TY - JOUR

T1 - Integrated lithospheric modeling combining thermal, gravity, and local isostasy analysis

T2 - application to the NE Spanish Geotransect

AU - Zeyen, Hermann

AU - Fernandez, Manel

PY - 1994

Y1 - 1994

N2 - A two-dimensional algorithm to determine the steady state
thermal structure of the lithosphere that integrates thermal, gravity, and
local isostasy analyses is presented. Gravity analyses together with seismic
data are used to constrain spatial variations in density and crustal structure,
while absolute elevation is used to determine the lithospheric mantle
thickness. The calculation is performed using a finite element technique that
links the different physical equations. The program optionally calculates the
temperature at any material boundary and, with given rheological parameters,
the strength distribution and the total lithospheric strength in selected
columns. We apply the algorithm to the Northeastern Spanish Geotransect which
extends from the Pyrenees to the Balearic Promontory and along which a strong
variation in crustal and lithospheric thickness is evident. We assess the use
of two different inferred density models for the lithospheric mantle: The first
assumes a linear decrease in density with increasing temperature using the
asthenospheric density as a reference; the second model assumes a constant
density for the whole lithospheric mantle. Although conceptually the two
hypotheses differ substantially, the results obtained do not show significant
differences. Lithospheric thicknesses of 120–130 km below the Pyrenees, 60–65
km in the Valencia Trough, and 65–75 km below the Balearic Promontory are
deduced. In all cases the mean lithospheric mantle density has to be 40–60 kg m−3 higher
than the asthenospheric density. The algorithm is shown to be a powerful tool
in lithospheric thermal modeling especially in areas where surface heat flow is
poorly constrained because of the temperature-density-elevation relationship.

AB - A two-dimensional algorithm to determine the steady state
thermal structure of the lithosphere that integrates thermal, gravity, and
local isostasy analyses is presented. Gravity analyses together with seismic
data are used to constrain spatial variations in density and crustal structure,
while absolute elevation is used to determine the lithospheric mantle
thickness. The calculation is performed using a finite element technique that
links the different physical equations. The program optionally calculates the
temperature at any material boundary and, with given rheological parameters,
the strength distribution and the total lithospheric strength in selected
columns. We apply the algorithm to the Northeastern Spanish Geotransect which
extends from the Pyrenees to the Balearic Promontory and along which a strong
variation in crustal and lithospheric thickness is evident. We assess the use
of two different inferred density models for the lithospheric mantle: The first
assumes a linear decrease in density with increasing temperature using the
asthenospheric density as a reference; the second model assumes a constant
density for the whole lithospheric mantle. Although conceptually the two
hypotheses differ substantially, the results obtained do not show significant
differences. Lithospheric thicknesses of 120–130 km below the Pyrenees, 60–65
km in the Valencia Trough, and 65–75 km below the Balearic Promontory are
deduced. In all cases the mean lithospheric mantle density has to be 40–60 kg m−3 higher
than the asthenospheric density. The algorithm is shown to be a powerful tool
in lithospheric thermal modeling especially in areas where surface heat flow is
poorly constrained because of the temperature-density-elevation relationship.

UR - http://www.scopus.com/inward/record.url?scp=0028558057&partnerID=8YFLogxK

U2 - 10.1029/94JB00898

DO - 10.1029/94JB00898

M3 - Article

VL - 99

SP - 18089

EP - 18102

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - B9

ER -