Phengite - Wikipedia
Phengite is a series name for dioctahedral micas of composition K (Al,Mg) 2 (OH) 2 (Si,Al) 4 O 10. It is common for Mg or Fe 2+ to substitute for Al on the Y site and a corresponding increase in Si on the Z site in the mica group formula X2Y4–6Z8 O 20 (OH, F) 4. Similar to muscovite but with addition of magnesium.
Phengite: Mineral information, data and localities. - mindat.org
Phengite is an aluminous true mica which contains a relatively high amount of tetrahedrally co-ordinated Si (>3.1 apfu). As the Si amount increases, additional octahedrally co-ordinated cations are necessary for charge balance.
Phengite - an overview | ScienceDirect Topics
Phengite is defined as a main K-rich phase in high-pressure rocks, commonly used for dating subduction-zone metamorphism with the K–Ar (Ar–Ar) method. AI generated definition based on: Journal of Asian Earth Sciences, 2011
The mineral chemistry, near-infrared, and mid-infrared reflectance ...
2013年9月1日 · Phengite is the main potassic dioctahedral mica identified at the Olympic Dam iron oxide–copper–gold (IOCG) deposit, South Australia, where its mineral chemistry is quite variable. These differences can be explained by contrasting degrees of hydrothermal alteration.
Phengite
At first glance, this specimen of "Phengite" (a series between Muscovite and Celadonite) is an ordinary Mica crystal, but when strongly backlit, and viewed from the side, one can see the most intense internal blue-green color. This is a most surprising specimen considering that Mica is rarely colorful, let alone has such a ...
Titanium in phengite: a geobarometer for high temperature eclogites ...
2009年6月12日 · Phengite chemistry has been investigated in experiments on a natural SiO 2 –TiO 2-saturated greywacke and a natural SiO 2 –TiO 2 –Al 2 SiO 5-saturated pelite, at 1.5–8.0 GPa and 800–1,050°C. High Ti-contents (0.3–3.7 wt %), Ti-enrichment with temperature, and a strong inverse correlation of Ti-content with pressure are the ...
Phengite geobarometry based on the limiting assemblage with …
Tests of the new geobarometer with published analytical and PT data on natural phengite-bearing rocks are handicapped by the paucity of reliable values, but also by the obvious lack of equilibration of phengite compositions in many rocks that show zonation of their phengites or even more than one generation of potassic white micas with ...
Empirical phengite geobarometer: Background, calibration, and ...
2017年2月17日 · Phengite is a common metamorphic mineral stable in a wide pressure range. The dependence of pressure on silicon content established in the mid-20th century allowed us to propose a phengite-based geobarometer. Recently, the phengite geobarometer was calibrated by Caddik and Thompson (2008) but in the narrow pressure range.
Mg-Phengite in Carbonate Rock Syngenetically Formed from
2020年7月27日 · In this study, we report a hydrothermal-originated authigenic Mg-phengite-series mineral, which occurred as polycrystalline aggregates (Type 1), pore-fillings (Type 2) and well-crystallized lath form (Type 3) from the Haengmae Formation, a dolomite–pebble-bearing fine sand-sized dolostone, in South Korea.
Cold deep subduction recorded by remnants of a ... - Nature
2018年7月17日 · For the temperatures of 650 and 670 °C, the garnet–clinopyroxene–phengite (Grt–Cpx–Phen) barometer 22 gives peak pressures of 2.49 and 2.46 GPa, respectively (Supplementary Table 8).