Statistical evaluation of stream sediment geochemical data from Tchangue-Bikoui drainage system, Southern Cameroon: a regional perspective

Figures & data

Figure 1. (a) Location map of the study area, Southern Cameroon. (b) Drainage system of the Southern Cameroon. Various streams or tributaries flowing within this basin drain into the Lokoundje River, a major river that drains into the atlantic ocean. The area of study within this basin is the Tchangue-Bikoui drainage system. (c) Sample location map within the Tchangue-Bikoui drainage system. In all 50 samples were collected from active stream sediments.

Figure 2. Lithostructural map of Cameroon (modified from Caron et al., 2010) showing the major structural domains in Cameroon. Red box shows the location of the Tchangue-Bikoui drainage system within the Nyong Paleoproterozoic series, Southern Cameroon.

Figure 3. Graduated symbol plot for visible Au by panning and weighing technique (g/t) superimposed on the drainage map of the Tchangue – Bikoui drainage area, South Cameroon. Large red bubbles indicate locations with elevated Au content.

Table 1. Basic statistical parameters for stream sediment geochemical data obtained from the study area

Element	No	Range	Min	Max	Mode	Median	Mean	Std.D	Skewness	Kurtosis
Au	16	3.90	0.10	4.00	1.00	1.00	1.44	1.30	0.97	−0.01
Ag	16	0.64	0.00	0.64	0.00	0.04	0.09	0.15	3.41	12.54
As	20	143.97	0.03	144.00	0.50	24.00	37.23	45.66	1.26	0.65
Ba	20	176.00	11.00	187.00	23.00	33.50	53.10	54.43	1.88	2.25
Co	19	58.00	28.00	86.00	40.00	52.00	54.79	18.32	0.12	−1.23
Cu	20	98.00	37.00	135.00	37.00	72.00	75.05	35.42	0.31	−1.54
Cr	20	396.00	14.00	410.00	33.00	42.00	169.35	161.63	0.43	−1.79
Hg	19	3.00	0.00	3.00	0.02	0.20	0.75	1.02	1.37	0.71
Ni	20	275.00	12.00	287.00	12.00	133.50	143.00	99.08	0.10	−1.44
Y	20	45.00	7.00	52.00	23.00	27.50	27.60	10.22	0.26	0.95
Zr	20	31.00	4.00	35.00	23.00	23.50	23.00	8.58	−0.99	0.95
V	20	257.00	25.00	282.00	27.00	141.50	148.95	107.51	0.02	−2.03
Sc	20	43.00	4.00	47.00	37.00	34.50	28.55	15.37	−0.68	−1.26
Sr	20	291.00	6.00	297.00	7.00	105.00	103.15	86.98	0.94	0.78
Rb	20	14.00	1.00	15.00	1.00	3.50	5.05	4.35	1.18	0.26
Hf	20	7.00	1.00	8.00	1.00	3.00	3.65	2.28	0.48	−1.10
Zn	20	139.00	25.00	164.00	78.00	101.50	100.75	45.29	−0.31	−1.01
Sb	20	2.00	0.00	2.00	0.10	0.30	0.44	0.46	2.19	6.03
Mo	20	6.80	0.20	7.00	3.00	1.50	2.30	2.06	0.87	−0.16

Table 2. Pearson’s linear correlation coefficient matrix derived from stream sediment samples

	Au	Ag	As	Ba	Co	Cu	Cr	Hg	Ni	Y	Zr	V	Sc	Sr	Rb	Hf	Zn	Sb	Mo	Pb
Au	1.00	0.18	−0.55	−0.08	0.06	−0.07	−0.07	−0.05	0.22	−0.19	−0.10	0.33	−0.24	0.45	0.26	0.01	0.16	−0.23	−0.09	0.00
Ag		1.00	0.18	−0.20	0.41	0.19	−0.02	−0.04	0.11	0.31	−0.12	−0.32	−0.15	−0.26	−0.27	0.43	0.16	−0.20	0.19	0.28
As			1.00	0.01	−0.15	−0.12	−0.04	0.24	−0.35	0.16	0.19	−0.51	−0.01	−0.40	−0.16	0.03	−0.05	−0.04	0.45	0.37
Ba				1.00	0.05	−0.03	0.16	0.33	−0.21	−0.12	−0.12	−0.07	−0.50	−0.13	0.26	0.28	0.23	0.26	0.13	−0.20
Co					1.00	0.22	−0.31	−0.15	−0.09	0.41	−0.06	−0.05	−0.23	−0.08	0.15	0.34	0.14	−0.09	0.06	0.22
Cu						1.00	0.35	−0.16	0.27	0.33	0.04	−0.11	0.05	−0.14	−0.17	0.16	−0.04	−0.01	−0.33	0.01
Cr							1.00	−0.16	0.19	0.26	0.34	0.03	0.18	−0.03	−0.11	0.19	0.19	0.12	0.20	−0.14
Hg								1.00	0.00	−0.26	−0.14	0.15	0.02	0.10	0.26	−0.05	0.38	−0.08	−0.01	−0.15
Ni									1.00	−0.28	−0.14	0.35	0.18	−0.05	−0.39	0.07	0.31	−0.08	−0.25	0.15
Y										1.00	0.51	−0.18	0.14	−0.16	0.19	0.39	0.02	0.05	0.35	0.12
Zr											1.00	0.22	0.37	0.08	0.31	0.12	−0.02	−0.12	0.58	−0.02
V												1.00	0.37	0.41	0.43	−0.20	0.09	0.15	−0.02	−0.03
Sc													1.00	0.30	0.01	−0.24	0.04	0.01	−0.02	−0.17
Sr														1.00	0.70	−0.21	0.27	0.19	−0.06	−0.23
Rb															1.00	0.02	0.23	0.30	0.24	−0.11
Hf																1.00	0.17	0.27	0.45	0.17
Zn																	1.00	−0.22	−0.06	−0.28
Sb																		1.00	0.17	0.15
Mo																			1.00	0.51
Pb																				1.00

Table 3. Main factors (sum of squares of loadings >1) loading, communalities, explained variance and proportion of total variance for stream sediment samples from the Tchangue-Bikoui drainage system, South Cameroon

	Factor 1	Factor 2	Factor 3	Factor 4	Factor 5	Communalities
Sums of Squared Loadings	4.387	3.341	2.726	2.676	2.463
Rotated factor loadings
Component
Au	−0.282	0.822	0.201	−0.138	−0.183	0.848
Ag	0.711	−0.042	−0.228	−0.085	0.053	0.570
As	0.637	−0.345	−0.122	−0.090	0.164	0.574
Ba	−0.019	0.210	0.913	0.192	−0.029	0.915
Co	−0.409	0.084	0.402	0.483	0.032	0.571
Cu	0.192	−0.052	0.194	0.001	0.701	0.569
Cr	0.872	0.165	−0.048	0.004	0.206	0.833
Hg	−0.209	−0.100	0.589	0.185	−0.534	0.719
Ni	0.086	0.929	−0.251	−0.021	0.111	0.947
Y	0.393	−0.446	−0.105	0.586	−0.117	0.721
Zr	0.452	0.065	−0.107	0.726	0.208	0.790
V	−0.399	0.702	0.084	0.494	0.223	0.953
Sc	0.192	0.223	−0.797	0.447	0.006	0.921
Sr	−0.341	0.434	−0.593	0.188	−0.120	0.706
Rb	−0.271	−0.159	0.030	0.881	−0.275	0.951
Hf	0.776	−0.028	0.311	−0.049	−0.119	0.717
Zn	0.267	0.358	0.075	0.203	−0.672	0.697
Sb	−0.305	−0.697	0.128	0.293	0.339	0.797
Mo	0.917	−0.087	−0.038	0.274	0.086	0.933
Pb	0.163	0.089	−0.193	0.085	0.885	0.862
Explained variance	21.934	16.705	13.630	13.381	12.316
Proportion of total variance	21.934	38.638	52.269	65.650	77.966

Figure 4. Graduated symbol plot for (a) Au (ppb), (b) Ni (ppm), (c) V (ppm) and (d) Sr (ppm) superimposed on the drainage map of the Tchangue – Bikoui drainage area, South Cameroon. High positive scores (large bubbles) indicate locations with anomalous concentrations.

Figure 5. Graduated symbol plot for (a) Mo (ppm), (b) Cr (ppm), (c) Hg (ppm), (d) Ag (ppm), (e) As (ppm) and (f) Zr (ppm) superimposed on the drainage map of the Tchangue – Bikoui drainage area, South Cameroon. High positive scores (large bubbles) indicate locations with anomalous concentrations.

Figure 6. Graduated symbol plot for (a) Pb (ppm) and (b) Cu (ppm) superimposed on the drainage map of the Tchangue – Bikoui drainage area, South Cameroon. High positive scores (large bubbles) indicate locations with anomalous concentrations.

Caron, V., Ekomane, E., & Mahieux, G., Moussango, P.,& Ndjeng, E.(2010).The Mintom Formation(new): Sedimentology and geochemistry of a Neoproterozoic, Paralic succession in south-east Cameroon. Journal of African Earth Sciences, 57, 367–385. https://doi.org/https://doi.org/10.1016/j.jafrearsci.2009.11.006

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