نتایج جستجو برای: lithospheric mantle

تعداد نتایج: 17971  

2012
Walter D. Mooney Jeroen Ritsema Yong Keun Hwang

A joint analysis of global seismicity and seismic tomography indicates that the seismic potential of continental intraplate regions is correlated with the seismic properties of the lithosphere. Archean and Early Proterozoic cratons with cold, stable continental lithospheric roots have fewer crustal earthquakes and a lower maximum earthquake catalog moment magnitude (Mcmax). The geographic shear...

2006
MEGAN BECKER ANTON P. LE ROEX

Bulk-rock geochemical compositions of hypabyssal kimberlites, emplaced through the Archaean Kaapvaal craton and Proterozoic Namaqua–Natal belt, are used to estimate close-to-primary magma compositions of Group I kimberlites (Mg-number 1⁄4 0 82–0 87; 22–28 wt % MgO; 21–30 wt % SiO2; 10–17 wt % CaO; 0 2–1 7 wt % K2O) and Group II kimberlites (Mgnumber 1⁄4 0 86–0 89; 23–29 wt % MgO; 28–36 wt % SiO...

2007
J. Huw Davies

Slab breakoff is the buoyancy-driven detachment of subducted oceanic lithosphere from the light continental lithosphere that follows it during continental collision. In a recent paper Davies and von Blanckenburg [1994] have assessed the physical conditions leading to breakoff by quantitative thermomechanical modeling and have predicted various consequences in the evolution of mountain belts. Br...

2008
Jeroen van Hunen Peter E. van Keken Andrew Hynes Geoffrey F. Davies

Today, plate tectonics is the dominant tectonic style on Earth, but in a hotter Earth tectonics may have looked different due to the presence of more melting and associated compositional buoyancy as well as the presence of a weaker mantle and lithosphere. Here we review the geodynamic constraints on plate tectonics and proposed alternatives throughout Earth’s history. Observations suggest a 100...

2007
Thorsten J. Nagel Roger Buck

Numerical experiments reproduce the fundamental architecture of magma-poor rifted margins such as the Iberian or Alpine margins if the lithosphere has a weak mid-crustal channel on top of strong lower crust and a horizontal thermal weakness in the rift center. During model extension, the upper crust undergoes distributed collapse into the rift center where the thermally weakened portion of the ...

2003
R. S. Huismans S. A. P. L. Cloetingh

We examine a number of first order features of Pannonian basin evolution in terms of the feedback relation between passive far-field induced extension and active Raleigh-Taylor instable upwelling of the asthenosphere. We show that active mantle upwelling following a phase of passive extension are viable mechanisms explaining the Pannonian basin formation. The dynamic interplay between far-field...

1999
Paul J. Tackley

Plate tectonics and mantle convection are different aspects of the same, coupled system, yet mantle convection calculations do not exhibit plate tectonic behavior unless it is imposed by the modeler. This paper explores the quest for self-consistent incorporation of plate tectonics into mantle convection models, and presents new results and parameterizations. Simulations of convection with buoy...

2014
Valentina Magni Pierre Bouilhol Jeroen van Hunen

We investigate the dehydration processes in subduction zones and their implications for the water cycle throughout Earth's history. We use a numerical tool that combines thermo-mechanical models with a thermodynamic database to examine slab dehydration for present-day and early Earth settings and its consequences for the deep water recycling. We investigate the reactions responsible for releasi...

2011
J. Fullea M. R. Muller A. G. Jones

[1] The electrical conductivity of mantle minerals is highly sensitive to parameters that characterize the structure and state of the lithosphere and sublithospheric mantle, and mapping its lateral and vertical variations gives insights into formation and deformation processes. We review state‐of‐the‐art conductivity models based on laboratory studies for the most relevant upper mantle minerals...

2017
A Vauchez Guilhem Barruol Andrea Tommasi

The frequently observed parallelism between rifts and the pre­ existing orogenic fabric of continents suggests that the inherited tectonic fabric of the lithosphere influences the rupture of continents. We propose that the existence of a pervasive fabric in the lithospheric mantle induces an anisotropie strength in the lithosphere, that guides the propagation of continental rifts. Subcrustal ma...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید