Pub Date : 2024-04-01DOI: 10.1007/s00269-024-01271-y
Yao Yao, Xi Liu, Xueyan Du, Lili Zhang, Hongsheng Yuan
Iron hydroxide FeO2Hx (x ≤ 1) and ferrous iron chloride FeCl2 can adopt the HP-PdF2-type (space group: (P{a_{overline 3 }}), Z = 4) structure in the lowermost mantle, potentially contributing to the geochemical cycles of hydrogen and chlorine within Earth’s deep interior, respectively. Here we investigate the high-pressure behavior of HP-PdF2-type FeCl2 by X-ray diffraction (XRD) and Raman measurements in laser-heated diamond anvil cells. Our results show that HP-PdF2-type FeCl2 can be formed at 60‒67 GPa and 1650‒1850 K. Upon cold decompression, the diffraction peaks at pressures above 10 GPa can be indexed to the HP-PdF2-type structure. Intriguingly, the calculated cell volumes reveal a remarkable decrease of ΔV / V = ∼ 14% between 36 and 40 GPa, which is possibly caused by a pressure-induced spin transition of Fe2+ (HS: high-spin → LS: low-spin). We also observe distinct changes in Raman spectra at 33‒35 GPa, practically coinciding with the onset pressures of isostructural phase transition in XRD results. Our observations combined with previous studies conducted at megabar pressures suggest that HP-PdF2-type FeCl2, with a wide pressure stability range, if present in subducting slabs, could facilitate the transport of chlorine from the middle lower mantle to the outer core.
{"title":"Pressure-induced large volume collapse and possible spin transition in HP-PdF2-type FeCl2","authors":"Yao Yao, Xi Liu, Xueyan Du, Lili Zhang, Hongsheng Yuan","doi":"10.1007/s00269-024-01271-y","DOIUrl":"10.1007/s00269-024-01271-y","url":null,"abstract":"<div><p>Iron hydroxide FeO<sub>2</sub>H<sub><i>x</i></sub> (<i>x</i> ≤ 1) and ferrous iron chloride FeCl<sub>2</sub> can adopt the HP-PdF<sub>2</sub>-type (space group: <span>(P{a_{overline 3 }})</span>, <i>Z</i> = 4) structure in the lowermost mantle, potentially contributing to the geochemical cycles of hydrogen and chlorine within Earth’s deep interior, respectively. Here we investigate the high-pressure behavior of HP-PdF<sub>2</sub>-type FeCl<sub>2</sub> by X-ray diffraction (XRD) and Raman measurements in laser-heated diamond anvil cells. Our results show that HP-PdF<sub>2</sub>-type FeCl<sub>2</sub> can be formed at 60‒67 GPa and 1650‒1850 K. Upon cold decompression, the diffraction peaks at pressures above 10 GPa can be indexed to the HP-PdF<sub>2</sub>-type structure. Intriguingly, the calculated cell volumes reveal a remarkable decrease of Δ<i>V</i> / <i>V</i> = ∼ 14% between 36 and 40 GPa, which is possibly caused by a pressure-induced spin transition of Fe<sup>2+</sup> (HS: high-spin → LS: low-spin). We also observe distinct changes in Raman spectra at 33‒35 GPa, practically coinciding with the onset pressures of isostructural phase transition in XRD results. Our observations combined with previous studies conducted at megabar pressures suggest that HP-PdF<sub>2</sub>-type FeCl<sub>2</sub>, with a wide pressure stability range, if present in subducting slabs, could facilitate the transport of chlorine from the middle lower mantle to the outer core.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-15DOI: 10.1007/s00269-024-01269-6
Shanrong Zhang, Wen Liang, Mengzeng Wu, Qifa Zhong, Dawei Fan
To investigate the quantitative relationship between the crystal structure and composition of Mn-bearing calcite, the solid solutions of Ca1–xMnxCO3 (x = 0.1, 0.3, 0.5, 0.7, 0.9) with continuous MnCO3 mol% content were synthesized at 1 GPa and 700 °C using high-purity CaCO3 and MnCO3 powders as starting materials. The run products were analysized by electron probe, powder X-ray diffraction and Raman spectroscopy. The CaO wt% and MnO wt% of the resulting products are consistent with the expected compositions. The powder X-ray diffraction results show that the products are single phase without any impurities. All diffraction peaks of samples with varying MnCO3 mol% contents can be indexed by the calcite-type structure carbonates ACO3 (R-3c space group; A is a divalent cation), confirming the previous results that there is the completely continuous solid solution between CaCO3 and MnCO3 end members. The unit-cell parameters and volumes of the solid solutions decrease as the MnCO3 mol% content increases, presenting a linear relationship of Ca–Mn ideal miscibility, which is perfectly consistent with the rigid body model of A-site substitution in ACO3. Besides, as MnCO3 mol% content increases, the bond distance of A–O decreases linearly, while the bond distance of C–O changes like a parabola. Therefore, the addition of Mn makes the bond distance of A–O shorten, resulting in the decrease of unit-cell parameters and volumes for Ca1–xMnxCO3. Furthermore, two exterior vibrations (T and L) of the crystal lattice and two internal vibrations (ν4 and ν1) within the CO32− unit are assigned in the Raman spectra of these solid solutions. The characteristic vibration modes T, L, and ν4 as a whole increase with the increasing of MnCO3 mol% content, whereas the characteristic vibration mode ν1 as a whole decreases with the increase of MnCO3 mol% content. These variations in Raman vibration modes are related to the radius of substituted ions.
{"title":"Crystal structure of calcite-type Ca1–xMnxCO3 solid solution by X-ray diffraction and Raman spectroscopy","authors":"Shanrong Zhang, Wen Liang, Mengzeng Wu, Qifa Zhong, Dawei Fan","doi":"10.1007/s00269-024-01269-6","DOIUrl":"10.1007/s00269-024-01269-6","url":null,"abstract":"<div><p>To investigate the quantitative relationship between the crystal structure and composition of Mn-bearing calcite, the solid solutions of Ca<sub>1–<i>x</i></sub>Mn<sub><i>x</i></sub>CO<sub>3</sub> (<i>x</i> = 0.1, 0.3, 0.5, 0.7, 0.9) with continuous MnCO<sub>3</sub> mol% content were synthesized at 1 GPa and 700 °C using high-purity CaCO<sub>3</sub> and MnCO<sub>3</sub> powders as starting materials. The run products were analysized by electron probe, powder X-ray diffraction and Raman spectroscopy. The CaO wt% and MnO wt% of the resulting products are consistent with the expected compositions. The powder X-ray diffraction results show that the products are single phase without any impurities. All diffraction peaks of samples with varying MnCO<sub>3</sub> mol% contents can be indexed by the calcite-type structure carbonates ACO<sub>3</sub> (<i>R-3c</i> space group; A is a divalent cation), confirming the previous results that there is the completely continuous solid solution between CaCO<sub>3</sub> and MnCO<sub>3</sub> end members. The unit-cell parameters and volumes of the solid solutions decrease as the MnCO<sub>3</sub> mol% content increases, presenting a linear relationship of Ca–Mn ideal miscibility, which is perfectly consistent with the rigid body model of A-site substitution in ACO<sub>3</sub>. Besides, as MnCO<sub>3</sub> mol% content increases, the bond distance of A–O decreases linearly, while the bond distance of C–O changes like a parabola. Therefore, the addition of Mn makes the bond distance of A–O shorten, resulting in the decrease of unit-cell parameters and volumes for Ca<sub>1–<i>x</i></sub>Mn<sub><i>x</i></sub>CO<sub>3</sub>. Furthermore, two exterior vibrations (T and L) of the crystal lattice and two internal vibrations (ν<sub>4</sub> and ν<sub>1</sub>) within the CO<sub>3</sub><sup>2−</sup> unit are assigned in the Raman spectra of these solid solutions. The characteristic vibration modes T, L, and ν<sub>4</sub> as a whole increase with the increasing of MnCO<sub>3</sub> mol% content, whereas the characteristic vibration mode ν<sub>1</sub> as a whole decreases with the increase of MnCO<sub>3</sub> mol% content. These variations in Raman vibration modes are related to the radius of substituted ions.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140153737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-26DOI: 10.1007/s00269-024-01270-z
D. Heuser, E. Petrishcheva, F. Ingegneri, C. L. Lengauer, E. Dachs, C. Hauzenberger, R. Abart
The equilibrium partitioning of Na and K between alkali feldspar and NaCl–KCl salt melt was determined at 800 (^circ)C, 850 (^circ)C, 900 (^circ)C, 950 (^circ)C and 1000 (^circ)C and close to ambient pressure. Four different natural gem-quality alkali feldspars with low degree of Al–Si ordering covering the range from orthoclase to high sanidine and with slightly different minor element concentrations were used as starting materials. The partitioning curves obtained for the four feldspars are indistinguishable indicating that Na–K partitioning independent of the differences of Al–Si ordering state and minor element concentrations existing amongst these feldspars. A sub-regular two parameter Margules type solution model was fitted to the partitioning data, and the excess Gibbs energy describing the thermodynamic non-ideality of the alkali feldspar solid-solution and the respective Margules parameters (W_{text {g}text {K}}) and (W_{text {g}text {Na}}) including their temperature dependence expressed as (W_g=W_h-TW_s) were determined:
The corresponding solvus has a critical temperature slightly above 650 (^circ)C and is well comparable with earlier direct experimental determinations of the low-sanidine-albite solvus curve. Comparison of the vibrational excess entropy determined from low-temperature heat capacity measurements with the total excess entropy derived from the temperature dependence of the excess Gibbs energy yields a negative configurational contribution to the excess entropy pointing towards short-range Na–K ordering on the alkali site.
{"title":"Thermodynamic mixing properties of disordered alkali feldspar solid-solution from Na–K partitioning and low-temperature calorimetry","authors":"D. Heuser, E. Petrishcheva, F. Ingegneri, C. L. Lengauer, E. Dachs, C. Hauzenberger, R. Abart","doi":"10.1007/s00269-024-01270-z","DOIUrl":"10.1007/s00269-024-01270-z","url":null,"abstract":"<div><p>The equilibrium partitioning of Na and K between alkali feldspar and NaCl–KCl salt melt was determined at 800 <span>(^circ)</span>C, 850 <span>(^circ)</span>C, 900 <span>(^circ)</span>C, 950 <span>(^circ)</span>C and 1000 <span>(^circ)</span>C and close to ambient pressure. Four different natural gem-quality alkali feldspars with low degree of Al–Si ordering covering the range from orthoclase to high sanidine and with slightly different minor element concentrations were used as starting materials. The partitioning curves obtained for the four feldspars are indistinguishable indicating that Na–K partitioning independent of the differences of Al–Si ordering state and minor element concentrations existing amongst these feldspars. A sub-regular two parameter Margules type solution model was fitted to the partitioning data, and the excess Gibbs energy describing the thermodynamic non-ideality of the alkali feldspar solid-solution and the respective Margules parameters <span>(W_{text {g}text {K}})</span> and <span>(W_{text {g}text {Na}})</span> including their temperature dependence expressed as <span>(W_g=W_h-TW_s)</span> were determined: </p><div><div><span>$$begin{aligned} W_{text {g}text {K}}&= 19754 pm 3140 Jcdot ,,{hbox {mol}},,^{-1} - T cdot 2.33 pm 2.67 Jcdot ,,{hbox {mol}},,^{-1}cdot K^{-1} W_{text {g}text {Na}}&= 14916 pm 4272 Jcdot ,,{hbox {mol}},,^{-1} - T cdot 3.55 pm 3.64 Jcdot {hbox {mol}},,^{-1}cdot K^{-1} end{aligned}$$</span></div></div><p>The corresponding solvus has a critical temperature slightly above 650 <span>(^circ)</span>C and is well comparable with earlier direct experimental determinations of the low-sanidine-albite solvus curve. Comparison of the vibrational excess entropy determined from low-temperature heat capacity measurements with the total excess entropy derived from the temperature dependence of the excess Gibbs energy yields a negative configurational contribution to the excess entropy pointing towards short-range Na–K ordering on the alkali site.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-024-01270-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139978708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-12DOI: 10.1007/s00269-023-01263-4
Ruiqi Chen, Oleg I. Siidra, Vera A. Firsova, Valery L. Ugolkov, Natalia S. Vlasenko, Vladimir N. Bocharov, Angel M. Arevalo-Lopez, Marie Colmont, Igor V. Tokarev
The metamict fergusonite-(Y) with the formula (Y0.70Ln0.20Ca0.13U0.02Th0.02)∑1.07(Nb0.72Ta0.17W0.06Ti0.04)∑1(O3.97(OH)0.11F0.08Cl0.03) · 2.12H2O from the Blyumovskaya Pit, Ilmeny Mountains (Russia) was studied by the means of high-temperature X-ray diffraction, thermal analysis, Raman spectroscopy and microprobe analysis. Thermal expansion was studied for both tetragonal (α-fergusonite) and monoclinic (β-fergusonite) polymorphs. The expansion of β-fergusonite is anisotropic and strongly negative along the α33. In contrast, α-fergusonite exhibits a relatively isotropic thermal expansion upon heating. The volume CTE (αV) for β-fergusonite varies in the range 22.87(94)–75.4(2.5) × 10–6 ºC−1, whereas α-fergusonite has αV = 32.33(57)–31.66(49) × 10-6 ºC−1 in the temperature range 850–1200 °C. After heating to 1100 °C, the mineral develops a porous texture, and the radioactivity is reduced by 37%, which can be attributed to the partial volatilization of some radionuclides. In situ experiments revealed the complete sequence of the thermal evolution of the metamict fergusonite-(Y) for the first time.
通过高温 X 射线衍射、热分析、拉曼光谱和微探针等手段,研究了俄罗斯伊尔梅尼山 Blyumovskaya 矿坑中的铁素体(Y),其化学式为(Y0.70Ln0.20Ca0.13U0.02Th0.02)∑1.07(Nb0.72Ta0.17W0.06Ti0.04)∑1(O3.97(OH)0.11F0.08Cl0.03)- 2.通过高温 X 射线衍射、热分析、拉曼光谱和微探针分析,对来自俄罗斯伊尔梅尼山 Blyumovskaya 矿坑的 12H2O 钛铁矿进行了研究。对四方(α-铁素体)和单斜(β-铁素体)多晶体的热膨胀进行了研究。β-铁素体的膨胀是各向异性的,沿α33方向呈强烈的负膨胀。相反,α-铁素体在加热时表现出相对各向同性的热膨胀。在 850-1200 °C 的温度范围内,β-铁素体的体积热膨胀系数(αV)变化范围为 22.87(94)-75.4(2.5) × 10-6 ºC-1,而 α-铁素体的 αV = 32.33(57)-31.66(49) × 10-6 ºC-1。加热到 1100 °C 后,该矿物出现多孔质地,放射性降低了 37%,这可能是由于部分放射性核素挥发所致。原位实验首次揭示了偏闪铁素体-(Y)热演化的完整顺序。
{"title":"Thermal evolution of the metamict fergusonite-(Y)","authors":"Ruiqi Chen, Oleg I. Siidra, Vera A. Firsova, Valery L. Ugolkov, Natalia S. Vlasenko, Vladimir N. Bocharov, Angel M. Arevalo-Lopez, Marie Colmont, Igor V. Tokarev","doi":"10.1007/s00269-023-01263-4","DOIUrl":"10.1007/s00269-023-01263-4","url":null,"abstract":"<div><p>The metamict fergusonite-(Y) with the formula (Y<sub>0.70</sub><i>Ln</i><sub>0.20</sub>Ca<sub>0.13</sub>U<sub>0.02</sub>Th<sub>0.02</sub>)<sub>∑1.07</sub>(Nb<sub>0.72</sub>Ta<sub>0.17</sub>W<sub>0.06</sub>Ti<sub>0.04</sub>)<sub>∑1</sub>(O<sub>3.97</sub>(OH)<sub>0.11</sub>F<sub>0.08</sub>Cl<sub>0.03</sub>) · 2.12H<sub>2</sub>O from the Blyumovskaya Pit, Ilmeny Mountains (Russia) was studied by the means of high-temperature X-ray diffraction, thermal analysis, Raman spectroscopy and microprobe analysis. Thermal expansion was studied for both tetragonal (<i>α</i>-fergusonite) and monoclinic (<i>β</i>-fergusonite) polymorphs. The expansion of <i>β</i>-fergusonite is anisotropic and strongly negative along the <i>α</i><sub>33</sub>. In contrast, <i>α</i>-fergusonite exhibits a relatively isotropic thermal expansion upon heating. The volume CTE (<i>α</i><sub><i>V</i></sub>) for <i>β</i>-fergusonite varies in the range 22.87(94)–75.4(2.5) × 10<sup>–6</sup> ºC<sup>−1</sup>, whereas <i>α</i>-fergusonite has <i>α</i><sub><i>V</i></sub> = 32.33(57)–31.66(49) × 10<sup>-</sup><sup>6</sup> ºC<sup>−1</sup> in the temperature range 850–1200 °C. After heating to 1100 °C, the mineral develops a porous texture, and the radioactivity is reduced by 37%, which can be attributed to the partial volatilization of some radionuclides. In situ experiments revealed the complete sequence of the thermal evolution of the metamict fergusonite-(Y) for the first time.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-09DOI: 10.1007/s00269-023-01266-1
Hiroshi Kojitani, Mei Gonai, Yoshiyuki Inaguma, Masaki Akaogi
High-temperature X-ray diffraction measurements of calcium ferrite (CF)-type MgAl2O4 were performed in a temperature range of 300–673 K at atmospheric pressure. From temperature dependence of the unit cell volume, thermal expansivity (α) was determined to be α(T) = (2.46 ± 0.13) × 10–5 + (1.2 ± 0.3) × 10–8T in 1/K. Thermoelastic parameters of isothermal bulk modulus at zero pressure (KT0), its pressure derivative (KT′) and temperature derivative [(∂KT0/∂T)P] of MgAl2O4 CF were optimized by iteration calculation combining the least squares fitting of a third-order Birch–Murnaghan equation of state to previous P–V–T data with α calculation using the Grüneisen relation equation, α = γthCV/(KT0V) where γth and CV are thermal Grüneisen parameter and isochoric heat capacity, respectively. γth was constrained by the α measured in this study. When pressure data were rescaled by Au equations of state which are different from that adopted in the previous study and temperature data were corrected using pressure dependence of electromotive force of a W–Re thermocouple, KT0, KT′ and (∂KT0/∂T)P were assessed to be 216(4) GPa, 3.9(3) and − 0.027(3) GPa/K, respectively. It was suggested that the optimized α was about 17% lower than that determined by the previous study at 2000 K.
{"title":"Experimental determination of thermal expansivity of calcium ferrite-type MgAl2O4 and its application to thermodynamical assessment of thermoelastic parameters","authors":"Hiroshi Kojitani, Mei Gonai, Yoshiyuki Inaguma, Masaki Akaogi","doi":"10.1007/s00269-023-01266-1","DOIUrl":"10.1007/s00269-023-01266-1","url":null,"abstract":"<div><p>High-temperature X-ray diffraction measurements of calcium ferrite (CF)-type MgAl<sub>2</sub>O<sub>4</sub> were performed in a temperature range of 300–673 K at atmospheric pressure. From temperature dependence of the unit cell volume, thermal expansivity (<i>α</i>) was determined to be <i>α</i>(<i>T</i>) = (2.46 ± 0.13) × 10<sup>–5</sup> + (1.2 ± 0.3) × 10<sup>–8</sup> <i>T</i> in 1/K. Thermoelastic parameters of isothermal bulk modulus at zero pressure (<i>K</i><sub><i>T</i>0</sub>), its pressure derivative (<i>K</i><sub><i>T</i></sub>′) and temperature derivative [(∂<i>K</i><sub><i>T</i>0</sub>/∂<i>T</i>)<sub><i>P</i></sub>] of MgAl<sub>2</sub>O<sub>4</sub> CF were optimized by iteration calculation combining the least squares fitting of a third-order Birch–Murnaghan equation of state to previous <i>P</i>–<i>V</i>–<i>T</i> data with <i>α</i> calculation using the Grüneisen relation equation, <i>α</i> = <i>γ</i><sub>th</sub><i>C</i><sub><i>V</i></sub>/(<i>K</i><sub><i>T</i>0</sub><i>V</i>) where <i>γ</i><sub>th</sub> and <i>C</i><sub><i>V</i></sub> are thermal Grüneisen parameter and isochoric heat capacity, respectively. <i>γ</i><sub>th</sub> was constrained by the <i>α</i> measured in this study. When pressure data were rescaled by Au equations of state which are different from that adopted in the previous study and temperature data were corrected using pressure dependence of electromotive force of a W–Re thermocouple, <i>K</i><sub><i>T</i>0</sub>, <i>K</i><sub><i>T</i></sub>′ and (∂<i>K</i><sub><i>T</i>0</sub>/∂<i>T</i>)<sub><i>P</i></sub> were assessed to be 216(4) GPa, 3.9(3) and − 0.027(3) GPa/K, respectively. It was suggested that the optimized <i>α</i> was about 17% lower than that determined by the previous study at 2000 K.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-09DOI: 10.1007/s00269-023-01267-0
Carlos Pimentel, Carlos Gutiérrez-Ariza, Antonio G. Checa, C. Ignacio Sainz-Díaz, Julyan H. E. Cartwright
Menilites, intriguing botryoidal rocks found in Galera, Granada, Spain, have been examined through a multidisciplinary approach integrating mineralogical analysis and advanced imaging techniques. Characterized as opal and dolomite-bearing rocks, their complex morphologies and diverse internal structures prompted an investigation into their origin. Employing microfocus X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy and X-ray computed tomography, we present a detailed study of the menilites, revealing opal-A, opal-CT, dolomite and quartz as primary constituents. Notably, the internal homogeneity contrasts with the diverse external shapes. The proposed hypothesis suggests a seismic influence in menilite formation. Seismic events in porous environments above the water table may induce fluidization, resulting in the distinctive menilite structures. Osmotic pressure differences between nodules and the surrounding rock, coupled with fluidization during seismic events, could explain the observed morphologies. Validation of the proposed hypothesis requires further fieldwork and analogue experimentation. This study contributes valuable insights into the mineralogical composition, internal structures and potential formation mechanisms of menilites, laying the groundwork for future research in the field of sedimentary geology and mineralogy.
在西班牙格拉纳达的加莱拉发现的梅尼洛石是一种引人入胜的植物状岩石,我们采用多学科方法,结合矿物学分析和先进的成像技术对其进行了研究。这些岩石的特征是含有蛋白石和白云石,其复杂的形态和多样的内部结构促使人们对其起源进行研究。通过使用微焦 X 射线衍射、扫描电子显微镜与能量色散 X 射线光谱以及 X 射线计算机断层扫描技术,我们对红云岩进行了详细研究,发现其主要成分为蛋白石-A、蛋白石-CT、白云石和石英。值得注意的是,内部的均匀性与外部形状的多样性形成了鲜明对比。所提出的假设表明,月光石的形成受到了地震的影响。地下水位以上多孔环境中的地震事件可能会引起流化,从而形成独特的红云岩结构。结核与周围岩石之间的渗透压差,再加上地震事件期间的流化,可以解释观察到的形态。验证提出的假设需要进一步的实地考察和模拟实验。这项研究为了解月锰矿的矿物组成、内部结构和潜在形成机制提供了宝贵的见解,为今后在沉积地质学和矿物学领域开展研究奠定了基础。
{"title":"Mineralogical description and hypothesis on the formation of menilites from Galera, Granada (Spain)","authors":"Carlos Pimentel, Carlos Gutiérrez-Ariza, Antonio G. Checa, C. Ignacio Sainz-Díaz, Julyan H. E. Cartwright","doi":"10.1007/s00269-023-01267-0","DOIUrl":"10.1007/s00269-023-01267-0","url":null,"abstract":"<div><p>Menilites, intriguing botryoidal rocks found in Galera, Granada, Spain, have been examined through a multidisciplinary approach integrating mineralogical analysis and advanced imaging techniques. Characterized as opal and dolomite-bearing rocks, their complex morphologies and diverse internal structures prompted an investigation into their origin. Employing microfocus X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy and X-ray computed tomography, we present a detailed study of the menilites, revealing opal-A, opal-CT, dolomite and quartz as primary constituents. Notably, the internal homogeneity contrasts with the diverse external shapes. The proposed hypothesis suggests a seismic influence in menilite formation. Seismic events in porous environments above the water table may induce fluidization, resulting in the distinctive menilite structures. Osmotic pressure differences between nodules and the surrounding rock, coupled with fluidization during seismic events, could explain the observed morphologies. Validation of the proposed hypothesis requires further fieldwork and analogue experimentation. This study contributes valuable insights into the mineralogical composition, internal structures and potential formation mechanisms of menilites, laying the groundwork for future research in the field of sedimentary geology and mineralogy.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139768225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrical resistivity measurements on oriented FeTiO3 ilmenite using single crystals at high pressures proves that FeTiO3 ilmenite shows anisotropic electrical resistivity. The resistivity in the direction perpendicular to the c-axis decreased monotonously with increasing pressure. In contrast, the resistivity in the parallel direction to the c-axis initially decreased and slightly increased with increasing pressure above 6 GPa. It then resumed decreasing above 8 GPa. The hallow-shape of the curvature was observed. Neutron and synchrotron X-ray diffraction experiments provided an accurate picture of the pressure-induced changes of the FeTiO3 ilmenite structure. FeTiO3 transforms neither into perovskite nor LiNbO3 phase under pressures up to 28 GPa. However, different compression curves were observed for both FeO6 and TiO6 octahedra below 8 GPa. FeO6 is more compressible and flexible than TiO6. Among Fe–Fe, Ti–Ti and Fe–Ti interatomic distances, the shortest Fe–Ti distance presents the highest electrical restivity and electron mobility according to Fe2+Ti4+ and Fe3+Ti3+ by electron super-exchange mechanism, which is enhanced during compression. At high pressure, the electron configuration of Fe2+ (3d6) is more strongly changed than Ti4+ (3d0) and the former cation is the emphasized by Jahn–Teller effect in the ligand field of C3v molecular symmetry. The anisotropic electrical resistivity and non-uniform structure change of Fe–Ti interatomic distance can be explained by possible spin transition. The spin transition of FeKβ from high-spin to intermediate-spin state is possible in the electronic state change of FeTiO3.
{"title":"Anisotropic electrical conductivity changes in FeTiO3 structure transition under high pressure","authors":"Takamitsu Yamanaka, Yuki Nakamoto, Masafumi Sakata, Katsuya Shimizu, Takanori Hattori","doi":"10.1007/s00269-023-01261-6","DOIUrl":"10.1007/s00269-023-01261-6","url":null,"abstract":"<div><p>Electrical resistivity measurements on oriented FeTiO<sub>3</sub> ilmenite using single crystals at high pressures proves that FeTiO<sub>3</sub> ilmenite shows anisotropic electrical resistivity. The resistivity in the direction perpendicular to the <i>c</i>-axis decreased monotonously with increasing pressure. In contrast, the resistivity in the parallel direction to the <i>c</i>-axis initially decreased and slightly increased with increasing pressure above 6 GPa. It then resumed decreasing above 8 GPa. The hallow-shape of the curvature was observed. Neutron and synchrotron X-ray diffraction experiments provided an accurate picture of the pressure-induced changes of the FeTiO<sub>3</sub> ilmenite structure. FeTiO<sub>3</sub> transforms neither into perovskite nor LiNbO<sub>3</sub> phase under pressures up to 28 GPa. However, different compression curves were observed for both FeO<sub>6</sub> and TiO<sub>6</sub> octahedra below 8 GPa. FeO<sub>6</sub> is more compressible and flexible than TiO<sub>6</sub>. Among Fe–Fe, Ti–Ti and Fe–Ti interatomic distances, the shortest Fe–Ti distance presents the highest electrical restivity and electron mobility according to Fe<sup>2+</sup>Ti<sup>4+</sup> and Fe<sup>3+</sup>Ti<sup>3+</sup> by electron super-exchange mechanism, which is enhanced during compression. At high pressure, the electron configuration of Fe<sup>2+</sup> (3<i>d</i><sup>6</sup>) is more strongly changed than Ti<sup>4+</sup> (3<i>d</i><sup>0</sup>) and the former cation is the emphasized by Jahn–Teller effect in the ligand field of <i>C</i><sub>3<i>v</i></sub> molecular symmetry. The anisotropic electrical resistivity and non-uniform structure change of Fe–Ti interatomic distance can be explained by possible spin transition. The spin transition of Fe<i>Kβ</i> from high-spin to intermediate-spin state is possible in the electronic state change of FeTiO<sub>3</sub>.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139683152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The characteristic behavior of magnetic remanence correlated with mineralogical textures and composition was observed using low-temperature magnetometry, microscopy, and chemical analysis of three isocubanite samples collected from hydrothermal deposits in the Okinawa Trough and a sample transformed from natural cubanite via heating. Both zero-field remanence acquired at 5 K and field cooling remanence acquired at 300–5 K of all samples sharply decreased with increasing temperature at approximately 100 K. In addition, low-temperature cycling of isothermal remanence at 300 K exhibited a transition at approximately 100 K; remanence increased with decreasing temperature and vice versa. The intensity of remanence at low temperature and sharpness of the transition varied across samples with different compositions and microscopic textures, that is, the presence or absence of chalcopyrite lamellae and their widths. The sample obtained from a hydrothermal chimney, in which the magnetic transition was most clearly observed, was also subjected to X-ray diffraction, Mössbauer spectroscopy, electrical resistivity, and magnetic hysteresis measurements. The obtained results were generally consistent with those reported previously for unnamed mineral CuFe3S4 with an ordered cation arrangement. The low-temperature magnetic behavior of isocubanite possibly depends on the degree of cation ordering and can be regarded as an indicator of chemical composition and cooling history. Therefore, low-temperature magnetometry is useful for the detection of isocubanite and a potentially powerful technique for the prompt estimation of its composition and texture, contributing to our understanding of the formation process of hydrothermal deposits.
利用低温磁力测定法、显微镜和化学分析,对从冲绳海槽热液矿床采集的三个异方解石样本和一个通过加热从天然方解石转化而来的样本进行了观察,发现了磁性剩磁与矿物纹理和成分相关的特征行为。所有样品在 5 K 时获得的零磁场剩磁和在 300-5 K 时获得的磁场冷却剩磁都随着温度的升高而在大约 100 K 时急剧下降。不同成分和微观纹理(即黄铜矿薄片的存在与否及其宽度)的样品在低温下的剩磁强度和转变的尖锐程度各不相同。对从热液烟囱中获得的样品也进行了 X 射线衍射、莫斯鲍尔光谱、电阻率和磁滞测量,在该样品中磁性转变最为明显。所获得的结果与之前报道的具有有序阳离子排列的未命名矿物 CuFe3S4 的结果基本一致。异古巴尼特的低温磁性可能取决于阳离子的有序程度,可被视为化学成分和冷却历史的指标。因此,低温磁力测量法有助于检测异古巴涅石,也是迅速估算其成分和质地的潜在有力技术,有助于我们了解热液矿床的形成过程。
{"title":"Low-temperature magnetic behavior of isocubanite from seafloor hydrothermal deposits in the Okinawa Trough","authors":"Chie Kato, Masao Ohno, Tadahiro Hatakeyama, Yasuhiro Yamada, Fuminori Honda, Kazuhiko Shimada, Toshiro Nagase, Shuhei Totsuka-Shiiki, Yoshihiro Kuwahara, Jun-ichiro Ishibashi","doi":"10.1007/s00269-023-01264-3","DOIUrl":"10.1007/s00269-023-01264-3","url":null,"abstract":"<div><p>The characteristic behavior of magnetic remanence correlated with mineralogical textures and composition was observed using low-temperature magnetometry, microscopy, and chemical analysis of three isocubanite samples collected from hydrothermal deposits in the Okinawa Trough and a sample transformed from natural cubanite via heating. Both zero-field remanence acquired at 5 K and field cooling remanence acquired at 300–5 K of all samples sharply decreased with increasing temperature at approximately 100 K. In addition, low-temperature cycling of isothermal remanence at 300 K exhibited a transition at approximately 100 K; remanence increased with decreasing temperature and vice versa. The intensity of remanence at low temperature and sharpness of the transition varied across samples with different compositions and microscopic textures, that is, the presence or absence of chalcopyrite lamellae and their widths. The sample obtained from a hydrothermal chimney, in which the magnetic transition was most clearly observed, was also subjected to X-ray diffraction, Mössbauer spectroscopy, electrical resistivity, and magnetic hysteresis measurements. The obtained results were generally consistent with those reported previously for unnamed mineral CuFe<sub>3</sub>S<sub>4</sub> with an ordered cation arrangement. The low-temperature magnetic behavior of isocubanite possibly depends on the degree of cation ordering and can be regarded as an indicator of chemical composition and cooling history. Therefore, low-temperature magnetometry is useful for the detection of isocubanite and a potentially powerful technique for the prompt estimation of its composition and texture, contributing to our understanding of the formation process of hydrothermal deposits.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-023-01264-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139683046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-28DOI: 10.1007/s00269-023-01265-2
Yurii V. Seryotkin
The high-pressure structural evolution of a natural hydroxyapophyllite-(K) K0.96 Ca4.01[Al0.01Si7.99O20]((OH)0.95F0.05)·(H2O)8.14, Z = 2, a = 8.9699(1), c = 15.8934(3) Å, space group P4/mnc, from the Hatrurim Basin, Negev Desert, compressed in penetrating (ethanol:water 8:1 mixture) medium up to 5 GPa, was studied by single-crystal X-ray diffraction with a diamond anvil cell. The results clearly demonstrate the absence of pressure-induced hydration in the structure. Within 3 GPa, the compression mechanism is similar to that known in fluorapophyllite-(K). The compression in the plane of silicate layer proceeds via the relative rotation of the four-membered rings. The compression along the c-axis proceeds through the shortening of the inter-layer distance, whereas the thickness of silicate layer remains almost unchanged. As a result, the pressure-induced changes in the unit-cell metrics are similar to those for fluorapophyllite-(K). At about 3 GPa, hydroxyapophyllite-(K) undergoes a phase transition with the symmetry lowering to orthorhombic (space group Pnnm). The symmetry of the high-pressure phase allows deformation of the four-membered rings of the silicate layer, which is impossible within tetragonal symmetry. In this case, the structure is compressed much more along the a-axis than along the b-axis. As a result, the orthorhombic phase of hydroxyapophyllite-(K) is more compressible compared to fluorapophyllite-(K).
天然羟基叶绿石-(K) K0.96 Ca4.01[Al0.01Si7.99O20]((OH)0.95F0.05)-(H2O)8.14, Z = 2, a = 8.9699(1), c = 15.通过使用金刚石砧室进行单晶 X 射线衍射,研究了来自内盖夫沙漠 Hatrurim 盆地、在渗透介质(乙醇:水 8:1 混合物)中被压缩至 5 GPa、空间群为 P4/mnc 的 OO20]((OH)0.95F0.05-(H2O)8.14)。研究结果清楚地表明,该结构中不存在压力引起的水合作用。在 3 GPa 的范围内,压缩机制与已知的氟叶绿石-(K)类似。硅酸盐层平面内的压缩是通过四元环的相对旋转进行的。沿 c 轴的压缩是通过缩短层间距离进行的,而硅酸盐层的厚度几乎保持不变。因此,压力引起的单位晶胞度量变化与氟叶绿石(K)相似。在大约 3 GPa 的压力下,羟基叶蜡石(K)发生相变,对称性降低为正方晶(空间群 Pnnm)。高压相的对称性允许硅酸盐层的四元环发生变形,而这在四方对称性中是不可能发生的。在这种情况下,结构沿 a 轴的压缩程度远远大于沿 b 轴的压缩程度。因此,羟基叶绿石-(K)的正方相比氟叶绿石-(K)更容易压缩。
{"title":"Structure evolution of hydroxyapophyllite-(K) under high pressure","authors":"Yurii V. Seryotkin","doi":"10.1007/s00269-023-01265-2","DOIUrl":"10.1007/s00269-023-01265-2","url":null,"abstract":"<div><p>The high-pressure structural evolution of a natural hydroxyapophyllite-(K) K<sub>0.96</sub> Ca<sub>4.01</sub>[Al<sub>0.01</sub>Si<sub>7.99</sub>O<sub>20</sub>]((OH)<sub>0.95</sub>F<sub>0.05</sub>)·(H<sub>2</sub>O)<sub>8.14</sub>, <i>Z</i> = 2, <i>a</i> = 8.9699(1), <i>c</i> = 15.8934(3) Å, space group <i>P</i>4/<i>mnc</i>, from the Hatrurim Basin, Negev Desert, compressed in penetrating (ethanol:water 8:1 mixture) medium up to 5 GPa, was studied by single-crystal X-ray diffraction with a diamond anvil cell. The results clearly demonstrate the absence of pressure-induced hydration in the structure. Within 3 GPa, the compression mechanism is similar to that known in fluorapophyllite-(K). The compression in the plane of silicate layer proceeds via the relative rotation of the four-membered rings. The compression along the <i>c-</i>axis proceeds through the shortening of the inter-layer distance, whereas the thickness of silicate layer remains almost unchanged. As a result, the pressure-induced changes in the unit-cell metrics are similar to those for fluorapophyllite-(K). At about 3 GPa, hydroxyapophyllite-(K) undergoes a phase transition with the symmetry lowering to orthorhombic (space group <i>Pnnm</i>). The symmetry of the high-pressure phase allows deformation of the four-membered rings of the silicate layer, which is impossible within tetragonal symmetry. In this case, the structure is compressed much more along the <i>a</i>-axis than along the <i>b</i>-axis. As a result, the orthorhombic phase of hydroxyapophyllite-(K) is more compressible compared to fluorapophyllite-(K).</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139584400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-21DOI: 10.1007/s00269-023-01262-5
G. Zeff, B. Kalkan, K. Armstrong, M. Kunz, Q. Williams
The crystal structure and bonding environment of K2Ca(CO3)2 bütschliite were probed under isothermal compression via Raman spectroscopy to 95 GPa and single crystal and powder X-ray diffraction to 12 and 68 GPa, respectively. A second order Birch-Murnaghan equation of state fit to the X-ray data yields a bulk modulus, ({K}_{0}=46.9) GPa with an imposed value of ({K}_{0}^{prime}= 4) for the ambient pressure phase. Compression of bütschliite is highly anisotropic, with contraction along the c-axis accounting for most of the volume change. Bütschliite undergoes a phase transition to a monoclinic C2/m structure at around 6 GPa, mirroring polymorphism within isostructural borates. A fit to the compression data of the monoclinic phase yields ({V}_{0}=322.2) Å3(,)({K}_{0}=24.8) GPa and ({K}_{0}^{prime}=4.0) using a third order fit; the ability to access different compression mechanisms gives rise to a more compressible material than the low-pressure phase. In particular, compression of the C2/m phase involves interlayer displacement and twisting of the [CO3] units, and an increase in coordination number of the K+ ion. Three more phase transitions, at ~ 28, 34, and 37 GPa occur based on the Raman spectra and powder diffraction data: these give rise to new [CO3] bonding environments within the structure.
{"title":"High pressure raman spectroscopy and X-ray diffraction of K2Ca(CO3)2 bütschliite: multiple pressure-induced phase transitions in a double carbonate","authors":"G. Zeff, B. Kalkan, K. Armstrong, M. Kunz, Q. Williams","doi":"10.1007/s00269-023-01262-5","DOIUrl":"10.1007/s00269-023-01262-5","url":null,"abstract":"<div><p>The crystal structure and bonding environment of K<sub>2</sub>Ca(CO<sub>3</sub>)<sub>2</sub> bütschliite were probed under isothermal compression via Raman spectroscopy to 95 GPa and single crystal and powder X-ray diffraction to 12 and 68 GPa, respectively. A second order Birch-Murnaghan equation of state fit to the X-ray data yields a bulk modulus, <span>({K}_{0}=46.9)</span> GPa with an imposed value of <span>({K}_{0}^{prime}= 4)</span> for the ambient pressure phase. Compression of bütschliite is highly anisotropic, with contraction along the <i>c</i>-axis accounting for most of the volume change. Bütschliite undergoes a phase transition to a monoclinic <i>C</i>2/<i>m</i> structure at around 6 GPa, mirroring polymorphism within isostructural borates. A fit to the compression data of the monoclinic phase yields <span>({V}_{0}=322.2)</span> Å<sup>3</sup><span>(,)</span> <span>({K}_{0}=24.8)</span> GPa and <span>({K}_{0}^{prime}=4.0)</span> using a third order fit; the ability to access different compression mechanisms gives rise to a more compressible material than the low-pressure phase. In particular, compression of the <i>C</i>2/<i>m</i> phase involves interlayer displacement and twisting of the [CO<sub>3</sub>] units, and an increase in coordination number of the K<sup>+</sup> ion. Three more phase transitions, at ~ 28, 34, and 37 GPa occur based on the Raman spectra and powder diffraction data: these give rise to new [CO<sub>3</sub>] bonding environments within the structure.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-023-01262-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139515712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}