*5.5.3 Anion concentrations (SO4, Cl, HCO3, NO3, F, Br, and PO4)*

The major anion concentrations from the lake vary in concentrations in the order of -HCO3 > Cl > SO4. The highest concentration of in the LREE range from <0.5 to 5.5 mg/l and 0.0675 to 0.0321 mg/l, respectively, and were observed during

**5.5 Hydrogeochemistry of the Pidong Crater Lake**

**Figure 11.**

*Forecasting Volcanic Eruptions*

**Figure 12.**

**22**

*CAB = D,C, calc-alkaline basalts.*

Comparative hydrogeochemical parameters of previous study [7] and this present study is presented in **Table 5**. It shows clearly that pH and alkalinity have decreased overtime from 9.35 to ≥7.0 and from 335 to 145 mg/l, respectively as well

*Ternary diagram of Ti/100 – Zr – Y\*3 [12] for the volcanic rocks of the Jos Plateau Volcanic province. WPB = D, within plate basalts; OFB = B, ocean flood basalts; LKT = A,B low potassium tholeiitic basalts; and*

*Log Zr (ppm) versus Log (Zr/Y) (ppm) diagram [14] volcanic rocks of the Jos Plateau Volcanic province.*


**Table 5.**

*Comparative hydrogeochemical data of 1986 and the present study.* the dry season (October

9.35 to

**25**

**Figure 14.**

**6. Conclusion**

is worrisome.

(Basement rocks).

residual parent magma.

The increase in the concentrations of SO

coming in contact with meteoric water.

*Is a Volcanic Eruption Possible in Nigeria? DOI: http://dx.doi.org/10.5772/intechopen.84253*

–April). The concentrations of HCO

respectively) as well as the decrease in Alkalinity and pH from 335 to 141.5 mg/l and

relative to SMOW line shows that the Pidong Crater Lake is of meteoric origin.

i. This work presents and affirms the existence of relicts of past volcanic eruptions (dormant volcanoes) in Nigeria (Jos and Biu Plateaux).

ii. That these volcanic edifices were previous eruption sites suggest they are potential eruption sites. The proximity of these volcanic edifices to those of the Cameroon volcanic line, which has witnessed a series of volcanic activity,

iii. The mafic lavas in both the Jos and the Biu Plateaux volcanic provinces display geochemical compositions that are characteristic of alkaline basalts

iv. Petrologically, the basaltic rocks display compositions varying from basalt proper to basanite-tephrite-hawaiite, emplaced within the host crustal rocks

v. The chain of volcanoes evolved from the same basalt parent magma by crystal fractionation each cluster derived by partial melting of the same

4 2 , Cl ( <0.33

≈7.00, respectively. These variations in concentrations suggest a possible input of magmatic/fumaroles percolating upwards to shallow groundwater aquifers

been influenced by interacting percolating water and host rock chemistry.

*Spidergraph of rare earth elements (REEs) of Pidong Lake normalized to Chondrite [20].*

The oxygen and hydrogen isotope composition and plot of

3, Cl and F could have

∂ 2 H

–5. 67 mg/l,

–1.03 and 2.5

∂ 18O and

**Figure 14.** *Spidergraph of rare earth elements (REEs) of Pidong Lake normalized to Chondrite [20].*

the dry season (October–April). The concentrations of HCO3, Cl and F could have been influenced by interacting percolating water and host rock chemistry.

The increase in the concentrations of SO4 <sup>2</sup>, Cl (<0.33–1.03 and 2.5–5. 67 mg/l, respectively) as well as the decrease in Alkalinity and pH from 335 to 141.5 mg/l and 9.35 to ≈7.00, respectively. These variations in concentrations suggest a possible input of magmatic/fumaroles percolating upwards to shallow groundwater aquifers coming in contact with meteoric water.

The oxygen and hydrogen isotope composition and plot of ∂ 18O and ∂ <sup>2</sup> H relative to SMOW line shows that the Pidong Crater Lake is of meteoric origin.
