Identification of Ophiolites in the Baimuxia-Mengangxia Area in the Eastern Part of the North Qilian Mountains and Their Regional Tectonic Significance

doi:10.19657/j.geoscience.1000-8527.2020.047

Abstract

Abstract:

In order to strengthen the investigation of Early Paleozoic Archipelagic arc-basin-system ophiolitic mélange in North Qilian,the Baimuxia-Mengangxia ophiolite is selected for petrographic, chronological and geochemistry study.Baimuxia-Mengangxia ophiolite is located in Huzhu County, Haidong City, Qinghai Province,tectonically located in the middle-eastern section of the North Qilian orogenic belt.The ophiolite is mainly composed of peridotite,gabbro and basic volcanic rocks,making up a relatively complete ophiolite unit.Single zircon LA-ICP-MS U-Pb isotope dating of gabbro was carried out, and the weighted average age of ²⁰⁶Pb/²³⁸U was (525.2 ± 1.1) Ma (MSWD=0.06).It represents the age of ophiolite formation, corresponding to the Early Cambrian.Petrogeochemical studies show that: The basic volcanic rocks in the ophiolite belong to tholeiite series, showing the geochemical characteristics of oceanic island basalts; in basalts Th/Yb-Nb/Yb and TiO₂/Yb-Nb/Yb tectonic discrimination diagrams, it shows that the formation environment of the ophiolite is not related to subduction.Through detailed field investigation and regional comparison, it is considered that the ophiolite represents the northern Qilian oceanic crust of the Early Paleozoic, and together with the ophiolites such as Yushigou-Chuancigou, it constitutes the Dabanshan-Yushigou ophiolite belt.

Key words: North Qilian orogenic belt, Baimuxia-Mengangxia ophiolite, LA-ICP-MS zircon U-Pb dating, OIB

CLC Number:

LIU Jiandong, LI Wufu, WANG Guoliang, DONG Jinshen, CAO Jinshan, LI Honggang, ZHAO Zhongguo. Identification of Ophiolites in the Baimuxia-Mengangxia Area in the Eastern Part of the North Qilian Mountains and Their Regional Tectonic Significance[J]. Geoscience, 2022, 36(01): 244-258.

Figures/Tables 11

References 43

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序号	Pb /10^-6	U /10^-6	同位素比值					年龄/Ma
序号	Pb /10^-6	U /10^-6	²⁰⁶Pb/ ²³⁸U	²⁰⁷Pb/ ²³⁵U	²⁰⁷Pb/ ²⁰⁶Pb	²⁰⁸Pb/ ²³²Th	²³²Th/ ²³⁸U	²⁰⁶Pb/ ²³⁸U	1σ	²⁰⁷Pb/ ²³⁵U	1σ	²⁰⁷Pb/ ²⁰⁶Pb	1σ
1	9	106	0.084 6	0.676 2	0.058 0	0.039 9	0.215 0	523	3	524	15	529	61
2	11	131	0.084 9	0.676 7	0.057 8	0.030 8	0.366 0	525	3	525	11	522	48
3	21	235	0.084 9	0.677 9	0.057 9	0.029 4	0.469 7	525	3	525	7	527	30
4	11	126	0.084 9	0.677 3	0.057 9	0.030 7	0.310 4	525	3	525	10	525	40
5	33	351	0.084 9	0.677 9	0.057 9	0.029 2	0.667 7	525	3	526	5	528	22
6	24	262	0.085 0	0.678 0	0.057 9	0.028 6	0.527 5	526	3	526	6	525	26
7	34	358	0.085 0	0.679 3	0.058 0	0.030 5	0.601 0	526	3	526	6	529	26
8	35	378	0.084 8	0.673 5	0.057 6	0.031 9	0.565 3	525	3	523	6	516	24
9	8	93	0.084 7	0.677 8	0.058 0	0.033 2	0.319 9	524	3	525	18	531	76
10	19	215	0.084 7	0.677 2	0.058 0	0.031 3	0.466 1	524	3	525	8	528	34
11	15	165	0.085 0	0.679 4	0.058 0	0.031 4	0.396 7	526	3	526	11	529	45
12	31	320	0.084 7	0.677 3	0.058 0	0.034 4	0.644 8	524	3	525	6	530	24
13	22	242	0.084 9	0.679 4	0.058 1	0.030 6	0.543 8	525	3	526	7	532	31
14	8	97	0.084 8	0.677 9	0.058 0	0.031 5	0.354 0	525	3	526	14	529	57
15	5	58	0.084 8	0.679 0	0.058 1	0.038 1	0.148 5	525	5	526	23	532	86
16	17	193	0.084 7	0.677 1	0.058 0	0.030 1	0.448 5	524	3	525	9	529	39
17	7	82	0.085 1	0.679 0	0.057 9	0.032 0	0.324 0	526	3	526	16	525	67
18	8	90	0.084 9	0.676 9	0.057 9	0.027 7	0.334 8	525	3	525	14	524	58
19	14	180	0.084 8	0.675 4	0.057 8	0.029 3	0.062 8	525	3	524	8	521	31
20	14	157	0.084 9	0.680 3	0.058 1	0.028 9	0.481 7	525	3	527	9	534	38
21	21	228	0.085 0	0.677 5	0.057 8	0.032 6	0.468 7	526	3	525	8	521	34
22	10	109	0.085 0	0.678 6	0.057 9	0.032 7	0.347 8	526	3	526	14	525	55
23	8	92	0.084 9	0.679 0	0.058 0	0.031 3	0.271 6	525	3	526	15	531	61
24	36	349	0.084 8	0.678 2	0.058 0	0.021 9	1.294 2	525	3	526	19	529	78
25	11	121	0.085 0	0.676 6	0.057 7	0.038 9	0.293 2	526	3	525	13	519	54
26	18	192	0.085 0	0.679 0	0.057 9	0.033 5	0.627 6	526	4	526	10	528	39
27	1	16	0.085 3	0.850 2	0.072 3	0.028 4	0.106 0	528	6	625	85	995	293
28	8	93	0.084 9	0.678 9	0.058 0	0.031 6	0.250 1	525	3	526	18	529	73
29	11	121	0.085 2	0.679 7	0.057 9	0.034 0	0.412 1	527	4	527	22	524	90
30	10	113	0.085 0	0.679 9	0.058 0	0.031 2	0.346 5	526	3	527	17	531	69
31	10	117	0.084 8	0.678 7	0.058 0	0.026 9	0.369 2	525	3	526	12	531	51
32	8	98	0.084 8	0.676 1	0.057 8	0.029 5	0.342 3	525	3	524	15	523	62

序号	Pb /10^-6	U /10^-6	同位素比值					年龄/Ma
序号	Pb /10^-6	U /10^-6	²⁰⁶Pb/ ²³⁸U	²⁰⁷Pb/ ²³⁵U	²⁰⁷Pb/ ²⁰⁶Pb	²⁰⁸Pb/ ²³²Th	²³²Th/ ²³⁸U	²⁰⁶Pb/ ²³⁸U	1σ	²⁰⁷Pb/ ²³⁵U	1σ	²⁰⁷Pb/ ²⁰⁶Pb	1σ
1	9	106	0.084 6	0.676 2	0.058 0	0.039 9	0.215 0	523	3	524	15	529	61
2	11	131	0.084 9	0.676 7	0.057 8	0.030 8	0.366 0	525	3	525	11	522	48
3	21	235	0.084 9	0.677 9	0.057 9	0.029 4	0.469 7	525	3	525	7	527	30
4	11	126	0.084 9	0.677 3	0.057 9	0.030 7	0.310 4	525	3	525	10	525	40
5	33	351	0.084 9	0.677 9	0.057 9	0.029 2	0.667 7	525	3	526	5	528	22
6	24	262	0.085 0	0.678 0	0.057 9	0.028 6	0.527 5	526	3	526	6	525	26
7	34	358	0.085 0	0.679 3	0.058 0	0.030 5	0.601 0	526	3	526	6	529	26
8	35	378	0.084 8	0.673 5	0.057 6	0.031 9	0.565 3	525	3	523	6	516	24
9	8	93	0.084 7	0.677 8	0.058 0	0.033 2	0.319 9	524	3	525	18	531	76
10	19	215	0.084 7	0.677 2	0.058 0	0.031 3	0.466 1	524	3	525	8	528	34
11	15	165	0.085 0	0.679 4	0.058 0	0.031 4	0.396 7	526	3	526	11	529	45
12	31	320	0.084 7	0.677 3	0.058 0	0.034 4	0.644 8	524	3	525	6	530	24
13	22	242	0.084 9	0.679 4	0.058 1	0.030 6	0.543 8	525	3	526	7	532	31
14	8	97	0.084 8	0.677 9	0.058 0	0.031 5	0.354 0	525	3	526	14	529	57
15	5	58	0.084 8	0.679 0	0.058 1	0.038 1	0.148 5	525	5	526	23	532	86
16	17	193	0.084 7	0.677 1	0.058 0	0.030 1	0.448 5	524	3	525	9	529	39
17	7	82	0.085 1	0.679 0	0.057 9	0.032 0	0.324 0	526	3	526	16	525	67
18	8	90	0.084 9	0.676 9	0.057 9	0.027 7	0.334 8	525	3	525	14	524	58
19	14	180	0.084 8	0.675 4	0.057 8	0.029 3	0.062 8	525	3	524	8	521	31
20	14	157	0.084 9	0.680 3	0.058 1	0.028 9	0.481 7	525	3	527	9	534	38
21	21	228	0.085 0	0.677 5	0.057 8	0.032 6	0.468 7	526	3	525	8	521	34
22	10	109	0.085 0	0.678 6	0.057 9	0.032 7	0.347 8	526	3	526	14	525	55
23	8	92	0.084 9	0.679 0	0.058 0	0.031 3	0.271 6	525	3	526	15	531	61
24	36	349	0.084 8	0.678 2	0.058 0	0.021 9	1.294 2	525	3	526	19	529	78
25	11	121	0.085 0	0.676 6	0.057 7	0.038 9	0.293 2	526	3	525	13	519	54
26	18	192	0.085 0	0.679 0	0.057 9	0.033 5	0.627 6	526	4	526	10	528	39
27	1	16	0.085 3	0.850 2	0.072 3	0.028 4	0.106 0	528	6	625	85	995	293
28	8	93	0.084 9	0.678 9	0.058 0	0.031 6	0.250 1	525	3	526	18	529	73
29	11	121	0.085 2	0.679 7	0.057 9	0.034 0	0.412 1	527	4	527	22	524	90
30	10	113	0.085 0	0.679 9	0.058 0	0.031 2	0.346 5	526	3	527	17	531	69
31	10	117	0.084 8	0.678 7	0.058 0	0.026 9	0.369 2	525	3	526	12	531	51
32	8	98	0.084 8	0.676 1	0.057 8	0.029 5	0.342 3	525	3	524	15	523	62

岩性	样品号	SiO₂	TiO₂	Al₂O₃	Fe₂O₃	FeO	MnO	MgO	CaO	Na₂O	K₂O	P₂O₅	烧失量	总量
橄榄岩	MGX01	35.07	0.07	1.17	5.46	3.27	0.12	28.90	8.68	0.02	0.03	0.02	16.08	98.89
	MGX02	40.61	0.10	1.06	5.63	3.45	0.13	34.35	2.27	0.01	0.03	0.05	12.09	99.78
	MGX03	38.85	0.06	2.40	7.53	1.30	0.12	36.92	0.23	0.32	0.03	0.04	11.91	99.73
辉长岩	MGX04	46.16	0.34	15.51	1.35	5.08	0.10	11.18	14.27	0.81	0.10	0.05	4.88	99.83
	MGX05	49.76	0.31	15.12	1.12	6.40	0.14	10.55	10.25	2.09	0.99	0.07	2.83	99.63
	MGX06	48.71	0.57	17.42	0.70	5.70	0.11	9.06	11.30	2.15	0.83	0.07	3.22	99.84
	MGX07	49.42	0.69	13.85	2.12	8.10	0.18	8.91	11.20	2.16	0.77	0.04	2.05	99.49
	MGX08	48.68	1.58	13.76	2.21	8.70	0.18	5.56	9.11	4.28	0.34	0.23	5.07	99.70
	MGX09	48.09	1.72	15.47	4.38	7.40	0.24	5.38	8.87	3.31	0.82	0.26	3.70	99.64
	MGX10	46.88	2.69	13.28	3.32	10.25	0.21	6.26	11.13	2.26	0.33	0.15	2.90	99.66
	MGX11	46.67	2.58	13.61	3.85	10.20	0.22	6.37	10.44	2.62	0.35	0.29	2.43	99.63
	MGX12	45.37	2.14	13.75	4.39	8.05	0.18	5.68	12.72	1.96	0.21	0.25	4.76	99.46
	MGX13	49.52	2.23	13.02	3.77	8.80	0.19	5.25	9.92	3.42	0.50	0.31	2.70	99.63
	MGX14	48.25	2.33	13.81	3.85	9.05	0.20	5.93	9.62	3.35	0.92	0.31	2.06	99.68
玄武岩	MGX15	49.74	2.14	13.25	3.25	8.90	0.17	5.07	9.67	3.41	0.47	0.28	2.93	99.28
	MGX16	46.92	3.36	15.79	3.05	10.25	0.11	6.01	8.04	2.73	1.22	0.42	1.77	99.67
	MGX17	50.21	3.56	15.12	2.79	10.65	0.15	4.31	7.71	2.24	0.56	0.47	2.13	99.90
	MGX18	50.10	2.64	16.55	2.07	9.15	0.12	4.85	5.92	2.83	0.43	0.28	4.74	99.68
	MGX19	48.18	2.45	14.97	6.17	4.83	0.12	6.66	8.32	1.86	0.74	0.32	5.14	99.76
	MGX20	47.30	3.47	14.94	8.45	4.35	0.20	7.57	8.12	2.09	0.39	0.58	2.42	99.88
	MGX21	45.75	2.70	14.86	5.94	7.40	0.22	8.67	7.23	0.28	0.88	0.38	5.45	99.76
岩性	样品号	La	Ce	Pr	Nd	Sm	Eu	Gd	Tb	Dy	Ho	Er	Tm	Yb
橄榄岩	MGX01	2.00	3.22	0.44	1.71	0.28	0.17	0.28	0.05	0.25	0.05	0.13	0.02	0.14
	MGX02	2.17	5.87	0.82	3.76	0.82	0.25	0.64	0.07	0.41	0.07	0.18	0.02	0.15
	MGX03	2.04	3.79	0.57	2.21	0.44	0.11	0.50	0.09	0.61	0.13	0.37	0.06	0.46
辉长岩	MGX04	2.91	6.73	0.80	4.58	1.22	0.47	1.21	0.18	1.13	0.23	0.60	0.08	0.53
	MGX05	5.91	11.88	1.48	6.06	1.33	0.51	1.60	0.31	2.01	0.43	1.22	0.21	1.38
	MGX06	1.96	5.12	0.83	4.07	1.37	0.61	1.76	0.31	2.18	0.41	1.16	0.18	1.14
	MGX07	3.79	6.51	0.84	3.76	1.17	0.60	1.61	0.33	2.14	0.46	1.32	0.22	1.45
	MGX08	11.91	26.24	4.17	19.61	4.76	1.48	5.57	1.04	6.51	1.34	3.85	0.63	4.10
	MGX09	11.18	25.03	3.63	17.47	4.69	1.51	5.31	0.97	6.13	1.24	3.61	0.59	3.57
	MGX10	8.02	18.98	2.93	14.04	4.09	1.34	4.40	0.81	5.15	1.06	2.98	0.47	2.88
	MGX11	11.47	29.09	4.64	22.80	6.49	2.07	7.01	1.32	7.99	1.59	4.60	0.71	4.38
	MGX12	10.01	25.00	3.81	18.16	4.81	1.63	5.05	0.90	5.35	1.03	2.84	0.42	2.66
	MGX13	17.17	37.04	5.57	25.68	6.18	2.14	6.71	1.21	6.99	1.40	3.78	0.61	3.86
	MGX14	17.44	38.94	5.58	25.28	5.81	2.19	6.47	1.11	6.47	1.26	3.30	0.55	3.38
玄武岩	MGX15	13.67	30.34	4.67	22.00	5.37	1.87	6.26	1.13	6.74	1.35	3.63	0.59	3.81
	MGX16	32.20	63.91	8.43	36.29	8.02	2.58	7.26	1.15	6.23	1.08	2.82	0.39	2.35
	MGX17	28.22	57.93	7.81	34.83	8.23	2.63	7.63	1.30	6.99	1.23	3.11	0.44	2.48
	MGX18	19.86	40.81	5.48	24.71	6.17	2.11	6.21	1.04	5.59	1.00	2.4	0.35	1.93
	MGX19	22.77	43.96	5.63	24.46	5.82	1.79	5.53	0.89	4.93	0.88	2.29	0.32	1.75
	MGX20	34.71	72.39	9.50	41.05	9.00	2.95	7.43	1.11	5.42	0.91	2.10	0.28	1.56
	MGX21	22.79	49.71	6.60	28.82	6.53	2.18	6.62	0.99	5.39	0.98	2.45	0.33	2.00
岩性	样品号	Lu	Y	Sr	Rb	Ba	Th	Ta	Nb	Zr	Hf	Ti	K	P
橄榄岩	MGX01	0.02	1.39	63.50	1.83	206.70	0.44	0.07	0.46	6.80	0.18	507	301	105
	MGX02	0.02	2.05	12.84	0.63	68.77	0.31	0.26	0.66	12.79	0.47	684	284	249
	MGX03	0.07	3.36	12.60	2.97	8.90	1.10	0.10	0.80	9.60	0.32	410	284	199
辉长岩	MGX04	0.07	5.66	395.50	1.55	47.94	0.37	0.33	0.85	15.06	0.63	2 147	874	230
	MGX05	0.21	10.74	298.70	37.78	191.70	2.36	0.24	2.02	24.00	0.80	1 920	8 490	316
	MGX06	0.15	11.31	275.50	30.32	122.60	1.29	0.39	2.05	32.78	1.27	3 537	7 131	316
	MGX07	0.21	11.21	182.00	2.39	194.10	0.85	0.29	1.28	19.40	0.65	4 245	6 560	179
	MGX08	0.60	33.59	204.50	5.84	82.80	1.04	0.73	8.95	156.20	5.21	10 010	2 983	1 061
	MGX09	0.54	33.12	427.40	10.69	355.50	0.17	0.93	12.74	128.50	3.71	10 748	7 095	1 183
	MGX10	0.41	28.61	225.70	5.95	136.10	0.61	0.60	7.85	107.00	2.96	16 667	2 831	677
	MGX11	0.63	42.66	251.40	2.95	166.40	0.38	0.93	11.80	167.00	5.75	15 913	2 989	1 302
	MGX12	0.37	27.38	465.70	1.34	152.70	0.13	0.94	13.62	126.60	3.70	13 547	1 841	1 152
	MGX13	0.56	35.32	304.30	7.72	80.70	2.01	1.29	14.42	173.70	5.79	13 792	4 282	1 396
	MGX14	0.49	31.16	287.80	18.45	190.10	1.84	1.18	14.22	172.80	5.76	14 309	7 823	1 386
玄武岩	MGX15	0.56	33.28	274.80	8.39	95.60	6.08	1.17	12.96	164.80	5.49	13 315	4 049	1 268
	MGX16	0.30	29.61	828.50	21.05	412.70	3.61	3.08	40.68	245.00	5.79	20 575	10 345	1 872
	MGX17	0.31	32.33	378.70	14.87	242.90	2.63	2.66	38.16	250.50	5.80	21 829	4 755	2 098
	MGX18	0.24	24.96	392.00	7.09	439.70	2.00	1.90	25.58	168.00	4.68	16 670	3 760	1 287
	MGX19	0.22	23.20	495.10	12.88	235.70	3.27	2.51	34.89	170.70	4.52	15 523	6 492	1 476
	MGX20	0.20	23.40	745.70	10.77	283.20	3.92	2.08	25.52	256.20	6.17	21 345	3 322	2 597
	MGX21	0.28	24.93	905.90	35.09	73.62	3.78	1.67	22.11	199.20	5.95	17 163	7 746	1 759

岩性	样品号	SiO₂	TiO₂	Al₂O₃	Fe₂O₃	FeO	MnO	MgO	CaO	Na₂O	K₂O	P₂O₅	烧失量	总量
橄榄岩	MGX01	35.07	0.07	1.17	5.46	3.27	0.12	28.90	8.68	0.02	0.03	0.02	16.08	98.89
	MGX02	40.61	0.10	1.06	5.63	3.45	0.13	34.35	2.27	0.01	0.03	0.05	12.09	99.78
	MGX03	38.85	0.06	2.40	7.53	1.30	0.12	36.92	0.23	0.32	0.03	0.04	11.91	99.73
辉长岩	MGX04	46.16	0.34	15.51	1.35	5.08	0.10	11.18	14.27	0.81	0.10	0.05	4.88	99.83
	MGX05	49.76	0.31	15.12	1.12	6.40	0.14	10.55	10.25	2.09	0.99	0.07	2.83	99.63
	MGX06	48.71	0.57	17.42	0.70	5.70	0.11	9.06	11.30	2.15	0.83	0.07	3.22	99.84
	MGX07	49.42	0.69	13.85	2.12	8.10	0.18	8.91	11.20	2.16	0.77	0.04	2.05	99.49
	MGX08	48.68	1.58	13.76	2.21	8.70	0.18	5.56	9.11	4.28	0.34	0.23	5.07	99.70
	MGX09	48.09	1.72	15.47	4.38	7.40	0.24	5.38	8.87	3.31	0.82	0.26	3.70	99.64
	MGX10	46.88	2.69	13.28	3.32	10.25	0.21	6.26	11.13	2.26	0.33	0.15	2.90	99.66
	MGX11	46.67	2.58	13.61	3.85	10.20	0.22	6.37	10.44	2.62	0.35	0.29	2.43	99.63
	MGX12	45.37	2.14	13.75	4.39	8.05	0.18	5.68	12.72	1.96	0.21	0.25	4.76	99.46
	MGX13	49.52	2.23	13.02	3.77	8.80	0.19	5.25	9.92	3.42	0.50	0.31	2.70	99.63
	MGX14	48.25	2.33	13.81	3.85	9.05	0.20	5.93	9.62	3.35	0.92	0.31	2.06	99.68
玄武岩	MGX15	49.74	2.14	13.25	3.25	8.90	0.17	5.07	9.67	3.41	0.47	0.28	2.93	99.28
	MGX16	46.92	3.36	15.79	3.05	10.25	0.11	6.01	8.04	2.73	1.22	0.42	1.77	99.67
	MGX17	50.21	3.56	15.12	2.79	10.65	0.15	4.31	7.71	2.24	0.56	0.47	2.13	99.90
	MGX18	50.10	2.64	16.55	2.07	9.15	0.12	4.85	5.92	2.83	0.43	0.28	4.74	99.68
	MGX19	48.18	2.45	14.97	6.17	4.83	0.12	6.66	8.32	1.86	0.74	0.32	5.14	99.76
	MGX20	47.30	3.47	14.94	8.45	4.35	0.20	7.57	8.12	2.09	0.39	0.58	2.42	99.88
	MGX21	45.75	2.70	14.86	5.94	7.40	0.22	8.67	7.23	0.28	0.88	0.38	5.45	99.76
岩性	样品号	La	Ce	Pr	Nd	Sm	Eu	Gd	Tb	Dy	Ho	Er	Tm	Yb
橄榄岩	MGX01	2.00	3.22	0.44	1.71	0.28	0.17	0.28	0.05	0.25	0.05	0.13	0.02	0.14
	MGX02	2.17	5.87	0.82	3.76	0.82	0.25	0.64	0.07	0.41	0.07	0.18	0.02	0.15
	MGX03	2.04	3.79	0.57	2.21	0.44	0.11	0.50	0.09	0.61	0.13	0.37	0.06	0.46
辉长岩	MGX04	2.91	6.73	0.80	4.58	1.22	0.47	1.21	0.18	1.13	0.23	0.60	0.08	0.53
	MGX05	5.91	11.88	1.48	6.06	1.33	0.51	1.60	0.31	2.01	0.43	1.22	0.21	1.38
	MGX06	1.96	5.12	0.83	4.07	1.37	0.61	1.76	0.31	2.18	0.41	1.16	0.18	1.14
	MGX07	3.79	6.51	0.84	3.76	1.17	0.60	1.61	0.33	2.14	0.46	1.32	0.22	1.45
	MGX08	11.91	26.24	4.17	19.61	4.76	1.48	5.57	1.04	6.51	1.34	3.85	0.63	4.10
	MGX09	11.18	25.03	3.63	17.47	4.69	1.51	5.31	0.97	6.13	1.24	3.61	0.59	3.57
	MGX10	8.02	18.98	2.93	14.04	4.09	1.34	4.40	0.81	5.15	1.06	2.98	0.47	2.88
	MGX11	11.47	29.09	4.64	22.80	6.49	2.07	7.01	1.32	7.99	1.59	4.60	0.71	4.38
	MGX12	10.01	25.00	3.81	18.16	4.81	1.63	5.05	0.90	5.35	1.03	2.84	0.42	2.66
	MGX13	17.17	37.04	5.57	25.68	6.18	2.14	6.71	1.21	6.99	1.40	3.78	0.61	3.86
	MGX14	17.44	38.94	5.58	25.28	5.81	2.19	6.47	1.11	6.47	1.26	3.30	0.55	3.38
玄武岩	MGX15	13.67	30.34	4.67	22.00	5.37	1.87	6.26	1.13	6.74	1.35	3.63	0.59	3.81
	MGX16	32.20	63.91	8.43	36.29	8.02	2.58	7.26	1.15	6.23	1.08	2.82	0.39	2.35
	MGX17	28.22	57.93	7.81	34.83	8.23	2.63	7.63	1.30	6.99	1.23	3.11	0.44	2.48
	MGX18	19.86	40.81	5.48	24.71	6.17	2.11	6.21	1.04	5.59	1.00	2.4	0.35	1.93
	MGX19	22.77	43.96	5.63	24.46	5.82	1.79	5.53	0.89	4.93	0.88	2.29	0.32	1.75
	MGX20	34.71	72.39	9.50	41.05	9.00	2.95	7.43	1.11	5.42	0.91	2.10	0.28	1.56
	MGX21	22.79	49.71	6.60	28.82	6.53	2.18	6.62	0.99	5.39	0.98	2.45	0.33	2.00
岩性	样品号	Lu	Y	Sr	Rb	Ba	Th	Ta	Nb	Zr	Hf	Ti	K	P
橄榄岩	MGX01	0.02	1.39	63.50	1.83	206.70	0.44	0.07	0.46	6.80	0.18	507	301	105
	MGX02	0.02	2.05	12.84	0.63	68.77	0.31	0.26	0.66	12.79	0.47	684	284	249
	MGX03	0.07	3.36	12.60	2.97	8.90	1.10	0.10	0.80	9.60	0.32	410	284	199
辉长岩	MGX04	0.07	5.66	395.50	1.55	47.94	0.37	0.33	0.85	15.06	0.63	2 147	874	230
	MGX05	0.21	10.74	298.70	37.78	191.70	2.36	0.24	2.02	24.00	0.80	1 920	8 490	316
	MGX06	0.15	11.31	275.50	30.32	122.60	1.29	0.39	2.05	32.78	1.27	3 537	7 131	316
	MGX07	0.21	11.21	182.00	2.39	194.10	0.85	0.29	1.28	19.40	0.65	4 245	6 560	179
	MGX08	0.60	33.59	204.50	5.84	82.80	1.04	0.73	8.95	156.20	5.21	10 010	2 983	1 061
	MGX09	0.54	33.12	427.40	10.69	355.50	0.17	0.93	12.74	128.50	3.71	10 748	7 095	1 183
	MGX10	0.41	28.61	225.70	5.95	136.10	0.61	0.60	7.85	107.00	2.96	16 667	2 831	677
	MGX11	0.63	42.66	251.40	2.95	166.40	0.38	0.93	11.80	167.00	5.75	15 913	2 989	1 302
	MGX12	0.37	27.38	465.70	1.34	152.70	0.13	0.94	13.62	126.60	3.70	13 547	1 841	1 152
	MGX13	0.56	35.32	304.30	7.72	80.70	2.01	1.29	14.42	173.70	5.79	13 792	4 282	1 396
	MGX14	0.49	31.16	287.80	18.45	190.10	1.84	1.18	14.22	172.80	5.76	14 309	7 823	1 386
玄武岩	MGX15	0.56	33.28	274.80	8.39	95.60	6.08	1.17	12.96	164.80	5.49	13 315	4 049	1 268
	MGX16	0.30	29.61	828.50	21.05	412.70	3.61	3.08	40.68	245.00	5.79	20 575	10 345	1 872
	MGX17	0.31	32.33	378.70	14.87	242.90	2.63	2.66	38.16	250.50	5.80	21 829	4 755	2 098
	MGX18	0.24	24.96	392.00	7.09	439.70	2.00	1.90	25.58	168.00	4.68	16 670	3 760	1 287
	MGX19	0.22	23.20	495.10	12.88	235.70	3.27	2.51	34.89	170.70	4.52	15 523	6 492	1 476
	MGX20	0.20	23.40	745.70	10.77	283.20	3.92	2.08	25.52	256.20	6.17	21 345	3 322	2 597
	MGX21	0.28	24.93	905.90	35.09	73.62	3.78	1.67	22.11	199.20	5.95	17 163	7 746	1 759