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| Titel |
Subduction-related High- to Ultrahigh-Potassic Rocks of the Ankara-Erzincan Suture Belt of Turkey: a geochemical and isotopic approach to source and petrogenesis |
| VerfasserIn |
S. Can Genc, Fatma Gulmez, Zekiye Karacık, Okan Tüysüz, Dejan Prelevic, Michael F. Roden, Willis E. Hames, M. Zeki Billor |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098848
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| Publikation (Nr.) |
 EGU/EGU2014-14565.pdf |
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| Zusammenfassung |
| A Late Cretaceous Volcano-sedimantary Succession (LCVS) trends parallel to Neo-Tethyan
Suture in North Central Anatolia. Volcanic members of the LCVS consist mainy of coeval
leucite phonolite/tephrites, trachytes, lamprophyres and andesitic rocks. Obtained Ar-Ar ages
reveal that the volcanic activity occurred between 73.6±0.18 and 76.78±0.19 Ma,
contemporaneous with the subduction of the Neo-Tethyan ocean beneath the Pontides. The
volcanic rocks of LCVS are classified as alkaline, High- to ultrahigh-K, and silica-saturated
and silica-unsaturated, geochemically. Rare calc-alkaline andesitic lavas are also occur within
the volcanic sucession.
Except the calc-alkaline samples, magmatic members of LCVS have similar major and trace
element concentrations similar to the plagioleucitites or ultrapotassic rocks of the active
orogenic zones (i.e. the Roman Province ultrapotassic series, Peccerillo, 2005). The
multi element patterns on N-MORB- and Chondrite-normalized spider diagrams are
characterized by significant LILE and LREE enrichments relative to HFSE and
HREE, and display apparent Nb and Ta depletions, implying the subduction-related
magmas.
87Sr/86Sr(i) (0.704493-0.706090) and 143Nd/144Nd(i) (0.512523-0.512680) isotope ratios are
close to the mantle array, and are also in between the Aeolian Islands CA-Potassic rocks
(Peccerillo, 2005), BSE and the circum-Mediterranean anorogenic Cenozoic igneous
province (CiMACI, Lustrino&Wilson, 2007). Variable Mg# (33-60) evidences that these
rocks are the products of evolved melts. The lead isotope values display a trend between EMI
and DM, suggesting that the crustal involvement is more effective process during
the generation of some lamprophyres relative to the other ultrapotassic rocks of
LCVS.
The results of clinopyroxene thermobarometry calculations reveal significant differences in
depth of crystallization for the rock suites. Some trace element abundances and inter
elemental ratios together with their co-variations show that the magmatic rock suites of
LCVS had different crystallization history. REE melting modelings suggest a common mantle
source, which contains variable amount of spinel lerzolite and garnet lerzolitic
proportions. Considering the presence of some phlogopite-bearing clinopyroxenite
xenolits in the lamprophyre and the leucite-bearing rocks, we propose that the LCVS
ultrapotassic rocks were possibly derived from the low degree partial melting of veined
SCLM.
Keywords: High- to Ultrahigh-K, Isotope, Ar-Ar, Cretaceous, Turkey, Veined SCLM
Lustrino, M., Wilson, M., 2007. ESR 81, 1-65.
Peccerillo, A., 1995. Springer-Verlag. 365pp. |
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