Geochemical constraints on the Cenozoic, OIB-type alkaline volcanic rocks of NW Turkey: Implications for mantle sources and melting processes

Aldanmaz, Ercan; Köprübaşı, Nezihi; Gürer, Ömer Feyzi; Kaymakçı, Nuretdin; Gourgaud, Alain

doi:10.1016/j.lithos.2005.04.003

Cited by 153 publications

(89 citation statements)

References 43 publications

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“…Pooled fractional melt calculations have been used to model the composition (depleted vs. primitive mantle) and mineralogy (lherzolite containing either spinel or garnet or a 50:50 mix representing melting across the transition zone) of the source region (Aldanmaz et al, 2006;Kerr et al, 2004Kerr et al, , 2009. Partition coefficients are averages from Salters et al (2002) and McDade et al (2003).…”

Section: Resultsmentioning

confidence: 99%

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Yang

Kerr

et al. 2018

Journal of Asian Earth Sciences

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A B S T R A C T The Carboniferous Bayingou ophiolitic mélange is exposed in the North Tianshan accretionary complex in the southwestern part of the Central Asian Orogenic Belt (CAOB). The mélange is mainly composed of serpentinised ultramafic rocks (including harzburgite, lherzolite, pyroxenite, dunite and peridotite), pillowed and massive basalts, layered gabbros, radiolarian cherts, pelagic limestones, breccias and tuffs, and displays blockin-matrix structures. The blocks of ultramafic rocks, gabbros, basalts, cherts, and limestones are set in a matrix of serpentinised ultramafic rocks, massive basalts and tuffs. The basaltic rocks in the mélange show significant geochemical heterogeneity, and two compositional groups, one ocean island basalt-like, and the other mid-ocean ridge-like, can be distinguished on the basis of their isotopic compositions and immobile trace element contents (such as light rare earth element enrichment in the former, but depletion in the latter). The more-enriched basaltic rocks are interpreted as remnants/fragments of seamounts, derived from a deep mantle reservoir with low degrees (2-3%) of garnet lherzolite mantle melting. The depleted basalts most likely formed by melting of a shallower spinel lherzolite mantle source with ∼15% partial melting. It is probable that both groups owe their origin to melting of a mixture between plume and depleted MORB mantle. The results from this study, when integrated with previous work, indicate that the Junggar Ocean crust (comprising a significant number of seamounts) was likely to have been subducted southward beneath the Yili-Central Tianshan block in the Late Devonian-Early Carboniferous. The seamounts were scraped-off and accreted along with the oceanic crust in an accretionary wedge to form the Bayingou ophiolitic mélange. We present a model for the tectonomagmatic evolution of this portion of the CAOB involving prolonged intra-oceanic subduction with seamount accretion

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Section: Resultsmentioning

confidence: 99%

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Yang

Kerr

et al. 2018

Journal of Asian Earth Sciences

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“…The geological characteristics of western Turkey have been introduced previously (e.g., Aldanmaz et al 2000Aldanmaz et al , 2006Yılmaz et al 2001;Alıcı et al 2002;Kaymakçı et al 2007), and only a brief description for each of the sampling sites will be given here. Abundant Early-Middle Miocene (>15 Ma) active margin-type major volcanic activity in western Turkey is followed by locally developed, OIB-type, sodium-rich, intraplate alkaline volcanism of Late Miocene to Quaternary age (<11 Ma; Aldanmaz et al 2000Aldanmaz et al , 2006Alıcı et al 2002;Kaymakçı et al 2007).…”

Section: Geological Summary and Sample Descriptionmentioning

confidence: 99%

“…Abundant Early-Middle Miocene (>15 Ma) active margin-type major volcanic activity in western Turkey is followed by locally developed, OIB-type, sodium-rich, intraplate alkaline volcanism of Late Miocene to Quaternary age (<11 Ma; Aldanmaz et al 2000Aldanmaz et al , 2006Alıcı et al 2002;Kaymakçı et al 2007). The products of the Early to Middle Miocene volcanism cover a wide area in western Turkey (Fig.…”

Section: Geological Summary and Sample Descriptionmentioning

confidence: 99%

“…On the basis of Sr-Nd isotopic values and incompatible trace element abundances, previous studies interpreted the lavas to be of sublithospheric origin with magma generation by small-degree melting of compositionally anomalous regions in the shallow convecting mantle (e.g., Aldanmaz 2002;Aldanmaz et al 2006). No inferences, however, have been made to explain the mechanisms that created these compositionally anomalous domains that are characterized by systematic enrichments in both Sr-Nd isotopes and highly incompatible element abundances compared to ambient mantle compositions.…”

Section: Introductionmentioning

confidence: 99%

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Source components and magmatic processes in the genesis of Miocene to Quaternary lavas in western Turkey: constraints from HSE distribution and Hf–Pb–Os isotopes

Aldanmaz

Pickard

Meisel

et al. 2015

Contrib Mineral Petrol

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crystallization trends indicate distinctly lower bulk partition coefficients for IPGE in more evolved lavas, possibly reflecting a change in the fractionating assemblages. Pd and Re in the primitive melts display negative correlations with MgO, demonstrating moderately incompatible behavior of these elements during fractionation, while the significantly scattered variation in Pt against MgO may indicate the effects of micronuggets of a Pt-rich alloy. Osrich alkaline primary lavas (>50 ppt Os) exhibit a limited range of 187 Os/ 188 Os (0.1361-0.1404), with some xenolith-bearing lavas displaying depletions in 187 Os/ 188 Os (0.1131-0.1232), suggesting slight compositional modification of primitive melts through contamination with highly depleted, Os-rich mantle lithosphere. More radiogenic Os isotope ratios ( 187 Os/ 188 Os > 0.1954) in the evolved lavas reflect contamination of the magmas by high 187 Os/ 188 Os crustal material during shallow differentiation. The OIB-type lavas show limited variations in Hf and Pb isotopes with Hf ratios correlate negatively with 208 Pb*/ 206 Pb*, suggesting the effects of similar mantle processes on the evolution of time-integrated Th/U and Lu/Hf. These lavas have distinctly higher 176 Hf/ 177 Hf and lower 208 Pb*/ 206 Pb* than the Early-Middle Miocene lavas of the region, which are interpreted as melts of enriched mantle with an overprint by sediment-derived subduction component. The source region for the OIB-type alkaline melts is interpreted to be a sub-lithospheric reservoir enriched in Hf and Pb isotopes with respect to depleted MORB mantle. Combined evaluation of Hf, Pb, and Os isotopes suggests that the relative enrichment in this domain is related to mixing of ancient oceanic crust with the ambient mantle through long-term plate recycling processes.Abstract Hf-Pb-Os isotope compositions and highly siderophile element (HSE) abundance variations are used to evaluate the mantle source characteristics and possible effects of differentiation processes in lavas from western Turkey, where the eruption of Late Miocene to Quaternary OIB-type intraplate mafic alkaline lavas followed pre-Middle Miocene convergent margin-type volcanism. Concentrations of Os, Ir, and Ru (IPGE) in the OIB-type intraplate lavas decrease with fractionation for primitive melts (MgO > 10 wt%), suggesting that these elements reside predominantly in olivine and associated HSE retaining trace phases and behave compatibly during olivine-dominated fractionation. Fractional Communicated by

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“…The temporal distribution of the magmatism in this region shows different phases of magma generation with distinct geochemical signatures mainly in the late Eocene, late Miocene and Plio-Quaternary Eyuboglu et al, 2010Eyuboglu et al, , 2011aEyuboglu et al, ,b,c,d,e, 2012Eyuboglu et al, , 2013a. Mantle-derived volcanic rocks with oceanic-island basalt (OIB)-like geochemical features with and/or without subduction fingerprints are commonly found in the Turkish-Iranian High Plateau (e.g., Aldanmaz et al, 2006;Dilek and Altunkaynak, 2009;Kheirkhah et al, 2009;Elitok et al, 2010;Allen et al, 2013).…”

Section: Introductionmentioning

confidence: 96%

Late Miocene K-rich volcanism in the Eslamieh Peninsula (Saray), NW Iran: Implications for geodynamic evolution of the Turkish–Iranian High Plateau

et al. 2014

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a b s t r a c tKeywords: High-K lavas Geochemistry, Sr-Nd-Pb isotopes, Post-collisional magmatism Iran Post-collisional volcanism in northwestern Iran is represented by the Saray high-K rocks including leucite-bearing under-saturated and leucite-free silica saturated rocks. We report Ar-Ar age data which constrain the age as ca. 11Ma (late Miocene). Most of clinopyroxene phenocrysts from the volcanic rocks have complex oscillatory zoning, with high Ti and Al cores, low Ti and high Al mantled clinopyroxenes, grading into low Ti and Al outer rims. All the rocks are highly enriched in incompatible trace elements and have identical Sr-Nd-Pb isotopes. Enrichment in incompatible elements and other geochemical features for the Saray lavas suggest a metasomatized sub-continental lithospheric mantle (SCLM) as the magma source. The negative Nb- Ta Pb isotopic values of the Saray lavas imply the involvement of slab terrigenous sediments and/or a continental lithosphere. Isotopically, the volcanic rocks define a binary trend, representing 5-8% mixing between the primary mantle and sediment melts. Our melting models suggest residual garnet in the source and are incompatible with partial melting of amphibole and/or phlogopite bearing lherzolites, although the complex geochemical features might indicate the result of mixing between melts produced by different sources or a homogenous melt passing through a compositionally-zoned mantle during multiple stages of partial melting and melt migration. The geochronological, geochemical and isotopic data for the Saray rocks suggest that these Late Miocene magmas were derived from a small degree of partial melting of subduction-metasomatized (subcontinental) lithospheric mantle source in a post-collisional setting.

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Geochemical constraints on the Cenozoic, OIB-type alkaline volcanic rocks of NW Turkey: Implications for mantle sources and melting processes

Cited by 153 publications

References 43 publications

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Source components and magmatic processes in the genesis of Miocene to Quaternary lavas in western Turkey: constraints from HSE distribution and Hf–Pb–Os isotopes

Late Miocene K-rich volcanism in the Eslamieh Peninsula (Saray), NW Iran: Implications for geodynamic evolution of the Turkish–Iranian High Plateau

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