- Tytuł:
- Ba- and Ti-enriched dark mica from the UHP metasediments of the Seve Nappe Complex, Swedish Caledonides
- Autorzy:
-
Majka, Jarosław
Kruszewski, Łukasz
Rosen, Ake
Klonowska, Iwona - Powiązania:
- https://bibliotekanauki.pl/articles/127580.pdf
- Data publikacji:
- 2015
- Wydawca:
- Polskie Towarzystwo Mineralogiczne
- Tematy:
-
oxyannite
oxy-ferrokinoshitalite
calcic gneiss
Scandinavian Caledonides - Opis:
- We report on the occurrence of peculiar Ba- and Ti-enriched dark mica in metasedimentary rocks that underwent high-pressure metamorphism in the diamond stability field followed by decompression to granulite facies conditions. The mica occurs as well-developed preserved laths in a quartzofeldspathic matrix. The mean concentrations of BaO and TiO2 in the mica are 11.54 and 7.80wt%, respectively. The maximum amounts of these components are 13.38wt% BaO and 8.45wt% TiO2. The mean crystallochemical formula can be expressed as (K0.54Ba0.39Na0.02Ca0.01)Σ0.96(Fe1.37Mg0.85Ti0.50Al0.29Mn0.01Cr0.01)Σ3.03(Si2.59Al1.41)Σ4.00O10(OH1.30O0.66F0.02S0.01)Σ1.99, with oxyannite, oxy-ferrokinoshitalite and siderophyllite as dominating end-members. Based on the petrographical observations, it is proposed that the dark mica was formed at a rather late stage in the evolution of the parental rock, i.e. under granulite facies conditions.
- Źródło:
-
Mineralogia; 2015, 46, 1/2; 45-50
1899-8291
1899-8526 - Pojawia się w:
- Mineralogia
- Dostawca treści:
- Biblioteka Nauki
Artykuł