رسالة جامعية
Sulfur behavior and redox conditions in Etnean hydrous basalts inferred from melt inclusions and experimental glasses
| العنوان: | Sulfur behavior and redox conditions in Etnean hydrous basalts inferred from melt inclusions and experimental glasses |
|---|---|
| المؤلفون: | Gennaro, Mimma Emanuela |
| المساهمون: | Gennaro, M., ROTOLO, Silvio Giuseppe, AIUPPA, Alessandro |
| بيانات النشر: | Palermo Università degli Studi di Palermo |
| المجموعة: | IRIS Università degli Studi di Palermo |
| مصطلحات موضوعية: | sulfur, silicate melt inclusions, experiments, XANES Fe3+/ΣFe ratio, oxygen fugacity, Settore GEO/07 - Petrologia E Petrografia |
| الوصف: | Sulfur is an important volatile component of magmas that presents different oxidation states, depending on the redox conditions and on the phase of occurence: in silicate melts it is typically dissolved as S6+ and/or S2-, in the gas phase it occurs principally as SO2 (S4+) and H2S (S2-). Here, we adopt Mount Etna as a case study to investigate sulfur behavior in hydrous basaltic magmas during magma differentiation and degassing. Mount Etna is a complex magmatic system characterized by a certain variability in terms of both eruptive style and composition of erupted products, and in which magmatic redox conditions are poorly constrained. In order to improve knowledge about sulfur behavior and redox conditions in Etnean magmas, this research integrates the study of natural olivine-hosted melt inclusions with an experimental study on S solubility in hydrous alkali basalts at magmatic conditions. We have investigated major element compositions, volatile contents, and Fe speciation of olivine-hosted melt inclusions from 6 eruptions of the last 15 ky. Samples were selected from FS eruption, which is the most primitive (picritic composition, Fo91), Mt. Spagnolo (the oldest) and more recent eruptions (2002/2003, 2006, 2008/2009, and 2013). Experimental glasses were synthesized in the range of pressure (200 MPa), temperature (1200 °C), and oxygen fugacity conditions (NNO = +0.2 to +1.7) relevant to the Etnean system. Experimental results suggest the important control of fO2 on the S abundance in Etnean hydrous magma. The highest S content (6454 ppm) was achieved at fO2 = NNO+1.7, while at lower fO2 (NNO = +0.2 to +0.9) and at the sulfide saturation the maximum sulfur content was 2400 ppm. S content and Fe speciation of the experimental glasses are useful to interpret melt inclusions data. The melt inclusions were entrapped at different depths inside the magmatic system (up to ~ 18 km, below crater level, corresponding to a pressure of almost 500 MPa) as defined by H2O-CO2 contents. They delineate a continuous ... |
| نوع الوثيقة: | doctoral or postdoctoral thesis |
| اللغة: | English French |
| العلاقة: | http://hdl.handle.net/10447/221451Test |
| الإتاحة: | http://hdl.handle.net/10447/221451Test |
| حقوق: | info:eu-repo/semantics/openAccess |
| رقم الانضمام: | edsbas.5E9533CB |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |