Bulletin of the National Research Centre

Table 1 Chemical analyses and weathering indices

From: Spheroidal weathering of basalt from Gebel Qatrani, Fayum Depression, Egypt

	1	2	3	4	5	6	7	Av
Core-stone
SiO₂	49.66	49.28	49.76	49.75	49.96	48.75	49.08	49.46
TiO₂	2.19	2.08	2.12	2.12	2.1	2.33	2.89	2.26
Al₂O₃	13.67	14.63	14.41	14.42	14.7	12.9	15.15	14.27
Fe₂O₃^T	14.98	13.91	13.82	13.88	13.58	13.62	13.58	13.91
MnO	0.13	0.15	0.15	0.15	0.15	0.16	0.15	0.15
MgO	6.68	6.92	6.95	6.96	6.62	6.19	6.33	6.66
CaO	9.72	9.41	9.94	9.84	10.03	9.84	9.76	9.79
Na₂O	2.39	2.13	2.19	2.17	2.21	2.34	2.58	2.29
K₂O	0.78	0.73	0.81	0.8	0.79	0.79	0.78	0.78
P₂O₅	0.26	0.21	0.21	0.21	0.22	0.24	0.3	0.24
LOI	0.50	0.61	0.31	0.25	0.21	0.85	0.66	0.48
Total	100.97	100.07	100.66	100.54	100.56	99.92	100.24	100.42
Weathering indices*
WIP	71.5	69.3	71.3	70.1	70.6	72.9	72.4	71.16
CIA	38.4	41.2	39.3	39.8	39.8	36.9	40.4	39.40
CIW	38.7	41.3	39.9	40.2	40.2	37.2	40.8	39.76
MIA(O)	37.4	38.0	37.0	37.1	37.5	36.0	38.3	37.33
Shell around core-stone
SiO₂	50.68	52.21	52.68	48.73	48.90	50.70	50.11	50.57
TiO₂	2.00	2.00	2.10	2.20	2.00	2.20	2.80	2.19
Al₂O₃	14.70	16.32	16.57	16.44	16.70	15.90	17.15	16.25
Fe₂O₃^T	15.00	12.08	12.18	14.88	14.50	14.62	15.58	14.12
MnO	0.14	0.15	0.15	0.14	0.13	0.13	0.13	0.14
MgO	5.80	4.20	4.29	5.96	4.62	4.19	4.38	4.78
CaO	8.10	8.00	7.16	7.80	8.03	7.81	7.50	7.77
Na₂O	2.00	2.00	2.00	2.01	2.00	1.90	1.99	1.99
K₂O	0.72	0.70	0.65	0.65	0.70	0.70	0.72	0.69
P₂O₅	0.24	0.41	0.30	0.22	0.20	0.23	0.25	0.26
LOI	0.80	1.20	1.50	1.20	1.90	1.50	0.38	1.21
Total	100.16	99.27	99.76	100.73	100.72	99.87	100.99	100.21
Weathering indices^a
WIP	62.7	58.0	50.9	61.0	59.2	55.8	55.3	57.56
CIA	44.7	48.1	50.4	48.2	47.8	47.6	50.1	48.13
CIW	44.9	47.8	50.4	48.5	48.3	47.9	50.9	48.39
MIA(O)	41.2	46.0	47.3	44.2	46.4	47.3	49.0	45.91

^aSee text

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