Phase relations of phlogopite with magnesite from 4 to 8 GPa
| dc.contributor.author | Enggist, Andreas | |
| dc.contributor.author | Chu, Linglin | |
| dc.contributor.author | Luth, Robert W. | |
| dc.date.accessioned | 2022-05-27T01:13:51Z | |
| dc.date.available | 2022-05-27T01:13:51Z | |
| dc.date.issued | 2012 | |
| dc.description.abstract | To evaluate the stability of phlogopite in the presence of carbonate in the Earth's mantle, we conducted a series of experiments in the KMAS-HO-CO system. A mixture consisting of synthetic phlogopite (phl) and natural magnesite (mag) was prepared (phl-mag; wt%) and run at pressures from 4 to 8 GPa at temperatures ranging from 1,150 to 1,550°C. We bracketed the solidus between 1,200 and 1,250°C at pressures of 4, 5 and 6 GPa and between 1,150 and 1,200°C at a pressure of 7 GPa. Below the solidus, phlogopite coexists with magnesite, pyrope and a fluid. At the solidus, magnesite is the first phase to react out, and enstatite and olivine appear. Phlogopite melts over a temperature range of ~150°C. The amount of garnet increases above solidus from ~10 to ~30 modal% to higher pressures and temperatures. A dramatic change in the composition of quench phlogopite is observed with increasing pressure from similar to primary phlogopite at 4 GPa to hypersilicic at pressures ≥5 GPa. Relative to CO-free systems, the solidus is lowered such, that, if carbonation reactions and phlogopite metasomatism take place above a subducting slab in a very hot (Cascadia-type) subduction environment, phlogopite will melt at a pressure of ~7.5 GPa. In a cold (40 mWm) subcontinental lithospheric mantle, phlogopite is stable to a depth of 200 km in the presence of carbonate and can coexist with a fluid that becomes Si-rich with increasing pressure. Ascending kimberlitic melts that are produced at greater depths could react with peridotite at the base of the subcontinental lithospheric mantle, crystallizing phlogopite and carbonate at a depth of 180-200 km. | |
| dc.description.uri | http://library.macewan.ca/cgi-bin/SFX/url.pl/7NB | |
| dc.identifier.citation | Enggist, A., Chu, L., & Luth, R. (2012). Phase relations of phlogopite with magnesite from 4 to 8 GPa. Contributions To Mineralogy & Petrology, 163(3), 467-481. doi:10.1007/s00410-011-0681-9 | |
| dc.identifier.doi | https://doi.org/10.1007/s00410-011-0681-9 | |
| dc.identifier.uri | https://hdl.handle.net/20.500.14078/292 | |
| dc.language | English | |
| dc.language.iso | en | |
| dc.rights | All Rights Reserved | |
| dc.subject | carbonated peridotite | |
| dc.subject | experimental petrology | |
| dc.subject | mantle | |
| dc.subject | melting | |
| dc.title | Phase relations of phlogopite with magnesite from 4 to 8 GPa | en |
| dc.type | Article |