The thermal regime of the Eastern Alps along the TRANSALP profile

The results of petrophysical laboratory measurements and inverse modelling were utilized to estimate the 2-D, steady-state conductive thermal regime in the Eastern Alpine crust and heat flow at the Moho along the TRANSALP profile. Temperature dependence of thermal conductivity and specific heat capacity as well as of heat production rate and density were measured on a set of magmatic, metamorphic and sedimentary rocks, representing different depth levels of the Eastern Alpine crust. The results show that in the temperature range from 25-300°C thermal diffusivity relates linearly to thermal conductivity. Based on the approach that thermal resistivity is a linear function of temperature whose slope increases with the thermal conductivity at a temperature of 0°C, two general equations for the temperature dependence of thermal conductivity for Eastern Alpine rocks were formulated. The inversion studies show that while the large a priori standard deviation of particularly the heat production rate in the upper crust can be significantly reduced a posteriori, the variance of the middle crust heat production rate remains comparatively large. Using two extreme models with maximum and minimum heat production rates in the middle crust the range of Moho temperatures and heat flow can be estimated. Depending on different assumptions about the composition of the middle crust we obtain maximum temperatures of around 900°C ± 30% in the lowermost parts of the European crust. In the Alpine root and in the Southern Alps, maximum temperatures are 700-800°C ± 10% and 600°C ± 10%, respectively. Moho heat flow varies from 5-25 mW m-2 and is largest underneath the European plate and lowest underneath the Alpine root. The effect of paleoclimate and exhumation was estimated, performing 1-D transient forward simulation and an analytical approach. The main paleoclimatic signal of -6.5 K was detected in a depth of 2 km. As exhumation leads to an elevation of temperature that increases with depth, the resulting transient signal in the uppermost 2 km amounts to zero. The utilized "worst case scenario" leads to a maximum exhumation signal of around 80 K at a depth of 50 km.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Vosteen, Hans-Dieter

Contributors dc:contributor

• Clauser, Christoph

• info:eu-repo/classification/ddc/550
• Geowissenschaften
• Angewandte Geophysik
• Ostalpen
• TRANSALP
• Inversion
• Geothermik
• Gesteinsphysik
• Numerische Modellierung
• Wärmeleitfähigkeit
• Wärmekapazität
• Temperaturleitfähigkeit
• Geothermics
• heat conduction
• rock physics
• numerical simulation
• Eastern Alps

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121104%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:59307