Equilibrium assemblages and Phase Diagrams Christian de Capitani
Equilibrium assemblages and Phase Diagrams Christian de Capitani With the help of: (chronologically) What is the Theriak-Domino Software? Petrogenetic grid > < equilibrium assemblage diagram Some applications It is with tremendous ill grace that I grudgingly acknowledge the contribution of a few other people. (Hugh Grant, 1995) Tom Brown Hugh Greenwood Rob Berman Marcus Kirschen Christian Meyre Thorsten Nagel Konstantin Petrakakis Philipp Hunziker Romain Bousquet Fred Gaidies Doug Tinkham
What is the Theriak-Domino Software? The THERIAK-DOMINO Software is a program collection to calculate and plot thermodynamic functions, equilibrium assemblages and equilibrium assemblage diagrams: Theriak: stable mineral assemblage and phase compositions for a given bulk composition at specified P, T conditions. Domino: - equilibrium assemblage diagrams (P, T, a, ln(a)) - Pseudo-binary or pseudo-ternary phase diagrams - isopleths, density, volume or modal distributions - and more Therbin, Therter: binary and ternary phase diagrams Thalia, Thermo: thermodynamic functions (T, P or composition) Guzzler, Explot, Makemap, Plotxy: transform graphics information to postscript files
What is the aim of thermodynamic modeling?
Nature Experiments, Theory
Nature Experiments, Theory
Nature Models, Software Experiments, Theory Database
Nature Models, Software Experiments, Theory Software Theriak-Domino Database
Nature Models, Software Experiments, Theory Database Software Theriak-Domino Prediction
Nature Models, Software Experiments, Theory Database Software Theriak-Domino Prediction
Petrogenetic grids: Focus on reactions 1. System (eg. K 2 O-Mg. O-Al 2 O 3 -Si. O 2 -H 2 O) 2. Choose phases (eg. for pelites: Qz, Sil, And, Ky, Stau, Alm, Grs, Py, etc. ) 3. Calculate all reactions 4. Schreinemakers
Petrogenetic grids: Focus on reactions P-T phase diagram showing the experimental results of Koziol and Newton (1988), and the equilibrium curve for reaction (2737). Open triangles indicate runs in which An grew, closed triangles indicate runs in which Grs + Ky + Qtz grew, and half-filled triangles indicate no significant reaction. The univariant equilibrium curve is a best-fit regression of the data brackets. The line at 650 o. C is Koziol and Newton’s estimate of the reaction location based on reactions involving zoisite. The shaded area is the uncertainty envelope. After Koziol and Newton (1988) Amer. Mineral. , 73, 216 -233
Petrogenetic grids: Focus on reactions K 2 O-Mg. O-Al 2 O 3 -Si. O 2 -H 2 O K 2 O-Fe. O-Mg. O-Al 2 O 3 -Si. O 2 -H 2 O P-T grid for pelites, after Spear and Cheney (1989). (in. F. Spear (1993): Metamorphic Phase Equilibria and Pressure-Temperature-Time Paths.
Petrogenetic grids: Focus on reactions K 2 O-Na 2 O-Ca. O-Fe. O-Mg. O-Al 2 O 3 -Si. O 2 -H 2 O 85 possible phases: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 I 26 27 28 29 30 31 32 AKERMANITE 33 COESITE ANTIGORITE 34 CORUNDUM BRUCITE 35 ALPHA CRISTOBALITE CHRYSOTILE 36 BETA CRISTOBALITE DIASPORE 37 LOW TRIDYMITE GEHLENITE 38 HIGH TRIDYMITE HEMATITE 39 ANDALUSITE HERCYNITE 40 KYANITE KALSILITE 41 SILLIMANITE KAOLINITE 42 FAYALITE LAWSONITE 43 FORSTERITE ALEUCITE 44 GROSSULAR 65 CA-AL PYROXENE BLEUCITE 45 PYROPE 66 CLINOCHLORE LIME 46 ALMANDINE 67 DAPHNITE MAGNETITE 47 ALBITE 68 AMESITE MERWINITE 48 K-FELDSPAR 69 CORDIERITE(DRY) MONTICELLITE 49 ANORTHITE 70 FE_CORDIERITE NEPHELINE 50 ANNITE 71 MGCTD PERICLASE 51 PHLOGOPITE 72 FECTD PREHNITE 52 MARGARITE 73 ZOISITE PYROPHYLLITE 53 MUSCOVITE 74 CLINOZOISITE EPIDOTE SPINEL 54 CELADONITE 75 76 ANTHOPHYLLITE TALC 55 FE-CELADONITE TREMOLITE WOLLASTONITE 56 PARAGONITE 77 78 FETREMOLITE 57 FE-STAUROLITE 79 TSCHERMAKITE PSEUDOWOLLASTON 58 MG-STAUROLITE 80 PARGASITE 59 ORTHOENSTATITE 81 FEPARGASITE HEULANDITE 60 PROTOENSTATITE GLAUCOPHANE LAUMONTITE 61 FERROSILITE 82 83 STEAM STILBITE 62 DIOPSIDE 84 OXYGEN WAIRAKITE 63 JADEITE 85 HYDROGEN PUMPELLYITE 2 64 HEDENBERGITE A-QUARTZ B-QUARTZ 11 4. 117· 10 reactions(maximum)
Equilibrium assemblage diagrams: Focus on equilibria Composition Obere Tiefenstufe Al allein Fe + Al Mg allein Mg + Al Mg + Ca Ca + Al Na + Al . . . . Na + Fe. Ka + Al. K + Fe + Mg Ti. . . Disthen Chloritoid, Granat Antigorit Chlorit Hornblende Zoisit, Epidot Albit, bei Si-Mangel Glaukophan. . . Na-Hornblenden. . . Muscovit. . . Biotit. . meist mit Ca und Si als Titanit Untere Tiefenstufe Disthen, Sillimanit Almandin Rhomb. Pyroxene; bei Si-Mangel Olivin Pyrop, Cordierit Diopsid, Omphacit Anorthitreicher Plagioklas Albitsubstanz im Plagioklas, bei Si-Mangel Na Al -Verbindung im Omphacit Ägirin als Beimischung im Omphacit Kalifeldspat Biotit Rutil Temperature F. Becke: Über Mineralbestand und Struktur der kristallinen Schiefer. Comptes Rendus IX. Congrès géol. internat. de Vienne 1903 Most people would sooner die than think; in fact, they do so. (Bertrand Russell)
Equilibrium assemblage diagrams: Focus on equilibria
Equilibrium assemblage diagrams: Focus on equilibria
Equilibrium assemblage diagrams: Focus on equilibria 1. Chemical composition, eg. : 2. Choose phases (eg. for pelites: Qz, Sil, And, Ky, Stau, Alm, Grs, Py, etc. ) 3. Calculate all reactions 4. Schreinemakers equilibrium assemblage diagram Si. O 2 Al 2 O 3 Fe. O Mg. O Ca. O Na 2 O K 2 O H 2 O 59. 58 12. 16 4. 87 2. 79 0. 53 1. 27 2. 69 30. 00
Equilibrium assemblage diagrams: Focus on equilibria Example of equilibrium calculation Input Output mols phase 2. 38 GARNET X(grossular) X(pyrope) X(almandine) 0. 038 0. 310 0. 652 1. 82 FSP X(albite) X(K-feldspar) X(anorthite) 0. 836 0. 022 0. 142 6. 35 wh_mica P and T X(muscovite) X( paragonite) X( M-celadonite) X( F-celadonite) 0. 717 0. 159 0. 090 0. 034 27. 40 Quartz T = 700 o. C P = 10000 Bar 23. 65 Steam bulk composition Si. O 2 Al 2 O 3 Mg. O Fe. O Ca. O Na 2 O K 2 O H 2 O mols 59. 58 12. 16 2. 79 4. 87 0. 53 1. 27 2. 69 30. 00 (excess) composition
Equilibrium assemblage diagrams: Focus on equilibria T. Nagel, C. de Capitani and M. Frey, J. metamorphic Geol. , 2002, 20, 309 -324
Eqiulibrium assemblage Phase Diagrams
Equilibrium assemblage diagrams When are the results of a prediction useful? When you learn something Simple problems: Summarize what is known Plan experimental work Test data and solution models Complex problems: Calculations help understand nature Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it. (Richard Feynman)
Equilibrium assemblage diagrams When are the results of a prediction useful? When you learn something Simple problems: Summarize what is known Plan experimental work Test data and solution models Complex problems: Calculations help understand nature When the results are unexpected Did we interpret our observations correctly? Is thermodynamic data correct? Is the software calculating correctly? Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it. (Richard Feynman)
Equilibrium assemblage diagrams When are the results of a prediction useful? When you learn something Simple problems: Summarize what is known Plan experimental work Test data and solution models Complex problems: Calculations help understand nature When the results are unexpected Did we interpret our observations correctly? Is thermodynamic data correct? Is the software calculating correctly? When the results are oviously wrong Opportunity to improve the database Fix bugs in the software Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it. (Richard Feynman)
Eqiulibrium assemblages and Phase Diagrams Petrogenetic grids >< equilibrium assemblage diagrams
Equilibrium assemblage diagrams: Simple problems Comparision Petrogenetic grid Equilibrium assemblage diagram focus reactions chemical equilibrium calculation input system and choice of phases bulk composition interpretation may be difficult very easy solution models • only activities of some phases needed • Thermodynamic properties and activities of all endmembers must be known • fixed compositions in input • compositions are calculated I don't necessarily agree with everything I say. (Marshall Mc. Luhan)
Equilibrium assemblage diagrams: applications
Equilibrium assemblage diagrams: testing databases Bulk composition: Si. O 2 Diagram: stable assemblages Database from TWQ Database from THERMOCALC coesite -quartz cr tr cr melt tr
Equilibrium assemblage diagrams: testing databases Bulk composition: Si. O 2 Diagram: densities [ccm/mol] Database from TWQ Database from THERMOCALC coesite -qtz quartz -qtz cr tr cr melt tr
Equilibrium assemblage diagrams: seismic velocities Physical properties of rocks use for seismic velocities Birch’s law (1964) 0. 6 GPa Vp Vp 1. 0 GPa Vp Vs Vs Velocity (km. s-1) 0. 2 GPa extended Birch’s law Vs Density (g. cm-3) V=aρ+b R. Bousquet, C. de Capitani, D. Arcay, Strasbourg 2006 Density (g. cm-3) Ludwig et al. , 1970
Equilibrium assemblage diagrams: seismic velocities Physical properties of rocks use for seismic velocities Pelites MORB density R. Bousquet, C. de Capitani, D. Arcay, Strasbourg 2006 density Gabbro density
Equilibrium assemblage diagrams: understanding rocks 1 mm T. Nagel, C. de Capitani and M. Frey, J. metamorphic Geol. , 2002, 20, 309 -324
Equilibrium assemblage diagrams: understanding rocks T. Nagel, de Capitani and them. M. Frey, Geol. , 2002, 20, 309 -324 If you cannot. C. convince them, confuse (Harry. J. S metamorphic Truman)
Equilibrium assemblage diagrams: understanding rocks T. Nagel, de Capitani and them. M. Frey, Geol. , 2002, 20, 309 -324 If you cannot. C. convince them, confuse (Harry. J. S metamorphic Truman)
Equilibrium assemblage diagrams: understanding rocks T. Nagel, C. de Capitani and M. Frey, J. metamorphic Geol. , 2002, 20, 309 -324
Equilibrium assemblage diagrams: understanding rocks GARNET (rim) GROSSULAR 0. 061 PYROPE 0. 209 ALMANDINE 0. 730 TWQ Garnet BIOTITE PHLOGOPITE ANNITE 0. 617 0. 383 WHITE MICA PARAGONITE MUSCOVITE 0. 128 0. 872 FELDSPAR ALBITE K-FELDSPAR ANORTHITE 0. 760 0. 018 0. 222 STAUROLITE FE-STAUROLITE 0. 906 MG-STAUROLITE 0. 094 T. Nagel, C. de Capitani and M. Frey, J. metamorphic Geol. , 2002, 20, 309 -324
Equilibrium assemblage diagrams: understanding rocks T. Nagel, C. de Capitani and M. Frey, J. metamorphic Geol. , 2002, 20, 309 -324
Equilibrium assemblage diagrams: understanding rocks T. Nagel, C. de Capitani and M. Frey, J. metamorphic Geol. , 2002, 20, 309 -324
Equilibrium assemblage diagrams: understanding rocks
Equilibrium assemblage diagrams: Final remarks Equilibrium calculations (THERIAK etc. ) are powerful tools to • visualize the implications of databases • help understanding natural processes • help to develop new eqations of state and solution models • help planning experimental work A conclusion is simply the place where someone got tired of thinking. (Arthur Block)
Equilibrium assemblage diagrams: Final remarks Equilibrium calculations (THERIAK etc. ) are powerful tools to • visualize the implications of databases • help understanding natural processes • help to develop new eqations of state and solution models • help planning experimental work Difficulties for beginners • software is a black box • low rate of succes (You get what you asked for but it may not what you wanted).
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