Acoustic characteristics of rocks from the SWIR hydrothermal fields

doi:10.3969/j.issn.1001-909X.2024.01.001

Abstract

Abstract:

The hydrothermal fields of the Southwest Indian Ridge (SWIR) have the potential to develop large scale sulfide deposits, and the SWIR sulfide mineral resource evaluation is currently underway. Measurement and analysis of petrophysical characteristics such as P-wave velocity of sulfides and different host rocks are the basis for processing and interpretation of near-bottom seismic exploration data. Through the systematic measurement of the physical properties of sulfides and host rocks in the SWIR hydrothermal areas, we have analyzed the characteristics of rock P-wave velocity variation and its influencing factors by combining rock physical properties (including density, porosity, P-wave velocity) and minerals. The results show that the P-wave velocity of SWIR rocks is influenced by the rock skeleton minerals, pore space and confining pressure. Due to the overall small porosity of the rocks, the effect on P-wave velocity is not significant, but the increase of the confining pressure gradually closes the rock microfractures and pores, and the P-wave velocity varies non-linearly exponentially. The alteration causes the change of mineral composition, which is the most critical factor affecting the P-wave velocity of the confining rocks. The results of single physical parameter measurements may have multiple solutions, and the joint measurement of multiple physical parameters such as wave velocity, density, magnetic and electrical properties is beneficial for lithological differentiation. The research results help identifying sulfides and host rocks, and provide important support for the seismic exploration of polymetallic sulfides in the Southwest Indian Ocean contract area of China.

Key words: Southwest Indian Ridge, deep-sea hydrothermal fields, rock acoustic properties, petrophysical measurements, P-wave velocity

CLC Number:

P714⁺.8

JIE Tianyu, ZHOU Jianping, TAO Chunhui, WANG Hanchuang, LI Qianyu, WU Tao, LIU Long. Acoustic characteristics of rocks from the SWIR hydrothermal fields[J]. Journal of Marine Sciences, 2024, 42(1): 1-12.

Figures/Tables 14

References 40

[1]	YU J Y, TAO C H, LIAO S L, et al. Resource estimation of the sulfide-rich deposits of the Yuhuang-1 hydrothermal field on the ultraslow-spreading Southwest Indian Ridge[J]. Ore Geology Reviews, 2021, 134: 104169.
[2]	张涛, LIN Jian, 高金耀. 西南印度洋中脊热液区的岩浆活动与构造特征[J]. 中国科学:地球科学, 2013, 43(11):1834-1846.
	ZHANG T, LIN J, GAO J Y. Magmatism and tectonic processes in Area A hydrothermal vent on the Southwest Indian Ridge[J]. Science China: Earth Sciences, 2013, 43(11): 1834-1846.
[3]	WU T, TIVEY M A, TAO C H, et al. An intermittent detachment faulting system with a large sulfide deposit revealed by multi-scale magnetic surveys[J]. Nature Communications, 2021, 12(1): 5642. DOI PMID
[4]	ZHU Z, TAO C, SHEN J, et al. Self-potential tomography of a deep-sea polymetallic sulfide deposit on Southwest Indian Ridge[J]. Journal of Geophysical Research: Solid Earth, 2020, 125(11): e2020JB019738.
[5]	JIAN H C, SINGH S C, CHEN Y J, et al. Evidence of an axial magma chamber beneath the ultraslow-spreading Southwest Indian Ridge[J]. Geology, 2017, 45(2): 143-146.
[6]	王伟, 牛雄伟, 阮爱国, 等. 西南印度洋中脊49.5°E离轴地壳结构[J]. 地球物理学报, 2018, 61(11):4406-4417. DOI
	WANG W, NIU X W, RUAN A G, et al. Off-axis crustal structure at the Southwest Indian Ridge (49.5°E)[J]. Chinese Journal of Geophysics, 2018, 61(11): 4406-4417.
[7]	MURTON B J, LEHRMANN B, DUTRIEUX A M, et al. Geological fate of seafloor massivesulphides at the TAG hydrothermal field (Mid-Atlantic Ridge)[J]. Ore Geology Reviews, 2019, 107: 903-925.
[8]	DOMENICO S N. Rock lithology and porosity determination from shear and compressional wave velocity[J]. Geophysics, 1984, 49(8): 1188-1195.
[9]	WILKENS R H, FRYER G J, KARSTEN J. Evolution of porosity and seismic structure of upper oceanic crust: Impor-tance of aspect ratios[J]. Journal of Geophysical Research: Solid Earth, 1991, 96(B11): 17981-17995.
[10]	黄威, 陶春辉, 邓显明, 等. 西南印度洋脊49°39'E热液活动区IODP钻探计划的科学意义[J]. 海洋学研究, 2009, 27(2):97-103.
	HUANG W, TAO C H, DENG X M, et al. Discussion and the scientific significance of IODP drilling to study in the 49°39'E vent field in Southwest Indian Ridge[J]. Journal of Marine Sciences, 2009, 27(2): 97-103.
[11]	TAO C H, WU T, JIN X B, et al. Petrophysical charac-teristics of rocks and sulfides from the SWIR hydrothermal field[J]. Acta Oceanologica Sinica, 2013, 32(12): 118-125.
[12]	GEORGEN J E, LIN J, DICK H J B. Evidence from gravity anomalies for interactions of the Marion and Bouvet hotspots with the Southwest Indian Ridge: Effects of transform offsets[J]. Earth and Planetary Science Letters, 2001, 187(3/4): 283-300.
[13]	陶春辉, 李怀明, 金肖兵, 等. 西南印度洋脊的海底热液活动和硫化物勘探[J]. 科学通报, 2014, 59(19):1812-1822.
	TAO C H, LI H M, JIN X B, et al. Seafloor hydrothermal activity and polymetallic sulfide exploration on the southwest Indian ridge[J]. Chinese Science Bulletin, 2014, 59: 2266-2276.
[14]	BAKER E T, EDMONDS H N, MICHAEL P J, et al. Hydrothermal venting in magma deserts: The ultraslow-spreading Gakkel and Southwest Indian Ridges[J]. Geoche-mistry, Geophysics, Geosystems, 2004, 5(8): Q08002.
[15]	LI J B, JIAN H C, CHEN Y J, et al. Seismic observation of an extremely magmatic accretion at the ultraslow spreading Southwest Indian Ridge[J]. Geophysical Research Letters, 2015, 42(8): 2656-2663.
[16]	TAO C H, LIN J, GUO S Q, et al. First active hydro-thermal vents on an ultraslow-spreading center: Southwest Indian Ridge[J]. Geology, 2012, 40(1): 47-50.
[17]	CANNAT M, SAUTER D, BEZOS A, et al. Spreading rate, spreading obliquity, and melt supply at the ultraslow spreading Southwest Indian Ridge[J]. Geochemistry, Geophysics, Geosystems, 2008, 9(4): Q04002.
[18]	SAUTER D, CANNAT M, MEYZEN C, et al. Propagation of a melting anomaly along the ultraslow Southwest Indian Ridge between 46°E and 52°20'E: Interaction with the Crozethotspot?[J]. Geophysical Journal International, 2009, 179(2): 687-699.
[19]	PLANKE S, CERNEY B, BÜCKER C J, et al. Alteration effects on petrophysical properties of subaerial flood basalts: Site 990, Southeast Greenland margin[C]// Proceedings of the Ocean Drilling Program, Scientific Results, 1999, 163: 17-28.
[20]	KASSAB M A, WELLER A. Study on P-wave and S-wave velocity in dry and wet sandstones of Tushka region, Egypt[J]. Egyptian Journal of Petroleum, 2015, 24(1): 1-11.
[21]	SPAGNOLI G, WEYMER B A, JEGEN M, et al. P-wave velocity measurements for preliminary assessments of the mineralization in seafloor massive sulfide mini-cores during drilling operations[J]. Engineering Geology, 2017, 226: 316-325.
[22]	GRÖSCHEL-BECKER H M, DAVIS E E, FRANKLIN J M. Data report: Physical properties of massive sulfide from site 856, middle valley, northern Juan de Fuca ridge[C]// Proceedings of the Ocean Drilling Program, Scientific Results, 1994, 139: 721-724.
[23]	WANG S S, CHANG L, WU T, et al. Progressive dissolution of titanomagnetite in high-temperature hydrothermal vents dramatically reduces magnetization of basaltic ocean crust[J]. Geophysical Research Letters, 2020, 47(8): e87578.
[24]	刘隆, 周建平, 吴涛, 等. 大洋中脊玄武岩磁性特征[J]. 地球物理学进展, 2021, 36(5):1880-1890.
	LIU L, ZHOU J P, WU T, et al. Magnetic characteristics of basalt on mid-ocean ridge[J]. Progress in Geophysics, 2021, 36(5): 1880-1890.
[25]	JOHNSTON J E, FRYER G J, CHRISTENSEN N I. Velocity-porosity relationships of basalts from the East Pacific Rise[C]// Proceedings of the Ocean Drilling Program, Scientific results, 1995, 142: 51-59.
[26]	CARLSON R L. The effect of hydrothermal alteration on the seismic structure of the upper oceanic crust: Evidence from Holes 504B and 1256D[J]. Geochemistry, Geophysics, Geosystems, 2011, 12(9): Q09013.
[27]	CARLSON R L. The effects of alteration and porosity on seismic velocities in oceanic basalts and diabases[J]. Geochemistry, Geophysics, Geosystems, 2014, 15(12): 4589-4598.
[28]	LUDWIG R J, ITURRINO G J, RONA P A. Seismic velocity-porosity relationship of sulfide, sulfate, and basalt samples from the TAG hydrothermal mound[C]// Proceedings of the Ocean Drilling Program, Scientific Results, 1998, 158: 313-328.
[29]	TSUJI T, ITURRINO G J. Velocity-porosity relationships in oceanic basalt from eastern flank of the Juan de Fuca Ridge: The effect of crack closure on seismic velocity[J]. Exploration Geophysics, 2008, 39(1): 41-51.
[30]	CHRISTENSEN N I, WEPFER W W, BAUD R D. Seismic properties of sheeted dikes from Hole 504B, ODP Leg 111[C]// Proceedings of the Ocean Drilling Program, Scientific results, 1989, 111: 171-176.
[31]	CHEN H, TAO C, REVIL A, et al. Induced polarization and magnetic responses of serpentinized ultramafic rocks from mid-ocean ridges[J]. Journal of Geophysical Research: Solid Earth, 2021, 126(12): e2021JB022915.
[32]	CARLSON R L, JAY MILLER D. Influence of pressure and mineralogy on seismic velocities in oceanicgabbros: Implications for the composition and state of the lower oceanic crust[J]. Journal of Geophysical Research: Solid Earth, 2004, 109(B9): B09205.
[33]	CHRISTENSEN N I. Elasticity of ultrabasic rocks[J]. Journal of Geophysical Research, 1966, 71(24): 5921-5931.
[34]	SEYLER M, CANNAT M, MÉVEL C. Evidence for major-element heterogeneity in the mantle source of abyssal peridotites from the Southwest Indian Ridge (52° to 68°E)[J]. Geochemistry, Geophysics, Geosystems, 2003, 4(2):9101.
[35]	徐浩波, 管清胜, 许明珠, 等. 蛇纹岩化作用对超慢速洋中脊拆离断层发育的影响[J]. 海洋学研究, 2021, 39(3):21-30.
	XU H B, GUAN Q S, XU M Z, et al. The effect of serpentinization on detachment faults at ultra-slow spreading mid-ocean ridge[J]. Journal of Marine Sciences, 2021, 39(3): 21-30. DOI
[36]	KHAKSAR, GRIFFITHS, MCCANN. Compressional- and shear-wave velocities as a function of confining stress in dry sandstones[J]. Geophysical Prospecting, 1999, 47(4): 487-508.
[37]	EBERHART-PHILLIPS D, HAN D H, ZOBACK M D. Empirical relationships among seismic velocity, effective pressure, porosity, and clay content in sandstone[J]. Geophysics, 1989, 54(1): 82-89.
[38]	FREUND D. Ultrasonic compressional and shear velocities in dry clastic rocks as a function of porosity, clay content, and confining pressure[J]. Geophysical Journal International, 1992, 108(1): 125-135.
[39]	JONES S M. Velocities and quality factors of sedimentary rocks at low and high effective pressures[J]. Geophysical Journal International, 1995, 123(3): 774-780.
[40]	BIRCH F. The velocity of compressional waves in rocks to 10 kilobars: 1[J]. Journal of Geophysical Research, 1960, 65(4): 1083-1102.

序号	样品类型	石英	斜长石	方解石	黄铁矿	蛇纹石	辉石	角闪石	磁铁矿	橄榄石	黏土矿物总量
B1	新鲜玄武岩	0	73.7	0	0	0	16.9	0	0	0	9.4
B2	新鲜玄武岩	0	84.2	0	0	0	10.1	0	0	2.0	3.7
B3	新鲜玄武岩	0	80.7	0	0	0	12.6	0	0	3.7	3.0
B4	新鲜玄武岩	0	68.6	0	0	0	20.1	0	0	11.3	0
B5	新鲜玄武岩	1.6	75.6	0	0	0	19.0	0	0	3.8	0
AB1	蚀变玄武岩	8.7	16.6	0	0	0	2.0	4.6	0	0	68.1
AB2	蚀变玄武岩	48.4	0	0	0	0	0	0	0	0	51.6
AB3	蚀变玄武岩	71.1	1.9	0	0	0	0	0	0	0	26.2
AB4	蚀变玄武岩	31.6	13.2	0	0	0	1.5	0	0	0	53.7
AB5	蚀变玄武岩	6.9	19.1	0	0	0	3.4	1.8	0	0	67.4
AB6	蚀变玄武岩	48.2	15.4	0	0	0	1.7	1.4	0	0	31.8
AB7	蚀变玄武岩	1.7	24.9	0	0	0	2.3	4.4	0	0	65.3
SR1	蛇纹岩	0	0	0	0	61.8	11.4	0	26.8	0	0
SR2	蛇纹岩	0	0	0	0	75.6	4.1	4.9	15.4	0	0
SR3	蛇纹岩	0	0	0	0	82.4	0	0	17.6	0	0
SR4	蛇纹岩	0	0	0	0	45.9	0	0	24.8	0	29.3
D1	辉绿岩	1.5	69.1	0	0	0	2.9	12.6	3.9	0	5.8
G1	辉长岩	1.2	66.8	0	0	0	4.1	19.7	3.2	0	2.5
G2	辉长岩	0.7	64.9	0	0	0	8.1	7.6	2.7	0	2.5
S1	硫化物	0	0	39.3	60.7	0	0	0	0	0	0
S2	硫化物	0	0	1.9	18.7	0	0	0	0	0	0
S3	硫化物	0	0	5.1	94.9	0	0	0	0	0	0
S4	硫化物	1.4	0	0	85.1	0	0	0	0	0	0
S5	硫化物	0.7	0	22.5	61.8	0	0	0	0	0	0

序号	样品类型	石英	斜长石	方解石	黄铁矿	蛇纹石	辉石	角闪石	磁铁矿	橄榄石	黏土矿物总量
B1	新鲜玄武岩	0	73.7	0	0	0	16.9	0	0	0	9.4
B2	新鲜玄武岩	0	84.2	0	0	0	10.1	0	0	2.0	3.7
B3	新鲜玄武岩	0	80.7	0	0	0	12.6	0	0	3.7	3.0
B4	新鲜玄武岩	0	68.6	0	0	0	20.1	0	0	11.3	0
B5	新鲜玄武岩	1.6	75.6	0	0	0	19.0	0	0	3.8	0
AB1	蚀变玄武岩	8.7	16.6	0	0	0	2.0	4.6	0	0	68.1
AB2	蚀变玄武岩	48.4	0	0	0	0	0	0	0	0	51.6
AB3	蚀变玄武岩	71.1	1.9	0	0	0	0	0	0	0	26.2
AB4	蚀变玄武岩	31.6	13.2	0	0	0	1.5	0	0	0	53.7
AB5	蚀变玄武岩	6.9	19.1	0	0	0	3.4	1.8	0	0	67.4
AB6	蚀变玄武岩	48.2	15.4	0	0	0	1.7	1.4	0	0	31.8
AB7	蚀变玄武岩	1.7	24.9	0	0	0	2.3	4.4	0	0	65.3
SR1	蛇纹岩	0	0	0	0	61.8	11.4	0	26.8	0	0
SR2	蛇纹岩	0	0	0	0	75.6	4.1	4.9	15.4	0	0
SR3	蛇纹岩	0	0	0	0	82.4	0	0	17.6	0	0
SR4	蛇纹岩	0	0	0	0	45.9	0	0	24.8	0	29.3
D1	辉绿岩	1.5	69.1	0	0	0	2.9	12.6	3.9	0	5.8
G1	辉长岩	1.2	66.8	0	0	0	4.1	19.7	3.2	0	2.5
G2	辉长岩	0.7	64.9	0	0	0	8.1	7.6	2.7	0	2.5
S1	硫化物	0	0	39.3	60.7	0	0	0	0	0	0
S2	硫化物	0	0	1.9	18.7	0	0	0	0	0	0
S3	硫化物	0	0	5.1	94.9	0	0	0	0	0	0
S4	硫化物	1.4	0	0	85.1	0	0	0	0	0	0
S5	硫化物	0.7	0	22.5	61.8	0	0	0	0	0	0

岩石类型	样品数量	数据统计	饱水密度/(g·cm^-3)	孔隙度/%	P波速度/ (m·s^-1)
岩石类型	样品数量	数据统计	饱水密度/(g·cm^-3)	孔隙度/%	常压	5 MPa	10 MPa	20 MPa	30 MPa
新鲜玄武岩	74	平均值	2.85	0.60	5 826	5 914	5 932	5 991	6 045
		最大值	2.93	3.69	6 552	6 589	6 626	6 651	6 762
		最小值	2.68	0	4 911	5 058	5 136	5 249	5 343
		标准差	0.05	0.87	360	329	347	337	328
蚀变玄武岩	19	平均值	2.69	1.37	4 929	5 166	5 054	5 114	5 162
		最大值	2.96	2.76	6 754	6 828	6 929	7 033	7 086
		最小值	2.51	0	3 968	4 044	4 097	4 150	4 178
		标准差	0.12	0.69	841	915	831	835	829
蛇纹岩	4	平均值	2.58	0.13	4 945	5 007	5 068	5 105	5 134
		最大值	2.63	0.30	5 289	5 324	5 383	5 431	5 467
		最小值	2.54	0	4 529	4 632	4 712	4 914	4 785
		标准差	0.04	0.14	362	337	326	326	326
辉长岩	3	平均值	2.91	0.28	5 812	5 988	5 990	6 076	6 195
		最大值	2.97	0.84	6 363	6 568	6 732	6 816	6 962
		最小值	2.81	0	5 376	5 407	5 471	5 537	5 638
		标准差	0.09	0.49	503	821	659	663	687
硫化物(块状硫化物和硫化物烟囱)	5	平均值	2.93	20.02	3 935
		最大值	3.23	28.72
		最小值	1.80	9.65
		标准差	0.56	6.57

岩石类型	样品数量	数据统计	饱水密度/(g·cm^-3)	孔隙度/%	P波速度/ (m·s^-1)
岩石类型	样品数量	数据统计	饱水密度/(g·cm^-3)	孔隙度/%	常压	5 MPa	10 MPa	20 MPa	30 MPa
新鲜玄武岩	74	平均值	2.85	0.60	5 826	5 914	5 932	5 991	6 045
		最大值	2.93	3.69	6 552	6 589	6 626	6 651	6 762
		最小值	2.68	0	4 911	5 058	5 136	5 249	5 343
		标准差	0.05	0.87	360	329	347	337	328
蚀变玄武岩	19	平均值	2.69	1.37	4 929	5 166	5 054	5 114	5 162
		最大值	2.96	2.76	6 754	6 828	6 929	7 033	7 086
		最小值	2.51	0	3 968	4 044	4 097	4 150	4 178
		标准差	0.12	0.69	841	915	831	835	829
蛇纹岩	4	平均值	2.58	0.13	4 945	5 007	5 068	5 105	5 134
		最大值	2.63	0.30	5 289	5 324	5 383	5 431	5 467
		最小值	2.54	0	4 529	4 632	4 712	4 914	4 785
		标准差	0.04	0.14	362	337	326	326	326
辉长岩	3	平均值	2.91	0.28	5 812	5 988	5 990	6 076	6 195
		最大值	2.97	0.84	6 363	6 568	6 732	6 816	6 962
		最小值	2.81	0	5 376	5 407	5 471	5 537	5 638
		标准差	0.09	0.49	503	821	659	663	687
硫化物(块状硫化物和硫化物烟囱)	5	平均值	2.93	20.02	3 935
		最大值	3.23	28.72
		最小值	1.80	9.65
		标准差	0.56	6.57

数据统计	方程(3)	方程(2)
数据统计	R²	R²	a	b	c
平均值	0.935	0.991	6 053	317	0.05
最大值	0.990	0.998	7 189	1 037	0.13
最小值	0.822	0.991	4 781	111	0.01
标准差	0.047	0.003	491	175	0.03