Ionic Ratio

Wet

Wetdry

Dry

Drywet

Interpretation

SO/Cl

0- 0.24

0 - 0.61

0.01 - 0.31

0 - 0.18

Sulphate reduction and suggests additional sources of Sulphate

Na/Cl

0 - 0.10

0 - 0.10

0 - 0.29

0 - 0.13

No Na-adsorption during freshening and absence of marine water.

Mg/Cl

0 - 2.0

0 - 4.87

0.02 - 2.70

0 - 4.12

Depict a cation-exchange and silicate weathering environment

Na/HCO

0 - 0.48

0 - 0.35

0 - 0.04

0 - 0.90

Low weathering of Na-feldspar or other Na-silicates.

Ca/HCO

0 - 22.80

0 - 12.62

0 - 1.66

0 - 78.82

Ca-silicate weathering from country rocks

Ca/SO

0 - 90.16

0 - 17.68

0 - 423.55

0 - 335.00

There is no gypsum dissolution in volcanic regions

Ca/Mg

0 - 8.98

0 - 52.20

0 - 49.36

0 - 366.67

Typical of coastal regions due to cation-exchange

Mg/Ca

0 - 524.17

0 - 50.33

0 - 13.72

0 - 48.94

Silicate weathering

(Ca + Mg)/(Na + K)

0 - 0.11

0 - 0.14

0 - 0.19

0 - 0.12

Occurrence of silicate weathering over carbonate weathering.

${\text{HCO}}_3^{-}$ /∑Anions

0 - 0.01

0 - 0.01

0 - 0.02

0 - 0.01

Rainwater

NO₃/∑Anions

0 - 0.01

0 - 0.02

0 - 0.01

0 - −0.01

No anthropogenicactivities.

SO₄/∑Anions

0 - 1.0

0 - 0.95

0.12 - 0.99

0 - 0.99

No oxidation of sulphides.

Cl⁻/∑Anions

−10.26 - 31.53

−4.51 - 2.02

−21.11 - 11.76

−11.12 - 1.88

Rock weathering and rainwater; increase in Wet, deplete in DryWet season

$\frac{{\text{Na}}^{+}+{\text{K}}^{+}-{\text{Cl}}^{-}}{{\text{Na}}^{+}+{\text{K}}^{+}-{\text{Cl}}^{-}+{\text{Ca}}^{2+}}$

0 - 0.09

0 - 1.0

0 - 0.22

0 - 1.0

Some plagioclase weathering in all seasons except Wet season

$\frac{{\text{Na}}^{+}}{{\text{Na}}^{+}+{\text{Cl}}^{-}}$

0 - 0.42

0.02 - 1.0

0.02 - 0.60

0 - 1.0

Sodium source other than halite-albite, ion exchange and rainwater

$\frac{{\text{Mg}}^{2+}}{{\text{Ca}}^{2+}+{\text{Mg}}^{2+}}$

0 - 1.0

0 - 1.0

0.90 - 1.0

0 - 1.0

Silicate weathering of ferromagnesian minerals but no evidence of granitic weathering

$\frac{{\text{Ca}}^{2+}}{{\text{Ca}}^{2+}+{\text{SO}}_4{}^{2-}}$

0 - 3316.02

0 - 439.35

18.13 - 3489.27

0 - 4876.00

Ion exchange/Calcium removal and Calcium source from silicates

$\frac{{\text{Ca}}^{2+}+{\text{Mg}}^{2+}}{{\text{SO}}_4{}^{2-}}$

0 - 0.71

0 - 2.40

0.02 - 1.48

0 - 1.68

No dolomite at all, Dedolomitization