Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Occurrence of fibrous chrysotile and tremolite in the Cankiri and Ankara regions, central Anatolia, Turkey

Tacit Kulah, Selahattin Kadir, Hulya Erkoyun, Jennifer Huggett and Esref Atabey
Occurrence of fibrous chrysotile and tremolite in the Cankiri and Ankara regions, central Anatolia, Turkey
Clays and Clay Minerals (April 2018) 66 (2): 146-172

Abstract

Numerous occurrences of asbestos minerals, notably chrysotile and tremolite, are to be found on fracture surfaces in thrust fault deformation zones of Cretaceous dunite-harzburgite and pyroxenite in the Cankiri and Ankara regions, central Anatolia, Turkey. Consequently, potential exists for the development of regional malignant mesothelioma. The means of serpentinization, such as reaction of seawater during accretion of the upper ophiolitic mantle crust in a subduction zone and/or following uplift of ophiolitic units and the influence of hydrothermal/meteoric fluids along fractures, were investigated. Cretaceous dunite-harzburgite and localized pyroxenite rocks are mainly composed of serpentinized olivine and pyroxene associated with opaque minerals and Fe-(oxyhydr)oxide phases. Smectite, chlorite, illite, kaolinite, hydromagnesite, goethite, quartz, and opal-CT are also present. Chrysotile and localized tremolite occur either as a mesh, a suboriented to oriented long-fiber bundle, or as fiber-filling millimetric micro-vein textures on relicts of olivine and pyroxene (enstatite, augite). The chrysotile and tremolite have non-pseudomorphic textures developed under high pressure and temperature. The textures suggest authigenic formation of chrysotile and tremolite via a dissolution and precipitation mechanism. Additionally, spherical structures of opal-CT and locally platy hydromagnesite crystals either enclose or are developed within chrysotile/tremolite fiber bundles. The leaching of MgO, Fe (sub 2) O (sub 3) , Al (sub 2) O (sub 3) , Ni, Cr, and Nb, an increase in the LREE/HREE ratio, and negative Eu anomalies in the dunite-harzburgite and pyroxenite, and asbestos samples suggest that the chrysotile and tremolite were derived from the serpentinization of olivine and pyroxene. The chrysotile and tremolite were developed along fractures by hydrothermal fluid alteration during accretion and/or following the uplift of ophiolitic units of the region under high pressure and temperature conditions. This interpretation is also supported by isotope data and the calculated formation temperature of 170-555 degrees C for chrysotile and tremolite. The average structural formulae for chrysotile and tremolite are (Na (sub 0.44) K (sub 0.03) )(Mg (sub 5.54) Fe (sub 0.09) Al (sub 0.05) Ca (sub 0.01) Mn (sub 0.001) ) (Si (sub 3.96) Al (sub 0.03) )O (sub 10) (OH) (sub 8) and (Na (sub 0.17) K (sub 0.07) )(Ca (sub 1.59) Mg (sub 0.19) Mn (sub 0.002) )(Mg (sub 4.72) Fe (sub 0.28) )(Si (sub 7.86) A l (sub 0.1) Fe (sub 0.06) )O (sub 22) (OH) (sub 2) , respectively.


ISSN: 0009-8604
EISSN: 1552-8367
Coden: CLCMAB
Serial Title: Clays and Clay Minerals
Serial Volume: 66
Serial Issue: 2
Title: Occurrence of fibrous chrysotile and tremolite in the Cankiri and Ankara regions, central Anatolia, Turkey
Affiliation: Kutahya Dumlupinar University, Department of Geological Engineering, Kutahya, Turkey
Pages: 146-172
Published: 201804
Text Language: English
Publisher: Clay Minerals Society, Chantilly, VA, United States
References: 96
Accession Number: 2018-080093
Categories: Geochemistry of rocks, soils, and sedimentsIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 5 tables, geol. sketch map
N39°55'00" - N39°55'00", E32°49'60" - E32°49'60"
N40°40'00" - N40°40'00", E33°25'00" - E33°25'00"
Secondary Affiliation: Eskisehir Osmangazi University, TUR, TurkeyNatural History Museum, GBR, United KingdomHacettepe University, TUR, Turkey
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Abstract, Copyright, Clay Minerals Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201844
Close Modal

or Create an Account

Close Modal
Close Modal