Publication Date:
2021-01-19
Description:
The Zagros thrust belt is a large orogenic zone located along the southwest region of
Iran. To obtain a better knowledge of this important mountain chain, we elaborated the first 3-D
model reproducing the thermal structure of its northwestern part, i.e., the Lurestan arc. This study
is based on a 3-D structural model obtained using published geological sections and available
information on the depth of the Moho discontinuity. The analytical calculation procedure took into
account the temperature variation due to: (1) The re-equilibrated conductive state after thrusting,
(2) frictional heating, (3) heat flow density data, and (4) a series of geologically derived constraints.
Both geotherms and isotherms were obtained using this analytical methodology. The results pointed
out the fundamental control exerted by the main basement fault of the region, i.e., the Main Frontal
Thrust (MFT), in governing the thermal structure of the crust, the main parameter being represented
by the amount of basement thickening produced by thrusting. This is manifested by more densely
spaced isotherms moving from the southwestern foreland toward the inner parts of orogen, as well
as in a lateral variation related with an along-strike change from a moderately dipping crustal ramp
of the MFT to the NW to a gently dipping crustal ramp to the SE. The complex structural architecture,
largely associated with late-stage (Pliocene) thick-skinned thrusting, results in a zone of relatively
high geothermal gradient in the easternmost part of the study area. Our thermal model of a large
crustal volume, besides providing new insights into the geodynamic processes affecting a major
salient of the Zagros thrust belt, may have important implications for seismotectonic analysis in an
area recently affected by a Mw = 7.3 earthquake, as well as for geothermal/hydrocarbon exploration
in the highly perspective Lurestan region.
Description:
Published
Description:
2140
Description:
1T. Struttura della Terra
Description:
JCR Journal
Keywords:
active tectonics
;
heat flow
;
3-D thermal modelling
;
thermal structure
;
temperature profile
;
04.07. Tectonophysics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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