TY - ABST

T1 - Density heterogeneity of the North American upper mantle from satellite gravity and a regional crustal model.

AU - Herceg, Matija

AU - Artemieva, Irina

AU - Thybo, Hans

PY - 2014/4

Y1 - 2014/4

N2 - We present a regional model for the density structure of the North American upper mantle. The residual mantlegravity anomalies are based on gravity data derived from the GOCE geopotential models with crustal correctionto the gravity field being calculated from a regional crustal model.We analyze how uncertainties and errors in the crustal model propagate from crustal densities to mantleresidual gravity anomalies and the density model of the upper mantle.Uncertainties in the residual upper (lithospheric) mantle gravity anomalies result from several sources: (i)uncertainties in the velocity-density conversion and (ii) uncertainties in knowledge of the crustal structure(thickness and average Vp velocities of individual crustal layers, including the sedimentary cover). In this study,we address both sources of possible uncertainties by applying different conversions from velocity to density andby introducing variations into the crustal structure which corresponds to the uncertainty of its resolution by highqualityand low-quality seismic models. We examine the propagation of these uncertainties into determinationsof lithospheric mantle density. Given a relatively small range of expected density variations in the lithosphericmantle, knowledge on the uncertainties associated with incomplete knowledge of density structure of the crust isof utmost importance for further progress in such studies.The new regional density model for the North American upper mantle complements an on-going study ofthe regional upper mantle velocity and density structure by other methods. Our new regional density model iscompared to regional and world-wide petrological data on upper mantle densities constrained by mantle-derivedxenoliths.

AB - We present a regional model for the density structure of the North American upper mantle. The residual mantlegravity anomalies are based on gravity data derived from the GOCE geopotential models with crustal correctionto the gravity field being calculated from a regional crustal model.We analyze how uncertainties and errors in the crustal model propagate from crustal densities to mantleresidual gravity anomalies and the density model of the upper mantle.Uncertainties in the residual upper (lithospheric) mantle gravity anomalies result from several sources: (i)uncertainties in the velocity-density conversion and (ii) uncertainties in knowledge of the crustal structure(thickness and average Vp velocities of individual crustal layers, including the sedimentary cover). In this study,we address both sources of possible uncertainties by applying different conversions from velocity to density andby introducing variations into the crustal structure which corresponds to the uncertainty of its resolution by highqualityand low-quality seismic models. We examine the propagation of these uncertainties into determinationsof lithospheric mantle density. Given a relatively small range of expected density variations in the lithosphericmantle, knowledge on the uncertainties associated with incomplete knowledge of density structure of the crust isof utmost importance for further progress in such studies.The new regional density model for the North American upper mantle complements an on-going study ofthe regional upper mantle velocity and density structure by other methods. Our new regional density model iscompared to regional and world-wide petrological data on upper mantle densities constrained by mantle-derivedxenoliths.

M3 - Conference abstract in journal

VL - 16

JO - Geophysical Research Abstracts

JF - Geophysical Research Abstracts

SN - 1607-7962

M1 - 5472

T2 - EGU General Assembly 2014

Y2 - 26 April 2014 through 2 May 2014

ER -