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Bayesian noise-reduction in Arabia/Somalia and Nubia/Arabia finite rotations since ~20 Ma: Implications for Nubia/Somalia relative motion

Iaffaldano, Giampiero; Hawkins, Rhys; Sambridge, Malcolm

Description

Knowledge of Nubia/Somalia relative motion since the Early Neogene is of particular importance in the Earth Sciences, because it (i) impacts on inferences on African dynamic topography; and (ii) allows us to link plate kinematics within the Indian realm with those within the Atlantic basin. The contemporary Nubia/Somalia motion is well known from geodetic observations. Precise estimates of the past-3.2-Myr average motion are also available from paleo-magnetic observations. However, little is...[Show more]

dc.contributor.authorIaffaldano, Giampiero
dc.contributor.authorHawkins, Rhys
dc.contributor.authorSambridge, Malcolm
dc.date.accessioned2015-12-13T22:16:17Z
dc.identifier.issn1525-2027
dc.identifier.urihttp://hdl.handle.net/1885/70787
dc.description.abstractKnowledge of Nubia/Somalia relative motion since the Early Neogene is of particular importance in the Earth Sciences, because it (i) impacts on inferences on African dynamic topography; and (ii) allows us to link plate kinematics within the Indian realm with those within the Atlantic basin. The contemporary Nubia/Somalia motion is well known from geodetic observations. Precise estimates of the past-3.2-Myr average motion are also available from paleo-magnetic observations. However, little is known of the Nubia/Somalia motion prior to ∼3.2 Ma, chiefly because the Southwest Indian Ridge spread slowly, posing a challenge to precisely identify magnetic lineations. This also makes the few observations available particularly prone to noise. Here we reconstruct Nubia/Somalia relative motions since ∼20 Ma from the alternative plate-circuit Nubia-Arabia-Somalia. We resort to trans-dimensional hierarchical Bayesian Inference, which has proved effective in reducing finite-rotation noise, to unravel the Arabia/Somalia and Arabia/Nubia motions. We combine the resulting kinematics to reconstruct the Nubia/Somalia relative motion since ∼20 Ma. We verify the validity of the approach by comparing our reconstruction with the available record for the past ∼3.2 Myr, obtained through Antarctica. Results indicate that prior to ∼11 Ma the total motion between Nubia and Somalia was faster than today. Furthermore, it featured a significant strike-slip component along the Nubia/Somalia boundary. It is only since ∼11 Ma that Nubia diverges away from Somalia at slower rates, comparable to the present-day one. Kinematic changes of some 20% might have occurred in the period leading to the present-day, but plate-motion steadiness is also warranted within the uncertainties. Key Points Bayesian inference to reduce finite-rotation noise Reconstruction of Nubia/Somalia motion since ∼20 Ma Nubia/Somalia relative motion changed at ∼11 Ma
dc.publisherAmerican Geophysical Union
dc.rightsAuthor/s retain copyright
dc.sourceGeochemistry, Geophysics, Geosystems. G3
dc.titleBayesian noise-reduction in Arabia/Somalia and Nubia/Arabia finite rotations since ~20 Ma: Implications for Nubia/Somalia relative motion
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume15
dc.date.issued2014
local.identifier.absfor040402 - Geodynamics
local.identifier.absfor040499 - Geophysics not elsewhere classified
local.identifier.ariespublicationU3488905xPUB2416
local.type.statusPublished Version
local.contributor.affiliationIaffaldano, Giampiero, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationHawkins, Rhys, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationSambridge, Malcolm, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.issue4
local.bibliographicCitation.startpage845
local.bibliographicCitation.lastpage854
local.identifier.doi10.1002/2013GC005089
local.identifier.absseo970104 - Expanding Knowledge in the Earth Sciences
dc.date.updated2015-12-11T07:24:55Z
local.identifier.scopusID2-s2.0-84901349077
local.identifier.thomsonID000336493400002
dcterms.accessRightsOpen Access
CollectionsANU Research Publications

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