Continental lithospheric mantle is heterogeneous in terms of modal and chemical composition. There are fundamental differences between cratonic and younger mantle (Boyd et al., 1997), and non-cratonic mantle has broad compositional variations worldwide (McDonough, 1990). Xenoliths of spinel peridotites in alkali basalts are direct samples of lithospheric mantle but it may not be clear whether a...

There is growing evidence that the top part of the oceanic mantle is pervasively serpentinized prior to subduction. Because the interior of a subducting slab heats up slowly, the serpentinized layer can be preserved for tens of Myr, thereby forming a weak zone that allows for mechanical decoupling between the oceanic crust and underlying lithospheric mantle. Once the crust is eclogitized, a she...

[1] Recent advances in computational petrological modeling provide accurate methods for computing seismic velocities and density within the lithospheric and sub-lithospheric mantle, given the bulk composition, temperature, and pressure within them. Here, we test an integrated geophysical-petrological inversion of Rayleighand Love-wave phase-velocity curves for fine-scale lithospheric structure....

The Tibetan Plateau results from the collision of the Indian and Eurasian Plates during the Cenozoic, which produced at least 2,000 km of convergence. Its tectonics is dominated by an eastward extrusion of crustal material that has been explained by models implying either a mechanical decoupling between the crust and the lithosphere, or lithospheric deformation. Discriminating between these end...

In Africa volumetrically minor, mid-plate volcanic rocks of Cenozoic age are concentrated in areas affected by Pan-African (500 _+ 150 Ma) crustal reactivation, and are virtually absent from cratonic areas. We interpret this as indicating that Pan-African areas are underlain by fertile lithospheric mantle and cratons by depleted lithospheric mantle, and propose a model to explain both the distr...

The rift-related magmas of the Proterozoic Gardar Igneous Province were emplaced across the contact between the South Greenland Archaean craton and the Palaeoproterozoic Ketilidian mobile belt. It has been suggested that the geochemistry of Gardar intrusive rocks in the two areas varies across the craton margin and that this reflects a lithospheric control. However, comparison of the geochemica...

[1] Comparison of analogue experiments at crustal and lithospheric scale provides essential information concerning the mode of deformation during lithospheric extension. This study shows that during extension, lithospheric deformation is controlled by the development of shear zones in the ductile parts. At lithospheric scale, the global deformation is initiated by the rupture of the brittle man...

Title of Dissertation: CREATION AND DESTRUCTION OF LITHOSPHERIC MANTLE BENEATH THE NORTH CHINA CRATON Jingao Liu, Ph.D., 2011 Dissertation directed by: Professor Roberta L. Rudnick, Geology Professor Richard J. Walker, Geology Mantle peridotites carried in volcanic rocks provide a window into the composition, age and origin of deep lithospheric mantle. Previous studies of mantle peridotites hav...

The aim of this work is to propose a first-order estimate of the crustal and lithospheric mantle geometry of the Arabia–Eurasia collision zone and to separate the measured Bouguer anomaly into its regional and local components. The crustal and lithospheric mantle structure is calculated from the geoid height and elevation data combined with thermal analysis. Our results show that Moho depth var...

Lithium elemental and isotopic compositions of olivines in peridotite xenoliths from Hebi in the North China Craton provide direct evidence for the highly variable δ(7)Li in Archean lithospheric mantle. The δ(7)Li in the cores of olivines from the Hebi high-Mg# peridotites (Fo > 91) show extreme variation from -27 to +21, in marked deviation from the δ(7)Li range of fresh MORB (+1.6 to +5.6) al...