Natrolitite, an unusual rock - Occurrence and petrographic and geochemical characteristics (eastern Turkey)

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dc.contributor.authorCiftci, Emin
dc.contributor.authorHogan, John P.
dc.contributor.authorKolayli, Hasan
dc.contributor.authorCadirli, Emin
dc.date.accessioned2019-08-01T13:38:39Z
dc.date.available2019-08-01T13:38:39Z
dc.date.issued2008
dc.departmentNiğde ÖHÜ
dc.description.abstractVery unusual rocks consisting of natrolite (>95 vol.%) pargasite (<5 vol.%) and rare albite (<1 vol. %) have been discovered in the Kop mountain range, eastern Turkey. We propose to call these rocks 'natrolitite' and 'pargasite natrolitite'. They were produced by Na Si metasomatism of dikes and stocks of diorite through replacement of the intermediate primary igneous plagioclase to produce natrolite. The metasomatic alteration produced concentric elliptical zones characterized by distinct mineral assemblages centered on intrusions of diorite. The Central Zone 1 consists of variably albitized diorite with preserved magmatic textures (albite +/- andesine +/- pargasite +/- quartz). Transition Zone 2 comprises natrolite-bearing diorite (natrolite +/- albite +/- andesine +/- pargasite +/- calcite +/- quartz). Marginal Zone 3 is a rock made up almost entirely of natrolite (natrolite +/- pargasite +/- albite +/- calcite +/- chlorite). Outer Zone 4 occurs along the boundary between the natrolitite and the surrounding serpentinite and consists of listvenite, a rock which comprises magnesite, quartz, calcite, mica, tale, and hematite, indicating a role for CO2 in the metasomatic reactions, consistent with the presence of calcite in the alteration zones. Zone 5 consists essentially of brecciated serpentinite with numerous hydrothermal quartz veins and calcite veins. Whole-rock compositions document an increase in Na2O, Al2O3, and H2O from the core (central zone) to the margin while CaO, MgO, and SiO2 decrease. Plagioclase abundance and composition also varies outwards from the central core rocks where it occurs as a primary magmatic phase (similar to 95 vol.% An(41-38)) to the alteration zones (<5 vol.% An(32-37)) due to partial to complete replacement of plagioclase by natrolite with or without rare albite. The natrolites exhibit little variation in Si/Al ratios, ranging between 1.45 and 1.61, and are similar in composition to those reported in the literature. Accompanying pargasitic amphibole also becomes progressively more sodic in composition from the core rocks to the marginal zone rocks. Our analysis indicates that albitization preceded the formation of natrolite and that the formation of natrolite, instead of other more typical alteration minerals (e.g. analcime and paragonite), reflects Na metasomatism at lower chemical potentials for Al2O3 and SiO2. Potential sources of Na could be hypersaline brines or leaching of country rocks, such as trondhjemites. The fluids were driven in hydrothermal convection cells set up by the intrusion of the diorites.
dc.identifier.doi10.1346/CCMN.2008.0560206
dc.identifier.endpage221
dc.identifier.issn0009-8604
dc.identifier.issue2
dc.identifier.scopus2-s2.0-48249083000
dc.identifier.scopusqualityQ2
dc.identifier.startpage207
dc.identifier.urihttps://dx.doi.org/10.1346/CCMN.2008.0560206
dc.identifier.urihttps://hdl.handle.net/11480/5258
dc.identifier.volume56
dc.identifier.wosWOS:000257103800006
dc.identifier.wosqualityQ2
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.institutionauthor[0-Belirlenecek]
dc.language.isoen
dc.publisherCLAY MINERALS SOC
dc.relation.ispartofCLAYS AND CLAY MINERALS
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.subjecteastern Turkey
dc.subjectKop mountains
dc.subjectlistvenite
dc.subjectmetasomatism
dc.subjectnatrolite
dc.subjectnatrolitite
dc.subjectpargasite
dc.subjectzeolites
dc.titleNatrolitite, an unusual rock - Occurrence and petrographic and geochemical characteristics (eastern Turkey)
dc.typeArticle

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