نتایج جستجو برای: lithospheric mantle
تعداد نتایج: 17971 فیلتر نتایج به سال:
The observed long-wavelength gravity and topography at the Tharsis Rise, and the inferred heat flux and melt generation rate, are modelled using a convection code. The code is axisymmetric and isoviscous and incorporates a conductive lid and the effects of lithospheric rigidity on the observables. Models which fit the observations have high mantle viscosities (5-28×10 Pa s) and 80% or less inte...
The Canary Island Seamount Province forms a scattered hotspot track on the Atlantic ocean floor ~1300 km long and ~350 km wide, perpendicular to lithospheric fractures, and parallel to the NW African continental margin. New (40)Ar/(39)Ar datings show that seamount ages vary from 133 Ma to 0.2 Ma in the central archipelago, and from 142 Ma to 91 Ma in the southwest. Combining (40)Ar/(39)Ar ages ...
Systematic exploration of the continental lithosphere by deep seismic reflection profiling over the past 20 years has revolutionized our view of the deep crust and upper mantle. Major geological features have been traced to lower crustal depths. Certain deep crustal features have been traced into the underlying mantle (fossil subduction zones?). Some geotectonic boundaries, considered by genera...
The Earth is composed of layers of different composition and physical properties, principally the solid central core, the fluid peripheral core, the viscous mantle, and the solid lithosphere. The lithosphere is comprised of the upper mantle and the crust, the outer shell of the Earth. There are two types of lithosphere, according to the crust resting on the solid mantle lithosphere (lithospheri...
A total of 73 peridotitic mantle xenoliths and a set of garnet and clinopyroxene xenocrysts from the recently discovered Jurassic Monk Hill kimberlite (UCO-H77A) in South Australia were used to constrain the thermal and compositional structure of the lithospheric mantle beneath the Adelaide Fold Belt, which is located at the southeastern margin of the Australian craton. The xenoliths contain mo...
[1] Integration of stress indicator data, gravity data, crustal kinematics data, and analysis of topography and recent vertical motions demonstrates the occurrence of consistently oriented spatial patterns of large-scale Alpine to recent intraplate deformation in Iberia. The inferred upper crustal and lithospheric deformation patterns and the timing of the associated expressions at or near the ...
Apersistent seismic gap is hypothesized in the Pollino area (southern Italy), at the boundary between the Apennines and the Calabrian arc. Presently, seismic swarms are active in the gap area, creating concerns for possible future large earthquakes. In this study, we model the deep Earth structure across the Pollino range to give new insights on the kinematics and tectonics of this enigmatic ar...
Lithospheric extension can generate passive margins that bound oceans worldwide. Detailed geological and geophysical studies in present and fossil passive margins have highlighted the complexity of their architecture and their multi-stage deformation history. Previous modeling studies have shown the significant impact of coarse mechanical layering of the lithosphere (2 to 4 layer crust and mant...
The surface uplift of mountain belts is generally assumed to reflect progressive shortening and crustal thickening, leading to their gradual rise. Recent studies of the Andes indicate that their elevation remained relatively stable for long periods (tens of millions of years), separated by rapid (1 to 4 million years) changes of 1.5 kilometers or more. Periodic punctuated surface uplift of moun...
Following the last glacial maximum (LGM), the demise of continental ice sheets induced crustal rebound in tectonically stable regions of North America and Scandinavia that is still ongoing. Unlike the ice sheets, the Alpine ice cap developed in an orogen where the measured uplift is potentially attributed to tectonic shortening, lithospheric delamination and unloading due to deglaciation and er...
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