南海IODP 349航次基底玄武岩中碳酸盐岩脉的岩石学特征*

doi:10.11978/2018007

摘要/Abstract

摘要：

国际大洋发现计划(International Ocean Discovery Program, IODP)349航次在南海东部次海盆和西南次海盆残留扩张脊附近的U1431和U1433站位首次钻取基底玄武岩, 通过对16块基底玄武岩内的碳酸盐岩脉薄片镜下观察以及激光拉曼光谱分析, 揭示碳酸盐矿物为方解石和文石, 为典型的洋壳低温热液蚀变次生矿物。U1431站位碳酸盐岩脉为独立的方解石脉、文石脉交替出现; 而U1433站位则存在方解石脉、文石脉和方解石-文石共生脉三种情况。此外, U1431站位在基底~42.1m处出现了平行的方解石脉和文石脉, 揭示U1431存在不同来源热液的多期活动, 即可能存在多次或多阶段不同的热液注入。U1431和U1433站位的碳酸岩脉中, 文石的矿物集合体形状基本一致, 呈块状、纤维状和放射纤维状; 而方解石存在差异, U1431的方解石以斑块状、块状、粒状和纤维状出现, 而U1433的方解石仅出现块状。U1431站位的碳酸盐岩脉的丰度明显高于U1433站位。这些均揭示U1431站位的低温热液活动强, 而U1433站位则相对弱。两个站位的热液活动不同很可能是由于区域地质环境的差异造成——U1431附近的巨大海山为其提供了热液补给, 而U1433远离热液的补给/渗漏点。

关键词: 基底碳酸盐岩脉, 激光拉曼光谱, 方解石和文石, 低温热液, 南海, IODP349航次

Abstract:

The basaltic basement in the South China Sea was cored for the first time during International Ocean Discovery Program (IODP) Exp 349. The basalt was collected from Sites U1431 and U1433 close to the fossil spreading ridge in East and Southwest Sub-basins, respectively. Carbonate veins (n=16) within the basalt were investigated under microscope and by the laser Raman spectra. At Site U1431, the carbonate veins consisted of calcite veins or aragonite veins, while at Site U1433 the carbonate veins are composed of either calcite veins, or aragonite veins, and calcite-aragonite mixed veins. Meanwhile, the calcite veins and aragonites alternated, and at ~42.1 m below basement, two calcite veins and one aragonite vein occurred parallel, likely indicating that multiple hydrothermal fluids of different sources have circulated there. At both sites, the textures of aragonite are generally the same-blocky, fibrous, and radiating fibers. However, it is not the case for calcite. At Site U1431, the calcite is clotted blocky, blocky, granule, and fibrous, while at Site U1433 the calcite only occur as blocks. The abundance of carbonate veins at Site U1431 is much higher than that at Site U1433. These suggest that the low-temperature hydrothermal circulation at Site U1431 is stronger than that at Site U1433. Different local geology and environment mostly lead to the differences in hydrothermal activity at these two sites: Site U1431 is close to a giant seamount that serves as a recharge site, while Site U1433 is far away from any recharge or discharge site.

Key words: carbonate veins, Laser Raman spectra, calcite, aragonite, low temperature hydrothermal fluid flow, South China Sea, IODP Exp349

中图分类号:

P578.6

许佳锐, 陈毅凤, 王宝云. 南海IODP 349航次基底玄武岩中碳酸盐岩脉的岩石学特征*[J]. 热带海洋学报, 2018, 37(6): 63-73.

Jiarui XU, Yifeng CHEN, Baoyun WANG. Petrography of carbonate veins in basement basalts from the South China Sea Exp. 349[J]. Journal of Tropical Oceanography, 2018, 37(6): 63-73.

图/表 9

图1

图2

图3

图4

图5

表1

南海碳酸盐岩脉的碳酸盐矿物拉曼位移"

岩脉编号		深度/mbsf	基底深度/m	碳酸盐矿物结构	矿物相	晶格振动
岩脉编号		深度/mbsf	基底深度/m	碳酸盐矿物结构	矿物相	平动	摆动	面内弯曲振动	对称伸缩振动	反对称伸缩振动*	面外弯曲振动*
U1431E-	39R-1-W, 10-13	910.12	20.41	块状	文石	153	206	706	1086	1463	/
	41R-2-W, 43-47	925.38	35.67	斑块状	方解石	155	283	713	1088	/	/
	41R-2-W, 43-47	925.38	35.67	粒状	方解石	154	282	713	1089	/	/
	41R-5-W, 21-23	928.67	38.96	纤维状/放射纤维状	文石	153	206	703	1085	1463	/
	41R-5-W, 21-23	928.67	38.96	粒状	文石	153	206	704	1086	/	/
	41R-7-W, 65-71	931.84	42.13	纤维状	方解石	155	282	713	1087	/	1749
				纤维状/放射纤维状	文石	154	206	706	1085	1463	/
				块状	文石	153	207	706	1086	/	/
	42R-4-W, 31-35	937.66	47.95	块状	方解石	156	284	713	1088	/	1749
	42R-4-W, 31-35	937.66	47.95	斑块状	方解石	153	282	712	1087	/	1749
	43R-2-W, 74-77	944.66	54.94	块状	方解石	155	283	713	1087	/	/
	46R-3-W, 114-118	976.16	86.45	块状	方解石	154	283	713	1087	1438	/
	47R-5-W, 5-9	987.22	97.51	块状/放射纤维状	文石	152	205	705	1084	1463	/
	49R-2-W, 136-138	993.88	104.17	纤维状	方解石	155	282	713	1087	1438	1749
	49R-2-W, 136-138	993.88	104.17	粒状	方解石	156	283	712	1088	/	/
	50R-3-W, 6-10	1003.80	114.09	纤维状	方解石	155	282	713	1087	1438	1749
U1433B-	66R-1-W, 63-65	805.84	10.34	块状	方解石	155	282	713	1087	/	1749
				纤维状	文石	152	206	705	1084	/	/
				块状	文石	153	206	705	1084	/	/
	66R-4-W, 11-16	809.38	13.88	块状	文石	152	206	704	1084	1461	/
	66R-4-W, 109-114	810.36	14.86	块状	方解石	155	281	712	1087	1437	1749
				块状	文石	152	206	704	1084	1461	/
				纤维状/放射纤维状	文石	152	205	704	1084	/	/
	68R-1-W, 86-90	820.58	25.08	块状	方解石	155	283	713	1087	/	/
	68R-1-W, 86-90	820.58	25.08	放射纤维状/块状	文石	152	206	705	1084	/	/
	75R-1-W, 120-122	854.91	59.41	块状	方解石	155	282	713	1087	/	/
	75R-3-W, 31-34	856.13	60.63	块状	方解石	155	282	713	1087	1437	1749

表1

图6

图7

图8

参考文献 36

[1]	杜广鹏, 范建良, 2010. 方解石族矿物的拉曼光谱特征[J]. 矿物岩石, 30(4): 32-35.
	DU GUANGPENG, FAN JIANLIANG, 2010. Characteristics of Raman spectral of calcite group minerals[J]. Journal of Mineralogy and Petrology, 30(4): 32-35 (in Chinese with English abstract).
[2]	ALT J C, HONNOREZ J, LAVERNE C, et al, 1986. Hydrothermal alteration of a 1 km section through the upper oceanic crust, Deep Sea Drilling Project Hole 504B: mineralogy, chemistry and evolution of seawater‐basalt interactions[J]. Journal of Geophysical Research, 91(B10): 10309-10335.
[3]	ALT J C, TEAGLE D A H.2003. Hydrothermal alteration of upper oceanic crust formed at a fast-spreading ridge: mineral, chemical, and isotopic evidence from ODP Site 801[J]. Chemical Geology, 201(3-4): 191-211.
[4]	ALT J C, TEAGLE D A H, LAVERNE C, et al, 1996. Ridge-flank alteration of upper ocean crust in the eastern Pacific: Synthesis of results for volcanic rocks of Holes 504B and 896A[G/OL]//ALT J C, KINOSHITA H, STOKKING L B, et al. Proceedings of the ocean drilling program, scientific results. College Station, TX (Ocean Drilling Program): 435-450. [2018-01-09]. .
[5]	BARCKHAUSEN U, ENGELS M, FRANKE D, et al, 2014. Evolution of the South China Sea: revised ages for breakup and seafloor spreading[J]. Marine and Petroleum Geology, 58: 599-611.
[6]	BRIAIS A, PATRIAT P, TAPPONNIER P, 1993. Updated interpretation of magnetic anomalies and seafloor spreading stages in the South China Sea: implications for the Tertiary tectonics of Southeast Asia[J]. Journal of Geophysical Research, 98(B4): 6299-6328.
[7]	COGGON R M, TEAGLE D A H, COOPER M J, et al, 2004. Linking basement carbonate vein compositions to porewater geochemistry across the eastern flank of the Juan de Fuca Ridge, ODP Leg 168[J]. Earth and Planetary Science Letters, 219(1-2): 111-128.
[8]	COGGON R M, TEAGLE D A H, SMITH-DUQUE C E, et al, 2010. Reconstructing past seawater Mg/Ca and Sr/Ca from mid-ocean ridge flank calcium carbonate veins[J]. Science, 327(5969): 1114-1117.
[9]	COOGAN L A, GILLIS K M, 2013. Evidence that low-temperature oceanic hydrothermal systems play an important role in the silicate-carbonate weathering cycle and long-term climate regulation[J]. Geochemistry, Geophysics, Geosystems, 14(6): 1771-1786.
[10]	DE CHOUDENS-SANCHEZ V, GONZALEZ L A, 2009. Calcite and aragonite precipitation under controlled instantaneous supersaturation: elucidating the role of CaCO3 saturation state and Mg/Ca ratio on calcium carbonate polymorphism[J]. Journal of Sedimentary Research, 79(6): 363-376.
[11]	DING WEIWEI, CHEN YIFENG, SUN ZHEN, et al, 2017. Chemical compositions and precipitation timing of basement calcium carbonate veins from the South China Sea[J]. Marine Geology, 392: 170-178.
[12]	EDWARDS H G M, VILLAR S E J, JEHLICKA J, et al, 2005. FT-Raman spectroscopic study of calcium-rich and magnesium-rich carbonate minerals[J]. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 61(10): 2273-2280.
[13]	ELDERFIELD H, WHEAT C G, MOTTL M J, et al, 1999. Fluid and geochemical transport through oceanic crust: a transect across the eastern flank of the Juan de Fuca Ridge[J]. Earth and Planetary Science Letters, 172(1-2): 151-165.
[14]	FERNÁNDEZ-DÍAZ L, PUTNIS A, PRIETO M, et al, 1996. The role of magnesium in the crystallization of calcite and aragonite in a porous medium[J]. Journal of Sedimentary Research, Section A: Sedimentary Petrology and Processes, 66(3): 482-491.
[15]	FISHER A T, DAVIS E E, HUTNAK M, et al, 2003. Hydrothermal recharge and discharge across 50 km guided by seamounts on a young ridge flank[J]. Nature, 421(6923): 618-621.
[16]	GIVEN R K, WILKINSON B H, 1985. Kinetic control of morphology, composition, and mineralogy of abiotic sedimentary carbonates[J]. Journal of Sedimentary Research, 55(1): 109-119.
[17]	HERMAN R G, BOGDAN C E, SOMMER A J, et al, 1987. Discrimination among carbonate minerals by Raman spectroscopy using the laser microprobe[J]. Applied Spectroscopy, 41(3): 437-440.
[18]	LI C F, LIN J, KULHANEK K, et al, 2015a. Proceedings of the international ocean discovery program, 349: South China Sea tectonics: college station, TX (international ocean discovery program) [G/OL].[2018-01-09]. .
[19]	LI CHUNFENG, LI JIABIAO, DING WEIWEI, et al, 2015b. Seismic stratigraphy of the central South China Sea basin and implications for neotectonics[J]. Journal of Geophysical Research, 120(3): 1377-1399.
[20]	LI CHUNFENG, SONG TAORAN, 2012. Magnetic recording of the Cenozoic oceanic crustal accretion and evolution of the South China Sea basin[J]. Chinese Science Bulletin, 57(24): 3165-3181.
[21]	LI CHUNFENG, XU XING, LIN JIAN, et al, 2014b. Ages and magnetic structures of the South China Sea constrained by deep tow magnetic surveys and IODP Expedition 349[J]. Geochemistry, Geophysics, Geosystems, 15(12): 4958-4983.
[22]	LI SANZHONG, GELDMACHER J, HAUFF F, et al, 2014a. Composition and timing of carbonate vein precipitation within the igneous basement of the Early Cretaceous Shatsky Rise, NW Pacific[J]. Marine Geology, 357: 321-333.
[23]	LI SANZHONG, SUO YANHUI, YU SHAN, et al, 2016. Orientation of joints and arrangement of solid inclusions in fibrous veins in the Shatsky Rise, NW Pacific: implications for crack‐seal mechanisms and stress fields[J]. Geological Journal, 51(S1): 562-578.
[24]	MCARTHUR J M, HOWARTH R J, SHIELDS G A, 2012. Strontium isotope stratigraphy[M]//GRADSTEIN F M, OGG J G, OGG G M. The geologic time scale. Amsterdam: Elsevier: 127-144.
[25]	MORSE J W, ARVIDSON R S, LÜTTGE A, 2007. Calcium carbonate formation and dissolution[J]. Chemical Reviews, 107(2): 342-381.
[26]	RAUSCH S, BÖHM F, BACH W, et al, 2013. Calcium carbonate veins in ocean crust record a threefold increase of seawater Mg/Ca in the past 30 million years[J]. Earth and Planetary Science Letters, 362: 215-224.
[27]	SCHRAMM B, 2004. Color atlas of low-temperature alteration features in basalts from the Southern East Pacific Rise[J]. Geochemistry, Geophysics, Geosystems, 5(6): Q06006.
[28]	SPINELLI G A, FISHER A T, 2004a. Hydrothermal circulation within topographically rough basaltic basement on the Juan de Fuca Ridge flank[J]. Geochemistry, Geophysics, Geosystems, 5(2): Q02001.
[29]	SPINELLI G A, GIAMBALVO E R, FISHER A T, 2004b. Sediment permeability, distribution, and influence on fluxes in oceanic basement[M]//DAVIS E E, ELDERFIELD H. Hydrogeology of the oceanic lithosphere. Cambridge: Cambridge University Press: 151-188.
[30]	TAYLOR B, HAYES D E, 1983. Origin and history of the South China Sea Basin[M]//HAYES D E. The tectonic and geologic evolution of southeast Asian seas and islands: Part 2, volume 27. Washington, DC: American Geophysical Union: 23-56.
[31]	THOMPSON G, 1991. Metamorphic and hydrothermal processes: basalt—seawater interactions[M]//FLOYD P A. Oceanic basalts. Dordrecht: Springer: 148-173.
[32]	WHEAT C G, ELDERFIELD H, MOTTL M J, et al, 2000. Chemical composition of basement fluids within an oceanic ridge flank: Implications for along-strike and across-strike hydrothermal circulation[J]. Journal of Geophysical Research, 105(B6): 13437-13447.
[33]	WHITE S N, 2009. Laser Raman spectroscopy as a technique for identification of seafloor hydrothermal and cold seep minerals[J]. Chemical Geology, 259(3-4): 240-252.
[34]	YAN QUANSHU, SHI XUEFA, CASTILLO P R, 2014. The late Mesozoic-Cenozoic tectonic evolution of the South China Sea: a petrologic perspective[J]. Journal of Asian Earth Sciences, 85: 178-201.
[35]	YATABE A, VANKO D A, GHAZI A M, 2000. Petrography and chemical compositions of secondary calcite and aragonite in Juan de Fuca Ridge basalts altered at low temperature [G/OL]//FISHER A, DAVIS E E, ESCUTIA C. Proceedings of the ocean drilling program, scientific results, College station, TX (ocean drilling program): 137-148. [2018-01-09].
[36]	ZHANG GUOLIANG, CHEN LIHUI, JACKSON M G, et al, 2017. Evolution of carbonated melt to alkali basalt in the South China Sea[J]. Nature Geoscience, 10(3): 229-235.