b'Education matters Cyrille Njiteu, University of Douala,studies and by comparison with someof particles during mesh adaptivity, the Cameroon: Mechanical behaviour of theglobal MOHO models: CRUST1.0 andtransfer of particle between processors, lithosphere in the North-Central AfricanGEMMA. Direct modelling 2.3/4 D showsand the interpolation of values between Region (Cameroon, Central Africanan increase of the magnetisation fromparticles and nodes of the mesh.Republic, Chad) and modelling the sourcesCameroon to Central African Republic.In Chapter 3, validation of the of the Bangui Magnetic Anomaly. In some local areas, the crust beneathimplemented particle-in-cell scheme is the BMA is magnetic. The BMA can beundertaken for a series of well-known associated with (4) a magnetic crust andthermo-chemical convection benchmark an intrusion of deep and dense materialstests. For each benchmark, particles such as mafic granulites and Banded Irontrack material composition as they are Formations. advected throughout the computational Christopher Mathews, Australiandomain, with material composition National University: Methods for trackingfeeding back onto the density field and material properties within an unstructured,influencing the buoyancy of materials. adaptive mesh computational modellingResults from the particle scheme are framework, with application to simulatingcompared with results from a field-based the development of seismic anisotrophy atcontrol volume, flux-limited conservative spreading centres and transform faults. difference scheme known as HyperC. Both schemes perform favourably The ability to accurately and efficientlyacross the series of benchmark tests, track material properties in a Lagrangianwith HyperC displaying superior mass sense during geodynamical flows,conservation and the particle scheme as well as evaluate how they evolveexhibiting superior shape preservation, through both space and time, is of vitalresulting in a smoother material interface The Central African sub-region inimportance to our understanding ofand the visualization of finer scale Cameroon and Central African Republicthe structure, dynamics and evolutionfeatures. The particle-in-cell scheme is marked in its intra-continental partof Earths mantle and lithosphere. Anis favoured, as it is more flexible in its by two particular mega-structures: theapproach for achieving this, widelyapplication to tracking generalized Congo Craton and the Central Africanadvocated by the geodynamicsmaterial properties, enabling it to be Orogenic Belt (CAOB). All of them arecommunity, is the so-called particle-inapplied to a wide range of geodynamical intersected by a gigantic anomaly whosecell technique. With this scheme, materialproblems, such as the tracking of sources are still unknown: the Banguiproperties are tracked by a large numbermaterial texture.Magnetic Anomaly (BMA). Differentof particles that are advected with the approaches to spectral analysis, appliedflow field. These properties can representIn Chapter 4, we develop the software to ground gravity and satellite magnetica wide range of parameters (e.g.package PyDRex, which is capable data, allowing determination of thematerial composition or strain) and theof converting tracked deformation Moho and Curie depths were applied.information they carry can be accessedparameters into predictions of material Similarly, a regularised non-linearduring a simulation to feed back intolattice-preferred orientation and inversion method based on satellite- the flow equations (e.g. compositionseismic anisotropy. The generation only gravity data, as well as the analysiscontrolling material density), as well asof lattice-preferred orientation and of the coherence function betweengenerate diagnostic fields for analysissubsequent observations of seismic the topography and the Complete(e.g. the generation of lattice-preferredanisotropy within Earths mantle yields Bouguer anomaly, allowed analysis of theorientation). some of the most direct constrains mechanical behaviour of the lithosphere,available on both past and present-thus highlighting (1) the deepest locationIn Chapter 2, we develop a particle-in-cellday deformation. By simulating these of the sources associated to the BMA; (2)scheme within an adaptive, unstructured,processes with geodynamics models, the link between the BMA and the longanisotropic mesh computationalit is possible to generate synthetic wavelength positive gravity anomaly atmodelling framework called Fluidity.seismic anisotropy predictions, which the northern edge of the Congo CratonRegions of geodynamic interest oftencan be compared with observations in in Cameroon; (3) the geological origin ofvary throughout a simulation, and thean attempt to constrain the prevalent the BMA. combination of the particle-in-cellflow regime in the upper mantle. scheme with a state-of-the-art adaptiveIn Chapter 5, we utilize the PyDRex Thus, it has been shown that themesh algorithm enables both the meshsoftware package with Fluidity and sources related with the BMA are a set ofresolution and particle density to capturedevelop three sets of oceanic plate relatively dense and magnetic structures.areas of interest with high resolution (orboundary models, being 2D and 3D Interactions with regional shear zonesdensity), while reducing resolution (ormid-ocean ridge models, and 3D mid-have also been demonstrated, showingdensity) in areas of little geodynamicocean ridge models with a transform the imprint of thermal, tectonic andinterest. This ensures that a high levelfault offset. We compare anisotropy seismic events on the setting ofof accuracy is maintained throughoutpredictions from these models with the magnetic sources. The crustalthe computational domain, while alsoseismic observations of anisotropy, architecture was validated by the seismicgreatly improving numerical efficiency.allowing inferences to be made on the results of 32 stations from the CameroonThe implementation of this scheme sawprevalent flow regime and distribution Broadband Seismic Experiment (CBSE),several inherent challenges which hadof material anisotropy surrounding those available from previous gravityto be overcome, including the treatmentoceanic plate boundaries.35 PREVIEW DECEMBER 2021'