Chapter IV MINERAL CHEMISTRY

Chapter IV MINERAL CHEMISTRY

Chapter-IV MINERAL CHEMISTRY 4.1 INTRODUCTION In this chapter, chemical analyses of different minerals present in various rocks of Mashhad granitoid plutons have been presented. Chemical composition of different minerals like feldspars, biotite and amphibole in granitoids will help to understand the various igneous process during the formation of different types of granitic rocks. Composition of igneous biotites will reflect the magma composition, because experimental work has shown that the mineral biotite in granitic rocks will continuously equilibrate with the host liquids. Apart from biotites, other ferro-magnesian minerals also reflect the whole rock composition and consequently the origin of granitoids. Electron Microprobe Analyses (EPMA) of different minerals have been carried out for those rock samples for which detailed information on microtextures are available. During EPMA analyses, care has been taken in recording any chemical zonation that exist in different silicate minerals by analysing the core and rim compositions. Wherever the mineral show significant zoning pattern in their chemistry, chemical zonation of such minerals have been reported. The mineral analyses reported in this chapter represent the mean of three to five data points during EPMA analyses. While carrying out EPMA analyses, different points have selected in minerals, avoiding alteration zones. While selecting minerals for EPMA, emphasis is given to analyse the co-existing mineral pairs like plagioclase and K-feldspar, plagioclase and amphibole, and titanium in amphibole and biotite. This is to evaluate the cation-exchange like Ca, Na and Al between two feldspars (plagioclase and K-feldspar) and Mg, Fe and Al between plagioclase and amphiboles and Ti content in amphibole and biotite. This has been done in order to evaluate the temperature and depth of crystallization of granitoids in the area using different thermodynamic models.

4.2 MINERAL CHEMISTRY Plagioclase: EPMA analyses of plagioclase present in different rocks of Mashhad granitoids has been analysed and presented along with structural formula. As described in Chapter II, porphyritic plagioclase present in diorites and granodiorites from Mashhad area exhibit strong zonation. Chemical analyses were carried out from core to rim of porphyritic plagioclase in both diorite and granodiorite and the data is presented in Table 4.1 and 4.2. The SiO 2 content in plagioclase vary from 49-65 to 60.50 wt.% with Al 2 O 3 content varying from 25 to 31-65 wt.%. Higher the value of SiO 2 in plagioclase, lower the value of Al 2 O 3 content, indicating negative correlation between these two chemical components. The amount of TiO 2 is negligible ( < 0.2 wt.%), with very low values of MnO ( < 0.04 wt.%), MgO ( < 0.03 wt.%) and Cr 2 O 3 (0.13 wt.%) component. Major variation is recorded mainly with respect to An and Ab component in plagioclase with very minor orthoclase component ( varying from 0.23 to 0.72 mole percent, Table 4.1 and 4.2). EPMA analyses of porphyritic, zoned plagioclase grains in diorite from core to rim is presented in Table 4.1. Plagioclase show significant zoning pattern with higher amount of CaO content ( An 61 ) indicating labradorite composition in the core to lower amount of CaO ( An 46 ) indicating andesine composition in the rim (Table 4.1). Chemical analyses of another grain of porphyritic plagioclase in granodiorite from Vakilabad show significant zoning pattern with core composition rich in anorthite component (An 58 ) indicating labradorite composition with rim composition poor in anorthite component (An 32 ), indicating andesine composition (Table 4.2). Plot of anorthite content in core and rim of plagioclase in diorite and granodiorite show presence of significant zoning pattern with increasing in albite component from core to rim with concomitant decrease in anorthite component from core to rim (Fig. 4.1 and 4.2).

EPMA analyses of different rocks from granodiorite, monzogranite, pink granite, tourmaline granite and leucogranite is presented in Table 4.3. They generally show higher amount of SiO 2 content varying from 60.80 to 65.76 wt.% with Al 2 O 3 content varying from 21.71 to 24.50 wt.% ( Table 4.3). The amount of TiO 2 ( < 0.01 wt.%), FeO (< 0.12 wt.%), MnO ( < 0.04 wt.%) with very low orthoclase component ( varying from 0.64 to 1.47 mole percent). There is a general decrease in anorthite in plagioclase from granodiorite to leucogranite with plagioclase of oligoclase in composition in granodiorite to mainly albite composition in tourmaline granites ( Table 4.3). K-feldspar: EPMA analyses of K-feldspars present in monzogranite, pink granite and tourmaline granites have presented in Table 4.5 along with structural formula. The SiO 2 content vary from 59.33 to 64.40 wt.% with Al 2 O 3 content varying from 17.98 to 25.21 wt.%. The amount of FeO ( < 0.31 wt.%), MnO ( < 0.06 wt.%), MgO ( < 0.79 wt.%) with very low anorthite component ( < 3.68 mole percent). There is a significant variation in orthoclase component with lower amount of orthoclase ( Or 81 ) in monzogranite to higher amount of orthoclase component in pink granite ( 93.67 ) and tourmaline granite ( 97.19). Biotite: Biotite is the common mafic mineral occurring in all types of rocks in the Mashhad granitoid plutons. Biotite show varying pleochroism from light yellow to dark brown in diorites and leucogranites and light yellowish green to brownish green colour in monzogranites, indicating variation in chemical composition of biotite in different granitoids. EMPA analyses of biotites from different rock types along with structural formula is presented in Table 4.6. Biotite show variation in SiO 2 content from 35.53 to 37.48 wt.% with TiO 2 content varying from 1.51 to 3.23 wt.%. (Table 4.6). The Al 2 O 3 content vary from 15.42 to 17.49 wt.% which

show negative correlation with silica. The amount of Cr 2 O 3 ( < 0.41 wt.%), MnO ( < 0.97 wt.%) and Na 2 O content ( < 0.13 wt.%) is very low. There is a significant variation in the content of FeO and MgO in different rock types. The X Mg vary from 0.32 to 0.20 ( Table 4.6). Higher values of X Mg ( 0.32) is recorded in diorites with lower X Mg values of 0.20 to 0.23) in pink granites and leucogranites (Table 4.6). The composition of biotite fall in the phlogopite-annite field in ASF diagram (Fig: 4.3). Chemical analyses of biotites when plotted on FeO Vs MgO, MgO Vs Al 2 O 3, FeO Vs Al 2 O 3 plot mainly in the fields of peraluminous granites with few samples plotting in the fields of calc-alkaline granites ( Fig. 4.4, 4.5 and 4.6). However, in the ternary MgO-FeO-Al 2 O 3 plots of biotite show a clear calcalkaline affinity ( Fig. 4.7). In the Fe 2+ - Fe 3+ - Mg diagram (Fig: 4.8), majority of biotites plot in the ilmenite granite with few plotting in magnetite granite. Amphibole: Chemical analyses of amphiboles present mainly in diorites exposed near Dehnow is presented in Table 4.7. The SiO 2 content in amphiboles vary from 43.69 to 43.71 wt.% with Al 2 O 3 content varying from 8.87 to 10.64 wt.%. The TiO 2 content vary from 0.74 to 1.52 wt.% with very low concentration of MnO ( < 0.73 wt.%) and Cr 2 O 3 ( < 0.04 wt.%). Chemical analyses of amphiboles when plotted on Si Vs Na+K diagram indicate that their composition vary from pargasite to tschermakite ( Fig.4. 9). In the Si Vs Na+K+Ca plots amphiboles show clear magmatic character with none of the amphiboles plotting in the field of post-magmatic amphiboles ( Fig. 4.10). Epidote: Chemical analyses of epidotes 28.34 wt.% are reported from different types of granitoids along with structural formula in Table 4.8. Epidotes occur both as magmatic mineral as well as an alteration product of plagioclase in many granitoids. They show variation in SiO 2 content from 37.86 to 38.67 wt.% with Al 2 O 3 content varying from 24.55 to 28.43 wt.%. The amount of

TiO 2 ( < 0.66 wt.%), MnO ( < 0.43 wt.%), Na 2 O ( < 0.03 wt.%), K 2 O (0.03 wt.%) and Cr 2 O 3 ( < 0.08 wt.%) is very low ( Table 4.8). Chemistry of tourmaline, muscovite and sphene is presented in Table 4.9. Tourmaline show pleochroism from light yellowish blue to yellowish brown in colour suggesting higher amount of FeO ( 12.55 wt.%). Chemical composition of magnetite and ilmenite is presented in Table 4.10. 4.3 P-T ESTIMATES Presence of plagioclase coexisting with amphibole and plagioclase with K-feldspar in many granitoids are well suited for the estimation of pressure and temperature during which they crystallized from the magma. Amphibole occur as an essential rock forming minerals in a wide variety of igneous and metamorphic rocks and they are especially abundant in calk-alkaline plutonic rocks. The common occurrence of amphiboles in granitoids indicate to its stability in hydrous magmatic environments. Since most of the above mineral pairs present in Mashhad granitoids exhibit magmatic texture and amphibole show typical magmatic chemistry, the composition of these mineral pairs can be used to calculate P-T conditions during which the minerals have crystallized from the magma. Apart from these, the mineral plagioclase in diorites show good magmatic zoning in support of the evidence that these are magmatic minerals crystallized directly from the melts. In the present study amphibole-plagioclase geothermobarometers and Two feldspar thermometers are being used to estimate the P-T conditions of formation of Mashhad granitoids. 4.3.1 Amphibole-Plagioclase thermobarometry Experimental studies have shown that amphiboles can be synthesized from a wide range of starting material over a pressure range of 1 to 23 kbar and at 400 to 1150 º C. This data suggest that amphibole has a considerable potential as an indicator of amphibole crystallisation condition at wide range of

P-T conditions. However, the compositional complexity in amphiboles has precluded its accurate thermodynamic evaluation ( Graham and Navrotsky, l984, Blundy and Holland, l990). The Al content of hornblende is not only a function of pressure but also temperature, mainly through an edenitic exchange, involving the substitution of Al for Si in the T site coupled with Na and K substitution for vacancies in the A site (Blundy and Holland, 1990). Pressures in hornblende-plagioclase can be calculated on the basis of temperature-independent barometric model given by Schmidt (1992), for the following reaction phlogopite + 2 quartz + 2 anorthite = tremolite + orthoclase + tschermakite exchange. Pressures can be estimated using the following reaction: P (±0.6kbar) = -3.01 + 4.76 Al tot, r 2 = 0.99 Where Al tot is the Al content of hornblende in atoms per formula unit (apfu). The Al tot content of hornblende can be used to determine the depth within the pressures ranging from 2.5 to 13 kbar with a precision of ±0.6 kbar (Schmidt, 1992). Schmidt s calibration data set and the mineral assemblages he has used in his paper are consistent with the samples of granitoids of Mashhad area. This has prompted us to use the above geobarometric model to obtain information on the probable depth under which the granitoids have been formed. Since the mineral chemistry of all the amphiboles in the Mashhad granitoids are of magmatic origin which are associated with magmatic plagioclase, the mineral assemblages present in the granitoids are well suited for the application of the above barometric model. Barometric model of Schmidt is applied to obtain the pressure input required to formulate the temperature using the model of Blundy & Holland (1990) and Holland & Blundy (1994). Blundy and Holland (1990) thermometric model is applied to the amphibole-plagioclase assemblages with silica saturated rocks based on the reaction: Edenite + Quartz = Tremolite + Albite. Modification of the this simple thermometric model of Blundy and Holland(1990) to the new two thermometric models of Holland

and Blundy (1994) based on non-ideal mixing in amphibole and plagioclase have overcome many problems in temperature calibration and extended the formulation over a wide range of amphibole-plagioclase parageneses. The modified model comes with accuracy in calculation of error ±40 C in the range of 400-1000ºC and 1 to 15 kbar, over a wide range of compositions. It is applicable to silica saturated and silica undersaturated rocks. Holland and Blundy (1994) calibrated the thermometer and defined the following conditions for using it: 1) Temperatures calculated can be in the range of 400-1000ºC 2) amphiboles should have Na A >0.02 pfu, Al VI < 1.8 pfu. 3) Si in amphibole shall be in the range of 6.0 7.7 pfu and 4) plagioclases with X An <0.90. Amphibole analyses from our area is extremely in accordance with the referred conditions and thus temperature is calculated on the basis of this thermometric model. Thermometric calculation is based on the reaction: Edenite + Quartz = Tremolite + Albite Site allocations used for the thermometric calculation (after Holland & Blundy,1994): A site = Na, K M4 site = Na, Ca M1,3 site = Fe 2+,Mg M2 site = Fe 2+, Mg, Al, Fe 3+ T1 site = Al, Si T2 site = Si Edenite-tremolite thermometer (for assemblages with quartz) is used in the calibration of temperature, is given by: Where the Y ab term is given by: for X ab >0.5 then Y ab = 0 Otherwise Y ab = 12.0(1-X ab ) 2-3.0 kj

(Where T is the temperature in Kelvin and P is the pressure in kbar). Application of hornblende-plagioclase geobarometer and thermometer for the Mashhad granitoids give pressure estimates of 4.93 to 5.47 kbar and temperature estimates of 604 to 716 C ( Table 4.11). 4.3.2 Two Feldspar thermometry Numerous thermometric models involve two feldspar and ternary feldspar methods which have been developed by various workers in recent years are based on the neighboring feldspar grain compositions. Elkins and Grove (1990) offer three calibrations for each feldspar pair based on exchange of albite, anorthite and orthoclase components respectively. Based on the calibration data of Elkins and Grove (1990), Putirka (2008) developed a precise and simpler thermometric model which delineates the systematic errors in the thermometric calculation. T- estimates are highly sensitive to even small changes in X Ab, X An and X Or, which are required to produce a reliable thermometer (Putirka 2008). Feldspar compositions of our samples fall well within the applicable conditions of the thermometric model which is consistently applicable to most of the igneous systems. The temperatures were retrieved by applying feldspar thermometry to plagioclase rims and coexisting K- feldspars to obtain the accurate values. Temperature is calculated based on the equation: The temperature model gives an error in calculation of ±30ºC. Applying the above equation a higher temperature estimate of 770 to 779ºC has been obtained at 5 kbar using the model of Elkins and Grove (1990) and Putirka (2008) for monzogranites. However, two-feldspar thermometer yields a lower temperature estimate of 403ºC and 379ºC for tourmaline granites and pink granites (Table 4.11).

Table: 4.11 Pressure-Temperature estimate for Mashhad Granitoids Rock name Minerals T P Reference Diorite Holland T and Blundy J (1994), Hbl-pl 604.3 C 4.93 kb M 13/1 Schmidt(1992) Diorite Holland T and Blundy J (1994), Hbl-pl 716 C 5.47 kb M 15/1 Schmidt(1992) Monzogranite Elkins and Grove(1990), Pl-Kfld 770 C 5 kb 5/1 Putirka (2008) Monzogranite Elkins and Grove(1990), Pl-Kfld 779 C 5 kb 6/1 Putirka (2008) T-Granite Elkins and Grove(1990), Pl-Kfld 401 C 5 kb M 1/1 Putirka (2008) Pinkgranite Elkins and Grove(1990), Pl-Kfld 378 C 5 kb M 8/3 Putirka (2008)

Table4.1 : Electron Microprobe Analyses (EPMA) wt% of zoned plagioclase in Diorite, Mashhad, NE, Iran Dehnow Sample No : M-13/1 Core rim SiO 2 52.25 52.00 49.65 52.87 55.93 55.61 55.79 56.96 TiO 2 0.02 0.0 0.0 0.0 0.01 0.0 0.0 0.01 Al 2 O 3 30.16 29.88 31.65 29.27 27.66 27.32 27.50 26.99 FeO 0.05 0.11 0.05 0.0 0.0 0.0 0.0 0.16 MnO 0.0 0.0 0.04 0.02 0.0 0.07 0.0 0.001 MgO 0.0 0.0 0.0 0.01 0.0 0.01 0.02 0.00 CaO 13.20 13.08 15.14 12.74 10.46 10.36 10.15 9.55 Na 2 O 0.48 4.28 3.13 4.53 5.73 5.90 5.84 6.17 K 2 O 0.10 0.06 0.0 0.08 0.07 0.05 0.11 0.11 Cr 2 O 3 0.10 0.0 0.09 0.0 0.0 0.08 0.0 0.11 Total 100.24 99.35 99.70 99.52 99.86 99.32 99.41 100.06 Structural Formula on the basis of 8 Oxygen atoms Si 2.374 2.376 2.272 2.408 2.520 2.520 2.524 2.557 Ti 0.001 0.00 0.0 0.0 0.0 0.0 0.0 0.00 Al 1.607 1.610 1.708 1.572 1.469 1.460 1.467 1.428 Fe 0.002 0.004 0.002 0.0 0.0 0.0 0.0 0.006 Mn 0.0 0.0 0.002 0.001 0.0 0.003 0.0 0.001 Mg 0.0 0.00 0.000 0.001 0.001 0.001 0.002 0.0 Ca 0.634 0.641 0.742 0.622 0.505 0.503 0.492 0.459 Na 0.397 0.379 0.281 0.401 0.500 0.519 0.512 0.537 K 0.006 0.003 0.0 0.005 0.004 0.003 0.007 0.006 Cr 0.004 0.00 0.003 0.0 0.00 0.003 0.000 0.004 Total 4.623 5.018 5.007 5.010 4.999 5.009 5.004 4.994 An 61.44 62.95 72.322 60.56 50.02 49.22 48.69 45.82 Ab 38.02 36.72 27.49 39.00 49.56 50.63 50.67 53.57 Or 0.54 0.33 0.0 0.44 0.42 0.23 0.64 0.61 Lab Lab Byt Lab Lab Ads Ads Ads

Table 4.2 : Electron Microprobe Analyses (EPMA) wt % of zoned plagioclase in Granodiorite, Mashhad, NE, Iran Sample No. M- 18/1 Core rim SiO 2 53.40 53.50 53.80 52.8 57.40 60.50 TiO 2 0.00 0.00 0.00 0.001 0.00 0.00 Al 2 O 3 28.90 28.40 28.80 29.60 26.7 25.00 FeO 0.16 0.13 0.04 0.02 0.00 0.00 MnO 0.03 0.013 0.00 0.00 0.00 0.00 MgO 0.03 0.02 0.01 0.01 0.01 0.01 CaO 11.9 11.7 12.20 12.40 9.29 6.74 Na 2 O 4.76 5.04 4.97 4.47 6.53 7.64 K 2 O 0.09 0.06 0.02 0.07 0.13 0.11 Cr 2 O 3 0.07 0.00 0.05 0.00 0.01 0.13 Total 99.27 98.98 99.84 99.34 100.06 100.00 Structural Formula on the basis of 8 Oxygen atoms Si 2.434 2.446 2.438 2.405 2.537 2.688 Ti 1.549 1.532 1.540 1.589 1.413 1.309 Al 0.0 0.000 0.000 0.000 0.0 0.0 Fe 0.006 0.005 0.002 0.001 0.0 0.0 Mn 0.001 0.005 0.000 0.0 0.0 0.0 Mg 0.002 0.001 0.001 0.001 0.001 0.001 Ca 0.581 0.573 0.590 0.605 0.446 0.321 Na 0.420 0.447 0.437 0.396 0.567 0.858 K 0.004 0.004 0.001 0.004 0.007 0.006 Cr 0.003 0.000 0.002 0.0 0.001 0.005 Total 5.002 5.013 5.010 5.000 5.008 4.987 An 57.76 55.98 57.41 60.32 43.72 32.56 Ab 41.75 43.66 42.51 39.31 55.57 66.53 Or 0.49 0.37 0.09 0.38 0.72 0.60 Lab Lab Lab Lab Ads Ads

Table 4.4 : Electron Microprobe Analyses (EPMA) wt% of plagioclase in Diorite, Mashhad, NE, Iran Sample No. M 15/1 M 13/1 SiO 2 56.90 56.2 56.3 52.40 53.5 57.20 63.58 TiO 2 0.0 0.01 0.0 0.03 0.01 0.00 0.00 Al 2 O 3 26.50 27.3 27.5 29.70 29.00 26.50 22.58 FeO 0.07 0.08 0.11 0.0 0.06 0.05 0.00 MnO 0.10 0.0 0.2 0.0 0.07 0.009 0.00 MgO 0.01 0.01 0.01 0.0 0.00 0.02 0.01 CaO 9.53 9.92 10.1 13 11.9 9.47 4.08 Na 2 O 6.45 5.93 6.03 4.37 4.79 6.49 9.42 K 2 O 0.09 0.08 0.10 0.13 0.11 0.09 0.10 Total 99.65 99.53 100.35 99.63 99.44 99.90 99.77 Structural Formula on the basis of 8 Oxygen atoms Si 2.568 2.539 2.531 2.386 2.433 2.574 2.815 Ti 1.410 1.451 1.454 1.596 1.558 0.000 0.000 Al 0.0 0.0 0.0 0.001 0.0 1.403 1.179 Fe 0.003 0.003 0.003 0.0 0.002 0.002 0.000 Mn 0.00 0.00 0.001 0.0 0.003 0.003 0.000 Mg 0.001 0.001 0.001 0.0 0.0 0.001 0.000 Ca 0.461 0.480 0.486 0.636 0.578 0.456 0.194 Na 0.565 0.519 0.526 0.386 0.422 0.566 0.809 K 0.005 0.005 0.006 0.008 0.007 0.005 0.006 Total 5.012 4.998 5.008 5.012 5.002 5.011 5.003 An 44.73 47.83 47.76 61.72 57.49 43.36 19.22 Ab 54.76 51.72 56.14 37.55 41.88 56.14 80.23 Or 0.50 0.45 0.50 0.74 0.63 0.50 0.55 Ads Ads Ads Lab Lab Ads Olg

Table 4.5: Electron Microprobe Analyses (EPMA) wt% of K-feldspar in Mashhad Granitoids, NE, Iran. Rock Name : Monzo Monzo Monz Pink Granite T-granite Sample No. M 5/1 M 6/1 M 8/1 M 8/3 M 1/1 SiO 2 62.90 59.33 63.21 64.40 64.00 TiO 2 0.01 0.00 0.00 0.00 0.00 Al 2 O 3 20.30 25.21 18.41 17.98 18.10 FeO 0.20 0.31 0.00 0.00 0.04 MnO 0.01 0.03 0.00 0.06 0.00 MgO 0.79 0.16 0.00 0.00 0.00 CaO 0.54 0.62 0.00 0.00 0.00 Na 2 O 1.64 0.92 1.08 0.70 0.31 K 2 O 12.6 12.13 14.06 15.78 16.3 Total 98.99 98.71 96.76 98.92 98.75 Structural Formula on the basis of 8 Oxygen atoms Si 2.904 2.738 2.977 3.003 3.000 Ti 0.000 0.000 0.000 0.000 0.000 Al 1.105 1.371 1.022 0.988 0.997 Fe 0.008 0.012 0.000 0.000 0.002 Mn 0.000 0.001 0.000 0.002 0.000 Mg 0.050 0.011 0.000 0.000 0.000 Ca 0.245 0.031 0.000 0.000 0.000 Na 0.134 0.083 0.098 0.063 0.028 K 0.673 0.714 0.877 0.9339 0.974 Total 5.253 4.973 4.998 4.993 5.002 An 2.92 3.68 0.00 0.00 0.00 Ab 16.03 9.99 10.06 6.33 2.809 Or 81.04 86.32 89.94 93.67 97.19

Table 4.7: Electron Microprobe Analyses (EPMA) wt% of amphibole in diorite, Mashhad, NE, Iran. M 13.1 M 13.1 M 15.1 M 15.1 SiO 2 43.69 44.63 43.71 43.17 TiO 2 1.52 0.74 0.96 1.14 Al 2 O 3 10.59 8.87 10.40 10.64 Cr 2 O 3 0.03 0.04 0.00 0.00 FeO 20.44 21.05 20.23 20.32 MnO 0.07 0.55 0.73 0.74 MgO 7.40 7.97 7.96 7.69 CaO 11.63 11.83 11.61 11.37 Na 2 O 0.97 0.81 1.14 1.14 K 2 O 0.84 0.78 0.88 0.82 Total 97.18 97.27 97.62 97.03 Structural formula on the basis of 23 oxygen atoms Si 6.562 6.703 6.508 6.473 Ti 0.172 0.084 0.108 0.129 Al 1.875 1.570 1.825 1.880 Cr 0.004 0.005 0.000 0.000 Fe 3+ 0.775 0.938 1.105 1.092 Fe 2+ 1.793 1.706 1.414 1.456 Mn 0.009 0.070 0.092 0.094 Mg 1.657 1.785 1.767 1.719 Ca 1.872 1.904 1.852 1.827 Na 0.282 0.236 0.329 0.331 K 0.161 0.149 0.167 0.157 Total 15.161 15.149 15.167 15.157 X Mg 0.48 0.51 0.55 0.54

Table 4.8 : Electron Microprobe Analyses (EPMA) wt % of epidote in Mashhad Granitoids, NE, Iran Rock name : Sample No : Diorite M-5/1 Diorite M-13/1 Granodiorite M-18/1 Granodiorite M-18/1 Granodiorite M-18/1 Granodiorite M-18/1 Monzogranite M-6/1 SiO 2 37.66 38.36 38.67 38.66 37.67 38.53 37.86 TiO 2 0.66 0.14 0 0.02 0.23 0.09 0.22 A1 2 0 3 25.08 27.9 28.34 28.26 24.55 26.77 26.08 FeO 9.06 7.21 6.68 5.79 10.03 7.52 9.16 MnO 0.18 0.43 0.21 0.25 0.11 0.36 0.41 MgO 0.02 0 0 0.01 0.02 0.02 0.01 CaO 24.21 24.42 24.34 24.05 23.55 23.44 23.91 Na 2 O 0.00 0 0 0.01 0.03 0 0.00 K 2 O 0.02 0 0 0.03 0 0 0.00 Cr 2 O 3 0.08 0 0.01 0.01 0 0.03 0.00 Total 96.97 98.46 98.25 97.09 96.19 96.76 97.65 Structural Formula on the basis of 13 oxygen atoms Si 3.169 3.139 3.155 3.177 3.203 3.204 3.159 A1 2.488 2.691 2.726 2.737 2.460 2.624 2.565 Ti 0.042 0.008 0 0.001 0.014 0.005 0.136 Fe 0.638 0.493 0.455 0.397 0.713 0.523 0.639 Mn 0.013 0.030 0.014 0.017 0.007 0.0254 0.029 Mg 0.003 0 0 0.001 0.002 0.002 0.001 Zn 0.00 0 0 0 0 0 0.00 Ca 2.183 2.142 2.128 2.118 2.146 2.089 2.138 Na 0.000 0 0 0.001 0.004 0 0.000 K 0.002 0 0 0.003 0 0 0.000 Cr 0.005 0.00 0.00 0,00 0.00 0.00 0.000 Total 8.543 8.505 8.481 8.455 8.553 8.476 8.545

Table 4.9 : Electron Microprobe Analyses (EPMA) wt% of tourmaline, muscovite and sphene in Granitoid of Mashhad, NE, Iran. Rock Name Tur-granite Tur-granite monzogranite Sample No: M 13/1 M 15/1 M 6/1 Mineral Name Tourmaline Muscovite sphene SiO 2 35.53 46.27 30.11 TiO 2 0.31 0.22 34.8 Al 2 O 3 32.13 32.33 1.80 FeO 12.55 3.99 1.55 MnO 0.16 0.00 0.11 MgO 3.13 0.68 0.00 CaO 0.25 0.00 28.30 Na 2 O 2.11 0.46 0.00 K 2 O 0.05 10.47 0.00 ZnO 0.19 0.21 0.0 Cr 2 O 3 0.03 0.07 0.00 BaO 0.00 0.00 0.41 Total 86.44 95.29 97.08 Structural Formula on the basis (31 O) (11 O) (20 O) Si 7.536 3.126 4.040 Al 8.033 2.623 o.287 Ti 0.049 0.011 3.546 Fe 2.226 0.225 0.180 Mn 0.026 0.000 0.013 Mg 0.991 0.068 0.000 Zn 0.030 0.010 0.000 Ca 0.056 0.000 4.109 Na 0.867 0.059 0.000 K 0.014 0.902 0.000 Cr 0.005 0.003 0.000 Ba 0.00 0.00 0.022 Total 19.836 7.030 12.231

Table 4.10: Electron Microprobe Analyses (EPMA) wt % of magnetite and ilmenite in Mashhad Granitoids, NE, Iran Rock Name Monzogranite Leucogranite Sample No. M-8/1 M24/1 Mineral Name Magnetite Ilmenite SiO 2 00.00 00.00 TiO 2 0.05 52.84 AI 2 O 3 0.06 00.00 FeO 92.2 40.54 MnO 0.04 6.14 MgO 0.01 0.06 CaO 0.02 0.56 Cr 2 0 3 0.07 0.00 Total 92.447 100.2 Structural Formula on the (4 O) (6 O) basis of Si 0 0 A1 0.004 0 Ti 0.002 2.005 Fe 3.983 1.710 Mn 0.002 0.263 Mg 0.001 0.005 Ca 0.001 0.011 cr 0.003 0.000 Total 3.996 3.994

Fig: 4.1 Plot of anorthite content in core and rim of plagioclase in diorite Fig: 4.2 Plot of anorthite content in core and rim in plagioclase in granodiorite

Fig: 4.3 Plot of biotite from Mashhad granitoid on ASF diagram (after Lambert, 1959) A = (100*Al)/(Si+Al+Fe+Mn+Mg) S = (100*Si)/(Si+Al+Fe+Mn+Mg) F = [100(Fe+Mg+Mn)]/(Si+Al+Fe+Mn+Mg) Fig: 4.4 MgO(wt%) vs FeO(wt%) for biotite from Mashhad granitoid plotted in discrimination diagram (Abdel-Rahman,1994 ).

Fig: 4.5. Al2O3(wt%) vs MgO(wt%) for biotite from Mashhad granitoid Fig: 4.6. Al2O3(wt%) vs FeO(wt%) for biotite from Mashhad granitoid A: Anorogenic alkaline suites: Calc-alkaline orogenic suites, P: Peraluminous suites

Fig: 4.7. Composition of biotite from Mashhad granitoids plotted in the discrimination diagrams of Abdel Rahman et al. 1994. A: Alkaline, P: Peraluminous,C: Calc-alkaline0 Fig: 4.8. Composition of biotite from Mashhad granitoids plotted in the Fe 2+ - Fe 3+ - Mg diagram of Wones & Eugster, 1965.

Fig: 4.9. Classification of amphibole on the basis of ratio of an +K to Si (Leake 1978). Fig: 4.10. Ratio of (Ca +K +Na) to Si determining magmatic and post magmatic amphibole, (Leake 1978).