《主量元素地球化学》ppt课件

1、Energy SourceAbsorptionDetectorSampleEmissionDetectorOutput withabsorption troughOutput withemission peakAbsorbedradiationEmittedradiationFigure 8-1. The geometry of typical spectroscopic instruments. From Winter (2001) An Introduction to Igneous and Metamorphic Petrology. Prentice Hall.ElementWt %

2、Oxide Atom %O60.8Si59.321.2Al15.36.4Fe7.52.2Ca6.92.6Mg4.52.4Na2.81.9Wt. % Oxides to Atom % ConversionOxideWt. %Mol Wt.Atom propAtom %SiO249.2060.090.8212.25TiO21.8495.900.020.29Al2O315.74101.960.314.62Fe2O33.79159.700.050.71FeO7.1371.850.101.48MnO0.2070.940.000.04MgO6.7340.310.172.50CaO9.4756.080.17

3、2.53Na2O2.9161.980.091.40K2O1.1094.200.020.35H2O+0.9518.020.111.58(O)4.8372.26Total99.066.69100.00Must multiply by # of cations in oxide Table Chemical analyses of some representative igneous rocks PeridotiteBasaltAndesiteRhyolitePhonoliteSiO242.2649.2057.9472.8256.19TiO20.631.840.870.280.62Al2O34.2

4、315.7417.0213.2719.04Fe2O33.613.793.271.482.79FeO6.587.134.041.112.03MnO0.410.200.140.060.17MgO31.246.733.330.391.07CaO5.059.476.791.142.72Na2O0.492.913.483.557.79K2O0.341.101.624.305.24H2O+3.910.950.831.101.57Total98.7599.0699.399.5099.23Figure 8-2. Harker variation diagram for 310 analyzed volcani

5、c rocks from Crater Lake (Mt. Mazama), Oregon Cascades. Data compiled by Rick Conrey (personal communication). Figure 8-2. Harker variation diagram for 310 analyzed volcanic rocks from Crater Lake (Mt. Mazama), Oregon Cascades. Data compiled by Rick Conrey (personal communication). 橄榄石橄榄石 (Fe,Mg)2Si

6、O4 SiO239% MgO40%斜方辉石斜方辉石 (Fe,Mg)2Si2O6 SiO254%普通辉石普通辉石 (CaNaK)Al(AlSi)2O6 SiO248%角闪石角闪石 CaNaK(Al4O11)2(OH) SiO239%黑云母黑云母 KAl(AlSiO3O10)(OH) SiO239% K2O10%石石 英英 SiO2 SiO2100%钾长石钾长石 KAlSi3O8 SiO271% K2O8% 斜长石斜长石 NaAlSi3/CaAl2Si2O8 SiO268-50%霞霞 石石 NaAlSiO4 SiO240% Na2O16%例例 钾长石钾长石 SiO2% 的计算的计算 K2O Al2

7、O3 6SiO2 SiO2 = 60.1* 6 / ( 44.2 + 102.4 + 60.1* 6 ) = 71%实实 用用 矿矿 物物 化化 学学Figure 8-2. AFM diagram for Crater Lake volcanics, Oregon Cascades. Data compiled by Rick Conrey (personal communication). hypothetical set of related volcanics.OxideBBAADRDRSiO250.254.360.164.966.271.5TiO21.10.80.70.60.50.3A

8、l2O314.915.716.116.415.314.1Fe2O3*10.49.26.95.15.12.8MgO7.43.72.81.70.90.5CaO10.08.25.93.63.51.1Na2O2.63.23.83.63.93.4K2O1.02.12.52.53.14.1LOI1.92.01.81.61.21.4Total99.599.2100.6100.099.799.2B = basalt, BA = basaltic andesite, A = andesite, D = dacite, RD = rhyo-dacite, R = rhyolite. Data from Ragla

9、nd (1989)Table 8-5. Chemical analyses (wt. %) of aFigure 8-6. Stacked variation diagrams of hypothetical components X and Y (either weight or mol %). P = parent, D = daughter, S = solid extract, A, B, C = possible extracted solid phases. For explanation, see text. From Ragland (1989). Basic Analytic

10、al Petrology, Oxford Univ. Press.Figure 8-7. Stacked Harker diagrams for the calc-alkaline volcanic series of Table 8-5 (dark circles). From Ragland (1989). Basic Analytical Petrology, Oxford Univ. Press.Thus the blue line the concentration of all other oxidesFigure 8-7. Stacked Harker diagrams for

11、the calc-alkaline volcanic series of Table 8-5 (dark circles). From Ragland (1989). Basic Analytical Petrology, Oxford Univ. Press.OxideWt%Cation NormSiO246.5ab18.3TiO21.4an30.1Al2O314.2di23.2Fe2O3*11.5hy4.7MgO10.8ol19.3CaO11.5mt1.7Na2O2.1il2.7K2O0Total98.1100Figure 8-8. Variation diagram on a catio

12、n basis for the fractional crystallization of olivine, augite, and plagioclase to form BA from B (Table 8-6). From Ragland (1989). Basic Analytical Petrology, Oxford Univ. Press.Figure 8-9. Equilateral triangle showing the solution to the bulk mineral extract (shaded area) best fitting the criteria

13、for the variation diagrams in Figure 8-8. From Ragland (1989). Basic Analytical Petrology, Oxford Univ. Press.Figure 8-11. Total alkalis vs. silica diagram for the alkaline and sub-alkaline rocks of Hawaii. After MacDonald (1968). GSA Memoir 116Figure 8-12. Left: the basalt tetrahedron (after Yoder

14、and Tilley, 1962). J. Pet., 3, 342-532. Right: the base of the basalt tetrahedron using cation normative minerals, with the compositions of subalkaline rocks (black) and alkaline rocks (gray) from Figure 8-11, projected from Cpx. After Irvine and Baragar (1971). Can. J. Earth Sci., 8, 523-548.NeAbQ1

15、07010601713Ab + TrTr + LAb + LNe + LLiquidAb + LNe + AbThermalDivideFAMCalc-alkaline TholeiiticFigure 8-14. AFM diagram showing the distinction between selected tholeiitic rocks from Iceland, the Mid-Atlantic Ridge, the Columbia River Basalts, and Hawaii (solid circles) plus the calc-alkaline rocks

16、of the Cascade volcanics (open circles). From Irving and Baragar (1971). After Irvine and Baragar (1971). Can. J. Earth Sci., 8, 523-548.Figure 18-2. Alumina saturation classes based on the molar proportions of Al2O3/(CaO+Na2O+K2O) (“A/CNK”) after Shand (1927). Common non-quartzo-feldspathic mineral

17、s for each type are included. After Clarke (1992). Granitoid Rocks. Chapman Hall.Figure 8-10a. Plot of CaO (green) and (Na2O + K2O) (red) vs. SiO2 for the Crater Lake data. Peacock (1931) used the value of SiO2 at which the two curves crossed as his “alkali-lime index” (dashed line). b. Alumina saturation indices (Shand, 1927) with analyses of the peraluminous granitic rocks from the Achala Batholith, Argentina (Lira and Kirschbaum, 1990). In S. M. Kay and C. W. Rapela (eds.), Plutonism from Antarctica to Alaska. Geol. Soc. Amer. Special