological Society of America

T247 Lithospheric Structure and Evolution of Cratons

Friday, 30 October 2020
10:00 AM - 2:00 PM
Meeting Rooms

A MULTI-OBSERVABLE JOINT INVERSION FOR SOUTHERN AND CENTRAL AFRICA IN FULL 3D

Paper number: T247-13
Program: Technical Sessions
Time: 12:40 PM – 12:50 PM

Authors

Ilya Fomin Presenting Author
Macquarie University, Sydney, NSW
Walid Ben Mansour
Macquarie University, Sydney, NSW
Walid Ben Mansour
Washington University in Saint Louis, Saint Louis, MO
Juan Carlos Afonso
Macquarie University, Sydney, NSW
Andrew Macdonald
De Beers Group, Johannesburg
Nicole Januszczak
Toronto, ON

Abstract

The thermochemical structure of the Earth’s lithosphere and sublithospheric upper mantle controls the pattern of geophysical observables and is closely linked to the spatial distribution of mineral deposits. Its imaging in 3D is a significant challenge due to the large number of factors that can affect geophysical signatures and the non-linearity of the inverse problem.

We have developed a new software (LITMOD3D_4inv) to perform a multi-observable joint inversion in full 3D, combining several independent sources of data (gravity, seismic and magnetotelluric observations supported with petrological data for mantle composition) to improve the sensitivity and parameter identifiability. The code uses Markov chain Monte-Carlo procedures with highly optimised forward problem solvers to sample the parameter space and determine geological structures and features with full characterisation of their uncertainties.

The program explored the thermochemical structure of the Kalahari craton and the Damara orogenic belt (Southern Africa), an area strongly affected by kimberlitic and carbonatitic volcanism. In this presentation, we will discuss the main results, interpretations in the terms of geological features and discuss the implications for evolutionary models of the region.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-359474

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