Revised Ti-in-biotite geothermometer for ilmenite- or rutile-bearing crustal metapelites

• Published in: Chinese science bulletin Vol. 60; no. 1; pp. 116 - 121
• Main Authors: Wu, Chun-Ming, Chen, Hong-Xu
• Format: Journal Article
• Language: English
• Published: Beijing Elsevier B.V 01.01.2015; Springer-Verlag; Science China Press
• Subjects: Application; Biotite; Calibration; Chemistry/Food Science; Contact; Earth Sciences; Engineering; Error; Geology; Geothermometer; Geothermometers; Humanities and Social Sciences; Iron; Life Sciences; magnesium; multidisciplinary; Physics; Science; Science (multidisciplinary); temperature; Thermometers; Ti content; Titanium dioxide; 修订; 地壳; 地质温度计; 天然金红石; 泥质; 轴承; 钛铁矿; 黑云母; Ti content; Error; Calibration; Biotite; Geothermometer; Application
• ISSN: 1001-6538; 2095-9273; 1861-9541; 2095-9281
• DOI: 10.1007/s11434-014-0674-y

In the present study, the Ti-in-biotite geother- mometer was revised using more than 300 natural rutile- or ilmenite-bearing metapelites collected worldwide. The formulation was empirically calibrated as ln[T（℃）]= 6.313 ＋0.22 41n（XTi ） -0.2881n（XFe ） -0. 4491n（XMg） ＋ 0.15P （GPa）, with Xj=j/（Fe＋Mg＋Al^Ⅵ＋Ti） in biotite, assuming ferric iron content of 11.6 mol% of the total iron in biotite. This thermometer is consistent with the well-calibrated garnet-biotite thermometer within error of i50 ℃ for most of the calibrant samples and can successfully distin- guish systematic temperature changes of different meta- morphic zones in both prograde and inverted metamorphic terranes as well as thermal contact aureoles. Thus, the thermometer truthfully reflects real geologic conditions and can be applied to TiO2-saturated metapelites metamor- phosed at the crustal level within the calibration ranges （450-840 ℃, 0.1-1.9 GPa, XTi = 0.02-0.14 in biotite）.