Bimodal Mixing Model on the Dolomite Alteration Geochemistry in the Yangshudixia Gold Deposit in Huairou, Beijing

doi:10.19657/j.geoscience.1000-8527.2020.062

Abstract

Abstract:

Altered rocks are important objects in the study of hydrothermal mineralization. The alteration belt is clear at the Yangshudixia gold deposit in the Huairou district of Beijing (China). A lateral surficial alteration profile on dolomite was selected to investigate the alteration geochemistry. Two dolomite samples were collected from each end of the profile, 2 altered samples with different alteration intensity were collected from the quartz vein in the profile, and 2 samples were collected from the quartz vein. Eleven major element oxides and 39 trace elements were analyzed on the 6 samples. The results indicate that the 2 dolomite and the 2 quartz vein samples have similar geochemical contents, while those of the 2 altered rocks are clearly different. Using the bimodal mixing model, two end-members of dolomite and quartz vein were first determined geochemically. Subsequently, the proportional function method and the plateau method were adopted to calculate the mixing ratios of the 2 altered samples based on the 11 major components. The calculation results show the technical defect of the proportional function method, in which the fitting results are much affected by the maximum value and the feasibility of the plateau method, and the median values were used to overcome the defect. According to the mixing ratios of the 2 altered samples calculated on 11 major components with the plateau method, the contents of other 39 trace elements were calculated on the bimodal mixing model for the 2 altered samples. Within the error of 0.3 log interval, the calculated values are similar to the analytical results. This indicates that the bimodal mixing model can well be used to explain the geochemical components of the altered dolomite at Yangshudixia. Our findings can help to reveal the formation mechanism of the dolomite alteration zone in the area.

Key words: Yangshudixia, Huairou, Beijing, gold deposit, quartz vein, proportional function method, plateau method

CLC Number:

YAO Ning, GONG Qingjie, WANG Xuyang, CHAO Yuede, PENG Cheng, WU Yuan, LIU Ningqiang. Bimodal Mixing Model on the Dolomite Alteration Geochemistry in the Yangshudixia Gold Deposit in Huairou, Beijing[J]. Geoscience, 2020, 34(05): 945-956.

Figures/Tables 13

References 30

[1]	陈淳福, 梁有彬. 内生金矿床围岩蚀变及其找矿意义[J]. 地质找矿论丛, 1990,5(3):63-70.
[2]	荆勇河, 田艳丽, 张瀚夫, 等. 围岩蚀变对内生金属矿床勘查的意义[J]. 西部资源, 2014(5):92-94.
[3]	高斌, 马东升. 围岩蚀变过程中地球化学组份质量迁移计算——以湖南沃溪Au-Sb-W矿床为例[J]. 地质找矿论丛, 1999,14(2):25-31.
[4]	张志超, 李楠, 戢兴忠, 等. 西秦岭阳山金矿带安坝矿床热液蚀变作用[J]. 岩石学报, 2015,31(11):3405-3419.
[5]	GRANT J A. The Isocon diagram—A simple solution to Gresens’ equation for metasomatic alteration[J]. Economic Geology, 1986,81:1-5. DOI URL
[6]	邓海琳, 涂光炽, 李朝阳, 等. 地球化学开放系统的质量平衡:1.理论[J]. 矿物学报, 1999,19(2):121-131.
[7]	凌其聪, 刘丛强. 层控夕卡岩型矿床成矿系统的元素活动性及质量迁移——以铜陵冬瓜山铜矿床为例[J]. 矿物学报, 2003,23(1):37-44.
[8]	VOLLMER R. Rb-Sr and U-Th-Pb systematics of alkaline rocks: the alkaline rocks from Italy[J]. Geochimica et Cosmochimica Acta, 1976,40(3):283-295. DOI URL
[9]	LANGMUIR C H, VOCKE R D, HANSON G N, et al. A general mixing equation with applications to Icelandic basalts[J]. Earth and Planetary Science Letters, 1978,37(3):390-392.
[10]	SULLIVAN M D, HASZELDINE R S, FALLICK A E. Linear coupling of carbon and strontium isotopes in Rotliegend Sandstone,North Sea: Evidence for cross-formational fluid flow[J]. Geology, 1990,18(12):1215-1218. DOI URL
[11]	SPERA F J. Energy-constrained open-system magmatic processes I: general model and energy-constrained assimilation and fractional crystallization (EC-AFC) Formulation[J]. Journal of Petrology, 2001,42(5):999-1018. DOI URL
[12]	BOHRSON W A. Energy-constrained open-system magmatic processes II: application of energy-constrained assimilation-fractional crystallization (EC-AFC) model to magmatic systems[J]. Journal of Petrology, 2001,42(5):1019-1041. DOI URL
[13]	GRESENS R L . Composition-volume relationships of metasomatism[J]. Chemical Geology, 1967,2:47-65. DOI URL
[14]	GONG Q J, DENG J, YANG L, et al. Behavior of major and trace elements during weathering of sericite-quartz schist[J]. Journal of Asian Earth Sciences, 2011,42(1/2):1-13. DOI URL
[15]	龚庆杰, 周连壮, 胡杨, 等. 胶东玲珑金矿田煌斑岩蚀变过程元素迁移行为及其意义[J]. 现代地质, 2012,26(5):1065-1077.
[16]	周连壮. 胶东玲珑金矿田西山矿段元素迁移行为及其意义[D]. 北京:中国地质大学(北京), 2013.
[17]	牛会良. 北京怀柔杨树底下金矿床地质特征[J]. 科学时代, 2012(12):195.
[18]	PASSCHIER C W, ZHANG J S, KONOPASEK J. Geometric aspects of synkinematic granite intrusion into a ductile shear zone—an example from the Yunmengshan core complex, northern China[J]. Geological Society,London,Special Publications, 2005,245(1):65-80. DOI URL
[19]	WANG T, GUO L, ZHENG Y, et al. Timing and processes of Late Mesozoic mid-lower-crustal extension in continental NE Asia and implications for the tectonic setting of the destruction of the North China Craton: Mainly constrained by zircon U-Pb ages from metamorphic core complexes[J]. Lithos, 2012,154(6):315-345. DOI URL
[20]	ZHU Guang, CHEN Yin, JIANG Dazhi, et al. Rapid change from compression to extension in the North China Craton during the Early Cretaceous: Evidence from the Yunmengshan metamorphic core complex[J]. Tectonophysics, 2015,656:91-110. DOI URL
[21]	北京市地质矿产局. 北京市区域地质志[J]. 北京: 地质出版社, 1991.
[22]	陈贤, 张传恒, 刘家军, 等. 蓟县常州沟组沉积特征及其地质意义[J]. 地层学杂志, 2014,38(2):236-244.
[23]	李怀永, 郝河, 马学利, 等. 北京市怀柔县崎峰茶金矿区普查地质报告 [R]. 北京:北京市地质矿产局101队, 1996: 11-12.
[24]	任国选, 孟祥化, 葛铭, 等. 蓟县地区雾迷山组硅质岩成因研究[J]. 沉积学报, 2008,26(1):70-76.
[25]	吕金波, 卢耀如, 郑桂森, 等. 北京西山岩溶洞系的形成及其与新构造运动的关系[J]. 地质通报, 2010,29(4):502-509.
[26]	李中坚, 陈柏林, 董法先, 等. 北京怀柔崎峰茶—得田沟金矿田断裂构造及其控矿作用[J]. 地质力学学报, 1998,( 2):23-31.
[27]	崔艳合, 彭明生. 北京市得田沟金矿床矿物特征和金的赋存状态[J]. 矿床地质, 1994,13(3):260-270.
[28]	XIE X J, CHENG H X. Sixty years of exploration geochemistry in China[J]. Journal of Geochemical Exploration, 2014,139:4-8. DOI URL
[29]	LI M, XI X H, XIAO G Y, et al. National multi-purpose regional geochemical survey in China[J]. Journal of Geochemical Exploration, 2014,139:21-30. DOI URL
[30]	BAUMGARTNER L P, OLSEN S N. A least-squares approach to mass transport calculations using the isocon method[J]. Economic Geology, 1995,90(5):1261-1270. DOI URL

样号	岩性	SiO₂	Al₂O₃	TFe₂O₃	MgO	CaO	Na₂O	K₂O	烧失量	总量	Ti	P	Mn
D05	白云岩	0.72	0.07	0.15	24.30	29.00	0.06	0.01	45.60	99.91	38	114	104
D02	白云岩	2.08	0.02	0.06	24.20	28.60	0.06	0.01	44.90	99.93	44	96	54
D03	蚀变岩	30.00	0.06	0.16	16.10	20.70	0.05	0.02	32.80	99.89	66	76	286
D04	蚀变岩	42.30	0.16	0.13	12.70	17.60	0.06	0.04	27.00	99.99	45	105	94
D06	石英脉	96.70	1.69	0.29	0.20	0.14	0.07	0.44	0.37	99.90	316	216	86
D07	石英脉	96.10	1.91	0.30	0.40	0.16	0.52	0.20	0.26	99.85	785	116	92
最大值	—	96.70	1.91	0.30	24.30	29.00	0.52	0.44	45.60	99.99	785	216	286
最小值	—	0.72	0.02	0.06	0.20	0.14	0.05	0.01	0.26	99.85	38	76	54
检出限	—	0.10	0.05	0.05	0.05	0.05	0.05	0.05	0.01	—	50	10	10
D25Avg	白云岩	1.40	0.05	0.11	24.30	28.80	0.06	0.01	45.30	99.92	41	105	79
D67Avg	石英脉	96.40	1.80	0.30	0.30	0.15	0.30	0.32	0.32	99.88	551	166	89

样号	岩性	SiO₂	Al₂O₃	TFe₂O₃	MgO	CaO	Na₂O	K₂O	烧失量	总量	Ti	P	Mn
D05	白云岩	0.72	0.07	0.15	24.30	29.00	0.06	0.01	45.60	99.91	38	114	104
D02	白云岩	2.08	0.02	0.06	24.20	28.60	0.06	0.01	44.90	99.93	44	96	54
D03	蚀变岩	30.00	0.06	0.16	16.10	20.70	0.05	0.02	32.80	99.89	66	76	286
D04	蚀变岩	42.30	0.16	0.13	12.70	17.60	0.06	0.04	27.00	99.99	45	105	94
D06	石英脉	96.70	1.69	0.29	0.20	0.14	0.07	0.44	0.37	99.90	316	216	86
D07	石英脉	96.10	1.91	0.30	0.40	0.16	0.52	0.20	0.26	99.85	785	116	92
最大值	—	96.70	1.91	0.30	24.30	29.00	0.52	0.44	45.60	99.99	785	216	286
最小值	—	0.72	0.02	0.06	0.20	0.14	0.05	0.01	0.26	99.85	38	76	54
检出限	—	0.10	0.05	0.05	0.05	0.05	0.05	0.05	0.01	—	50	10	10
D25Avg	白云岩	1.40	0.05	0.11	24.30	28.80	0.06	0.01	45.30	99.92	41	105	79
D67Avg	石英脉	96.40	1.80	0.30	0.30	0.15	0.30	0.32	0.32	99.88	551	166	89

样号	岩性	Mo	W	Cu	Ag	Au	Zn	Cd	Hg	Sn	Pb	As	Sb	Bi
D05	白云岩	0.30	0.2	2.5	243	1.35	29.5	4 151	51.7	1.9	18.1	0.10	0.04	0.52
D02	白云岩	0.60	0.2	3.0	154	1.66	11.5	2 918	3.3	1.1	11.5	0.10	0.04	0.56
D03	蚀变岩	0.35	0.2	2.8	478	0.95	54.6	1 476	15.0	0.7	12.2	0.45	0.03	0.60
D04	蚀变岩	0.35	0.2	1.5	175	1.07	6.9	1 643	52.5	0.8	6.2	0.10	0.05	0.24
D06	石英脉	0.18	0.9	2.6	210	0.74	19.7	99	68.3	1.3	14.2	4.85	0.03	0.08
D07	石英脉	0.34	3.7	8.4	326	1.50	9.3	75	43.3	0.9	20.3	1.11	0.01	0.55
最大值	-	0.60	3.7	8.4	478	1.66	54.6	4 151	68.3	1.9	20.3	4.6	0.05	0.60
最小值	-	0.18	0.2	1.5	154	0.74	6.9	75	3.3	0.7	6.2	0.1	0.01	0.08
检出限	-	0.02	0.3	1.0	20	0.20	5.0	20	0.5	1.0	2.0	0.2	0.05	0.05
D25Avg	白云岩	0.45	0.2	2.7	199	1.50	20.5	3 535	27.5	1.5	14.8	0.09	0.22	0.54
D67Avg	石英脉	0.26	2.3	5.5	268	1.12	14.5	87	55.8	1.1	17.2	2.98	0.02	0.31
样号	岩性	Li	Be	Sr	Ba	Rb	Cs	Sc	V	Cr	Co	Ni	La	Y
D05	白云岩	13.7	0.30	28.2	56	8.7	3.33	36.3	2.9	2.4	1.89	9.49	1.3	2.0
D02	白云岩	10.6	0.20	32.2	86	6.5	2.22	29.5	1.0	2.4	1.63	9.18	1.2	1.2
D03	蚀变岩	7.4	0.21	25.6	93	4.5	1.27	21.4	4.3	5.2	2.46	9.71	1.0	3.2
D04	蚀变岩	5.7	0.18	22.9	73	4.5	1.33	14.4	1.3	3.5	0.86	5.93	0.8	0.7
D06	石英脉	15.9	0.18	3.7	331	20.9	1.29	0.71	5.7	7.0	0.23	0.82	4.1	2.2
D07	石英脉	2.9	0.30	3.7	126	12.3	0.62	0.77	8.7	7.3	0.40	0.98	4.9	4.6
最大值	-	15.9	0.30	32.0	331	21.0	3.33	36.3	9.0	7.0	2.46	10.00	4.9	4.6
最小值	-	2.9	0.18	3.7	56	4.5	0.62	0.71	1.0	2.4	0.23	0.82	0.8	0.7
检出限	-	1.0	0.20	0.4	5	1.0	0.20	0.60	0.3	0.2	0.20	0.20	1.0	1.0
D25Avg	白云岩	12.1	0.25	30.2	71	7.6	2.77	32.9	1.9	2.4	1.76	9.33	1.2	1.6
D67Avg	石英脉	9.4	0.24	3.7	228	16.6	0.96	0.74	7.2	7.1	0.32	0.90	4.5	3.4
样号	岩性	Zr	Hf	Nb	Ta	Th	U	B	F	Ga	In	Tl	Ge	Se
D05	白云岩	12.0	0.36	0.5	0.53	0.2	0.32	38	55	0.4	0.09	0.62	0.09	0.10
D02	白云岩	9.4	0.29	0.5	2.02	0.2	0.16	30	384	0.4	0.07	0.52	0.11	0.03
D03	蚀变岩	7.4	0.22	0.5	0.37	0.3	0.34	35	124	0.4	0.03	0.24	0.30	0.15
D04	蚀变岩	5.5	0.16	0.5	0.40	0.2	0.15	40	107	0.2	0.04	0.30	1.02	0.10
D06	石英脉	18.4	0.58	1.9	0.15	1.9	1.01	146	218	2.4	0.01	0.43	0.97	0.17
D07	石英脉	19.9	0.61	5.3	0.08	0.5	1.14	319	132	3.5	0.01	0.16	0.47	0.12
最大值	—	20.0	0.61	5.3	2.02	1.9	1.14	319	384	3.5	0.09	0.62	1.02	0.17
最小值	—	5.5	0.16	0.5	0.08	0.2	0.15	30	55	0.2	0.01	0.16	0.09	0.03
检出限	—	5.0	0.20	2.0	0.10	0.2	0.10	1	100	2.0	0.01	0.1	0.10	0.01
D25Avg	白云岩	10.7	0.33	0.5	1.27	0.2	0.24	34	219	0.4	0.08	0.57	0.10	0.07
D67Avg	石英脉	19.2	0.59	3.6	0.12	1.2	1.07	233	175	3.0	0.01	0.29	0.72	0.14

样号	岩性	Mo	W	Cu	Ag	Au	Zn	Cd	Hg	Sn	Pb	As	Sb	Bi
D05	白云岩	0.30	0.2	2.5	243	1.35	29.5	4 151	51.7	1.9	18.1	0.10	0.04	0.52
D02	白云岩	0.60	0.2	3.0	154	1.66	11.5	2 918	3.3	1.1	11.5	0.10	0.04	0.56
D03	蚀变岩	0.35	0.2	2.8	478	0.95	54.6	1 476	15.0	0.7	12.2	0.45	0.03	0.60
D04	蚀变岩	0.35	0.2	1.5	175	1.07	6.9	1 643	52.5	0.8	6.2	0.10	0.05	0.24
D06	石英脉	0.18	0.9	2.6	210	0.74	19.7	99	68.3	1.3	14.2	4.85	0.03	0.08
D07	石英脉	0.34	3.7	8.4	326	1.50	9.3	75	43.3	0.9	20.3	1.11	0.01	0.55
最大值	-	0.60	3.7	8.4	478	1.66	54.6	4 151	68.3	1.9	20.3	4.6	0.05	0.60
最小值	-	0.18	0.2	1.5	154	0.74	6.9	75	3.3	0.7	6.2	0.1	0.01	0.08
检出限	-	0.02	0.3	1.0	20	0.20	5.0	20	0.5	1.0	2.0	0.2	0.05	0.05
D25Avg	白云岩	0.45	0.2	2.7	199	1.50	20.5	3 535	27.5	1.5	14.8	0.09	0.22	0.54
D67Avg	石英脉	0.26	2.3	5.5	268	1.12	14.5	87	55.8	1.1	17.2	2.98	0.02	0.31
样号	岩性	Li	Be	Sr	Ba	Rb	Cs	Sc	V	Cr	Co	Ni	La	Y
D05	白云岩	13.7	0.30	28.2	56	8.7	3.33	36.3	2.9	2.4	1.89	9.49	1.3	2.0
D02	白云岩	10.6	0.20	32.2	86	6.5	2.22	29.5	1.0	2.4	1.63	9.18	1.2	1.2
D03	蚀变岩	7.4	0.21	25.6	93	4.5	1.27	21.4	4.3	5.2	2.46	9.71	1.0	3.2
D04	蚀变岩	5.7	0.18	22.9	73	4.5	1.33	14.4	1.3	3.5	0.86	5.93	0.8	0.7
D06	石英脉	15.9	0.18	3.7	331	20.9	1.29	0.71	5.7	7.0	0.23	0.82	4.1	2.2
D07	石英脉	2.9	0.30	3.7	126	12.3	0.62	0.77	8.7	7.3	0.40	0.98	4.9	4.6
最大值	-	15.9	0.30	32.0	331	21.0	3.33	36.3	9.0	7.0	2.46	10.00	4.9	4.6
最小值	-	2.9	0.18	3.7	56	4.5	0.62	0.71	1.0	2.4	0.23	0.82	0.8	0.7
检出限	-	1.0	0.20	0.4	5	1.0	0.20	0.60	0.3	0.2	0.20	0.20	1.0	1.0
D25Avg	白云岩	12.1	0.25	30.2	71	7.6	2.77	32.9	1.9	2.4	1.76	9.33	1.2	1.6
D67Avg	石英脉	9.4	0.24	3.7	228	16.6	0.96	0.74	7.2	7.1	0.32	0.90	4.5	3.4
样号	岩性	Zr	Hf	Nb	Ta	Th	U	B	F	Ga	In	Tl	Ge	Se
D05	白云岩	12.0	0.36	0.5	0.53	0.2	0.32	38	55	0.4	0.09	0.62	0.09	0.10
D02	白云岩	9.4	0.29	0.5	2.02	0.2	0.16	30	384	0.4	0.07	0.52	0.11	0.03
D03	蚀变岩	7.4	0.22	0.5	0.37	0.3	0.34	35	124	0.4	0.03	0.24	0.30	0.15
D04	蚀变岩	5.5	0.16	0.5	0.40	0.2	0.15	40	107	0.2	0.04	0.30	1.02	0.10
D06	石英脉	18.4	0.58	1.9	0.15	1.9	1.01	146	218	2.4	0.01	0.43	0.97	0.17
D07	石英脉	19.9	0.61	5.3	0.08	0.5	1.14	319	132	3.5	0.01	0.16	0.47	0.12
最大值	—	20.0	0.61	5.3	2.02	1.9	1.14	319	384	3.5	0.09	0.62	1.02	0.17
最小值	—	5.5	0.16	0.5	0.08	0.2	0.15	30	55	0.2	0.01	0.16	0.09	0.03
检出限	—	5.0	0.20	2.0	0.10	0.2	0.10	1	100	2.0	0.01	0.1	0.10	0.01
D25Avg	白云岩	10.7	0.33	0.5	1.27	0.2	0.24	34	219	0.4	0.08	0.57	0.10	0.07
D67Avg	石英脉	19.2	0.59	3.6	0.12	1.2	1.07	233	175	3.0	0.01	0.29	0.72	0.14