5. Results 1 Chemical properties
5.3 X-ray diffraction
The relationships between sulfur minerals and SCR are shown in Figure 16. Mud sample (site 616-02-028, 200-250 cm) and peat sample (site 616-02-112) have quite high pHFOX (>4) because these samples have high calcite and organic matter contents respectively.
Bivariate relationship between sulfur minerals and SCR for A, E, B, coffee rock, mud and peat horizons and sulfur minerals and SCR of A, E, B and coffee rock horizons are shown in the Figure 16a, b). The Figure 16b plot omits data for the mud and peat samples which makes the relationship nonsignificant showing that the apparently significant relationships in Figure 16a is specious due to the bimodal distribution of these data. One reason for the absence of a relationship is because the sulfur minerals were determined on the fine fraction whereas whole soil samples were used for SCR analysis.
Synchrotron XRD is an excellent technique for identification of minor constituent minerals. However, synchrotron XRD was unable to detect very small amounts of sulfide minerals in some A, E, B, coffee rock, mud, peat samples with with very low SCR
contents (less than 0.005%) (Appendix Figures 18, 24 and 25). TEM and SEM enabled the identification very small amount of pyrite in these samples where pyrite was not detected by SXRD (Figures 17-24) indicating that acidification (low pHFOX) is generally due to the presence of pyrite (and very low buffering). [The samples shown in Figures 17-24 were also used for the Murdoch University soil column experiment.].
Table 2 Mineralogical composition (semi quantitative %) of the fine fraction of soil samples (based on synchrotron XRD)*.
No Site Horizon Depth (cm) pHF pHFOX SCR
(%)
GW (cm) Ill Kao Pyr S Jar Mar Mac Micro Na Ca
Feld
Alb Am Gib Goe Qua Zir Ilm Hal Cal Ara
003 616-01-005 Coffee rock 180-200 6.3 4.7 no data 640 - 0.8 - - - - - 0.6 - - - 2.0 - 96.6 - - - - -
022 616-02-031 Coffee rock1 200-300 5.3 3.2 < 0.02 75 - 0.1 - - - - - 0.2 - - - 0.3 - 99.4 - - - - -
023 616-02-031 Coffee rock2 200-300 5.3 3.2 < 0.02 75 - 0.5 - - - - - 1.8 - - - 1.9 - 95.8 - - - - -
034 616-01-003 Coffee rock 175-200 5.0 3.6 no data 490 - 0.5 - - - - - 0.8 - - - 0.5 - 98.2 - - - - -
040 616-01-014 C1 horizon 800-900 6.3 5.3 no data 1350 - 0.4 - - - - - 1.3 - - - 3.2 - 95.1 - - - - -
052 616-02-068 E3 horizon 375-600 7.2 1.8 <0.02 200 0.3 2.8 8.7 0.7 - - - 14.3 - - - 1.8 - 71.4 - - - - -
055 616-02-080 Coffee rock 200-400 5.3 3.2 <0.02 200 - 3.6 0.4 - - - - - - - - 1.7 - 94.4 - - - - -
058 616-02-082 E2 horizon 200-300 5.0 1.8 0.02 50 - 1.0 2.3 - - - - 10.8 - - - 0.6 - 85.3 - - - - -
059 616-02-082 B horizon 300-400 5.8 1.6 0.11 50 - 33.2 3.2 0.3 - - - 4.1 - - - 0.3 - 59.0 - - - - -
060 616-02-082 2E horizon 400-500 6.2 1.6 0.26 50 - 0.7 8.3 - - 0.2 - 10.8 - - - 0.7 - 79.3 - - - - -
061 616-02-082 Coffee rock 500-600 6.7 1.5 no data 50 - 1.6 6.7 0.5 - - - 8.6 - - - 1.6 - 77.7 - - 3.3 - -
062 616-02-087 Coffee rock1 200-300 6.1 3.9 no data 150 - - - - - - - 1.2 - - - 0.9 - 97.9 - - - - -
063 616-02-087 Coffee rock2 300-400 6.0 4.1 no data 150 - - - - - - - - - - - 11.7 - 88.3 - - - - -
069 616-01-019 B horizon 250-300 4.4 3.9 no data 400 - 0.9 - - - - - 2.0 - - - 0.5 - 96.6 - - - - -
086 616-02-085 A horizon 0-70 6.1 3.9 no data 150 - 52.7 - - - - - 47.3 - - - - - - - - - - -
087 616-02-085 B1 horizon 100-300 6.7 2.0 0.28 150 - 4.9 - 1.5 - - 3.8 3.6 3.8 - - - - 82.4 - - - - -
088 616-02-085 B2 horizon 300-400 7.1 2.0 0.80 150 1.8 3.5 9.0 - - - - 9.0 - 9.4 - 2.5 - 64.8 - - - - -
089 616-02-085 Mud 400-600 7.4 2.6 0.40 150 - 0.7 - 0.2 3.1 - - 0.7 1.7 - - - - 91.9 1.9 - - - -
090 616-02-028 B horizon 30-100 4.3 2.3 0.27 150 - 0.6 - - 0.6 0.8 - 0.8 - 1.8 - - - 95.5 - - - - -
091 616-02-028 Mud1 100-200 6.6 3.0 0.89 150 - - 1.5 - - - - 4.5 3.0 - - - - 91.0 - - - - -
092 616-02-028 Mud2 200-250 7.4 6.0 no data 150 0.8 1.9 16.0 - - - - 2.9 1.8 - 1.4 - - 64.6 - 1.4 - 9.2 -
095 616-02-094 A1 horizon 0-100 4.0 1.9 0.09 350 - 1.3 - - 5.2 - - 2.0 - - - - - 91.5 - - - - -
096 616-02-094 A2 horizon 100-175 4.3 2.8 <0.02 350 - 0.2 - - 2.0 - - 2.6 - - - - - 95.2 - - - - -
097 616-02-094 E horizon 175-600 5.9 3.6 0.03 350 0.1 0.2 0.2 - - - - 0.9 - - - - - 98.6 - - - - -
098 616-02-100 A horizon 0-80 8.0 5.5 no data 200 - 1.6 - 1.5 - - - 4.7 - - - 1.8 - 77.5 - - - 12.9 -
099 616-02-100 Peat 80-110 7.8 4.2 no data 200 - - - - - - - - - - - - - 100.0 - - - - -
100 616-02-100 Peat/Ehorizon 110-200 7.1 3.3 0.08 200 - 0.7 2.6 - - 0.9 - 3.2 - - - - - 92.6 - - - - -
101 616-02-100 E horizon 200-600 6.4 2.1 0.02 200 - 1.0 1.0 - - - - 8.9 - - - - - 89.1 - - - - -
Ill = Illite, Kao = Kaolinite, Pyr = Pyrite, S = Elemental S, Jar = Jarosite, Mar = Marcasite, Mac = Mackinawite, Micro = Microcline, Na Ca Feldspar, Alb = Albite, Am = Amphibole, Gib = Gibbsite, Goe = Goethite, Qua = Quartz, Zir = Zircon, Ilm = Ilmenite, Hal = Halite, Cal = Calcite, Ara = Aragonite, - = not detected.
* allophane is present in most coffee rock and some other samples but could not be detected by synchrotron XRD due to its diffuse reflections and the nature of background scattering from the glass capillary sample holder.
Table 2 (Cont.) Mineralogical composition (semi quantitative %) of the fine fraction of soil samples (based on synchrotron XRD)*.
No Site Horizon Depth
(cm)
pHF pHFOX SCR
(%) GW (cm)
Ill Kao Pyr S Jar Mar Mac Micro Na Ca
Feld
Alb Am Gib Goe Qua Zir Ilm Hal Cal Ara
102 616-02-099 E horizon 25-200 7.2 3.5 < 0.02 50 - - - - - - - - - - - - 100.0 - - - - -
103 616-02-099 B1 horizon 200-300 7.1 2.5 0.10 50 - 5.1 3.8 - - - - 4.3 - - - - - 86.8 - - - - -
104 616-02-099 B2 horizon 300-400 7.2 1.8 0.12 50 - 0.3 3.8 - - - - 1.5 - - - - - 94.4 - - - - -
105 616-02-099 2E horizon 400-600 6.8 2.1 0.05 50 - 0.4 7.6 - - - - 1.8 - - - - - 90.2 - - - - -
106 616-02-101 A horizon 0-75 7.4 3.8 < 0.02 150 - 1.2 - 0.4 - - - 6.2 - - - 1.1 - 91.2 - - - - -
107 616-02-101 Peat1 150-200 7.4 5.4 no data 150 - - 4.7 - - - - 6.0 - - - - - 89.3 - - - - -
108 616-02-101 Peat2 200-350 7.1 1.6 0.74 150 - - 4.3 - - - - 5.5 - - - - - 82.3 - - - 7.9 -
109 616-02-101 E horizon 350-600 8.5 2.0 0.05 150 - 0.2 1.8 - - - - 10.0 - - - - - 88.1 - - - - -
110 616-02-009 E1 horizon 225-250 5.8 4.9 no data 180 - 0.3 - - - - - 7.4 - - - - - 92.3 - - - - -
112 616-02-105 A horizon 0-160 7.8 4.7 no data 170 - 3.3 - - - - - 6.2 - - - - - 90.5 - - - - -
113 616-02-105 Peat 250-360 6.3 1.4 1.97 170 - - 61.9 - - - - - - - - - - 38.1 - - - - -
114 616-02-105 Peat/Ehorizon 360-480 6.7 2.0 0.08 170 - 0.2 1.6 0.1 - - - 3.2 0.2 - - - - 94.6 - - - - -
115 616-02-105 E horizon 480-700 7.1 3.9 0.05 170 - 0.2 0.1 - - - - 5.5 - - - - - 93.9 - - 0.4 - -
116 616-02-106 A horizon 0-50 4.3 2.2 < 0.02 180 - 1.1 - - 3.7 - - 3.4 - - - - - 90.7 - - 1.1 - -
117 616-02-106 E horizon 50-700 4.9 2.1 0.04 180 - 0.3 1.2 0.4 - - - 8.2 1.3 - - - - 88.7 - - - - -
119 616-02-112 Mud 125-200 7.7 6.4 no data 100 - - - - - - - 4.1 - - - - - 3.1 - - 11.3 81.5 -
120 616-02-112 Peat 200-300 7.6 4.3 0.60 100 - - 27.5 - - - - 8.6 - - - - - - - - 63.9 - -
121 616-02-112 B horizon 300-400 7.5 3.9 no data 100 - 0.4 1.3 - - - - 1.9 - - - - - 59.0 - - - 37.3 -
122 616-02-112 C horizon 400-600 7.9 6.5 no data 100 - - 0.4 - - - - 0.9 - - - - - 7.9 - - - 90.9 -
123 616-02-113 A horizon 0-50 6.5 3.9 no data 50 - 0.8 - - - - - 6.9 - - - - - 92.3 - - - - -
124 616-02-113 E1 horizon 50-250 7.6 3.7 < 0.02 50 - 0.3 - - - - - 7.1 - 0.7 - - - 92.0 - - - - -
125 616-02-113 E2 horizon 250-300 7.6 1.6 0.10 50 - 0.3 1.9 - - - - 5.7 - 5.9 - - - 86.2 - - - - -
127 616-02-122 E horizon 20-235 6.3 3.6 <0.02 240 - 0.2 - - - - - 2.6 - - - - - 97.1 - - - - -
128 616-02-122 B horizon 235-315 6.9 4.4 no data 240 - 1.0 - - - - - 5.4 - - - 0.8 - 92.7 - - - - -
130 616-02-122 2E3 horizon 500-700 6.5 1.9 < 0.02 240 0.2 0.3 - - - - - 17.5 - - - 0.2 - 81.8 - - - - -
131 616-02-127 E horizon 40-100 5.9 4.1 no data 200 - 0.2 - - - - - 0.5 - - - - - 99.3 - - - - -
132 616-02-127 Coffee rock 100-235 5.2 3.1 < 0.02 200 - - - - - - - 2.7 - - - - - 97.3 - - - - -
133 616-02-127 2E1 horizon 235-300 5.0 3.2 < 0.02 200 - 0.4 - - - - - 1.8 - - - - - 97.8 - - - - -
134 616-02-127 2E2 horizon 300-600 6.1 2.3 < 0.02 200 - 0.4 - - - - - - - - - - - 99.6 - - - - -
Ill = Illite, Kao = Kaolinite, Pyr = Pyrite, S = Elemental S, Jar = Jarosite, Mar = Marcasite, Mac = Mackinawite, Micro = Microcline, Na Ca Feldspar, Alb = Albite, Am = Amphibole, Gib = Gibbsite, Goe = Goethite, Qua = Quartz, Zir = Zircon, Ilm = Ilmenite, Hal = Halite, Cal = Calcite, Ara = Aragonite, - = not detected.
* allophane is present in most coffee rock and some other samples but could not be detected by synchrotron XRD due to its diffuse reflections and the nature of background scattering from the glass capillary sample holder.
Table 2 (Cont.) Mineralogical composition (semi quantitative %) of the fine fraction of soil samples (based on synchrotron XRD)*.
No Site Horizon Depth
(cm)
pHF pHFOX SCR
(%) GW (cm)
Ill Kao Pyr S Jar Mar Mac Micro Na Ca
Feld
Alb Am Gib Goe Qua Zir Ilm Hal Cal Ara
135 616-02-131 A horizon 0-50 7.4 4.9 no data 200 - 1.4 - - - - - 2.4 - - 1.7 0.8 - 93.7 - - - - -
136 616-02-131 E horizon 50-325 7.3 4.2 <0.02 200 - 0.9 - - - - - 3.1 - - - 0.4 - 95.6 - - - - -
137 616-02-131 B horizon 325-425 6.4 3.6 <0.02 200 0.2 0.9 - - - - - 0.8 - - - - 0.2 97.8 - - - - -
138 616-02-131 2E horizon 425-600 6.3 4.2 <0.02 200 0.1 0.1 - - - - - 0.8 0.8 - - - - 98.2 - - - - -
139 616-02-136 A horizon 0-25 7.0 4.4 no data 180 - - - - - - - 2.2 - - - - - 97.8 - - - - -
140 616-02-136 Coffee rock 200-260 6.6 3.6 no data 180 - 9.6 - - - - - 8.5 - - - - - 81.9 - - - - -
141 616-02-136 E horizon 260-600 6.3 2.0 0.02 180 0.2 1.2 0.6 0.8 - 2.5 - 16.4 - - - - - 78.3 - - - - -
142 616-02-068 A horizon 0-25 5.9 4.8 no data 200 - - - - - - - 2.1 - - - - - 97.9 - - - - -
143 616-02-068 E horizon 25-200 6.1 4.7 <0.02 200 - - - - - - - 19.1 - - - - - 77.6 - - - 3.3 -
144 616-02-068 Coffee rock 200-300 5.6 2.7 0.04 200 - 0.5 - - - - - 5.0 - - - 0.2 - 94.3 - - - - -
145 616-02-068 B1 horizon 300-400 6.3 1.2 <0.02 200 - 0.9 0.4 0.4 - - - 6.3 - - - 0.8 - 91.2 - - - - -
146 616-02-068 B2 horizon 400-500 6.7 1.4 <0.02 200 - 1.3 0.8 - - - - 7.1 - - - 1.3 - 89.5 - - - - -
147 616-02-068 B3 horizon 500-600 7.3 1.4 <0.02 200 - 1.4 2.6 0.8 - - - 12.1 - - - 1.2 - 81.9 - - - - -
150 616-02-065 Peat1 0-20 6.5 3.7 <0.02 150 - 2.6 - - - - - 2.6 - - - - - 94.8 - - - - -
154 616-02-065 Coffee rock1 480-560 6.0 1.6 <0.02 150 - 2.9 1.9 - - - - 1.4 - - - 4.8 - 88.9 - - - - -
156 616-02-065 Coffee rock3 650-700 5.9 1.6 <0.02 150 - 0.5 - - - - - 2.8 - - - 1.3 - 95.4 - - - - -
158 616-02-122 B/E horizon 700-900 6.2 2.2 no data 240 - 0.3 - - - - - 4.5 - - - 0.6 - 94.6 - - - - -
159 616-02-122 2E2 horizon 375-500 6.2 1.9 no data 240 - 1.1 - - - - - 12.6 - - - 0.6 - 85.7 - - - - -
161 Ellenbrook E horizon 0-150 4.5 4.5 no data 700 - 0.1 - - - - - 0.1 - - - - - 99.8 - - - - -
162 Ellenbrook Coffee rock 150-200 4.0 3.1 no data 700 - 5.7 - - - - - - - - - - - 94.3 - - - - -
163 Ellenbrook B horizon 200-500 2.6 1.9 no data 700 - 0.8 - - - - - 7.1 - - - - - 92.1 - - - - -
164 Ellenbrook Coffee rock 200 4.3 3.00 no data 700 - 7.1 - - - - - 33.9 - - - 2.1 - 56.9 - - - -
167 Ellenbrook Coffee rock 150-200 4.6 1.9 no data 700 - 1.0 - - - - - 1.2 - - - 1.0 - 96.8 - - - - -
169 616-02-155 E horizon 50-150 9.1 5.5 no data 250 - - - - - - - 2.8 - - - - - 77.3 - - - 18.8 1.1
171 616-02-155 B horizon 500-600 8.3 7.1 no data 250 - 1.6 - - - - - - - - - 0.4 - 98.1 - - - - -
174 616-02-145 B horizon 450-475 7.1 2.6 no data 220 - 12.9 - - - - - 2.7 - - - 4.5 2.9 77.0 - - - - -
178 616-02-158 Coffee rock2 300-400 5.6 2.1 no data 290 - 0.7 - - - - - 3.4 - - - 1.8 - 94.1 - - - - -
Ill = Illite, Kao = Kaolinite, Pyr = Pyrite, S = Elemental S, Jar = Jarosite, Mar = Marcasite, Mac = Mackinawite, Micro = Microcline, Na Ca Feldspar, Alb = Albite, Am = Amphibole, Gib = Gibbsite, Goe = Goethite, Qua = Quartz, Zir = Zircon, Ilm = Ilmenite, Hal = Halite, Cal = Calcite, Ara = Aragonite, - = not detected.
* allophane is present in most coffee rock and some other samples but could not be detected by synchrotron XRD due to its diffuse reflections and the nature of background scattering from the glass capillary sample holder.
Table 2 (Cont.) Mineralogical composition (semi quantitative %) of the fine fraction of soil samples (based on synchrotron XRD)*.
No Site Horizon Depth (cm) pHF pHFOX SCR
(%) GW
(cm)
Ill Kao Pyr S Jar Mar Mac Micro Na Ca
Feld
Alb Am Gib Geo Qua Zir Ilm Hal Cal Ara
N1 616-01-005 B horizon 620-630 5.5 2.7 0.014 640 - 0.6 - - - - - 0.6 - - - 0.8 - 98.0 - - - - -
N2 616-02-068 B horizon 450 7.2 1.8 0.027 200 - 0.9 1.8 - - - - 5.3 - - - 1.1 - 90.9 - - - - -
N4 616-02-179 B horizon 375-400 6.1 1.6 0.013 320 - 1.0 0.5 - - 0.6 - 1.2 - - - 0.7 - 96.1 - - - - -
N6 616-02-078 B horizon 400-500 4.8 1.5 0.014 200 - 0.2 1.6 - - - - 0.3 - - - - - 97.6 - - 0.3 - -
N7 616-02-081 B horizon 400-800 6.2 1.4 0.052 300 - 0.3 1.7 - - 0.7 - 3.9 - - - - - 93.4 - - - - -
N8 616-02-110 B horizon 200-500 6.3 1.8 0.036 180 - 1.0 12.3 - - - - 2.8 - - - - - 26.2 - - - 57.7 -
N9 616-02-174 B horizon 250-550 5.5 2.5 <0.005 310 - 0.2 - - - - - 0.2 - - - - - 99.6 - - - - -
N10 616-02-065 B horizon 200 5.7 3.0 0.005 150 - 1.2 - - - - - 2.5 - - - - - 96.3 - - - - -
Ill = Illite, Kao = Kaolinite, Pyr = Pyrite, S = Elemental S, Jar = Jarosite, Mar = Marcasite, Mac = Mackinawite, Micro = Microcline, Na Ca Feldspar, Alb = Albite, Am = Amphibole, Gib = Gibbsite, Goe = Goethite, Qua = Quartz, Zir = Zircon, Ilm = Ilmenite, Hal = Halite, Cal = Calcite, Ara = Aragonite, - = not detected.
* allophane is present in most coffee rock and some other samples but could not be detected by synchrotron XRD due to its diffuse reflections and the nature of background scattering from the glass capillary sample holder.
Table 3 Semi quantitative SXRD analyses for sulfur minerals in the fine fraction and some soil properties.
Pyr S Jar Mar Mac
Sample No.
Site Horizon Depth
(cm)
pHF pHFOX SCR
(%)
GW (cm)
(---%---)
095 616-02-094 A horizon 0-100 4 50 2.13 0.09 350 - - 5.2 - -
096 616-02-094 A horizon 100-175 4.27 2.77 <0.02 350 - - 2.0 - -
098 616-02-100 A horizon 0-80 8.00 5.53 no data 200 - 1.5 - - -
106 616-02-101 A horizon 0-75 7.43 3.77 <0.02 150 - 0.4 - - -
116 616-02-106 A horizon 0-50 4.25 2.20 <0.02 180 - - 3.7 - -
052 616-02-068 E horizon 375-600 7.21 1.76 <0.02 200 8.7 0.7 - - -
058 616-02-082 E horizon 200-300 5.04 1.84 0.02 50 2.3 - - - -
060 616-02-082 E horizon 400-500 6.18 1.60 0.26 50 8.3 - - 0.2 -
097 616-02-094 E horizon 175-600 5.88 3.56 0.03 350 0.2 - - - -
101 616-02-100 E horizon 200-600 6.43 2.07 0.02 200 1.0 - - - -
105 616-02-099 E horizon 400-600 6.76 2.06 0.05 50 7.6 - - - -
109 616-02-101 E horizon 350-600 8 52 1.99 0.05 150 1.8 - - - -
115 616-02-105 E horizon 480-700 7.11 3.90 0.05 170 0.1 - - - -
117 616-02-106 E horizon 50-700 4 90 2.13 0.04 180 1.2 0.4 - - -
125 616-02-113 E horizon 250-300 7.60 1.57 0.10 50 1.9 - - - -
141 616-02-136 E horizon 260-600 6.32 1.97 0.02 180 0.6 0.8 - 2.5 -
059 616-02-082 B horizon 300-400 5.78 1.55 0.11 50 3.2 0.3 - - -
087 616-02-085 B horizon 100-300 6.69 2.02 0.28 150 - 1.5 - - 3.8
088 616-02-085 B horizon 300-400 7.10 1.95 0.80 150 9.0 - - - -
090 616-02-028 B horizon 30-100 4.33 2.25 0.27 150 - - 0.6 0.8 -
103 616-02-099 B horizon 200-300 7.08 2.54 0.10 50 3.8 - - - -
104 616-02-099 B horizon 300-400 7.20 1.83 0.12 50 3.8 - - - -
121 616-02-112 B horizon 300-400 7.45 3.93 no data 100 1.3 - - - -
145 616-02-068 B horizon 300-400 6.30 1.18 <0.02 200 0.4 0.4 - - -
146 616-02-068 B horizon 400-500 6.73 1.40 <0.02 200 0.8 - - - -
147 616-02-068 B horizon 500-600 7.28 1.35 <0.02 200 2.6 0.8 - - -
N2 616-02-068 B horizon 450 7.20 1.80 0.027 200 1.8 - - - -
N4 616-02-179 B horizon 375-400 6.10 1.60 0.013 320 0.5 - - 0.6 -
N6 616-02-078 B horizon 400-500 4.80 1.50 0.014 200 1.6 - - - -
N7 616-02-081 B horizon 400-800 6.20 1.40 0.052 300 1.7 - - 0.7 -
N8 616-02-110 B horizon 200-500 6.30 1.80 0.036 180 12.3 - - - -
055 616-02-080 Coffee rock 200-400 5.30 3.17 <0.02 200 0.4 - - - -
061 616-02-082 Coffee rock 500-600 6.73 1.50 no data 50 6.7 0.5 - - -
154 616-02-065 Coffee rock 480-560 6.00 1.57 <0.02 150 1.9 - - - -
089 616-02-085 Mud 400-600 7.43 2.56 0.40 150 - 0.2 3.1 - -
091 616-02-028 Mud 100-200 6.63 2.98 0.89 150 1.5 - - - -
092 616-02-028 Mud 200-250 7.35 5.98 no data 150 16.0 - - - -
100 616-02-100 Peat 110-200 7.06 3.24 0.08 200 2.6 - - 0.9 -
107 616-02-101 Peat 150-200 7.37 5.37 no data 150 4.7 - - - -
108 616-02-101 Peat 200-350 7.13 1.60 0.74 150 4.3 - - - -
113 616-02-105 Peat 250-360 6.25 1.43 1.97 170 61.9 - - - -
114 616-02-105 Peat 360-480 6.65 1.98 0.08 170 1.6 0.1 - - -
120 616-02-112 Peat 200-300 7.62 4.30 0.60 100 27.5 - - - -
122 616-02-112 C horizon 400-600 7.86 6.46 no data 100 0.4 - - - -
- = not detected, Pyr = Pyrite; S = Elemental S; Jar = Jarosite; Mar = Marcasite; Mac = Mackinawite, SCR = Chromium reducible sulfur; GW = Groundwater level
Figure 15 The spatial distribution of pyrite content (semi quantitative %) of the fine fraction of soil samples (based on synchrotron XRD) related to water table contours for the Perth region.
Figure 16 Bivariate relationship between (a) sulfur minerals (%) and SCR of A, E, B, coffee rock, mud and peat horizons (%), (b) sulfur minerals (%) and SCR of A, E, B and coffee rock horizons. RHS plots omit the mud and peat samples which make the relationship nonsignificant showing that the LHS relationships are specious due to the bimodal distribution of these data.
y = 0.029x + 0.041 R2 = 0.66
0.0 0.5 1.0 1.5 2.0 2.5
0 10 20 30 40 50 60 70
Sulfur minerals (%)
Scr (%)
A horizon E horizon B horizon Coffee rock Mud Peat
(a)
y = 0.021x + 0.020 R2 = 0.18
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
0 2 4 6 8 10 12 14
Scr (%)
A horizon E horizon B horizon Coffee rock
(b)
Sulfur minerals (%)
Figure 17 (a) SEM backscattered electron image (b) TEM transmission electron micrograph and x-ray spectrum of fine fraction pyrite from the B horizon (620-630 cm, site 616-01-005) (pHF = 5.5, pHFOX = 2.7, SCR = 0.014%), pyrite was not detected by SXRD however at high magnification rare pyrite crystals can be seen (SP = Single crystal pyrite).
Figure 18 (a) SEM secondary electron image (b) TEM transmission electron micrograph and x-ray spectrum of fine fraction pyrite from the B horizon (450 cm, site 616-02-068) (pHF = 7.2, pHFOX = 1.8, SCR = 0.027%) (F = Framboidal pyrite, SP
B horizon (N_01)
Pyrite Fe: S ≈ 1: 2 Pyrite Fe: S ≈ 1: 2
(a)
(b)
SP
SP
S
Fe
S
Fe
Fe
B horizon (N_02)
(b) Pyrite
Fe: S ≈ 1: 2 Pyrite Fe: S ≈ 1: 2
(a)
F
SP
SP SP
K
SP
S
Fe
S
Fe
Fe
Figure 19 (a) SEM backscattered electron image (b) TEM transmission electron micrograph and x-ray spectrum of fine fraction pyrite from the B horizon 375-400 cm, site 616-02-179) (pHF = 6.1, pHFOX = 1.6, SCR = 0.013%) (F = Framboidal pyrite, SP
= Single crystal pyrite, K = Kaolin).
Figure 20 (a) SEM backscattered electron image (b) TEM transmission electron micrograph and x-ray spectrum of fine fraction pyrite from the B horizon (400-500 cm, site 616-02-078) (pHF = 4.8, pHFOX = 1.5, SCR = 0.014%) (F = Framboidal pyrite, SP = Single crystal pyrite, K = Kaolin).
B horizon (N_04) (a)
Pyrite Fe: S ≈ 1: 2
F SP
SP
S
Fe
(b) Pyrite
Fe: S ≈ 1: 2
K
SP
S
Fe
Fe
B horizon (N_06)
(a) Pyrite
Fe: S ≈ 1: 2
F SP
SP
SP SP
S
Fe
(b) Pyrite
Fe: S ≈ 1: 2
K SP
S
Fe
Fe
Figure 21 (a) SEM secondary electron image (b) TEM transmission electron micrograph and x-ray spectrum of fine fraction pyrite from the B horizon (400-800 cm, site 616-02-081) (pHF = 6.2, pHFOX = 1.4, SCR = 0.052%) (F = Framboidal pyrite, SP = Single crystal pyrite, K = Kaolin).
Figure 22 SEM secondary electron image and x-ray spectrum of fine fraction pyrite from the B horizon (200-500 cm, site 616-02-110) (pHF = 6.3, pHFOX = 1.8, SCR = 0.036%) (F = Framboidal pyrite, SP = Single crystal pyrite).
B horizon (N_07) (a)
(b)
Pyrite Fe: S ≈ 1: 2
Pyrit e Fe: S ≈ 1: 2
F
K SP
SP
F
SP SP
K
SP F
S
Fe
Fe S
Fe
Pyrite Fe: S ≈ 1: 2
B horizon (N_08)
F
SP F
SP
SP SP
SP
SP
S
Fe
Figure 23 (a) SEM backscattered electron image (b) TEM transmission electron micrograph and x-ray spectrum of fine fraction pyrite from the B horizon (250-550 cm, site 616-02-174) (pHF = 5.5, pHFOX = 2.5, SCR = <0.005%). Pyrite was not detected by SXRD however at high magnification rare pyrite crystals can be seen (SP
= Single crystal pyrite).
Figure 24 (a) SEM backscattered electron image with no evident pyrite (b) TEM transmission electron micrograph and x-ray spectrum of fine fraction pyrite from the B horizon (200 cm, site 616-02-065) (pHF = 5.7, pHFOX = 3.0, SCR = 0.005%). Pyrite was not detected by SXRD and SEM however at high magnification rare pyrite crystals can be seen.
B horizon (N_10)
(b) Pyrite
Fe: S ≈ 1: 2 Pyrite
(a)
Diatom
Phytolith Quartz
Quartz
S
Fe
Fe
B horizon (N_09)
(a) Pyrite
Fe: S ≈ 1: 2
SP Fe
S
(b)
Pyrite Fe: S ≈ 1: 2 Anhedral pyrite
SP
S
Fe
Fe