Upper Man Tie
Upper Man Tie : The zone of the earth immediately underneath the crust of the earth marked on its upper boundary by the Mohorovicic discontinuity, extending to a depth of 400 km and characterized by regional dissimilarities in seismic velocity profile. Because of a combination of inadequate and sometimes conflicting data, both from seismology and from laboratory experiments, there is no full consensus about the nature of the Upper Mande. The petrological models that have been proposed start from the plausible assumption that the composition of the primitive mande must have been such that it yields a basaltic magma upon melting and then predict the mineral assemblages formed by the remaining residue as a function of depth or pressure from laboratory experiments. As early as 1922, Goldschmidt proposed an Earth consisting of a 120-km thick silicate layer on top of an eclogite mande. D.L. Anderson argues that the volume of the lunar crust, which represents 10% of the moon, contrasts significandy with the 0.5% found for the Earth. If the Earth's mande is as well differentiated as that of the Moon, this would result in a basalt layer with a thickness of several hundred kilometers
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