TY - JOUR

T1 - Receiver function analysis of the crust and upper mantle in Fennoscandia - isostatic implications

AU - Frassetto, Andrew

AU - Thybo, Hans

PY - 2013/11/1

Y1 - 2013/11/1

N2 - The mountains across southern Norway and other margins of the North Atlantic Ocean appear conspicuously high in the absence of recent convergent tectonics. We investigate this phenomenon with receiver functions calculated for seismometers deployed across southern Fennoscandia. These are used to constrain the structure and seismic properties of the lithosphere and primarily to measure the thickness and infer the bulk composition of the crust. Such parameters are key to understanding crustal isostasy and assessing its role, or lack thereof, in supporting the observed elevations. Our study focuses on the southern Scandes mountain range that has an average elevation >1.0 km above mean sea level. The crust-mantle boundary (Moho) is ubiquitously imaged, and we occasionally observe structures that may represent the base of the continental lithosphere or other thermal, chemical, or viscous boundaries in the upper mantle. The Moho resides at similar to 25-30 km depth below mean sea level in southeastern coastal Norway and parts of Denmark, similar to 35-45 km across the southern Scandes, and similar to 50-60 km near the Norwegian-Swedish border. That section of thickest crust coincides with much of the Transscandinavian Igneous Belt and often exhibits a diffuse conversion at the Moho, which probably results from the presence of a high wave speed, mafic lower crust across inner Fennoscandia. A zone of thinned crust (

AB - The mountains across southern Norway and other margins of the North Atlantic Ocean appear conspicuously high in the absence of recent convergent tectonics. We investigate this phenomenon with receiver functions calculated for seismometers deployed across southern Fennoscandia. These are used to constrain the structure and seismic properties of the lithosphere and primarily to measure the thickness and infer the bulk composition of the crust. Such parameters are key to understanding crustal isostasy and assessing its role, or lack thereof, in supporting the observed elevations. Our study focuses on the southern Scandes mountain range that has an average elevation >1.0 km above mean sea level. The crust-mantle boundary (Moho) is ubiquitously imaged, and we occasionally observe structures that may represent the base of the continental lithosphere or other thermal, chemical, or viscous boundaries in the upper mantle. The Moho resides at similar to 25-30 km depth below mean sea level in southeastern coastal Norway and parts of Denmark, similar to 35-45 km across the southern Scandes, and similar to 50-60 km near the Norwegian-Swedish border. That section of thickest crust coincides with much of the Transscandinavian Igneous Belt and often exhibits a diffuse conversion at the Moho, which probably results from the presence of a high wave speed, mafic lower crust across inner Fennoscandia. A zone of thinned crust (

KW - receiver functions

KW - continental margins

KW - lithospheric structure

KW - Fennoscandia

KW - isostasy

KW - Vp/Vs ratio

KW - Receiver functions

KW - Continental margins

KW - Lithospheric structure

KW - Fennoscandia

KW - Isostasy

KW - Vp/Vs ration

U2 - 10.1016/j.epsl.2013.07.001

DO - 10.1016/j.epsl.2013.07.001

M3 - Journal article

VL - 381

SP - 234

EP - 246

JO - Earth and Planetary Science Letters

JF - Earth and Planetary Science Letters

SN - 0012-821X

ER -