Major elements data
10
Major elements data •Differenciation •Magmatic series
description
Major elements data. Differenciation Magmatic series. 22. 10. Al. O. MgO. 2. 3. 17. 5. 0. 12. 15. 10. FeO*. 10. CaO. 5. 5. 0. 0. 4. 6. 3. Na. O. 2. K. O. 4. 2. 2. 2. 1. 0. 0. 45. 50. 55. 60. 65. 70. 75. 45. 50. 55. 60. 65. 70. 75. SiO. SiO. 2. - PowerPoint PPT Presentation
Transcript of Major elements data
Major elements data
•Differenciation•Magmatic series
12
17
22
Al2O3
0
5
10
MgO
0
5
10FeO*
0
2
4
6
Na2O
0
5
10
15
CaO
45 50 55 60 65 70 750
1
2
3
4
K2O
SiO2
45 50 55 60 65 70 75
SiO2
Bivariate Bivariate (x-y) (x-y)
diagramsdiagrams
HarkerHarkerdiagram diagram
forforCraterCraterLakeLake
12
10
8
6
4
2
35 40 45 50 55 60 65
%SiO2
%N
a 2O
+ K
2O
Alkaline
Subalkaline
Alkali vs. Silica diagram for Hawaiian volcanics:Alkali vs. Silica diagram for Hawaiian volcanics:Seems to be two distinct groupings: Seems to be two distinct groupings: alkalinealkaline and and subalkalinesubalkaline
F
A M
Calc-alkaline
T
ho leiitic
AFM diagram:AFM diagram: can further subdivide the subalkaline can further subdivide the subalkaline magma series into a magma series into a tholeiitictholeiitic and a and a calc-alkalinecalc-alkaline series series
Figure 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 of the Cascade volcanics (open circles). From Irving and Baragar (1971). After Irvine and Baragar (1971). Can. J. Earth Sci., 8, 523-548.
F
A M
Rhyolite
Dacite
Andesite
Basaltic Andesite
Ferro-Basalt
Basalt
Calc-alkaline
Tholeiitic
Basalt
B-A
A
D
R
Al2O3 K2O
CaO
Al2O3
K2O
CaO
Al2O3
CaO
biotitemuscovitecordieriteandalusitegarnet
pyroxenehornblendebiotite
aegirineriebeckitearfvedsonite
Peraluminous Metaluminous Peralkaline
mol
es
Na2ONa2O
K2O
Na2O
CaO
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 minerals for each type are included. After Clarke (1992). Granitoid Rocks. Chapman Hall.
AlkalineCalc-alkalineTholeitic
Series Alkali content
Fe-Mg Al
Alkaline High Fe-rich Metaluminous to peralkaline
Sub-alkaline
Calc-alkaline
Low to moderate
Mg-rich Metaluminous to per-aluminous
Tholeitic Low Fe-rich Metaluminous
CharacteristicSeries Convergent Divergent Oceanic ContinentalAlkaline yes yes yesTholeiitic yes yes yes yesCalc-alkaline yes
Plate Margin Within Plate
A world-wide survey suggests that there may be A world-wide survey suggests that there may be some important differences between the three seriessome important differences between the three series
After Wilson (1989). Igneous Petrogenesis. Unwin Hyman - Kluwer
