Size-dependent chemical depletion of sediments in glacial environments: a case study of Mandakini Valley, central Himalaya, India

Figures & data

Figure 1. Location of the study area, representing the catchment area of Chorabari glacier (solid line), Chorabari Lake (dotted lines), and the physiographical setup of the area

Figure 2. Average meteorological conditions of Chorabari Lake for the period 2011–2013

Table 1. Statistical composition parameters of the parent rock used in the present study

	Na2O	MgO	Al2O3	SiO2	P2O5	K2O	CaO	TiO2	MnO	Fe2O3
Weight %
Max	9.8	11.7	15.7	73.4	0.5	6.7	46.2	4.1	0.3	12.5
Min	0.0	0.0	0.8	10.6	0.0	0.1	0.7	0.0	0.0	0.1
Mean	2.8	2.1	13.0	70.1	0.1	1.8	2.2	0.2	0.0	2.9
SD	2.9	3.7	5.3	20.6	0.1	2.3	15.5	1.3	0.1	3.8
CV	102.5	174.2	40.3	29.4	112.1	131.9	699.2	680.6	201.8	131.6
Rocks containing high (>9%) CaO content
Max	3.6	11.7	13.0	55.0	0.5	1.4	46.2	4.1	0.3	12.5
Min	0.0	2.2	0.8	10.6	0.0	0.1	9.3	0.0	0.0	0.2
Mean	0.5	4.7	4.0	47.8	0.1	0.4	22.6	0.2	0.1	4.7
SD	1.9	4.9	6.3	23.8	0.2	0.7	18.7	2.3	0.1	6.2
CV	416.7	104.3	159.9	49.9	190.2	164.1	82.8	1527.8	144.3	131.7

CV, coefficient of determination (%); SD, standard deviation.

Table 2. Statistical parameters for sediments of different grain size, representing trace element concentrations

Particle size	Na2O	MgO	Al2O3	SiO2	P2O5	K2O	CaO	TiO2	MnO	Fe2O3	LOI
Weight %
Clay
Max	2.3	6.0	19.6	76.0	0.2	6.0	2.2	1.2	0.1	8.8	3.7
Min	1.4	0.9	12.0	51.6	0.1	2.8	1.3	0.3	0.0	2.5	0.9
Mean	1.8	3.2	17.2	61.5	0.2	5.0	1.9	0.8	0.1	5.9	2.2
SD	0.2	1.1	2.3	6.7	0.0	0.9	0.3	0.2	0.0	1.7	0.8
CV	13.5	34.8	13.2	10.9	20.8	17.9	17.1	26.8	22.7	29.1	37.8
Coarse sand
Max	2.4	2.7	16.7	79.4	0.2	4.9	2.1	0.7	0.1	5.0	2.8
Min	1.7	0.9	9.7	64.8	0.1	2.2	1.5	0.2	0.0	2.5	0.9
Mean	2.0	1.4	13.6	71.3	0.1	3.7	1.7	0.4	0.1	3.3	1.1
SD	0.2	0.7	2.3	5.1	0.1	0.8	0.2	0.2	0.0	0.9	0.7
CV	12.5	48.9	16.8	7.2	47.5	22.8	12.6	35.5	48.1	27.9	59.3
Sand
Max	2.6	4.7	19.5	80.6	0.2	5.4	2.9	1.0	0.2	7.4	3.2
Min	1.5	0.7	9.6	55.8	0.1	2.0	1.4	0.2	0.0	1.8	0.8
Mean	2.1	1.4	13.8	71.9	0.1	3.6	1.8	0.4	0.0	3.3	1.3
SD	0.2	0.9	2.4	5.9	0.0	0.8	0.2	0.2	0.0	1.3	0.5
CV	9.8	64.1	17.4	8.2	23.2	21.6	13.0	43.2	49.1	38.8	40.1
GSS
Max	2.7	1.7	14.8	69.6	0.2	4.1	1.9	0.4	0.0	3.5	3.0
Min	2.6	1.5	14.1	68.3	0.2	4.0	1.7	0.4	0.0	3.4	2.0
Mean	2.7	1.6	14.7	69.5	0.2	4.0	1.9	0.4	0.0	3.4	2.3
SD	0.0	0.1	0.4	0.7	0.0	0.0	0.1	0.0	0.0	0.1	0.5
CV	1.2	4.9	2.5	1.0	3.4	0.9	5.8	3.7	3.2	3.0	22.6

CV, coefficient of determination (%); GSS, glacial suspended sediments; SD, standard deviation.

Table 3. Statistical parameters for sediments of different grain size, representing trace element concentrations

Particle size	Ba	Cr	V	Sc	Co	Ni	Cu	Zn	Ga	Pb	Th	Rb	U	Sr	Y	Zr	Nb
PPM
Clay
Max	847	155	169	15	25	75	67	132	28	29	23	395	10	110	39	254	32
Min	546	26	41	5	7	12	9	36	13	5	7	133	2	80	16	81	7
Mean	686	77	112	11	14	37	27	86	21	24	14	271	3	100	33	167	21
SD	70	29	33	3	4	15	14	25	4	7	3	70	2	8	7	45	6
CV	10	37	29	24	29	41	54	30	19	28	25	26	58	8	21	27	28
Coarse sand
Max	666	139	96	10	12	29	25	76	21	30	23	264	12	107	30	198	19
Min	537	29	33	6	8	11	8	34	12	22	7	115	2	89	23	101	6
Mean	609	48	59	8	9	17	11	46	16	24	9	182	5	94	29	126	10
SD	43	36	22	1	2	7	6	13	3	3	7	45	4	6	3	34	4
CV	7	75	37	18	19	42	50	29	19	12	77	25	85	6	9	27	39
Sand
Max	745	106	143	13	16	55	45	109	24	34	24	311	8	108	37	254	26
Min	432	19	31	5	5	9	8	25	10	20	7	104	2	84	19	105	5
Mean	617	38	59	8	10	17	11	48	17	24	11	189	3	98	28	135	11
SD	75	20	27	2	3	11	8	19	3	2	4	49	1	5	5	33	5
CV	12	51	45	23	28	62	76	41	19	9	34	26	41	5	17	24	44
GSS
Max	636	45	66	7	9	19	20	59	19	44	21	239	4	98	20	218	13
Min	569	35	60	6	7	17	16	51	18	36	17	229	3	92	19	180	11
Mean	600	40	62	7	7	17	18	56	19	40	17	235	4	98	20	181	12
SD	34	5	3	1	1	1	2	4	1	4	2	5	1	3	1	22	1
CV	6	13	5	9	16	7	11	7	3	10	14	2	14	4	3	12	8

CV, coefficient of determination (%); GSS, glacial suspended sediments; SD, standard deviation.

Figure 3. Petrography of major rock types at Chorabari glacier catchment

Figure 4. Distribution of (a) major oxides (wt %) and (b) trace elements (ppm) in sediments of different grain-size classes, normalized to their distribution in the underlying bedrock. Error bars are 2σ standard deviations, reflecting both uncertainty in the bedrock composition and variability in the sampled sediment

Figure 5. Percentage change for individual elements vs. chemical index of alteration for major elements of clay, sand, coarse sand and glacier suspended sediments (GSS). The percentage change is on the ordinate and the chemical index of alteration is on the abscissa

Figure 6. The percentage change of fractions of different grain sizes presenting feldspar alteration through sodium and calcium (weight %) as the most leached elements compared to the parent rock composition

Figure 7. X-ray diffractograms of the separated clay sized fraction showing palygoskite with associated illite in the clayey sample (L2), whereas in sandy samples sepiolite and illite, along with non-clay minerals (with traces of calcite) and diffraction patterns collected after glycolation, show a peak shift due to -OH adsorption. Anor, anorthite; gly., glycolated

Figure 8. Bivariate plot of major elements to determine the extent of correlation for various immobile and mobile elements for all possible weathering cases. (a), P plotted with Ca to determine the association of P with calcsilicate rocks; (b), P plotted with Al to determine the association of P with aluminosilicate rocks; (c), Fe plotted with with Al to understand the association of Fe with aluminosilicate rocks; (d), Ca plotted with Al to determine the association of calcium- and magnesium-phase dissolution with calcsilicate rocks

Figure 9. Bivariate plots for molar proportions of major elements to study the release of elements from micaceous minerals. (a) Correlation of Mg with Al/Si to determine the association of Mg with minerals containing mica; (b) correlation of K with Al/Si to determine the association of Mg with minerals containing mica

Figure 10. Al₂O₃-(CaO+Na₂O)-K₂O diagram of glacial sediments suggesting the weathering history of the catchment. Chl, chlorite; Ka, kaolinite; Gi, gibbsite. The dotted line represents the overall trend of weathering, and the dashed line represents the metasomatic trend and the corresponding pre-metasomatized chemical index of alteration (CIA) values for premetasomatized samples

Figure 11. (a). Chemical maturity of sediments in all sets of weathering environments, suggesting a link between changing climatic conditions and the resulting sedimentation in the catchment. (b) Bivariate plots of Al₂O₃ and K₂O depicting the decomposition of K-feldspars and muscovite during progressive weathering, and the possible origin of sediments close to the illite line (Cox and Lowe 1995)

Figure 12. UCC normalized ratio of major oxide composition by weight %. Ganga River catchment suspended sediment data from Singh (2010); Higher Himalayan Crystalline data from Galy and France-Lanord (2001); Pindari Glacier suspended sediment data from Pandey et al. (2002); clay, sand, coarse sand, and glacial suspended sediments (GSS) data from the present study

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