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.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613051/index.pdf |
| Date | 01 March 2011 |
| Creators | Ozdemir, Yavuz |
| Contributors | Gulec, Nilgun |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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