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Crustal fluid flow in hot continental extension; tectonic framework of geothermal areas and mineral deposits in western Anatolia

Klaus Gessner, Vanessa Markwitz and Talip Gungor
Crustal fluid flow in hot continental extension; tectonic framework of geothermal areas and mineral deposits in western Anatolia (in Characteristics of ore-forming systems from geological, geochemical and geophysical studies, Klaus Gessner (editor), T. G. Blenkinsop (editor) and P. Sorjonen-Ward (editor))
Special Publication - Geological Society of London (July 2017) 453 (1): 289-311

Abstract

Lithospheric thinning and crustal extension have shaped the Alpine orogen in western Anatolia since the late Oligocene, resulting in the denudation of one of Earth's largest metamorphic core complexes, the Menderes Massif. We review locations and characteristics of geothermal fields and of Miocene mineral deposits in the context of crustal structure and geodynamic processes. Thermal spring locations show a close spatial association with active fault zones; the largest geothermal areas are located in the widest graben and at fault intersections, but show little relation to volcanic activity. During the first stage of tectonic denudation in the Miocene, epithermal, porphyry-type gold and structurally controlled base-metal deposits formed synchronously with K-rich volcanic and plutonic complexes in the northern Menderes Massif. Depositional environments favoured the formation of lignite, sedimentary uranium and borate deposits. Throughout this phase of extension in a hot continental setting, secondary porosity caused by brittle faulting of metamorphic basement rocks provided the key pathways for fluids and magmas. Although the Menderes Massif has remained in a similar position relative to active plate boundaries from the Miocene to the present, three significant changes in subcontinental mantle dynamics affected the nature of hydrothermal flow. First, the partial removal of lithospheric mantle changed the primary source component of magmatic rocks and metals from metasomatized lithosphere mantle to asthenospheric mantle. Secondly, surface uplift and progressive crustal extension led to segmentation of the Miocene land surface along NNE-SSW- and east-west-orientated fault zones, which changed the overall structural control on crustal permeability. Finally, hydrothermal flow changed from locally magmatic driven, to focused flow of topographically and thermally driven fluids in the crust, with high background heat flow caused by regional upwelling of the asthenosphere. The Menderes Massif is a continental tectonic domain that has experienced rapid thinning of lithospheric mantle and crustal extension in an overall convergent plate tectonic setting. The tectonic and geodynamic framework for evolving hydrothermal activity in western Anatolia may be applicable to other ore-forming systems in hot, extending continental crust in Earth's history. Supplementary material: Supplement 1: Compilation of 124 thermal spring temperature measurements from Akkus et al. (2005); Supplement 2: Compilation of 127 geothermal well temperature measurements from Akkus et al. (2005) is available at https://doi.org/10.6084/m9.figshare.c.3803935


ISSN: 0305-8719
Coden: GSLSBW
Serial Title: Special Publication - Geological Society of London
Serial Volume: 453
Serial Issue: 1
Title: Crustal fluid flow in hot continental extension; tectonic framework of geothermal areas and mineral deposits in western Anatolia
Title: Characteristics of ore-forming systems from geological, geochemical and geophysical studies
Author(s): Gessner, KlausMarkwitz, VanessaGungor, Talip
Author(s): Gessner, Klauseditor
Author(s): Blenkinsop, T. G.editor
Author(s): Sorjonen-Ward, P.editor
Affiliation: University of Western Australia, Centre for Exploration Targeting, Crawley, West. Aust., Australia
Pages: 289-311
Published: 20170728
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 168
Accession Number: 2017-066975
Categories: Solid-earth geophysicsEconomic geology, general, deposits
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, geol. sketch maps
N36°00'00" - N40°00'00", E26°00'00" - E30°00'00"
Secondary Affiliation: Dokuz Eylul University, TUR, Turkey
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 201735
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