Lecture 2- Geochemistry PV.pdf

,ATMOPHILE . .---N---.., ✓ Lithophile - rock-loving : He Ne Ar Kr Xe : LITHOPHILE , mineral ✓ Chalcophile - ore-loving mineral ✓ Atmophile - gas-loving mineral I LiBeB " Q Fl t Sc Ti Rb Sr Y Zr Nb Cs Ba REE Hf atmosphere and hydrosphere I I Na Mg Al Si H Cl Br I ~ K Ca '------~-...

,ATMOPHILE . .---N---.., ✓ Lithophile - rock-loving : He Ne Ar Kr Xe : LITHOPHILE , mineral ✓ Chalcophile - ore-loving mineral ✓ Atmophile - gas-loving mineral I LiBeB " Q Fl t Sc Ti Rb Sr Y Zr Nb Cs Ba REE Hf atmosphere and hydrosphere I I Na Mg Al Si H Cl Br I ~ K Ca '------~-- ✓ Siderophile - iron-loving mineral ,- crust, mantle and stony meteorites U Th ..--·- ·- · • - · - · - · -·'\ Earth's core and Wj C P W Ta • - - - - - - - + - - - iron meteorites -, .J. fi:"t 0 .I a:. ...................!........................ f l '- • . Fe Ni Co Ga Sn WI Ru Rh Pd \ Ge As Se Oj ci5 · !v I Cr Mn Zn "1 : • i : S Os Ir Pt Au: Mo Sb Te ·, : Re Cu Ag Cd In Hg Tl Pb Bi '--·-·-·-·L·-·-·-./· ••..... CHALCOPHILE.....• sulphide minerals structure, Atomic structure and property Specifics almost certainly not known (exact 0/o, for example) but some general facts (or "rules") known. ■ Only 1 0 elements - H, He, C, N, 0, Ne, Mg, Si, S, and Fe - al I with atomic numbers less than 27, show appreciable abundance. Of these, H and He far outweigh the other 8. ■ Abundances show a rapid exponential decrease for elements of the lower atomic numbers, followed by an almost constant value for the heavier elements. ■ Elements adjacent to Helium (I. e~ Li, Be) are very low in relative abundance ■ Elements of even atomic number are more abundant than those of odd atomic number on either side. This regularity was first recognized by Oddo and Harkins (c. 1 91 5) and is sometimes referred to as the Oddo- Harkins rule. ■ Isotopes with mass numbers which are multiples of 4 (alpha particle mass number) have enhanced abundances. ■ There is a pronounced abundance peak at atomic number 26 and smaller peaks at several other heavier atomic numbers (such as Oxygen) -3 - t - - - - - - - - - - - - - - - - - t - - - i ~ - - - 1 0 10 20 30 40 50 60 70 90 100 Atomic Number tZ) ■ ■ ■ Eliminate Oddo-Harkins effect 1 1 1 Make y-scale more functio nal by normalizing to a standard Estimates of primordial mantle REE Atomic structure and property Components of an atom The neutron - play the crucial role of overcoming the repulsive forces between protons, thus binding the nucleus to a tight structural unit. Atomic number (Z) - refers to the number of proton in an atom of an element; it is the same for any atom of the element; this number serves to distinguish an element from another. Atomic mass (A) - the average mass of the atoms o an element; to a close approximation, the number of protons plus the number of neutrons in an atom of an element. . - Ntw Ou10nat10n . _ f orme1 Onian41ion N~l=~~ §ymbol __.. Atomic weight - the sum of the masses of its naturally occurring isotopes weighted in accordance with their abundances. Nome __. A.tomic 'N•ight ____.,. 1 H @ -252.9 -259.3 0.07 1 ...,_Crystal S truc-t ur• ---- oen11ty ,.__.trCl Hydrogen 1.00794 1s' v11ence~,neu ..,_ Cot1rigu1•tion --r---------- --rChe'Tlical kinetics activation energy (£1) --t-- ---1 aragonite 11G thermodynamics L---~--L-calcite Supercritical fluid --. Criliallpoi11I Normal melting poinl Solid ■ ■ Thermodynamics - concerned on the free energy changes associated with chemical equilibrium between phases, and provides the tools for working out which mineral assemblages will be stable under which conditions. Chemical kinetics - deals with the mechanics of the reactions that lead to equilibrium, and the rates at which they occur. 1 -------- - -------- / Norma~ boiling point Liqllid 1 6.0 x 10-3 ---- --------- ---- ; , ~ 0.0098 100 374.4 Critical point Phase boundary (vapour+ liquid coexist) VAPOUR Point C Therefore A 6 =3 =I (3 phases. ky + stll + andal) ( I component, Al2S1O!>) 3+F=l+2 F= 0 an invariant equilibrium <P C 0 Point B Kyanite Sillim anite Therefore (2 phases. ky + sill) C= I ( I component Al2SiOs) 2+F= l +2 F= I a univanant equ,ltbrium </> = 2 2 Andalusite 400 600 Point A Therefore <f, = I ( I phase, ky) C= I ( I component. Al 2SiO~) +f=l+2 F= 1 a dwariant cond1t1on Application of the Gibb's Phase Rule to a unary system ■ Solid ice F=C-P+2=2 C = 1 (only H2O) P = 1 (solid) ■ Heating/ melting of ice F=C-P+2=1 C = 1 (only H2 O} P =2 (solid & liq) ■ Tri pie point F=C-P+2=0 C = 1 (only H2O) P = 3 (sol, liq & vap) 2 18 water water vapor 0006 o/ o\1 T C hrtp://serc.corleron.edu/ reseorch_educadon/ equilibrio/ phoseru/e.html Application of the Gibb's Ph se Rule to a unary system 2 water p • Curve (Univariant) P=2,F=1 ice • i water vapor 0.00 at \ CC1 T oc J • Field (Divariant) P=l,F=2 • Triple Point (Invariant) 37• http://serc_c,arleton. edu/reseorch_ education/equ;J;bria/phase_ru/e. html P=3 F=O ' Application of the Gibl,'s P 1ase R11le to a unary diagram Aluminosilicat e system: polymorphs of Al 2SiO5 ■ Unary: C =· 1 ■ Triple Junction (3.8 kbar $Jlllmanlla and S00°C) P=3,F=O ■ soo,., eoo re~c ,cm P=2, F=l 800 fi.ttp/ /serc...corletorr_edu/ researctr_ educotion/ eq11iJibria/phoseroJe.htmJ Curve (Univariant) ■ Field {Divariant) P=l F=2 I Phase Diagram ► Solidus is the locus of m ,soo Q melt • pt~loclase.u 0 NaAtSl30e (Ab component) 20 60 pe,cen1 CaAf2Si20e by mass 80 100 CaAI 2Sj zO. (An· component) Eutectic equilibrium diagr am with solid solution (Pb - So ,Al- Si) M ' '' L 1 ··· ·•··i:, · Cy ' '' I T3 ~ I L+j3 ''' ' f f __ . ..,J...... ............. . t~.3-... . ............. ......... ... J. . ....... . .............. . . . . . ............................L. . ...... . . f3 I I ' '' t I 't J I ' . '' I f I I I ' '' I I C Concentratio n of B in A www.substech.com 1900 I Fo + Liq 1600 C I I I I d 1500 Qz + En Fo + En l 20 40 MgSiO3 60 En Figure 2 80 Critical point C 22,089 Q. =-... Water (liquid) Ice (solid) 'i? Q) ::I (/) (/) 101 ... Q) Q. 0.6 Water vapor (gas) A 0 0.01 Fayalite (Fe) 100 374 Solvus and Hypersolvus Phase Diagram KAISi 3O8-NaAISi 3O8 System at 0.1 MPa (1 atm.) 1400-----------------.6 liquid 1200 ---ir 29% Na-feldspar (.J 0 ... 1000 ...m (I,) ::::::, (I,) C. E single feldspar 800 ~ 600 two feldspars 450 · ------- ----------• ------------------------------ · 400-+-_.........___......,___________..... 0 KA~~i,O, ~ 20 40 60 \ 80 a~;i,O, -1eldspar composition l' "' "Na"-feldspar composition Ab99 Qr12 Sub-solvus Phase Diagram KAISi 3O8-NaAISi 3O8 System at 500 MPa (5 Kbar) 1000 - - - - - - - - - - - - - - - - - - liquid 900 u 0 75% liquid 25% K-feldspar 800 Q) i... ::::, f! Q) CJ 0 700 C. E ~ u 00 o~ 650 600 0 si~gle feldspar : 500 L l".'JO feldspars : 400 0 KAISi30 s Or K-fe/dspar Ab,.Ort6 40 80 liquid Ab59 Or4 , 100 NaAISi30 a Ab Source : https: / / serc.car/eton.edu / research_education/eq uilibria/binary_diagram s.html t ver-RBle► To compute the am oun of soltd hase: LIQUID - l ► Co ). m U 0 OLIO Fracti:0n oft e, so i1 d phase, X - - 1 \ - t., • •• 2. l 0.11 4.94 11 4.43 1.47 t 4 55.9 1.45 16.l 3.58 5.17 0.17 3.05 5.94 4.76 l.78 t Mg/Md 50.3 1.54 15.7 3.48 6.23 0.18 5.46 7.93 3.62 1.43 I Mg/Md 50.5 l.7 16.2 3.32 5.86 0.17 5.8 9.04 3.72 1.43 • Mg/Md 48.5 1.4 17 2 .84 5.41 0.16 6.63 9.42 3.01 1.62 ' •• Mg/Md 51 0.95 16.6 2.76 5.24 0.15 6.7 8.94 3.25 1.26 I ; Mg/Md 51.8 1.31 15.5 3.95 5.8 0.12 4.23 7.1 5 3.fl9 2.77 • S)1ll 6-1.5 1.02 16.3 1.18 1.16 0.05 1.12 3.75 9.45 0.06 I Syr1 63 l.l 15.Y 1.66 1.57 0.1 1.04 4.18 5.96 4.01 Syn 61 1.14 15.5 3.76 4.11 0.14 i.12 3.15 5.73 3.02 ' 2.96 3.1 7 0.12 0.9 1 2.52 : • • ' = • Syn 0.86 • •• 1.97 ' •• • . ~ . ♦ • Trace elements (<0.1 wt 0/o) • Expressed in ppm or ppb • Lanthanides or rare earth elements (REEs) - La, Ce Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb & Lu • Platinum group of elements (PGEs) - Ru , Rh, Pd, Os, Ir & Pt • Transition metals - Sc, Ti, V, Cr, Mn, Co, Ni, Cu & Zn • Rb, Sr, Y, Zr, Nb, Cs, Ba, Hf, Ta, Pb, Th & U 1 B.D. Payot I Geoloqy 250 Iqneous Petroloqy (Lee) 5 - Chemieal Petroloqy II: Trace Elements ......... ~ H~ . H ,,.. 3 ,I LI Bf ..., . ,.II u- . 19 K ,.;; G0 ' 12 ... ,, ,'!!. ?O I 24 ll Tl Cr i\111 ... ~ ~ • 4, - --- 37 ..ss.,.... C& .. " Rb 18 r ll7 - Fr Ra - 11:h D1 - . ., . ~I ..... , 42 1\10 ..... '"' IJ 2& 29 ll J2 Co NI Cu Zn Ga Ge H ~s 16 Ru Rb Pd cc.,;, ,, ·- ,. ~ - - ·- ..,~ ◄7 4ll ◄\I Cd In ,! 41 IH l l l w 81 !'2 Tl Pb 1 ll IH 30 .-... " .. ... ' -.,, -so ,~.. -.... ., .. Rt Os Ir r1 Au Ilg .'":' ~,., 107 10~ 110 111 Ill Rf 811 I~ 11 ,,_ .,.. ...... llf ., .... 'b .,,. 73 la ,__ IOS " I -- .:·, Ac I◄ I 'N 72 ·- 4 27 16 f• -= - - Ob re · - ••r • : • .1441• ,,. 4: -- -74 \\ 10o 7S -~ - • .L..LJ. Hs •!ll.'1 ---- , I'm 'm ,, e '""r•.-: " - ,.. ,., 7 n i, .. ~ .. I 0 C 13 711 ' 1., ~ J n Zr 1·•·· .., 76 y r,.: ~ 10 B , n ...... "" ... ' Ca .... s LREE •·· • 15 p . . .~ ,'"'t 33 As ...... 16 ., J4 St 0 •10 F Nt . .. . . ·• 17 a ":H ., "••a .,.,. ..-. SI Sl -. ... Te I . b .. ~, i:-, .... .~ 8,1 Ui - Po 18 Ar Br SJ ,:.. -.u· 115 I 36 Kr ~-,-; 54 x, ..-,~ 86 Rn ._ ,_ ,.. Fm I. 0 r,,.. d 4.0 3.0 2.0 Billions of Years Before Present 1.0 0.0 Magma Composition Using Geochemistry Sm/Nd - Signature as a function of magma assimilation process unng partIa Evolution curve is opposite to Rb - Sr melting, Sm is compatible to melt ~ b' oasa" '?,~~ compared to Nd 0~ 0.514 ~~~ -&0-...: ~# ~0.._e/) 0.512 - ~o0~ '3Nd 144Nd 1 If the magma has high value of 87Sr/86Sr and low J:,,O~ ,,_~0~ 0.510 ~ __,_,,,.,., : I I : ~ ~ -- ,.n0va~i- - - : l8~~: __...-:-- I I a - - - - - 'ched mantle or melt (lower ~m/Ndl ~volutlon of enn l 0.508 l Partial melting or enrichment event : Chondrite 0.506 - Meteorite I I I I I I value of I I 147Nd/144Nd, 4 3 2 0.5 Time (Ga before present) Therefore it undergone mixing. I Figure 9 15 Estimated Nd isotopic evolution of the Earth 's upper mantle assuming a large-scale melting or enrichment event at 3 O Ga b p After Wilson (1989). Igneous Petrogenesis Unwin Hyman/Kluwer. Source: https:f /slidep/ayer.com/slide/4997242/ tholeiitic ., ., ,, , , , -- ' '' calc-alkaline series ' '' '' Magma Composition Using Geochemistry Mg# and Fo# ., Relationship of olivine and coexisting basalt/melt (Roeder and Emslie, 1970) 1 (F9 2+/Mg )olivine - - - -- == 0.3 (F92+/Mg )melt Where Fe 2+ and Mg = atomic proportions of ferrous iron and magnesium Magma Composition Using Geochemistry Mg# and Fo# • Magnesium number (Mg#) = shows the Fe:M,g in a rock 1 100 Mg Mg# = Mg/Fe2 + 1 100 (wt.% MgO/40.32) - - - - - - - -- -- - - - (wt.% MgO/40.32) + (wt 0/o FeO/71 .85) • Lherzolite - fertile unaltered mantle • Dunite & harzburgite - refractory resi'. dU urn after basalt has been extracted by partial m1eliting 15 f i gure 10-1 Brown and Mussett, A. E. (1993)c, The Inaccessible Earth: An fntegrated View of Its Structure and Composition. Chapman & Ha[IJKluwer. Magma Composition Using Geochemistry NiO I •I • Kilauea 0.50 -. 0.40 +-' ~ 0 Z ~· ,,.. "#. Batch • ~ ·~ . ••••• . ... Af 0.30 • 4 10% • • 4 M & .# X 20% 0.20 . Fractional ~---------------------------1 0.10 81.0 83.0 85.0 87.0 89.0 Fo content {%) 91.0 'Tlr . AJ 0 18 (d ~ r el ng~ C n, 1. ' 018 n Vole nic l,n: MORB tshallo~ El Salvador ~ l 'Ill E- OR 0.1 0. 1.0 NblYb ·o c tu g Magma Composition Using Geochemistry Maior Elemets - Harker Diagram ., , 22 HARKER DIAGRAMS I ....• . .. ·- Alp, 17 "t.'. Fee>- SiO2 vs other major oxides 10 •.... ~ .. ... MgO .. . ...... . "'' - : - ~.,·...... 5 '···;~ . .. . I 12 Alfred Harker (1909) ~:·:·. 10 , 6 • . ·c-.., 0 ' 15 ~ .. ~, .. ° CaO 1 .,...... ~ ........ 0 0 ' I One of the most common variation diagrams 6 .;,i\\. - -~:·::·. ... Na,0 4 2 2 .. . . ~ . -~·''·. • "..... "• ,I, .,, •••c . • .., •• . ,: j!J' ~- 250 Igneous Petrology {Lee) J " I 50 I S5 60 SIOa 65 • 1.0 ... . ~•-•":;• . #- • Winter, 2001 I Geology . .. • • 2 45 1 " 3 0 B.D. Payot ' 4 ~o Tl0 2 0 0 Crater Lake (Mt. Mazama, Oregon) volcanic rocks :, 70 75 45 . . ·;. 50 . . .. ... ~ 55 P20 1 0.5 ............. 00 65 SiO, 70 0.0 75 4 - Chemical Petrology I: MaJor & Mmor Elements HARKER DIAGRAMS 10 Al20s MoO 17 increase of SiO2 = magmatic evolution ~ 12 10 a Parental magma? cao s 0 0 I Primary magma? 6 2 . N~O 4 Tl02 . ~ #, 2 I 0 0 4 ~o 1.0 3 .. 2 '.·":•· .. ~ Winter, 2001 B.D. Payot I Geology 250 Igneous Petrology (Lee) 55 ~ Si02 65 70 75 45 P~O~ .. 1 50 o., 50 55 60 65 70 0.0 75 SJO2 4 - Chemical Petrology I : MaJor & Mmor Elements Magma Composition Using Geochemistry Maior Elemets - Harker Diagram HARKER DIAGRAMS 10 Al2-0 3 Fractional crystallization MgO & FeO - mafics Cao - plag & px 6 12 FeO* Decrease in MgO, FeO* and Cao as SiO 2 increases = removal of early forming ol, px and plag from the cooling liquid MgO 17 0 15 10 10 5 5 0 0 6 ...... . .... . N~O 4 2 1102 2 0 4 K.iO 1.0 3 2 Winter, 2001 0 45 eao 60 SS 60 SiOa 66 70 76 46 so 66 80 SiO2 65 70 M 75 HARKER DIAGRAMS 10 Al20 3 5 Al 2O3 15 Cao decreases continuously, cpx possibly removing Ca but not Al Plag began to crystallize, removing both Ca and Al Winter, 2001 I 0 12 Increases then decreases B.D. Payot MgO 17 Geology 250 Igneous Petrol FeO" 10 ,o eao 6 5 0 0 6 2 N~O 1102 4 2 0 4 K.iO 1.0 3 2 ~ ~ ~ Si02 ~ - - -ro - - -~ - - -oo - - -~ - - -ro- - -~0.0 ro n~ S102 HARKER DIAGRAMS 10 Al20 3 5 Al 2O3 15 Cao decreases continuously, cpx possibly removing Ca but not Al Plag began to crystallize, removing both Ca and Al Winter, 2001 I 0 12 Increases then decreases B.D. Payot MgO 17 Geology 250 Igneous Petrol FeO" 10 ,o eao 6 5 0 0 6 2 N~O 1102 4 2 0 4 K.iO 1.0 3 2 ~ ~ ~ Si02 ~ - - -ro - - -~ - - -oo - - -~ - - -ro- - -~0.0 ro n~ S102 Magma Composition Using Geochemistry Maior Elemets - Total Alkali vs Silica (TAS) diagram Evolutionary sequence of magmas 16 Alkaline 14 • 12 told,te ~ 10 -~ 8 "'"' 0N • alkali rhyolite •• • :.::: - + z z subalkali ON (lj n • ••• • • 4 2 0 rhyoltle uo 6 30 40 -o basaltic andestte andesite '"' 0 l dacite V subalkali basalt ) 50 60 Si02 / mass 01o 70 {Gill, 2001} 80 ALKALINE: alkali basalt> trachybasalts > trachyandesite > trachyte/phonolite SUBALKALINE: basalt > andesite > dacite > rhyolite II • Thermal divide - separates the subalkaline from the alkaline fields at low P • Cannot cross this divide by fractional crystal lization; cannot derive one series from the other (at feast via low-P fractiona l crystalIization) OJ 1713 Liquid Thermal Divide 1070 Ne Ab B.D. Payot I Geology 250 Igneous Petrology {Lee) Q 4 - Chemical Petrology I: Major Be Minor Elements 1 ---.....-~iiiaiiilliii,ii-~----....--.~........-........--..-.-............ i i i i i l i i l o p i " " - . . - - . , . . . . _ ~........- . . . - Cs R·b 13a Th U K Nb Ta La Ce St Nd P Hf Zr Sm l Y Magma Composition Using Geochemistry Trace Elements . Europium anomaly when plagioclase is a fractionating pheno,c ryst or • a residual solid in source REE diagran1 for ·10°/4 batch n1elting of a hypothetical lherzolite with 20% plagiociase resulting in a pronounced negaUve Europium anomaly_ Fron1 Winter (200 'I}. ~ ~ "g 6.0 0 .c. 0, 1 ~ 4.0 Q. E al 0 2.0 La Ce Nd Sm Eu IOy Er atomic number _.,. Yb Lu Magma Composition Using Geochemistry Trace Elements Garnet concentrates the HREE and fractionates among them Thus if garnet is in equilibrium with the partial! melt (a residual phase in the source left behind) expect a steep(-) slope in RE and HREE - Table 9-1 _ Partition Coefficients (Cs/Cd for Some Commonly Used Trace 1 Elements rn Basaltic an d Andesitic Rocks Shallow (<40 km) partial melting of the m1antle wiII have p/agioclase in the residuum and a Eu anomaly will result Olivine 0.01 0.014 0.01 R I) Sr Ba Ni Cr La - c/'l Ce CQ) - Nd Sm l1JI Eu £.__ Dy ~ Er ~ 5 YI) Lu - CQ er.: 14_0 0 .7 0.007 0.006 0.006 0.007 0.007 0 .013 0.026 0.049 0.04 5 Opx 0 _022 0 _04 0 _013 5_0 10_0 0.03 0 _02 0 _03 0 _05 0 _05 0-15 023 0_34 0-42 Data from Rolhnsoll ( 1993}_ Cpx Garnet 0_031 0.042 0_06 0.012 0_026 0.023 7_0 34_0 0_056 0_092 0-23 0-445 0-474 0-582 0_583 0_542 0_506 0.955 1.345 0.001 0.007 0.026 0.102 n ,,. 3.17 6.56 11.5 11.9 Plag Amptl 0 _071 0_29 1_83 0-46 023 0-42 6_8 0.01 (J.01 2_0 0 _148 0 _082 0 _055 ~ 101! 1~ ~ 0 _02 0 .023 0 .019 3+ ·+ Eu /E 1.1 0-544 0_843 1_34 1_804 1_557 2_024 1_74 1_642 1_563 Magnetite 29_ 7.4 2_ 2_ 2_ 1_ 1_ 1_ 1.5 1.4 . Italics are est1ma~ed 11Ulll ...-- - - - - - - - - - - - - . . 67% 0 1 17% Opx 8.00 iI 17% Cpx Garnet and plagioclase effect on HREEs 6.00 ! ; 4.0J • 2.00 La Ce Nd Sm Eu Tb Er Yb Lu 1Q.C,J - 10.00. - - - - - - - - - - - - - - - - , 60% 0 1 15% Opx. 15% Cpx 10%Plag 8 .00 57% OI 14 % Opx 14% Cpx. 14% Grt 8.00 i 6.00 ~ l •i 4 .00 2.00 0.00 ._____.____.________......__.........._____.______._.....__...........____.______._.....___.._____,, La Ce Nd Sm Eu Tb Er Yb Lu La Ce Nd Sm Eu To Er Yb Lu Magma Composition Using Geochemistry Trace Elements A Brief Summary of Some Particularly Useful Trace Elements in Igneous Petrology Ele1nent Use as a Petrogenetic Indicator Ni, Co, Cr Highly compatible elements. Ni and Co - concentrated in olivine. Cr - spinel and cpx. High concentrations indicate a mantle source, limited fractionation, or crystal accumulation. Zr, Hf Very incompatible elements that do not substitute into major silicate phases (although may replace Ti in titanite or rutile). High concentrations i1mply an enriched source or extensive liquid evolution. Nb, Ta High field-strength elements that partition into Ti-rich phases (e.g. titanite, Ti-a:mphibole, Fe-Ti oxides). Typically low concentrations in subduction-related melts After Green 1990 B.D. Pavot l Geoloov 250 Ioneous Petroloov (Lee) 5 - Chemical Petrofoay II: Trace Elements Magma Composition Using Geochemistry Trace Elements Element Ru, Rh, Pd, Re, Os, Ir, Pd Use as a Peh·ogenetir Indicator Siderop hiles are mostly used to study 1 melting and crystall ization in mafic-ultramafic systems in which PGEs are typically hosted by sulfides. The Re/Os isotopic system is control led by initial PGE d ifferenti at ion and is appli,ed to mantle evolution and mafic melt processes. 1 Sc Concentrates in pyroxenes and may be used as an indicator of pyroxene fractionation Sr Substitutes for Ca in plagioclase (but not in pyroxene), and, to a lesser extent, for Kin K-feldspar. Behaves as a compatible element at low p, where plagioclase forms early, but as an incompatible element at higher P where plag ioclase is no longer stable. Magma Composition Using Geochemistry Trace Elements Element Use as a Pet1'ogenetic Indicator REE Myriad uses in modeling source characteristics and liquid evolution . Garnet accommodates the HREE moire than the LREE, and orthopyroxene and hornblende do so to a ~esser degree. Titan ite and plagioclase accommodates more LREE. Eu 2+ is strongly partitioned into plagioclase. y Commonly incomp,a tible. Strongly partitioned into garnet and amphibole. Titanite and apatite also concentrate Y, so the presence of these as accessories could have a significant effect. After Green 1990 B.D. Pavot I Geoloav 250 Ioneous Petroloav flee) 5 - Chemical Petroloov II: Trace Elements Multi-Element Fluorescence from 109 Cd Mn Mo Cu K Pb 22.1 keV Ni ~:::, 0 u 109 Au Ti Zr Rb Cd Excitation Source Atomic Absorption Spectroscopy Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state. In analytical chemistry the technique is used for determining the concentration of a particular element (the analyte) in a sample to be analyzed. AAS can be used to determine over 70 different elements in solution or directly in solid samples Wavelength selector Detector Atomizer Signal Processor Amplifier ,_..__ .. _,M>unc:1.,,,~. Li • Oe..ctlon Umlt E t ~ • Be □ • 0..'1-lppii _j_____L 7 " 11-IOOOII • Na 1 _j__L_ n H •• K - • Mg • Ca •~• oosipc r7 ...,.,_. • B ,:a Al N C 7 Si •• p • 0 • F " Cl .. Ar n Br u -!- !--- .J- ,.-++.- -Ls +- -!- -!- -!- +- -t•• °'a "',= --= Sc =--= ..=--=T=1--:,n=--=v-=---=-,=---=c==-r-""-=-""M '""'n--:.. :-::--Fe =---.., = -eo = - --= -=N=1- --= -.e==-u -=-=--=Z=-"""' n ..-. Ga .., Ge a.a As ,.. Se Kr ~-L-~+~+~~~~~~~~-L-4 ~4 :J.:_ :I_ L~ ~ :.i_ j Rh):&:_ if1Ag -_;:_ i:._ ~ :i_ ~ Wu L f.o IL i:_ ::_:j_ L ~ IL ~ D m '" Fr A a ,,.., ._ .. Ra - Ar. I ·1101 ,_, . A ,n • C ,_. • ,s . 1~ ,.,. .J, i:..:_·:.ii: ,:1_ l :1 :i:_ :_z .. J ~ - i' .. ~ ■- 1 ,m - ,.,. •- - I Ul7 ,.,. n, ;;01r •:ro , .. - I .- u 1 - •.u ,:n- ,:,o H N - An Ma,ss measured in grams mass Num1ber ,of Gram formU'r.a mass moles, moles Formula mass (mass of 1 mo:te) Source: http:/ /www.bbc.co.uk/bitesize/intermediate2/chemistry/building_b/ocks/the_mole/revision/ 2/ 6.02 X 10 1 mol 23 Source: https:f/ socratic.org / questions / howmany-atoms-are-present-in-48-60- g-of-mg / Molality =m = moles of solute kg of solvent mol kg Moles of solute Molarity (M) = Liters of solution Source: https: / /www.dummies.com/education/science /chemistry /how-to-meosureconcentrotion-usin g-molori fy-ond-percent-so/ution / m= - Source: https: //study. com/academy /lesson/mo/olity-definitionformulo. html %vol Volume of Component Volume of Solution X 100 %mass Mass of Component Mass of Solution X 100 Important Formulas □ Concentration: Unit Conv.ersion Mass of Solute Mass of Solution Mass of Solute Mass of Solution When diluting solutions use the formula • c1 v1 = c2 V2 Or • M1V1=M2V2 Where; • C1 is the initial concentration • C2 is the final concentration • V 1 is the initial volume • V 2 is the final volume • M 1 is the initial molarity • M 2 is the final molarity Source: http://wilfingchem.blogspot.com/2016/01 /dialing-it-down-w-dilutions.html I ~ = Ao • (½)1/h • time - half-life 1 final ; , mount initial amount This is the split factor... After a half- ife, one poun becomes ~ pound. I Taking natural logs of both sides gives: => In 2 = +AT~2 I •• t (1) N(t) = N0 (~)t t N(t) = N0 e - N(t) = r N0 e - J.t where N 0 is the initial quantity N 1 is the remaining quantity after time, t t 112 is the half-life 't is the mean lifetime A is the decay constant Half Life Sample Computation Using Natural Logarithm If an archaeologist found a fossil sample that contained 25% carbon- 14 in comparison to a living sample, the time of the fossil sample's death could be determined by rearranging equation 1, since Nt, N0, and t 112 are known. t N(t) t == == M ~ t½ 0 2 5730111ll Clo~) - 0 .693 =11460 Half Life Sample Computation using Logarithm Problr,rn: A Nuele,ar re,aetor produee,s 20kg of uranlum-232. If the, half life, of uranium Is about 10 ~e,ars, how loong will it take, to de,eav to 0.lkg1 Solution: N0 = 20kg N = 0.1kg t- I = 109 _1 (N~t)) 2 2 0 t: (t_1)lo9_1 (N~t>) 2 t = (10 ~r,ars) 2 ° 109 _1 ( ~) 20kg 2 = 535 ~r,ars ,\ ruie I ~--= the a e o the k _. .1 ineral _pecime111J, D • tlh.e numJber of at m 1 • dau_ghte1 p, odut.:l kXIlay.. P • th.e num r t' t m of Elhe pa UE ~-=-----~ l E1J • th.e illllll--ai I g1 aithm (~iE!hm to ba l • tlb • iIIJJ}Pi ·ate deca.y t.: 1sEatlJt. tod r e) .. ttlld ('fle d~. • c n ""'ta.ml I - 1~eili.1' parent i E.~ ~ • 1--e~~ t i h~2 1~ll fb r the oH \ 1ht1!: x.p-re •or1 : I ~11 - =----= Source: https: //pubs. usgs. gov/ gip / geotime /radiometric.html lhal -~if . Geochemical data on the Paleocene carbonate sequence of Santa Elena borehole. Major oxide-s. Sample Depth(m) Standard ES-17Vq Standard ES-17 US-60 US-50 US-42 US-34 U5-26 US-16 U.5-12 US-5 U5-3 306 .05 319.62 322.41 325.03 327.26 329.29 329.76 330.9 331.23 Fe2O1t MnO MgO Cao N¾O ~o Pz05 0.089 2.45 0 .76 0.03 S.36 40.79 0.04 1.72 0_015 10-55 0.082 2.485 0.797 0.034 5.754 41.67 0_016 1.629 0.006 1.94 250 1.57 5.29 OD1 0 .47 52.86 OJ5 0 .07 0.54 0 .34 1.15 2.71 0.05 0.07 51.57 52.80 47.30 43-.87 0.13 550 0.02 0.02 0.03 0.02 0.04 0.08 0.08 0 .13 0 .15 1.67 0.02 0.23 0.31 0.08 0.57 0.63 0.72 0.83 1.13 1.21 Si0 2 TiO2 9 ..8:3 6.89 720 7.73 7.07 0.03 0.05 0-07 0 .09 0.09 A120:3 1.25 1.60 1.68 1.82 1.78 Source: http:/ /www.scielo.org.mx/scielo.php?script=sci_arttext&pid=SOO J6-716920 J 0000200005 39.73 0..17 0.27 0.34 036 0.71 0.73 0 .93 3-9.20 0.13 1.00 11~08 36.60 0.13 11.41 37.37 0.15 1.16 1.11 1.40 4.66 7.25 9.78 9 .84 0.07 OJ6 0.14 0.05 0.07 0.08 0.17 0.10 0.11 0.11 0_11 i.n U ltrabas1c Int e rmed1at e ..- A lkaline Plalllnohte I Foidite I I Traf:hyte T racttydacite I I C) --- --- -----,,,,:,-.-- . I I I Trachyandes,te __ .,, .,, t a r1 achy- : oasalt .,, : 1-----~ ✓ ., ., ,, ., ., ., .,, ,. --- Rhyolite I I I I ,, .,,,, ,,. ., ffl ~ a, Q) m CG m ui <ii 0.) -0 ~ 0 (II> V> ("O ID a, ,:, ~ C ("O Su ~ ("O lkahne/Tho l utic 0 40 50 60 S i~ 70 80 mudston~ ,..-----~ . quartz subarkos percent matrix < 30µ V . ... k• ·os· 1·c •... ..-:-:-:-:-: .. .. .. . .. ni ~ e\ii \: ·1ft hi volcanic volcanic arenite . • • ·: : reni calclithit phy llarenite .__,.. ., 0 rock fragments S sedimentary 50 M metamorphic I I I I I I granite ; ~ rhyolite /f f quartz alkali feldspar syenite alkali feldspar syenite I ·e I quartz diorite quartz gabbro quartz anorthosite E '35 quartz syenite quartz quartz monzonite monzonlte foid-bearing monzonite fold foid monzodiorite foid monzogabbro quartz alkali feldspar trachyte P diorite alkali feldspar latite gabbro . trachyte --:::t::.::::---t-..::~-;-;..:-;--f----r::;1.-:,;::;---\ anorthos,te A +---+.....c..:::.=c..;..,t...:..::...+--:-:--,.:.la,.:.t1c.:.te::....,._-1 foid-bearing latile I fold-bearing diorite foid7bearing foid-bearing gabbro alkali feldspar foid-bearing anorthosite trachyte I I tephritic phonolite phonolitic ,' basanite ,' (olivine> 10 %) ,' phonolitic , tephrite ,' (olivine< 10 %),' basanite (olivine > 10 % tephrite (olivine < 10 % I I I I I I tephritic foidite Olivine Lherzolite Olivine websterite Websterite Clinopyroxenite