TY - JOUR

T1 - Compressibility and structure behaviour of maruyamaite (K-tourmaline) from the Kokchetav massif at high pressure up to 20 GPa

AU - Likhacheva, Anna Yu

AU - Rashchenko, S. V.

AU - Musiyachenko, Kira A.

AU - Korsakov, Andrey V.

AU - Collings, Ines E.

AU - Hanfland, Michael

N1 - Publisher Copyright: © 2019, Springer-Verlag GmbH Austria, part of Springer Nature.

PY - 2019/10/1

Y1 - 2019/10/1

N2 - The structural behaviour of maruyamaite (K-dominant tourmaline) X(K0.54Na0.28Ca0.19)Y(Mg1.3Al1.17Fe0.39Ti0.14)Z(Al5Mg)[Si5.95Al0.05O18](BO3)3V,W[O1.69(OH)2.31] from the ultrahigh-pressure metamorphic rocks of Kokchetav massif was studied using synchrotron based single-crystal diffraction up to 20 GPa. Within the whole pressure range the compression is regular and anisotropic, with the c direction being more compressible than the a direction. Fitting the V/P data with the 2nd and 3rd order Birch-Murnaghan equations of state gives: V0 = 1587.2(7) Å3, K0 = 115.6(9) GPa at fixed K′ = 4, and V0 = 1588(1) Å3, K0 = 112(3) GPa, K′ = 4.5(4). The bulk modulus values are slightly higher as compared to those found for dravite and cation-deficient synthetic K-dravite. The pressure evolution of the main structural parameters of K-tourmaline is similar to those of dravite. However, a minor change in the rigidity of local contacts of the X site with 6-membered ring, due to the presence of K, is apparently critical for stabilization of tourmaline structure within 15–20 GPa, which is evinced by the absence of the phase transition observed in dravite near 15.4 GPa. The stabilizing function of K becomes apparent at P > 15 GPa. The comparison of the HP structural behaviour of maruyamaite and dravite supports the recent suggestion that the large X site plays a secondary role in the elastic behaviour of tourmaline, compared to the octahedral framework. In addition, the present study reveals several new features of polyhedra distortions, which demonstrate their complex interaction on compression.

AB - The structural behaviour of maruyamaite (K-dominant tourmaline) X(K0.54Na0.28Ca0.19)Y(Mg1.3Al1.17Fe0.39Ti0.14)Z(Al5Mg)[Si5.95Al0.05O18](BO3)3V,W[O1.69(OH)2.31] from the ultrahigh-pressure metamorphic rocks of Kokchetav massif was studied using synchrotron based single-crystal diffraction up to 20 GPa. Within the whole pressure range the compression is regular and anisotropic, with the c direction being more compressible than the a direction. Fitting the V/P data with the 2nd and 3rd order Birch-Murnaghan equations of state gives: V0 = 1587.2(7) Å3, K0 = 115.6(9) GPa at fixed K′ = 4, and V0 = 1588(1) Å3, K0 = 112(3) GPa, K′ = 4.5(4). The bulk modulus values are slightly higher as compared to those found for dravite and cation-deficient synthetic K-dravite. The pressure evolution of the main structural parameters of K-tourmaline is similar to those of dravite. However, a minor change in the rigidity of local contacts of the X site with 6-membered ring, due to the presence of K, is apparently critical for stabilization of tourmaline structure within 15–20 GPa, which is evinced by the absence of the phase transition observed in dravite near 15.4 GPa. The stabilizing function of K becomes apparent at P > 15 GPa. The comparison of the HP structural behaviour of maruyamaite and dravite supports the recent suggestion that the large X site plays a secondary role in the elastic behaviour of tourmaline, compared to the octahedral framework. In addition, the present study reveals several new features of polyhedra distortions, which demonstrate their complex interaction on compression.

KW - crystal structure refinement

KW - High pressure

KW - K-tourmaline

KW - Kokchetav Massif

KW - Maruyamaite

KW - northern Kazakhstan

KW - single-crystal diffraction

KW - UHP metamorphism

KW - SYSTEM

KW - CORDIERITE

KW - DRAVITE

KW - SREF

KW - OSCILLATORY ZONED LIDDICOATITE

KW - ANJANABONOINA

KW - SINGLE-CRYSTAL DIFFRACTION

KW - PHASE

KW - CHEMISTRY

KW - MOSSBAUER

UR - http://www.scopus.com/inward/record.url?scp=85068178056&partnerID=8YFLogxK

U2 - 10.1007/s00710-019-00672-0

DO - 10.1007/s00710-019-00672-0

M3 - Article

AN - SCOPUS:85068178056

VL - 113

SP - 613

EP - 623

JO - Mineralogy and Petrology

JF - Mineralogy and Petrology

SN - 0930-0708

IS - 5

ER -