The hydrothermal diamond anvil cell (HDAC) for Raman spectroscopic studies of geologic fluids at high pressures and temperatures "

Transcription

1 The hydrothermal diamond anvil cell (HDAC) for Raman spectroscopic studies of geologic fluids at high pressures and temperatures " Christian Schmidt, I-Ming Chou*" GFZ German Research Centre for Geosciences, Potsdam, Germany" *U.S. Geological Survey, Reston, Virginia, U.S.A. "

2 Introduction hydrous fluids/melts in crust and mantle" crucial for element cycling"! properties of interest" - density! - viscosity! - sound velocity! - electrical conductivity! - phase transitions! - complexation,! speciation! - solubility, partitioning! - kinetics of mineral-fluid! and fluid-fluid interaction! " many of these properties need or should be studied " in situ at high P and T"

3 Introduction Bassett et al. (1993): HDAC " designed to study fluids in situ at lithospheric P-T conditions!!!! ~ 180 citations in scopus!! HDACs used particularly for experiments with hydrous fluids to 23 GPa at 750 C (Lin et al., 2004) and 1025±10 C at ~2 GPa (Audétat and Keppler, 2005)!

4 Construction central portion with sample chamber" objective lens of microscope ceramic support heater wires (Mo, Pt, PtRh, NiCr) tungsten carbide seat sample chamber, fluid metal gasket (Ir, Re ± Au coating) pressure sensor (e.g., quartz) thermocouples (K type) diamond anvils pressure generation

5 Construction upper and lower platen" design minimizes temperature gradient in sample chamber and permits accurate measurement + control of sample temperature!

6 Construction alignment of culet faces of anvils" interference color pattern indicates parallelism! of culet faces! rocker for rotation! sliding disk for translation! Smith and Fang (2009) "

7 Construction assembled HDAC on xyz-stage of Raman spectrometer" heater wires to thyristor-driven power supplies gas inlet thermocouple wires to temperature controllers driver screw with Belleville washer Bassett" et al. (1993) "

8 temperature measurement calibration using melting points" melting points at atmospheric pressure, e.g. of NaCl (halite) (800.7 C) CsCl (645 C) K 2 Cr 2 O 7 (398 C) heating to >500 C damages culet NaNO 3 (306.8 C) heating to >500 C damages culet S (112.8 C) azobenzene (68 C) triple points of water for calibration at low temperature ice I + liquid + vapor at 0.01 C, 0.6 kpa ice I + ice III + liquid at C, MPa

9 temperature measurement calibration using α-β quartz transition" 573 C 574 C displacive, very little hysteresis 574 C upon heating at 0.1 MPa optical observation under crossed polars should be cut parallel to c axis, section ~75 µm thick

10 pressure determination overview" indirectly: optical microscopy, measurement of phasetransition temperatures in solid calibrant fluid in sample (with application of appropriate EoS) directly: X-ray diffractometry or optical spectrometry, measurement of P-dependent property of a standard angle or energy positions of Bragg reflections of e.g. Au, Pt, NaCl, MgO. Rarely applied in studies on fluids frequency shifts of Raman or fluorescence lines of optical pressure sensors - fluorescence sensors: ruby (α-al 2 O 3 :Cr 3+ ), Sm:YAG, SrB 4 O 7 :Sm 2+ - Raman spectroscopic sensors (work often better at high T): α-quartz, berlinite (AlPO 4 ), zircon, c-bn, 13 C-diamond

11 pressure determination Raman bands: α-quartz" Intensity (10 3 counts) Raman spectra of -quartz P ~20 cm-1 GPa E C, 0.1 MPa A 1 A 1 A 1 E E E C, 2130 MPa wavenumber (cm -1 ) 464 ν P 464 " ~9 cm-1 GPa -1 E ν 206 : <2.5 GPa at RT, but high resolution ν 464 : to ~600 C, to ~3 GPa (10 GPa at RT) Schmidt and Ziemann (2000) "

12 Pressure determination Raman bands: ν 3 (SiO 4 ) band of zircon" intensity (10 3 counts) T P 1 (SiO 4 ) 3 (SiO 4 ) 700 C, 0.1 MPa 700 C, 2.36 GPa 23 C, 0.1 MPa 27 C, 1.95 GPa wavenumber, cm -1 ν 1008 : to ~1000 C, to ~10 GPa Schmidt et al. (in revision)" Raman shift, 3 (SiO 4 ), (cm -1 ) C, 5.81 cm -1 /GPa 200 C, (5.83 cm -1 /GPa) 300 C, (6.12 cm -1 /GPa) 400 C, (6.31 cm -1 /GPa) 500 C, (6.08 cm -1 /GPa) 600 C, 5.88 cm -1 /GPa 700 C, 5.87 cm -1 /GPa Pressure (GPa)

13 pressure determination Raman bands: ν 1055 (= ν TO ) of c-bn" c-bn Raman spectr. pressure scales to 900 K, 80 GPa (Datchi et al. 2007) to 3300 K, 70 GPa (Goncharov et al. 2007) inert nearly linear dependence of ν on P, but small ( ν/ P ~3 cm -1 GPa -1 ) Datchi and Canny (2004) "

14 pressure determination Raman bands: ν ν 462 of berlinite" ν 1111 and ν 462 : shift in opposite direction with P and T (ν ν 462 )/ P ~10 cm -1 GPa -1 reacts with aqueous fluids at elevated T Watenphul and Schmidt (2012) "

15 pressure determination fluorescence bands: ruby" most common technique to measure pressure in DACs doublet, at ambient P-T: R1 at ~14404 cm -1 (~ nm) R2 at ~14433 cm -1 (~ nm) ν/ P ~-7.5 cm -1 GPa -1 (=0.365 nmgpa -1 ) has been used to 0.55 TPa recent ruby pressure scales to ~300 GPa (e.g., Dorogokupets and Oganov 2007) original calibration by Piermarini et al. (1975) still valid to ~10 GPa Piermarini et al. (1975) "

16 pressure determination fluorescence bands: ruby" with increasing T: broadening R1 and R2 merge intensity decreases strong and nonlinear shift in wavenumber ( ν 1 / T ~ cm -1 K -1 ) accurate pressure determination becomes difficult at T >300 C, particularly at relatively low P to a few GPa Datchi et al. (2007) "

17 pressure determination fluorescence bands: SrB 4 O 7 :Sm 2+" single, very intense, fluorescence line at ~ nm at ambient PT ν/ P ~-5.5 cm -1 GPa -1 (=0.26 nmgpa -1 ) ν/ T ~ 0 in neon medium" still detectable at 900 K calibrated to 130 GPa (Datchi et al. 1997) drawback: quite soluble in aqueous fluids Datchi et al. (2007) "

18 pressure determination phase transitions and isochores in fluid" 4 4 Fluid 5 P-T path of experiment Pressure Schematic plan view of sample chamber Pressure medium (aqueous fluid) liquid-vapor curve Vapor Liquid Crystal liquid-vapor homogenization before and after heating 5 3 critical point Temperature isochore modified from Schmidt and Ziemann (2000) "

19 pressure determination dilute aqueous fluids: EoS of water" P, MPa Ice V Ice III Ice I Ice VI 50(VI) Tm(ice VI)=40 C Tm(ice VI) = 30 C Tm(ice VI) = 20 C Tm(ice V) = 0 C Tm(ice VI) = 10 C Tm(ice V) = -5 C Tm(ice V) = -10 C Tm(ice V) = -15 C liquid-vapor curve Tm(ice III) = -20 C Tm(ice I) = -20 C Tm(ice I) = -15 C Tm(ice I) = -10 C T, C Tm(ice I) = -5 C Tm(ice I) = 0.01 C g/cm3 Th(L+V=L) = 50 C 120(L) 140(L) Th(L+V=L) = 100 C g/cm3 160(L) 180(L) g/cm Th(L+V=L) = 200 C (L) 220(L) 230(L) 260(L) 270(L) Th(L+V=L) = 250 C (L) (L) 290(L) 310(L) Th(L+V=L) = 300 C g/cm (L) 330(L) Th(L+V=L) = 350 C (L) 360(L) 370(L) Th(crit) = C 360(V) 370(V) 350(V) Th(L+V=V) = 300 C g/cm g/cm g/cm g/cm g/cm g/cm3 equation of state: Wagner and Pruß (2002) "

20 pressure determination melting curve of pressure medium" Pressure, GPa 2 1 Ice VIII Ice VI Ice VII ice melting curves (Wagner et al. 1994) 33 C liquid H 2 O Ice VI 0 Ice II Ice V Ice III Ice I liquid H 2 O Temperature, C

21 pressure determination α-β quartz transition temperature" α-β quartz transition is sensitive to pressure (~260 K GPa -1 ), drawbacks: T too high for many HDAC experiments, high solubility in H 2 O other transitions applicable at lower T: BaTiO 3 (tetrag./cubic) Pb 3 (PO 4 ) 2 (monoclinic/trigonal) PbTiO 3 (tetrag./cubic) Bassett et al. (1996) "

22 techniques that have been applied to study aqueous fluids/melts in situ using HDACs" optical microscopy, microthermometry, falling sphere technique Raman spectroscopy synchrotron-radiation X-ray fluorescence and absorption spectroscopy inelastic X-ray scattering infrared absorption Brillouin spectroscopy laser-induced phonon spectroscopy electrical conductance measurements

23 Application optical microscopy, microthermometry " Example: experiment on H 2 O molal NaHCO 3 + SiO 2 "! fluid-1 = aqueous fluid! fluid-2 = 2nd fluid (H 2 O+! carbonate+silicate)! Qtz = quartz! NaHCO 3 = nahcolite! Na 2 CO 3 (s) = natrite! Thomas et al. (2011)"

24 Raman spectroscopy and HDAC In situ studies on geologic fluids" permits study of molecules and molecular ions of light elements in fluids at high P and T complexation, speciation, phase transitions, solubility, kinetics, e.g., complexation in H 2 O + KAlSi 3 O 8 fluids to 900 C, 2.3 GPa, phase diagram of H 2 O + 40 mass% KAlSi 3 O 8 (Mibe et al., 2008) silica speciation and solubility of quartz in H 2 O to 900 C, 1.4 GPa (Zotov and Keppler 2002) ammonium in aqueous fluids to 600 C, 1.3 GPa: silica and N speciation, silica solubility of Qz + Ky + Kfs/Ms in H 2 O ± NH 4 Cl, kinetics of Kfs to Ms reaction (Schmidt and Watenphul 2010) ice VII melting curve to 630 C, 22 GPa (Lin et al. 2004)

25 Raman spectroscopy and HDAC In situ studies on geologic fluids" Quantification (e.g. solubility measurement) possible in in some cases Difficulties: rather high detection limits for most species not all relevant species are Raman active or Raman distinguishable changes in the Raman scattering cross sections with P,T,X are unknown for most species

26 Raman spectroscopy and HDAC measurement of species concentration"

27 Raman spectroscopy and HDAC vertical scan of ν 1 -SO 4 2- intensity in fluid" upper diamond anvil aqueous Na 2 SO 4 fluid Z (µm) intensity of 1 -SO 4 2- band (cps) Schmidt (2009)"

28 Raman spectroscopy and HDAC change in ν 1 -SO 4 2- cross section with P and T! intensity g/cm 3 isochore 1.54 molal Na 2 SO 4 in HDAC Raman shift, cm -1 Schmidt (2009)" 100 C, 120 MPa 200 C, 320 MPa 300 C, 520 MPa 400 C, 720 MPa 500 C, 920 MPa 600 C, 1120 MPa probably effect of bond expansion with temperature on polarizability 1 -SO 4 2-,PT from Bose-Einstein factor n (population of energy states) n + 1 = (1 - e -hc j/k B T ) -1 theoretical g/cm3 isochore g/cm3 isochore liquid-vapor curve 1.54 molal Na 2 SO 4 in HDAC Temperature, C

29 Raman spectroscopy and HDAC m SiO 2 (aq) in Qz+Ky+Kfs/Ms+H 2 O±NH 4 Cl" Muscovite/ Tobelite K-feldspar/ Buddingtonite intensity (counts) Qz + Ky + Kfs + Ms/Tob m NH 4 Cl Qz + Ky + Kfs + Ms/Tob + 5 m NH 4 Cl Qz + Ky + Kfs + Ms + H 2 O Qz + H 2 O vapor 400 dimers trimers 600 Q 1 monomers H 4 SiO 4 (aq) Q MPa, 600 C 800 Raman shift (cm -1 ) background signal from diamond * * 1290 MPa, 600 C * * 730 MPa, 500 C * * 920 MPa, 600 C * * * * P V, 40 C 1000 intensity (counts), normalized to density of H 2 O Vapor H 2 O + NH 4 Cl Fluid Quartz Kyanite 100 µm after reaction at 500 C, 730 MPa C Qz m NH 4 Cl Qz + Ky + Kfs + Ms/Tob m NH 4 Cl Qz + H 2 O Qz + Ky + Kfs + Ms + H 2 O Qz + Ky + Kfs + H 2 O 575 MPa Raman shift (cm -1 ) 750 MPa 1290 MPa 970 MPa 920 MPa for calibration:" msio 2 (aq) " = 0.375" at 600 C, " 970 MPa " (Manning 1994)" Schmidt and Watenphul (2010)"

30 Raman spectroscopy and HDAC m SiO 2 (aq) in Qz+Ky+Kfs/Ms+H 2 O±NH 4 Cl" 9.6 m NH 4 Cl + Qz + Ky + Kfs, this study Schmidt and Watenphul (2010)" SiO 2 concentration in fluid (mol / kg H 2 O) C 355 MPa 9.6 m NaCl + Qz, NM m NH 4 Cl + Qz, this study 6.6 m NaCl + Qz, NM2000 H 2 O + Qz + Ky + Kfs, this study 500 C 780 MPa 600 C 575 MPa 500 C 1100 MPa 500 C 1100 MPa (+Ms/Tob) 600 C 920 MPa (+Ms) 600 C 750 MPa 600 C 750 MPa 600 C 1290 MPa 600 C 1290 MPa (+Ms/Tob) 500 C 555 MPa quartz solubility in H 2 O (mol SiO 2 / kg H 2 O)

31 Thank you for your attention!"