Differential Phanerozoic evolution of cratonic and non-cratonic lithosphere from a thermochronological perspective: São Francisco Craton and marginal orogens (Brazil)

Recycling deep cratonic lithosphere and generation of intraplate magmatism in the North China Craton

Early Cretaceous alkaline picrites and high-magnesium basalts from the North China craton provide evidence for recycling of continental lithosphere by density foundering. Both the picrites and basalts contain xenocrystic olivines with high Fo92-93 and low CaO (<0.10%), consistent with the lavas’ derivation from, or interaction with Archean mantle lithosphere. Most importantly, both the picritic...

Teleseismic imaging of the Slave craton and implications for the assembly of cratonic lithosphere

In this dissertation, I investigate the assembly and evolution of the Archean cratonic lithosphere by using two complementary seismological methods to image the lithospheric structure of the Slave craton in Canada. First, I perform surface wave tomographic inversions to constrain the depth dependence of Rayleigh wave phase velocity, shear wave velocity, and azimuthal anisotropy of the Slave cra...

Mantle Geochronology and the Age of the Sub-cratonic Lithosphere

Introduction High precision in situ analysis of trace-element compositions and isotope ratios has revolutionised geochronology and geochemistry over the past decade. Most of the advances are due to the proliferation of laser-ablation microprobe inductively coupled plasma mass spectrometry (ICP-MS) and the rapid development of the multi-collector (MC-) ICP-MS. One of the main benefits of in situ...

Is the African cratonic lithosphere wet or dry?

Thick continental lithosphere (tectosphere) beneath African cratons has been stable for ~2.5 b.y. despite its mechanical interaction with sublithospheric mantle. Water is known to have signifi cant infl uence on mechanical stiffness, and the depletion of water is often considered to be a key to preserving the thick lithosphere. Although water-rich environments indicated by the present water con...

Water content of the Tanzanian lithosphere from magnetotelluric data: Implications for cratonic growth and stability