Lithology of Likou Group from Around the Anhui-Jiangxi Boundary, South China: Implications for Post-orogenic Collapse of Supercontinent Breakup

doi:10.19657/j.geoscience.1000-8527.2019.002

Abstract

Abstract:

The Likou Group comprises a volcanic-sedimentary succession distributed to the north of the Qimen-Qiankou-Shexian fault zone near the boundary between Anhui and Jiangxi, South China. It is the upper part of Neoproterozoic epimetamorphic basement in the eastern part of the Jiangnan orogen. Interbedded basalt from the Dengjia and Pulin formations have Continental Arc Basalt (CAB)-like REE distribution ((La/Yb)_N=2.97-4.47) and trace-element patterns. The Dengjia and Pulin Formation basalts have Rittmann Index of 0.029-2.203 and 4.304-6.538, respectively, suggesting comagmatic products of different stages. The Dengjia, Pulin and Xiao’anli formations of the Likou Group have clear boundary surfaces and probably continuous rock formation, and therefore can be merged into one formation (still named Dengjia Formation). The Pulin and Xiao’anli formations represent the upper and top parts of the newly-defined Dengjia Formation, respectively. Basalt from the Dengjia Formation is dated to be (804.2±7.4) Ma by high-precision LA-ICP-MS U-Pb zircon dating. The zircons from interbedded basalt have initial¹⁷⁶Hf/¹⁷⁷Hf ratios of 0.281,837 to 0.282,076, ε_Hf(t) of -15.9 to -7.0, and two-stage Hf model ages of 2.16 to 2.68 Ga, indicating a magmatic source with significant ancient crustal input. The results may reflect that the intermediate stage of rifting had ended, and the magmatism had progressed to the earth surface. Sedimentary characteristics of the Likou Group indicate that the Neoproterozoic rift basin in the eastern part of the Jiangnan orogen was a passive rift basin, which was controlled mainly by subduction rollback, and the Rodinia plume activities may have also made significant impact to the tectonic evolution. We suggest that the rifting was resulted from the interactions between plate subduction and Rodinia superplume.

Key words: Likou Group, basalt, eastern part of Jiangnan orogen, rift basin, plume

CLC Number:

P534
P548

ZENG Yan, YU Xinqi, LIU Xiu, HU Jun, LIU Mengyan, WANG Zishen. Lithology of Likou Group from Around the Anhui-Jiangxi Boundary, South China: Implications for Post-orogenic Collapse of Supercontinent Breakup[J]. Geoscience, 2019, 33(03): 535-550.

Figures/Tables 13

Fig.1 Geotectonic location of the study area (a) and the distribution of Likou Group (b) (modified after reference[47])

Fig.2 Unconformities in the Neoproterozoic basement (modified after references[48-51])

Fig.3 Sedimentary sequence correlation and the location of Likou Group

Fig.4 Conglomerates of Zhentou Formation of Lower Likou Group

Fig.5 Cross-sections of Upper Likou Group in Xianggupeng and Xiao’anli

Fig.6 Cathodoluminescence (CL) images of representative zircons from basalts in Dengjia Formation (a), zircon U-Pb concordia diagram (b) and weighted average age diagram (c)

Fig.7 Diagram of εHf(t)-t of basalts from Dengjia Formation (a) and the probability plot of zircon Hf model ages (b)

Table 1 LA-ICP-MS zircon U-Pb dating results for the basalt in Dengjia Formation

测点号	含量/10^-6			Th/U	同位素比值±1σ				(年龄±1σ)/Ma
测点号	Pb	Th	U	Th/U	²⁰⁷Pb/²⁰⁶Pb	²⁰⁷Pb/²³⁵U	²⁰⁶Pb/²³⁸U		²⁰⁷Pb/²⁰⁶Pb	²⁰⁷Pb/²³⁵U	²⁰⁶Pb/²³⁸U
D1751-02	114.92	244.14	451.27	0.54	0.067 09±0.002 47	1.260 64±0.045 11	0.136 21±0.001 55	842.59±77.78		828.19±20.27	823.22±8.79
D1751-03	113.36	278.56	339.69	0.82	0.066 50±0.003 03	1.248 70±0.054 69	0.136 82±0.001 69	821.91±95.21		822.81±24.70	826.70±9.59
D1751-04	104.77	322.03	286.50	1.12	0.065 22±0.002 75	1.177 70±0.047 46	0.131 28±0.001 64	783.33±88.88		790.24±22.14	795.19±9.36
D1751-05	112.70	397.68	238.69	1.67	0.065 99±0.002 98	1.184 72±0.052 16	0.130 16±0.001 81	805.55±94.44		793.51±24.25	788.78±10.32
D1751-06	42.00	117.52	116.37	1.01	0.070 11±0.005 67	1.242 55±0.084 88	0.132 63±0.002 79	931.48±166.67		820.03±38.43	802.85±15.90
D1751-07	284.87	779.78	785.19	0.99	0.066 01±0.002 17	1.225 76±0.039 84	0.133 73±0.001 13	807.10±65.74		812.41±18.18	809.11±6.45
D1751-08	202.57	754.36	388.92	1.94	0.065 51±0.002 58	1.166 91±0.047 33	0.128 16±0.001 47	790.74±83.33		785.19±22.18	777.38±8.42
D1751-09	65.47	201.53	183.29	1.10	0.069 07±0.003 65	1.255 97±0.064 12	0.131 11±0.002 21	901.85±109.26		826.09±28.86	794.19±12.58
D1751-10	313.67	1 001.11	620.69	1.61	0.068 63±0.002 47	1.290 95±0.042 18	0.136 57±0.001 56	887.03±74.08		841.71±18.71	825.26±8.88
D1751-11	133.73	389.57	373.19	1.04	0.065 87±0.002 79	1.171 18±0.046 95	0.128 98±0.001 57	1200.00±83.18		787.20±21.97	782.05±8.99
D1751-12	143.15	443.39	343.83	1.29	0.068 68±0.002 84	1.256 71±0.048 99	0.132 82±0.001 63	900.00±113.89		826.43±22.05	803.95±9.28
D1751-13	167.50	486.92	455.30	1.07	0.066 18±0.002 19	1.222 64±0.039 18	0.133 35±0.001 54	812.96±68.52		810.98±17.91	807.00±8.77
D1751-15	151.98	450.64	437.78	1.03	0.065 64±0.002 81	1.180 22±0.047 47	0.130 07±0.001 29	794.44±90.74		791.41±22.11	788.27±7.37
D1751-16	82.56	190.34	306.51	0.62	0.066 20±0.003 04	1.197 79±0.052 24	0.131 34±0.001 73	812.96±91.66		799.56±24.14	795.52±9.86
D1751-17	169.19	492.13	478.67	1.03	0.065 08±0.002 38	1.190 60±0.040 76	0.132 67±0.001 31	775.93±77.77		796.24±18.90	803.11±7.45
D1751-20	122.55	230.87	523.61	0.44	0.067 39±0.002 40	1.258 04±0.043 48	0.135 93±0.001 49	849.99±92.99		827.03±19.56	821.62±8.49
D1751-21	186.85	516.29	480.14	1.08	0.065 51±0.002 25	1.224 81±0.042 71	0.135 54±0.001 39	790.74±72.22		811.97±19.50	819.41±7.93
D1751-25	252.19	712.60	721.22	0.99	0.066 54±0.002 21	1.223 15±0.040 03	0.132 69±0.001 24	833.33±73.15		811.21±18.29	803.19±7.08

Table 1 LA-ICP-MS zircon U-Pb dating results for the basalt in Dengjia Formation

测点号	含量/10^-6			Th/U	同位素比值±1σ				(年龄±1σ)/Ma
测点号	Pb	Th	U	Th/U	²⁰⁷Pb/²⁰⁶Pb	²⁰⁷Pb/²³⁵U	²⁰⁶Pb/²³⁸U		²⁰⁷Pb/²⁰⁶Pb	²⁰⁷Pb/²³⁵U	²⁰⁶Pb/²³⁸U
D1751-02	114.92	244.14	451.27	0.54	0.067 09±0.002 47	1.260 64±0.045 11	0.136 21±0.001 55	842.59±77.78		828.19±20.27	823.22±8.79
D1751-03	113.36	278.56	339.69	0.82	0.066 50±0.003 03	1.248 70±0.054 69	0.136 82±0.001 69	821.91±95.21		822.81±24.70	826.70±9.59
D1751-04	104.77	322.03	286.50	1.12	0.065 22±0.002 75	1.177 70±0.047 46	0.131 28±0.001 64	783.33±88.88		790.24±22.14	795.19±9.36
D1751-05	112.70	397.68	238.69	1.67	0.065 99±0.002 98	1.184 72±0.052 16	0.130 16±0.001 81	805.55±94.44		793.51±24.25	788.78±10.32
D1751-06	42.00	117.52	116.37	1.01	0.070 11±0.005 67	1.242 55±0.084 88	0.132 63±0.002 79	931.48±166.67		820.03±38.43	802.85±15.90
D1751-07	284.87	779.78	785.19	0.99	0.066 01±0.002 17	1.225 76±0.039 84	0.133 73±0.001 13	807.10±65.74		812.41±18.18	809.11±6.45
D1751-08	202.57	754.36	388.92	1.94	0.065 51±0.002 58	1.166 91±0.047 33	0.128 16±0.001 47	790.74±83.33		785.19±22.18	777.38±8.42
D1751-09	65.47	201.53	183.29	1.10	0.069 07±0.003 65	1.255 97±0.064 12	0.131 11±0.002 21	901.85±109.26		826.09±28.86	794.19±12.58
D1751-10	313.67	1 001.11	620.69	1.61	0.068 63±0.002 47	1.290 95±0.042 18	0.136 57±0.001 56	887.03±74.08		841.71±18.71	825.26±8.88
D1751-11	133.73	389.57	373.19	1.04	0.065 87±0.002 79	1.171 18±0.046 95	0.128 98±0.001 57	1200.00±83.18		787.20±21.97	782.05±8.99
D1751-12	143.15	443.39	343.83	1.29	0.068 68±0.002 84	1.256 71±0.048 99	0.132 82±0.001 63	900.00±113.89		826.43±22.05	803.95±9.28
D1751-13	167.50	486.92	455.30	1.07	0.066 18±0.002 19	1.222 64±0.039 18	0.133 35±0.001 54	812.96±68.52		810.98±17.91	807.00±8.77
D1751-15	151.98	450.64	437.78	1.03	0.065 64±0.002 81	1.180 22±0.047 47	0.130 07±0.001 29	794.44±90.74		791.41±22.11	788.27±7.37
D1751-16	82.56	190.34	306.51	0.62	0.066 20±0.003 04	1.197 79±0.052 24	0.131 34±0.001 73	812.96±91.66		799.56±24.14	795.52±9.86
D1751-17	169.19	492.13	478.67	1.03	0.065 08±0.002 38	1.190 60±0.040 76	0.132 67±0.001 31	775.93±77.77		796.24±18.90	803.11±7.45
D1751-20	122.55	230.87	523.61	0.44	0.067 39±0.002 40	1.258 04±0.043 48	0.135 93±0.001 49	849.99±92.99		827.03±19.56	821.62±8.49
D1751-21	186.85	516.29	480.14	1.08	0.065 51±0.002 25	1.224 81±0.042 71	0.135 54±0.001 39	790.74±72.22		811.97±19.50	819.41±7.93
D1751-25	252.19	712.60	721.22	0.99	0.066 54±0.002 21	1.223 15±0.040 03	0.132 69±0.001 24	833.33±73.15		811.21±18.29	803.19±7.08

Table 2 LA-MC-ICP-MS zircon Hf isotopic compositions of the basalt in Dengjia Formation

测点号	t/Ma	¹⁷⁶Yb/¹⁷⁷Hf±2σ	¹⁷⁶Lu/¹⁷⁷Hf±2σ	¹⁷⁶Hf/¹⁷⁷Hf±2σ	ε_Hf(0)	ε_Hf(t)±2σ	$t D M 1$ /Ga	$t D M 2$ /Ga	f_Lu/Hf	(¹⁷⁶Hf/ ¹⁷⁷Hf)_i
D1751-02	823	0.029 102±0.000 436	0.001 042±0.000 025	0.282 076±0.000 019	-24.6	-7.0±0.67	1.66	2.16	-0.97	0.282 060
D1751-03	827	0.034 611±0.001 095	0.001 163±0.000 034	0.282 056±0.000 019	-25.3	-7.7±0.68	1.69	2.20	-0.96	0.282 038
D1751-04	795	0.040 998±0.000 988	0.001 448±0.000 026	0.281 886±0.000 023	-31.3	-14.5±0.83	1.94	2.60	-0.96	0.281 865
D1751-05	789	0.021 631±0.000 370	0.000 800±0.000 013	0.282 057±0.000 020	-25.3	-8.3±0.71	1.67	2.21	-0.98	0.282 045
D1751-06	803	0.033 137±0.000 513	0.001 128±0.000 019	0.281 879±0.000 023	-31.6	-14.5±0.81	1.94	2.61	-0.97	0.281 862
D1751-07	809	0.024 849±0.000 695	0.000 857±0.000 028	0.281 838±0.000 017	-33.0	-15.7±0.59	1.98	2.68	-0.97	0.281 825
D1751-08	777	0.102 335±0.002 147	0.003 295±0.000 050	0.282 017±0.000 023	-26.7	-11.2±0.81	1.85	2.38	-0.90	0.281 969
D1751-09	794	0.047 785±0.000 477	0.001 678±0.000 013	0.281 861±0.000 022	-32.2	-15.6±0.78	1.99	2.67	-0.95	0.281 836
D1751-10	825	0.038 662±0.001 092	0.001 286±0.000 025	0.282 044±0.000 022	-25.7	-8.2±0.77	1.71	2.23	-0.96	0.282 025
D1751-11	782	0.036 988±0.000 257	0.001 218±0.000 002	0.281 884±0.000 020	-31.4	-14.8±0.71	1.93	2.61	-0.96	0.281 866
D1751-12	804	0.027 736±0.001 314	0.000 925±0.000 033	0.281 867±0.000 018	-32.0	-14.8±0.64	1.94	2.62	-0.97	0.281 853
D1751-13	807	0.036 572±0.000 212	0.001 184±0.000 006	0.281 837±0.000 018	-33.1	-15.9±0.63	2.00	2.70	-0.96	0.281 819
D1751-15	788	0.034 131±0.000 703	0.001 153±0.000 016	0.281 876±0.000 019	-31.7	-14.9±0.69	1.94	2.62	-0.97	0.281 859
D1751-16	796	0.027 492±0.000 765	0.000 927±0.000 028	0.282 047±0.000 022	-25.7	-8.6±0.78	1.69	2.23	-0.97	0.282 033
D1751-17	803	0.042 605±0.000 524	0.001 499±0.000 027	0.282 014±0.000 018	-26.8	-9.9±0.65	1.77	2.32	-0.95	0.281 991
D1751-20	822	0.053 113±0.000 596	0.001 944±0.000 027	0.281 841±0.000 019	-32.9	-15.9±0.66	2.03	2.71	-0.94	0.281 811
D1751-21	819	0.047 743±0.000 651	0.001 618±0.000 022	0.282 017±0.000 019	-26.7	-9.5±0.68	1.77	2.31	-0.95	0.281 992
D1751-25	803	0.044 079±0.001 466	0.001 497±0.000 042	0.282 033±0.000 018	-26.1	-9.2±0.62	1.74	2.28	-0.95	0.282 011

Table 2 LA-MC-ICP-MS zircon Hf isotopic compositions of the basalt in Dengjia Formation

测点号	t/Ma	¹⁷⁶Yb/¹⁷⁷Hf±2σ	¹⁷⁶Lu/¹⁷⁷Hf±2σ	¹⁷⁶Hf/¹⁷⁷Hf±2σ	ε_Hf(0)	ε_Hf(t)±2σ	$t D M 1$ /Ga	$t D M 2$ /Ga	f_Lu/Hf	(¹⁷⁶Hf/ ¹⁷⁷Hf)_i
D1751-02	823	0.029 102±0.000 436	0.001 042±0.000 025	0.282 076±0.000 019	-24.6	-7.0±0.67	1.66	2.16	-0.97	0.282 060
D1751-03	827	0.034 611±0.001 095	0.001 163±0.000 034	0.282 056±0.000 019	-25.3	-7.7±0.68	1.69	2.20	-0.96	0.282 038
D1751-04	795	0.040 998±0.000 988	0.001 448±0.000 026	0.281 886±0.000 023	-31.3	-14.5±0.83	1.94	2.60	-0.96	0.281 865
D1751-05	789	0.021 631±0.000 370	0.000 800±0.000 013	0.282 057±0.000 020	-25.3	-8.3±0.71	1.67	2.21	-0.98	0.282 045
D1751-06	803	0.033 137±0.000 513	0.001 128±0.000 019	0.281 879±0.000 023	-31.6	-14.5±0.81	1.94	2.61	-0.97	0.281 862
D1751-07	809	0.024 849±0.000 695	0.000 857±0.000 028	0.281 838±0.000 017	-33.0	-15.7±0.59	1.98	2.68	-0.97	0.281 825
D1751-08	777	0.102 335±0.002 147	0.003 295±0.000 050	0.282 017±0.000 023	-26.7	-11.2±0.81	1.85	2.38	-0.90	0.281 969
D1751-09	794	0.047 785±0.000 477	0.001 678±0.000 013	0.281 861±0.000 022	-32.2	-15.6±0.78	1.99	2.67	-0.95	0.281 836
D1751-10	825	0.038 662±0.001 092	0.001 286±0.000 025	0.282 044±0.000 022	-25.7	-8.2±0.77	1.71	2.23	-0.96	0.282 025
D1751-11	782	0.036 988±0.000 257	0.001 218±0.000 002	0.281 884±0.000 020	-31.4	-14.8±0.71	1.93	2.61	-0.96	0.281 866
D1751-12	804	0.027 736±0.001 314	0.000 925±0.000 033	0.281 867±0.000 018	-32.0	-14.8±0.64	1.94	2.62	-0.97	0.281 853
D1751-13	807	0.036 572±0.000 212	0.001 184±0.000 006	0.281 837±0.000 018	-33.1	-15.9±0.63	2.00	2.70	-0.96	0.281 819
D1751-15	788	0.034 131±0.000 703	0.001 153±0.000 016	0.281 876±0.000 019	-31.7	-14.9±0.69	1.94	2.62	-0.97	0.281 859
D1751-16	796	0.027 492±0.000 765	0.000 927±0.000 028	0.282 047±0.000 022	-25.7	-8.6±0.78	1.69	2.23	-0.97	0.282 033
D1751-17	803	0.042 605±0.000 524	0.001 499±0.000 027	0.282 014±0.000 018	-26.8	-9.9±0.65	1.77	2.32	-0.95	0.281 991
D1751-20	822	0.053 113±0.000 596	0.001 944±0.000 027	0.281 841±0.000 019	-32.9	-15.9±0.66	2.03	2.71	-0.94	0.281 811
D1751-21	819	0.047 743±0.000 651	0.001 618±0.000 022	0.282 017±0.000 019	-26.7	-9.5±0.68	1.77	2.31	-0.95	0.281 992
D1751-25	803	0.044 079±0.001 466	0.001 497±0.000 042	0.282 033±0.000 018	-26.1	-9.2±0.62	1.74	2.28	-0.95	0.282 011

Table 3 Major(%), trace(10-6) and rare earth(10-6) element compositions for basalts from Likou Group

岩石	样品号	SiO₂	TiO₂		Al₂O₃		Fe₂O₃T		MnO		MgO		CaO		Na₂O		K₂O		P₂O₅		烧失量		总量
香菇棚邓家组夹层玄武岩	D1751-y1	45.65	0.52		16.61		7.73		0.12		13.23		9.40		1.92		0.50		0.07		4.09		99.84
	D1751-y2	49.00	0.46		15.32		7.85		0.12		11.19		12.27		0.11		0.31		0.07		3.17		99.88
	D1751-y3	48.45	0.54		14.46		7.45		0.12		14.00		7.26		1.96		0.66		0.05		4.81		99.76
小安里铺岭组玄武岩	SA1831-y1	48.05	0.98		16.75		10.25		0.13		8.95		6.67		4.26		0.40		0.13		3.25		99.84
	SA1831-y2	47.60	0.84		16.45		10.63		0.15		9.11		6.58		4.36		0.34		0.12		3.54		99.72
	SA1831-y3	48.78	1.03		17.41		10.04		0.14		7.14		7.16		4.50		0.67		0.13		2.79		99.78
	SA1831-y4	47.54	0.96		16.52		8.66		0.43		8.33		5.52		4.75		0.70		0.12		6.29		99.82
	SA1831-y5	50.07	0.97		17.17		10.03		0.39		8.49		2.95		4.19		1.58		0.12		3.82		99.78
岩石	样品号	V		Cr		Co		Ni		Ga		Rb		Sr		Y		Zr		Nb		Cs
香菇棚邓家组夹层玄武岩	D1751-y1	183.30		828.40		54.41		265.40		13.25		18.17		177.40		16.73		97.59		1.41		1.73
	D1751-y2	160.20		818.80		54.39		249.50		14.51		10.00		134.20		18.79		89.45		1.13		0.90
	D1751-y3	167.35		1 164.27		62.92		415.75		14.01		26.21		115.41		17.11		83.50		1.76		1.60
小安里铺岭组玄武岩	SA1831-y1	197.20		403.50		48.92		156.20		18.22		19.00		516.40		26.49		118.00		4.20		4.16
	SA1831-y2	198.90		396.80		45.98		131.00		18.92		10.49		1 038.00		22.38		102.40		3.28		1.88
	SA1831-y3	226.80		320.80		40.09		109.90		18.24		11.64		562.00		22.42		111.00		3.86		2.50
	SA1831-y4	220.10		203.50		41.28		99.08		17.29		17.37		167.30		24.75		108.50		3.46		2.47
	SA1831-y5	231.70		214.90		44.67		108.50		18.72		46.88		201.90		29.48		122.60		3.76		2.89
岩石	样品号	Ba		La		Ce		Pr		Nd		Sm		Eu		Gd		Tb		Dy		Ho
香菇棚邓家组夹层玄武岩	D1751-y1	525.30		5.13		9.97		1.54		6.66		1.87		0.72		2.01		0.43		2.87		0.59
	D1751-y2	222.30		7.15		8.93		1.86		8.00		2.06		0.82		2.19		0.46		3.01		0.63
	D1751-y3	506.93		5.53		11.23		1.47		6.82		1.86		0.72		2.05		0.44		3.00		0.61
小安里铺岭组玄武岩	SA1831-y1	764.80		11.86		26.26		3.43		14.72		3.71		1.31		3.36		0.75		4.49		0.95
	SA1831-y2	1 265.00		9.64		21.42		2.81		12.04		3.03		1.54		2.79		0.63		3.75		0.80
	SA1831-y3	1 215.00		10.47		23.51		3.03		12.95		3.22		1.55		2.95		0.66		3.88		0.82
	SA1831-y4	1 330.00		10.45		23.32		2.92		12.47		3.23		1.50		2.98		0.68		4.14		0.88
	SA1831-y5	1 522.00		10.27		22.18		3.10		13.21		3.48		1.59		3.16		0.75		4.58		0.98
岩石	样品号	Er		Tm		Yb		Lu		Hf		Ta		Pb		Th		U
香菇棚邓家组夹层玄武岩	D1751-y1	1.77		0.26		1.73		0.25		2.46		0.21		3.62		1.16		0.29
	D1751-y2	1.88		0.27		1.80		0.26		2.21		0.53		3.88		1.00		0.23
	D1751-y3	1.78		0.30		1.78		0.28		2.25		0.14		5.08		1.18		0.32
小安里铺岭组玄武岩	SA1831-y1	3.09		0.40		2.66		0.40		3.03		0.44		10.39		1.69		0.46
	SA1831-y2	2.85		0.34		2.28		0.34		2.59		0.30		11.72		1.42		0.37
	SA1831-y3	2.60		0.35		2.37		0.35		2.85		0.40		11.94		1.62		0.44
	SA1831-y4	2.98		0.38		2.54		0.38		2.83		0.38		203.70		1.61		0.47
	SA1831-y5	3.04		0.42		2.87		0.43		3.20		0.38		64.43		1.84		0.48

Table 3 Major(%), trace(10-6) and rare earth(10-6) element compositions for basalts from Likou Group

岩石	样品号	SiO₂	TiO₂		Al₂O₃		Fe₂O₃T		MnO		MgO		CaO		Na₂O		K₂O		P₂O₅		烧失量		总量
香菇棚邓家组夹层玄武岩	D1751-y1	45.65	0.52		16.61		7.73		0.12		13.23		9.40		1.92		0.50		0.07		4.09		99.84
	D1751-y2	49.00	0.46		15.32		7.85		0.12		11.19		12.27		0.11		0.31		0.07		3.17		99.88
	D1751-y3	48.45	0.54		14.46		7.45		0.12		14.00		7.26		1.96		0.66		0.05		4.81		99.76
小安里铺岭组玄武岩	SA1831-y1	48.05	0.98		16.75		10.25		0.13		8.95		6.67		4.26		0.40		0.13		3.25		99.84
	SA1831-y2	47.60	0.84		16.45		10.63		0.15		9.11		6.58		4.36		0.34		0.12		3.54		99.72
	SA1831-y3	48.78	1.03		17.41		10.04		0.14		7.14		7.16		4.50		0.67		0.13		2.79		99.78
	SA1831-y4	47.54	0.96		16.52		8.66		0.43		8.33		5.52		4.75		0.70		0.12		6.29		99.82
	SA1831-y5	50.07	0.97		17.17		10.03		0.39		8.49		2.95		4.19		1.58		0.12		3.82		99.78
岩石	样品号	V		Cr		Co		Ni		Ga		Rb		Sr		Y		Zr		Nb		Cs
香菇棚邓家组夹层玄武岩	D1751-y1	183.30		828.40		54.41		265.40		13.25		18.17		177.40		16.73		97.59		1.41		1.73
	D1751-y2	160.20		818.80		54.39		249.50		14.51		10.00		134.20		18.79		89.45		1.13		0.90
	D1751-y3	167.35		1 164.27		62.92		415.75		14.01		26.21		115.41		17.11		83.50		1.76		1.60
小安里铺岭组玄武岩	SA1831-y1	197.20		403.50		48.92		156.20		18.22		19.00		516.40		26.49		118.00		4.20		4.16
	SA1831-y2	198.90		396.80		45.98		131.00		18.92		10.49		1 038.00		22.38		102.40		3.28		1.88
	SA1831-y3	226.80		320.80		40.09		109.90		18.24		11.64		562.00		22.42		111.00		3.86		2.50
	SA1831-y4	220.10		203.50		41.28		99.08		17.29		17.37		167.30		24.75		108.50		3.46		2.47
	SA1831-y5	231.70		214.90		44.67		108.50		18.72		46.88		201.90		29.48		122.60		3.76		2.89
岩石	样品号	Ba		La		Ce		Pr		Nd		Sm		Eu		Gd		Tb		Dy		Ho
香菇棚邓家组夹层玄武岩	D1751-y1	525.30		5.13		9.97		1.54		6.66		1.87		0.72		2.01		0.43		2.87		0.59
	D1751-y2	222.30		7.15		8.93		1.86		8.00		2.06		0.82		2.19		0.46		3.01		0.63
	D1751-y3	506.93		5.53		11.23		1.47		6.82		1.86		0.72		2.05		0.44		3.00		0.61
小安里铺岭组玄武岩	SA1831-y1	764.80		11.86		26.26		3.43		14.72		3.71		1.31		3.36		0.75		4.49		0.95
	SA1831-y2	1 265.00		9.64		21.42		2.81		12.04		3.03		1.54		2.79		0.63		3.75		0.80
	SA1831-y3	1 215.00		10.47		23.51		3.03		12.95		3.22		1.55		2.95		0.66		3.88		0.82
	SA1831-y4	1 330.00		10.45		23.32		2.92		12.47		3.23		1.50		2.98		0.68		4.14		0.88
	SA1831-y5	1 522.00		10.27		22.18		3.10		13.21		3.48		1.59		3.16		0.75		4.58		0.98
岩石	样品号	Er		Tm		Yb		Lu		Hf		Ta		Pb		Th		U
香菇棚邓家组夹层玄武岩	D1751-y1	1.77		0.26		1.73		0.25		2.46		0.21		3.62		1.16		0.29
	D1751-y2	1.88		0.27		1.80		0.26		2.21		0.53		3.88		1.00		0.23
	D1751-y3	1.78		0.30		1.78		0.28		2.25		0.14		5.08		1.18		0.32
小安里铺岭组玄武岩	SA1831-y1	3.09		0.40		2.66		0.40		3.03		0.44		10.39		1.69		0.46
	SA1831-y2	2.85		0.34		2.28		0.34		2.59		0.30		11.72		1.42		0.37
	SA1831-y3	2.60		0.35		2.37		0.35		2.85		0.40		11.94		1.62		0.44
	SA1831-y4	2.98		0.38		2.54		0.38		2.83		0.38		203.70		1.61		0.47
	SA1831-y5	3.04		0.42		2.87		0.43		3.20		0.38		64.43		1.84		0.48

Fig.8 TAS diagram for basalts from Likou Group(basemap after reference[68])

Fig.9 Chondrite-normalized REE patterns (a) and primitive mantle-normalized trace element spider diagram (b) of basalts from Likou group(basemap after reference[69])

Fig.10 Historic division of Likou Group and sedimentary model of Dengjia Formation(modified after reference[72])

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