Volcanostratigraphy And Petrogenesis Of Suphan Stratovolcano
| Autor: | Ozdemir, Yavuz |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: | |
| Druh dokumentu: | Ph.D. Thesis |
| Popis: | This study is concerned with volcanostratigraphic and petrologic evolution of the Sü phan, which is a 4050 m high Quaternary stratovolcano in eastern Anatolia. The eruptive products of Sü phan Stratovolcano, including transitional mildly alkaline to calc-alkaline rocks, are lavas, domes and pyroclastics ranging in composition from basalts to rhyolites. Ar-Ar age data from different levels of the volcanostratigrafic succession yield a range of 0.76-0.06 Ma. Textural features, wide temperature ranges obtained for intermediate members, and the linear trends of whole-rock geochemistry are strongly suggestive of magma mixing in the evolution of Sü phan volcanics. Presence of crystal clots in many lavas suggests that cogenetic plutonic rocks were also involved in the mixing process. Comparison of whole-rock, melt inclusion and glass chemistry data of Sü phan to data from experimental studies reported in literature indicate that the melt inclusions describe true liquid lines of descent from a common hydrous parent at pressures of ~500 MPa. EC-AFC modeling of trace element and isotopic compositions reveals 2-8% crustal contamination in the differentiated lavas. REE modeling indicates that primitive rocks of Sü phan volcanics were products of mixing of melts from spinel and garnet lherzolite sources, with contributions of 60% and 40%, respectively, in the mixture. A two-stage petrogenetic model is proposed for Suphan stratovolcano. Mantle- derived melts stall and undergo chemical differentiation in a deep hot zone in lower to mid-crust variably evolved melts ascending from this zone are arrested and mixed at a shallow level where they construct a sub-volcanic magma reservoir beneath Suphan. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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