**4. Field investigations**

Field investigations have revealed the existence of about 22 dormant volcanoes on the Jos Plateau region alone (**Table 1**) and are generally aligned in series of NNW–SSE trend [6–8] (**Figure 2**). None of these volcanoes have record of any activity in recent past [8, 9]. They are composed mainly of basaltic scoria and pyroclastic materials.

**Tables 1** and **2** present the inventory of the dormant volcanoes on the Jos Plateau and the Biu Plateau, respectively. From the NNW end are the Ganawuri volcanic line, Hoss volcanic line, Panyam (Sura) volcanic line and Gu (Jiblik) volcanic line (**Figure 2**). The Ganawuri line comprises from the north to south of the Bum, Jal, and Kwakwi volcanoes. The Hoss volcanic line consists of two volcanoes; Miango in the north and Hoss volcano in the south. The Miango line consists of five volcanoes from the north to the south viz.: Rukuba, Miango north, Miango south, Vom and Kassa volcanoes. The Southern-most end members are namely the Panyam and Gu volcanic lines. The Panyam volcanic line consists of seven volcanoes aligned in a NNE–SSW trending directions along a hypothetical fracture line [6, 10]; Dai volcano (referred to as Wushik volcano), Amshel volcano (referred to as Kugol volcano), Dutsin volcano, Kerang volcano, Tingyaras volcano, Ampang volcano (referred to as Mufil volcano), Pidong Crater Lake.

The Kerang twin volcanoes are located at Kerang town and its environs in the present Mangu Local Government Area, about 120 km from Jos, Plateau State (**Figure 1**). The Kerang I (Dustin) volcano has a peak of 1456 m above sea level and a crater diameter of 300 m. The volcanic pile consists of ash, lapilli, scoria, pumices, *Is a Volcanic Eruption Possible in Nigeria? DOI: http://dx.doi.org/10.5772/intechopen.84253*

Netherlands, Geological Survey Laboratory. For quality control, a duplicate geochemical analysis on the same basaltic rocks was carried out at the University of Cardiff, Wales using the Inductively Coupled Plasma Optical Emission Spectrome-

A constant monitoring of the Pidong Crater Lake through continuous water sampling 24–36 calendar months was done. The following physical parameters were recorded in the field using MT 806/pH/EC/TDS/Temp portable meter (pH, Temperature, Electrical Conductivity (EC), Total Dissolved Solids (TDS)). The water samples were collected in 100 ml polyethylene plastic bottles for cations and anion analysis. The sample for cations analysis was acidified with 0.1 M Nitric acid to prevent precipitating and bacterial growth. The following cations: Mg, Ca, Na, K, Cr, Ni, Co, Sc, V, Cu, Pb, Zn, Bi, Cd, Sn, W, Ma, As, Sb, Rb, Cs, Ba, Sr., Ga, Li, Ta, Nb, Hf, Zr, Y, Th, U, B, Fe & REEs were analyzed using ICP-MS method at Bureau Veritas Minerals Laboratory Limited, Canada while the anions: SO4, Cl, HCO3, NO3, F, Br and PO4 were carried out using colometry method at Maxxam Laboratory,

H), and (∂<sup>3</sup>

of the Pidong Crater Lake, Bwonpe Volcanic Spring and rainfall were analyzed at Activation Laboratory Ontario, Canada using cavity Ring down spectroscopy (CRDS) model L11 02-1 California, USA with V-SMOW standards with typical standards

Field investigations have revealed the existence of about 22 dormant volcanoes on the Jos Plateau region alone (**Table 1**) and are generally aligned in series of NNW–SSE trend [6–8] (**Figure 2**). None of these volcanoes have record of any activity in recent past [8, 9]. They are composed mainly of basaltic scoria and

**Tables 1** and **2** present the inventory of the dormant volcanoes on the Jos Plateau and the Biu Plateau, respectively. From the NNW end are the Ganawuri volcanic line, Hoss volcanic line, Panyam (Sura) volcanic line and Gu (Jiblik) volcanic line (**Figure 2**). The Ganawuri line comprises from the north to south of the Bum, Jal, and Kwakwi volcanoes. The Hoss volcanic line consists of two volcanoes; Miango in the north and Hoss volcano in the south. The Miango line consists of five volcanoes from the north to the south viz.: Rukuba, Miango north, Miango south, Vom and Kassa volcanoes. The Southern-most end members are namely the Panyam and Gu volcanic lines. The Panyam volcanic line consists of seven volcanoes aligned in a NNE–SSW trending directions along a hypothetical fracture line [6, 10]; Dai volcano (referred to as Wushik volcano), Amshel volcano (referred to as Kugol volcano), Dutsin volcano, Kerang volcano, Tingyaras volcano, Ampang

The Kerang twin volcanoes are located at Kerang town and its environs in the present Mangu Local Government Area, about 120 km from Jos, Plateau State (**Figure 1**). The Kerang I (Dustin) volcano has a peak of 1456 m above sea level and a crater diameter of 300 m. The volcanic pile consists of ash, lapilli, scoria, pumices,

H) and Carbon-14 (14C) isotopes

try (ICP-OES).

*Forecasting Volcanic Eruptions*

**3.4 Isotope study**

**4. Field investigations**

pyroclastic materials.

**8**

**3.3 Hydrogeochemical monitoring study**

Vancouver, Canada (subsidiary of Bureau Veritas Ltd).

deviation for 18O 0.1% and 1% for Tritium unit (TU).

volcano (referred to as Mufil volcano), Pidong Crater Lake.

Oxygen-18 (∂18O) and deuterium (∂<sup>2</sup>



#### **Table 1.**

*Inventory of the volcanoes of the Jos Plateau, Nigeria.*

breccias, basalts, boulders, and pyroclastic materials of various sizes. The Kerang II (Kerang) volcano has three craters with a peak height of 1510 m above sea level with a crater diameter ranging from 600 m to 1 km (**Table 1**). This volcano (Kerang II) is the second largest volcano on the Jos Plateau compared to the Jiblik volcano which has a peak height of 1670 m above sea level. The volcanic pile of the Kerang II volcano is composed of ash, lapilli, scoria, breccias, bombs, basaltic boulders and pyroclastic materials (lapilli, granitic and lava flows).

The Pidong volcano (Maar) has a series of three craters and aligned along the general North-South trend of the Panyam Volcanic Line [10]. The Pidong Maar consists of a sequence of pyroclastic materials (mixture of large fragments of basement rocks/pyroclastics, scoria and ash) and indicative of violent eruption [9]. The Gu volcanic line consist of five volcanoes from NW to SW namely Jiblik, Kagu, Katul and Lagdak volcanoes. The volcanic cones are composed essentially of volcanic ash, lapilli, bombs, tuff agglomerates, basalts and scoria. Most of them occur as single cinder cones (like at Miango, Wushik, Kerang Swan junction, etc.) but rarely as clusters of two or more volcanoes (for example Jiblik, Kassa, Kerang twin volcanoes, Pidong, etc.)

Also, the relatively large sizes of some of these volcanoes (Miango, Kassa, Jiblik, Kerang, etc.) suggest that quite a large volume of ejecta materials were spewed out covering quite a large landmass (valleys and low-lying plains) as lava flows. Lava flows apparently from the Jiblik volcanic can be traces to several kilometers south of the Jos Plateau escarpment. If any of these volcanoes erupt today with the same intensity and volume presumed, a large expanse of land would be buried and about 2 million people living around these volcanoes are potentially at risk.

altitude above sea level relative to those of the Jos Plateau, which extruded the

*Geological map of the 22 dormant volcanoes of the Jos Plateau showing sample locations. M = Miango*

by a large volume of volcanic ash and pyroclastic materials (for example, at Gwamya, Tilla Crater Lake, Gadam, Batadeka, Buratai, Katla volcanoes, etc.) (**Table 2**), suggesting that there was a tremendous spewing of ejecta materials (ashes and gases) into the atmosphere prior to the violent eruptions and/or in-

Also, unlike the volcanoes of the Jos Plateau, those of Biu Plateau are constituted

The major and trace elements geochemical compositions of the basaltic rock samples collected from the various volcanic cones in the Jos Plateau volcanic

already high-level Younger Granite bodies.

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

*volcanoes, K = Kassa volcanoes, S = Sura volcanoes, and G = Gu volcanoes.*

**5. Geochemical results and interpretations**

between the eruptions.

**Figure 2.**

**11**

The volcanoes of the Biu Plateau (**Table 2**) present similar physical and petrographic characteristics as those of the Jos Plateau region. The volcanoes also form near linear alignments from the north to the south and extend right through the low-lying Basement complex into the sedimentary formations of the Benue valley (Garkida-Gombi-Song areas in Adamawa State). The volcanoes are simple and never in clusters, but with very large craters of greater than 1 km, (Caldera). The volcanoes extruded directly the basement rocks and therefore are of lower

#### **Figure 2.**

breccias, basalts, boulders, and pyroclastic materials of various sizes. The Kerang II (Kerang) volcano has three craters with a peak height of 1510 m above sea level with a crater diameter ranging from 600 m to 1 km (**Table 1**). This volcano (Kerang II) is the second largest volcano on the Jos Plateau compared to the Jiblik volcano which has a peak height of 1670 m above sea level. The volcanic pile of the Kerang II volcano is composed of ash, lapilli, scoria, breccias, bombs, basaltic

20 Lakdak 7000 cone Scoraceous

The Pidong volcano (Maar) has a series of three craters and aligned along the general North-South trend of the Panyam Volcanic Line [10]. The Pidong Maar consists of a sequence of pyroclastic materials (mixture of large fragments of basement rocks/pyroclastics, scoria and ash) and indicative of violent eruption [9]. The Gu volcanic line consist of five volcanoes from NW to SW namely Jiblik, Kagu, Katul and Lagdak volcanoes. The volcanic cones are composed essentially of volcanic ash, lapilli, bombs, tuff agglomerates, basalts and scoria. Most of them occur as single cinder cones (like at Miango, Wushik, Kerang Swan junction, etc.) but rarely as clusters of two or more volcanoes (for example Jiblik, Kassa, Kerang twin volca-

Also, the relatively large sizes of some of these volcanoes (Miango, Kassa, Jiblik, Kerang, etc.) suggest that quite a large volume of ejecta materials were spewed out covering quite a large landmass (valleys and low-lying plains) as lava flows. Lava flows apparently from the Jiblik volcanic can be traces to several kilometers south of the Jos Plateau escarpment. If any of these volcanoes erupt today with the same intensity and volume presumed, a large expanse of land would be buried and about

The volcanoes of the Biu Plateau (**Table 2**) present similar physical and petrographic characteristics as those of the Jos Plateau region. The volcanoes also form near linear alignments from the north to the south and extend right through the low-lying Basement complex into the sedimentary formations of the Benue valley (Garkida-Gombi-Song areas in Adamawa State). The volcanoes are simple and never in clusters, but with very large craters of greater than 1 km, (Caldera). The volcanoes extruded directly the basement rocks and therefore are of lower

boulders and pyroclastic materials (lapilli, granitic and lava flows).

2 million people living around these volcanoes are potentially at risk.

noes, Pidong, etc.)

**10**

**S. No.**

**Name/ locality**

*Forecasting Volcanic Eruptions*

16 Pidong volcano

17 Jiblik volcano

18 Kagu volcano

19 Katul volcano

**Table 1.**

**Coordinates Estimated**

N09° 17<sup>0</sup> <sup>650</sup>″;E009° <sup>12</sup><sup>0</sup> <sup>312</sup>″

N09° 16<sup>0</sup> <sup>591</sup>″;E009° <sup>16</sup><sup>0</sup> <sup>890</sup>″

N09° 13<sup>0</sup> <sup>901</sup>″; 008° <sup>16</sup><sup>0</sup> <sup>383</sup>″

N09° 11<sup>0</sup> <sup>264</sup>″;E009° <sup>15</sup><sup>0</sup> <sup>795</sup>″

*Inventory of the volcanoes of the Jos Plateau, Nigeria.*

**population of people at risk**

100,000 Cinder

**Type of volcano**

Cone

**Diameter of crater**

50,000 Crater Lake 700 m 1378 m Scoria/

50,000 Cone 1 km 1060 m Scoraceous

5000 Cone 700 m 976 m Scoraceous

**Elevation (ASL)**

1 km 1228 m Scoraceous

**Materials deposited**

pyroclastics

basalt +garnet/ pyroclastics

> basalt/ pyroclastics

> basalt/ pyroclastics

> basalt/ pyroclastics

*Geological map of the 22 dormant volcanoes of the Jos Plateau showing sample locations. M = Miango volcanoes, K = Kassa volcanoes, S = Sura volcanoes, and G = Gu volcanoes.*

altitude above sea level relative to those of the Jos Plateau, which extruded the already high-level Younger Granite bodies.

Also, unlike the volcanoes of the Jos Plateau, those of Biu Plateau are constituted by a large volume of volcanic ash and pyroclastic materials (for example, at Gwamya, Tilla Crater Lake, Gadam, Batadeka, Buratai, Katla volcanoes, etc.) (**Table 2**), suggesting that there was a tremendous spewing of ejecta materials (ashes and gases) into the atmosphere prior to the violent eruptions and/or inbetween the eruptions.

### **5. Geochemical results and interpretations**

The major and trace elements geochemical compositions of the basaltic rock samples collected from the various volcanic cones in the Jos Plateau volcanic


**S/ No.**

**Name/ locality**

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

13 Versu Volcano

14 Dragna Volcano

15 Marama Volcano

16 Gwaram volcanic hill

17 Batadeka (i) Volcanic hill

18 Batadeka (ii) Volcanic hill

19 Kwatla Crater Lake

21 Buratai Volcanic Hill

22 Kona Uku Volcanic hills

23 Dutsen Kura (Bogur) Volcanic hill

24 Kukuwa (Gabai lga Yobe State)

**13**

20 Maldau N10°

**Coordinates Estimated**

E012° 07<sup>0</sup> . <sup>945</sup>″

N10° 39<sup>0</sup> .759″ E012° 08<sup>0</sup> .457″

N10°27<sup>0</sup>

N10° 270 .746″ E012° 090 .093″

N10° 390 .214″ E012° 080 .092″

N10° 410 . <sup>673</sup>″ E012° 070 .707″

N10° 420 . <sup>067</sup>″ E012° 070 .542″

N10° 420 .117″ E012° 060 .433″

430 .500 E012° 060 .979″

N10° 530 .926″ E012° 020 .8000

N10° 490 .814″ E012° 070 .062″

N10° 490 .313″ E012° 050 .978″

N11° 060 .387″ E011° 530 .689″

.132″ E012° 05<sup>0</sup> .820″

**population of people at risk**

**Type of volcano**

> Crater Lake

filled up by collapsed materials.

3000 Seasonal

5000 Caldera

Inhabited Seasonal

10,000 3 Cones

5000 Seasonal

clustered together

> Crater Lake

> Crater Lake

Inhabited Cone 350 m 907 m asl

**Diameter of crater**

150,000 Cone 1 km 735 m Scoraceous

8000 Cone 1 km 942 m Boulders of

3000 Cone 700 m 884 m Weathered

3000 Cone 1 km 1053 m asl Weathered

5000 Dome 700 m 718 m asl Weathered

5000 Plug 200 m 429 m asl Columnar

1.5 km 752 m asl Weathered

2 km 879 m asl Weathered

1.2 km 1011 m asl Weathered

**Elevation (asl)**

700 m 782 m asl Olivine basalt

3 km 750 m asl Weathered

**Materials deposited**

pyroclastic pile

scoraceous basa Basalt

basalt/ pyroclastics

scoriaceous basalt

scoriaceous basalt

scoriaceous basalt

scoriaceous basalt

scoriaceous basalt/ pyroclastics

scoriaceous basalt/ pyroclastics

scoriaceous basalt/ pyroclastics

basalt

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

**S/ No.**

**Name/ locality**

*Forecasting Volcanic Eruptions*

1 Tasha Village

2 After Tasha Village

3 Tagwaye (twin) volcanoes (In Kwaya Kusar LGA of Borno State)

4 Gadam Volcano (Kwayar Kusar LGA, Borno State)

5 Location 5 N10°

6 Location 6 N10° 300

7 TUM N10° 360

8 Wakama (a) (BCG Village)

9 Wakama (b)

10 Gwamya Volcano

11 Tilla Volcanic Hill

12 Tilla Crater Lake

**12**

**Coordinates Estimated**

<sup>388</sup>″ E011° 24<sup>0</sup> <sup>406</sup>″

N10°17<sup>0</sup>

N10° 16<sup>0</sup> .661″ E011° 27<sup>0</sup> .143″

N10° 30<sup>0</sup> .530″ E011° 30<sup>0</sup> .402″

N10° 310 .951″ E011° 530 .485″

320 .876″ E011° 570 .751″

. <sup>279</sup>″ E011° 500 <sup>726</sup>″

. 2540 E012° 060 <sup>564</sup>″

N10° 360 .4720 E012° 070 <sup>126</sup>″

N10° 370

N10° 330 .496″ E012° 060 .

<sup>341</sup>″

N10° 320 .549″ E012° 080 .477″

N10° 320 .336″

.2110 E012° 080 <sup>886</sup>″

**population of people at risk**

**Type of volcano**

5000 Cluster of 3 volcanic cones.

**Diameter of crater**

5000 Dome 427 m Massive/

15,000 2 Cones 200 m 512 m Olivine

30,000 Cone 250 m 479 m. asl Olivine Basalt

Inhabited Plug 683 m Basaltic

Inhabited Dome 826 m Vesicular

10,000 Dome 643 m asl Scoraceous

2500 Cone 1 km 677 m Scoraceous

2500 Caldera 10 km 701 m Scoraceous

6000 Cone 500 m 752 m Scoraceous

2500 Cone 500 m 910 m Scoraceous

10,000 Caldera 2 km 751 m Scoraceous

**Elevation (asl)**

50 m 426 m asl Massive

**Materials deposited**

basaltic rocks

vesicular basaltic rocks

basalts/ Agglomerates.

boulders/ Agglomerates/ tuff

Basaltic boulders/ Agglomerates/ tuff

> basalt with olivine/ zeolite/ Columnar basalt.

> > basalt

basalt

basalt/ pyroclastic pile

basalt/ pyroclastic pile

basalt/



**Table 2.**

*Inventory of the volcanoes of the Biu Plateau, Nigeria.*

province are presented in **Tables 3** and **4**. The volcanic cones situated at the northern end of the volcanic line here referred to as the north-western group are represented by Miango (M1 & M2) and Kassa (K1–5), while the south-eastern end group are represented by Jiblik (G1 &G2), Tingyaras (S1), Ampang (S2), Pidong (S3), Wulshik (S4), Kugol (S5) and Kerang (S6).

The rocks display similar SiO2 wt% contents (44.84–50.06 wt%) for the northwestern group of volcanoes (M1&2 and K1–5) and 45.26–46.25 wt% for S1–6 and 49.69 wt% for the Jiblik volcano (G1). However, the sample G2 from Jiblik with high SiO2 content of 64.21 wt% is exceptionally acidic and does not seem to be a basalt. Many of the rocks from the Kassa volcanoes (K1, K3, K4, and K5) display the highest SiO2 content (46.99–50.06 wt%) as opposed to those from Miango volcanoes (M1 &M2) and the southern volcanoes (S1–6) whose SiO2 contents are typical of a normal basalt (45.26–46.25 wt%).The Miango and the Kassa volcanoes display higher Fe2O3 contents (12.33–12.61 and 10.42–11.35 wt% respectively). The southern group (G1 & S1–6) displays lower Fe2O3 content; 9.83 wt% for the Jiblik volcano (G1); and a relatively higher but similar concentrations of between 11.25 and 11.92 wt% for the Panyam Volcanic line members (S1–6).

In general, the Al2O3 contents of all the basalts from the different volcanic cones are significantly high but vary narrowly inter/intra the volcanic cones (13.87–18.07 wt % for the north-western group and 12.41–18.07 wt% for the southern group (G1 & S1–6)). In terms of the MgO content, the southern group (S1–6) presents relatively higher values of between 10.71 and 12.58 wt% as against an average of 8.00 wt% for the northern group (M1–2 & K1–5). The CaO, Na2O, K2O and TiO2 contents for all the volcanoes vary narrowly; averagely 8; 3; 1.5 and 2 wt%, respectively.

Their Al2O3/TiO2 ratios vary narrowly and could be on that basis be subdivided into two groups; those with ratios between 5.53 and 5.69 and then those between 6.39 and 6.62 for the entire volcanic line (N-S) (**Figure 3**). This is further a

**Analyte symbol**

**15**

**SiO2**

**Al**

**O2 3**

**Fe**

**O2 3**

**MnO**

**MgO**

**CaO**

**Na**

**O2**

**K**

**O2**

**TiO2**

**P O2 5**

**LOI**

**Total**

**Al**

**O2 3/**

**CaO/**

**Al2O3/**

**(%)**

44.84

43.80

49.69

64.21

44.97

44.77

45.75

46.99

50.06

48.02

47.49

47.05

45.26

44.77

46.27

 13.02

 11.25

 0.163

 11.24

 9.21

 3.51

 1.69

 2.262

 0.69

 0.23

 99.35

 5.76

 4.07

 1.41

 12.82

 11.40

 0.166

 11.50

 9.58

 2.83

 1.65

 2.318

 0.61

 1.08

 98.73

 5.53

 4.13

 1.34

 13.52

 11.34

 0.162

 10.71

 9.47

 3.28

 1.70

 2.397

 0.62

 0.32

 98.78

 5.64

 3.95

 1.43

 13.87

 11.28

 0.160

 8.17

 9.36

 3.55

 1.59

 2.17

 0.64

 0.67

 98.52

 6.39

 4.31

 1.48

 14.17

 11.35

 0.167

 7.81

 9.29

 3.82

 1.58

 2.211

 0.64

 0.20

 98.74

 6.41

 4.20

 1.53

 18.07

 10.42

 0.164

 3.30

 7.74

 5.28

 2.80

 2.516

 0.84

 0.12

 99.27

 7.18

 3.08

 2.33

 14.23

 10.83

 0.149

 7.16

 8.9

 3.50

 1.22

 2.158

 0.37

<0.01

 98.57

 6.59

 4.12

 1.60

 13.99

 11.36

 0.630

 8.36

 9.47

 3.74

 1.53

 2.176

 0.60

 0.52

 98.95

 6.43

 4.35

 1.48

 16.00

 11.92

 0.161

 6.34

 8.16

 3.58

 2.21

 2.849

 0.70

 0.99

 98.66

 6.62

 2.86

 1.96

 12.48

 11.34

 0.165

 12.74

 9.39

 2.96

 1.50

 2.194

 0.57

 0.47

 98.58

 5.69

 4.28

 1.33

 12.41

 11.51

 0.166

 12.85

 9.43

 3.13

 1.62

 2.213

 0.59

 0.03

 98.92

 5.61

 4.26

 1.32

 14.74

 5.60

 0.087

 2.37

 3.91

 3.29

 3.54

 1.124

 0.43

 0.96

 100.3

 13.11

 3.48

 3.77

 14.90

 9.83

 0.142

 8.10

 7.07

 3.34

 1.70

 1.659

 0.47

 1.33

 98.81

 9.03

 4.26

 2.11

 15.01

 12.61

 0.166

 8.54

 8.32

 3.40

 1.87

 2.727

 0.74

 1.5

 98.68

 5.50

 3.05

 1.80

 15.02

 12.33

 0.166

 8.50

 8.86

 4.09

 1.88

 2.668

 0.76

<0.01

 98.83

 5.63

 3.32

 1.70

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

**(%)**

**(%)**

**(%)**

**(%)**

**(%)**

**(%)**

**(%)**

**(%)**

**(%)**

**(%)**

**(%)**

**TiO2**

**TiO2**

**CaO**

**unit**

M1 M2 G1 G2

S1 S2 S3 K1 K2 K3 K4 K5 S4 S5 S6 **Table 3.** *Major element* 

*compositions*

 *(in weight percentage)*

 *of volcanic rocks from the Jos Plateau Volcanic Province.*

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


**Table 3.**

*Major element compositions (in weight percentage) of volcanic rocks from the Jos Plateau Volcanic Province.*

province are presented in **Tables 3** and

*Inventory of the volcanoes of the Biu Plateau, Nigeria.*

The rocks display similar SiO

<sup>2</sup> content (46.99

<sup>3</sup> contents (12.33

2 O

% for the north-western group and 12.41

highest SiO

**S/ No.**

**Name/ locality**

*Forecasting Volcanic Eruptions*

26 Kurara Volcanic Hill (Garkida junction Adamawa State)

27 Song (Song-Gombi Road)

28 Song (Hawul Mountains)

**Table 2.**

25 Kukuwa II N11° 06

**Coordinates Estimated**

0 . 443 ″ E011° 53 0 . 534 ″

N10° 22 0 .460 ″ E012° 34 0 .284 ″

N9° 51 0 .036 ″ E012° 36 0 .383 ″

N9° 49 0 .504 ″ E012° 370 .155 ″

**population of people at risk**

**Type of volcano**

Plugs

5000 Several

**Diameter of crater**

50,000 Cone 1 km 661 m asl Weathered

50,000 Cone 700 m 477 m Weathered

250 m each

**Elevation (asl)**

200 m 435 m asl Columnar

**Materials deposited**

basalt

scoriaceous basalt/ pyroclastics

scoriaceous basalt/ pyroclastics

Weathered scoriaceous basalt/ pyroclastics

higher Fe

S1

**14**

of a normal basalt (45.26

In general, the Al

the northern group (M1

Their Al 2 O 3/TiO

2 O

represented by Miango (M1 & M2) and Kassa (K1

(S3), Wulshik (S4), Kugol (S5) and Kerang (S6).

**4**. The volcanic cones situated at the

–50.06 wt%) as opposed to those from Miango volca-

–46.25 wt%).The Miango and the Kassa volcanoes display

<sup>3</sup> contents of all the basalts from the different volcanic cones

2O, K

<sup>2</sup> ratios vary narrowly and could be on that basis be subdivided

–5), while the south-eastern end

420-1000 m asl

–11.35 wt% respectively). The south-

–6).

–18.07 wt% for the southern group (G1 &

2O and TiO

–50.06 wt%) for the north-

–6) presents relatively

<sup>2</sup> contents for all

northern end of the volcanic line here referred to as the north-western group are

10,000 4

different cones aligned N-S

group are represented by Jiblik (G1 &G2), Tingyaras (S1), Ampang (S2), Pidong

western group of volcanoes (M1&2 and K1–5) and 45.26–46.25 wt% for S1–6 and 49.69 wt% for the Jiblik volcano (G1). However, the sample G2 from Jiblik with high SiO2 content of 64.21 wt% is exceptionally acidic and does not seem to be a basalt. Many of the rocks from the Kassa volcanoes (K1, K3, K4, and K5) display the

noes (M1 &M2) and the southern volcanoes (S1–6) whose SiO2 contents are typical

are significantly high but vary narrowly inter/intra the volcanic cones (13.87–18.07 wt

higher values of between 10.71 and 12.58 wt% as against an average of 8.00 wt% for

–5). The CaO, Na

into two groups; those with ratios between 5.53 and 5.69 and then those between 6.39 and 6.62 for the entire volcanic line (N-S) (**Figure 3**). This is further a

the volcanoes vary narrowly; averagely 8; 3; 1.5 and 2 wt%, respectively.

–12.61 and 10.42

and 11.92 wt% for the Panyam Volcanic line members (S1

–6)). In terms of the MgO content, the southern group (S1

–2 & K1

ern group (G1 & S1–6) displays lower Fe2O3 content; 9.83 wt% for the Jiblik volcano (G1); and a relatively higher but similar concentrations of between 11.25

<sup>2</sup> wt% contents (44.84


*Southeastern volcanoes: G1—basalt of Jiblik volcano; S1—basalt of Timjagha'as volcano; S2—basalt of Ampang volcano; S3—basalt of Pidong volcano; S4—basalt of Wushik volcano; S5—basalt of Kogul volcano; S6—basalt of Kerang volcano. Northwestern volcanoes: M1—basalt of Miango North volcano; M2—basalt of Miango South volcano; K1—basalt of Kassa volcano; K2—basalt of Kassa volcano; K3—basalt of Kassa volcano; K4—basalt of Kassa volcano; K5—basalt of Kassa volcano.*

#### **Table 4.**

*Trace elements compositions (in ppm) of the basaltic rocks from the Jos Plateau Volcanic Province.*

reflection of the variations in Al2O3 contents of the basalts since TiO2 contents remain relatively constant. Similarly, their CaO/TiO2 and Al2O3/CaO ratios vary from 2.6 to 4.31 and 1.34–1.60 respectively. Such narrow difference in these ratios is expected from a low degree of magmatic differentiation of the same parent material by partial melting process (**Figures 3** and **4**).

Similarly, the rocks present subtle variations in incompatible element ratios Ba/Sr. and Zr/Y (0.73–0.90 and 8.77–9.35, respectively); all supportive of their subjection to low degree of magmatic differentiation and/or similar source.

#### **5.1 Silica versus major oxides correlation plots**

In the SiO2 versus MgO wt% plot, the southern volcanoes overwhelmingly display higher MgO contents as opposed to the lower values for the northern group of volcanoes (**Figure 5c**). It is expected that the Kassa volcanoes (K1–5) which are more differentiated (by their higher SiO2 contents) than the others to present lower MgO contents but instead display similar MgO contents. This scenario is true of their Fe2O3 contents. However, there is a weak negative correlation between Fe2O3, MgO, TiO2 and MnO versus silica indicating a progressive decrease of these oxides with differentiation (Miango-Southern group-Kassa) corresponding to compositional variations related to the removal of different proportions of olivine/pyroxenes from the melt as it becomes more felsic (**Figure 6a–d**).

recrystallization of clinopyroxenes in the early stages of crystallization. In general, there is a positive correlation depicting a progressive increase of CaO with differentiation from Miango to the southern group to Kassa (**Figure 5a–f**). This increase is not visible at the level of one volcano but several of them put together. The high Fe2O3, MgO and CaO could be as a result of the bulk crystallization of olivine, pyroxene and plagioclase during the early stages of differentiation. The progressive increase in the contents of Al2O3 corresponds with the increase in the alkaline metals content (Na2O+K2O) suggesting the crystallization of plagioclase with increased degree of differentiation. The alkaline oxides (Na2O+K2O) are correspondingly highest in the most differentiated rocks (K1–5) (**Figure 6d**). In a silica versus total alkali diagram (**Figure 7**), the rocks fall within the alkaline field and are therefore classified as predominantly alkaline basalts. Only a few rocks fall in the

**Figure 4.**

**17**

**Figure 3.**

*Plot of SiO2 versus Al2O3/TiO2 ratios.*

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

*Plot of SiO2 versus Al2O3/CaO ratios.*

The Kassa volcanoes in the northern group and those of the southern group exhibit higher CaO contents compared to lower CaO values at Miango (M1&M2) and also of the northern group. The observed high CaO content suggest the

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

**Figure 3.** *Plot of SiO2 versus Al2O3/TiO2 ratios.*

recrystallization of clinopyroxenes in the early stages of crystallization. In general, there is a positive correlation depicting a progressive increase of CaO with differentiation from Miango to the southern group to Kassa (**Figure 5a–f**). This increase is not visible at the level of one volcano but several of them put together. The high Fe2O3, MgO and CaO could be as a result of the bulk crystallization of olivine, pyroxene and plagioclase during the early stages of differentiation. The progressive increase in the contents of Al2O3 corresponds with the increase in the alkaline metals content (Na2O+K2O) suggesting the crystallization of plagioclase with increased degree of differentiation. The alkaline oxides (Na2O+K2O) are correspondingly highest in the most differentiated rocks (K1–5) (**Figure 6d**). In a silica versus total alkali diagram (**Figure 7**), the rocks fall within the alkaline field and are therefore classified as predominantly alkaline basalts. Only a few rocks fall in the

reflection of the variations in Al2O3 contents of the basalts since TiO2 contents remain relatively constant. Similarly, their CaO/TiO2 and Al2O3/CaO ratios vary from 2.6 to 4.31 and 1.34–1.60 respectively. Such narrow difference in these ratios is expected from a low degree of magmatic differentiation of the same parent material

*Trace elements compositions (in ppm) of the basaltic rocks from the Jos Plateau Volcanic Province.*

Similarly, the rocks present subtle variations in incompatible element ratios Ba/Sr. and Zr/Y (0.73–0.90 and 8.77–9.35, respectively); all supportive of their subjection to

**Ba ppm SR ppm Y ppm Sc ppm Zr ppm Be ppm V ppm Ba/Sr Zr/Y**

M1 619 840 25 19 234 2 161 0.74 9.36 M2 865 799 26 19 239 2 153 1.08 9.19 G1 518 637 18 15 205 2 122 0.81 11.39 G2 1215 723 26 12 328 3 121 1.68 12.62 S1 530 654 22 23 193 2 185 0.81 8.77 S2 554 646 21 22 190 2 178 0.86 9.05 S3 794 1098 24 15 228 2 174 0.72 12.00 K1 571 782 25 18 177 2 161 0.73 7.08 K2 551 460 43 20 155 2 171 1.20 3.06 K3 820 983 26 7 258 3 155 0.83 9.92 K4 672 758 38 19 176 2 164 0.89 4.63 K5 523 1095 24 18 177 2 157 0.48 7.36 S4 569 748 23 21 212 2 178 0.76 9.22 S5 585 697 23 23 204 2 180 0.84 8.84 S6 688 766 23 20 215 2 172 0.90 9.35 *Southeastern volcanoes: G1—basalt of Jiblik volcano; S1—basalt of Timjagha'as volcano; S2—basalt of Ampang volcano; S3—basalt of Pidong volcano; S4—basalt of Wushik volcano; S5—basalt of Kogul volcano; S6—basalt of Kerang volcano. Northwestern volcanoes: M1—basalt of Miango North volcano; M2—basalt of Miango South volcano; K1—basalt of Kassa volcano; K2—basalt of Kassa volcano; K3—basalt of Kassa volcano; K4—basalt of Kassa volcano; K5—basalt*

In the SiO2 versus MgO wt% plot, the southern volcanoes overwhelmingly display higher MgO contents as opposed to the lower values for the northern group of volcanoes (**Figure 5c**). It is expected that the Kassa volcanoes (K1–5) which are more differentiated (by their higher SiO2 contents) than the others to present lower MgO contents but instead display similar MgO contents. This scenario is true of their Fe2O3 contents. However, there is a weak negative correlation between Fe2O3, MgO, TiO2 and MnO versus silica indicating a progressive decrease of these oxides with differentiation (Miango-Southern group-Kassa) corresponding to compositional variations related to the removal of different proportions of olivine/pyrox-

The Kassa volcanoes in the northern group and those of the southern group exhibit higher CaO contents compared to lower CaO values at Miango (M1&M2) and also of the northern group. The observed high CaO content suggest the

by partial melting process (**Figures 3** and **4**).

**Analyte symbol unit**

*Forecasting Volcanic Eruptions*

*of Kassa volcano.*

**Table 4.**

**16**

**5.1 Silica versus major oxides correlation plots**

low degree of magmatic differentiation and/or similar source.

enes from the melt as it becomes more felsic (**Figure 6a–d**).

**Figure 5.** *(a–f) Plots of SiO2 versus major oxides of the volcanic rocks of the Jos Plateau Volcanic Province.province.*

sub-alkaline field which could be of tholeiitic character (high silica and Fe Contents). Furthermore, in a log (Zr/TiO2) versus SiO2 diagram (**Figure 8**), the bulk of the rocks fall in the alkaline field reaffirming their alkaline nature (**Figure 9**).

In respect to their Mg#, it varies very narrowly within the individual volcano signifying a subtle degree of differentiation (partial melting) and thus reflecting a low degree of magmatic differentiation and the consequent subtle compositional variations observed. However, for the entire volcanoes put together, the Mg# vary significantly from 27 to 56 suggesting formation of the rocks by fractional crystallization at larger scale. The southern volcanoes (S1–6) have the highest Mg# relative to those of the northern group (K1–5 and M1 & M2) (**Figure 10a–d**). When the rocks are plotted in Mg# versus Fe2O3 diagram (**Figure 10b**), a positive correlation is obtained indicating a progressive decrease in Fe2O3 with increasing degree of magmatic differentiation. The relatively similar Ba/Sr. and Zr/Y ratios for these rocks but with progressive decrease in Mg# lends credence to their derivation from

the same magma reservoir by differentiation. It appears that the rocks with the highest Mg# (samples S1–6) present compositions that are close to that of the parent materials since the magma did not suffer high degree of differentiation giving rise to a variety of rocks. The subtle variation of Mg# and the incompatible

*Silica versus Total Alkali diagram [11] of the volcanic rocks of the Jos Plateau (Alk = alkaline and*

*(a–d) Plots of SiO2 versus major oxides of the volcanic rocks of the Jos Plateau Volcanic Province.*

**Figure 6.**

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

**Figure 7.**

**19**

*Subalk = subalkaline).*

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

**Figure 7.**

sub-alkaline field which could be of tholeiitic character (high silica and Fe Contents). Furthermore, in a log (Zr/TiO2) versus SiO2 diagram (**Figure 8**), the bulk of the rocks fall in the alkaline field reaffirming their alkaline nature (**Figure 9**). In respect to their Mg#, it varies very narrowly within the individual volcano signifying a subtle degree of differentiation (partial melting) and thus reflecting a low degree of magmatic differentiation and the consequent subtle compositional variations observed. However, for the entire volcanoes put together, the Mg# vary significantly from 27 to 56 suggesting formation of the rocks by fractional crystallization at larger scale. The southern volcanoes (S1–6) have the highest Mg# relative to those of the northern group (K1–5 and M1 & M2) (**Figure 10a–d**). When the rocks are plotted in Mg# versus Fe2O3 diagram (**Figure 10b**), a positive correlation is obtained indicating a progressive decrease in Fe2O3 with increasing degree of magmatic differentiation. The relatively similar Ba/Sr. and Zr/Y ratios for these rocks but with progressive decrease in Mg# lends credence to their derivation from

*(a–f) Plots of SiO2 versus major oxides of the volcanic rocks of the Jos Plateau Volcanic Province.province.*

**Figure 5.**

*Forecasting Volcanic Eruptions*

**18**

*Silica versus Total Alkali diagram [11] of the volcanic rocks of the Jos Plateau (Alk = alkaline and Subalk = subalkaline).*

the same magma reservoir by differentiation. It appears that the rocks with the highest Mg# (samples S1–6) present compositions that are close to that of the parent materials since the magma did not suffer high degree of differentiation giving rise to a variety of rocks. The subtle variation of Mg# and the incompatible

*Plot of Log (Zr/TiO2) ratio versus SiO2 [12] of the volcanic rocks of Jos Plateau Volcanic province (Sub-AB = subalkaline basalts, AB = alkaline basalts).*

element ratios highlighted above are supportive of the derivation of these basalts by

*(a–d) Plot of some selected major oxides versus Mg# for the volcanic rocks of the Jos Plateau volcanic province.*

The geochemical data plotted in the ternary diagram of Ti/100-Zr-Y\*3 [12] show clearly that they were majorly emplaced within the continental crust (**Figures 11** and **12**). This fact distinct these basalts from those of the Island arc and the Mid Oceanic Ridge.

The incompatible elements when plotted in a spidergraph normalized to Chondrites in comparison with OIB (**Figure 13**) display a relatively similar pattern with slight enrichment in their incompatible elements. These characteristic features are typical of most alkali basaltic suites derived from a deeper mantle source akin to that

A sample by sample result is presented in **Table 5**. The Ar/Ar ages span between 1.3 and 2.5 Ma, confirm the earlier K-Ar ages of 2.1 and 1.9 0.31 Ma reported by [1] on dolerites on the Jos Plateau. The short interval in the radiometric ages suggests volcanic eruptions occurred at discrete times, separated by short periods of

non-activity at a mean age average of 0.55 Ma (CN3 = 2.500 0.318 Ma and CN5 = 1.970 0.173 Ma). This long period must have been dominated by profound erosion. The considerable long-time difference from the oldest to the youngest eruption suggests that there was relatively steady magma source overtime.

partial melting process of a magma from the same source.

**5.2 Tectonic environment of emplacement**

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

**5.3 Incompatible elements spidergraph**

of the OIB [12, 14, 16–19].

**5.4 Ar40-Ar39 dating**

**21**

**Figure 10.**

**Figure 9.** *SiO2 versus Na2O+K2O classification diagram of basalts of the Jos Plateau volcanoes [13].*

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

**Figure 10.** *(a–d) Plot of some selected major oxides versus Mg# for the volcanic rocks of the Jos Plateau volcanic province.*

element ratios highlighted above are supportive of the derivation of these basalts by partial melting process of a magma from the same source.

#### **5.2 Tectonic environment of emplacement**

The geochemical data plotted in the ternary diagram of Ti/100-Zr-Y\*3 [12] show clearly that they were majorly emplaced within the continental crust (**Figures 11** and **12**). This fact distinct these basalts from those of the Island arc and the Mid Oceanic Ridge.

#### **5.3 Incompatible elements spidergraph**

The incompatible elements when plotted in a spidergraph normalized to Chondrites in comparison with OIB (**Figure 13**) display a relatively similar pattern with slight enrichment in their incompatible elements. These characteristic features are typical of most alkali basaltic suites derived from a deeper mantle source akin to that of the OIB [12, 14, 16–19].
