Geochemistry of Cenozoic Basaltic Rocksaround Liuhe National Geopark, Jiangsu Province, Eastern China: Petrogenesis and Mantle Source

Cenozoic basalts found in Jiangsu province of eastern China include tholeiites and alkali basalts. The present paper analyzed the major, trace elements, rare earth elements of these Cenozoic basalts and combined with Sr-Nd isotopic compositions proposed by Chen et al. (1990)[1] in the literatures to discuss the petrogenesis of these basalts and the geochemical characteristics of the source mantle. Based on major, trace elements and fractional crystallization model established by Brooks and Nielsen (1982)[2] we suggest that the basaltic magma has experienced olivine + clinopyroxene fractionation during its evolution. The chemical compositions of basaltic rocks from Jiangsu province indicate that these basalts may belong to the same magmatic system. Spidergrams reveal that Cenozoic basalts from Jiangsu province have geochemical characteristics similar to those of ocean island basalts(OIB). The slight positive Nb and Ti anomalies found in basaltic rocks of this study suggest the presence of Ti-bearing minerals in the mantle source and these Ti-bearing minerals had contributed to basaltic magma during partial melting, indicating a metasomatic event might have occurred before the partial melting. Based on the Sr vs. Nd isotopic ratio plots, we suggest that Jiangsu basalts may be derived from partial melting of mantle source which may represent two-end members mixing of DMM and EM-I. Some Jiangsu basaltic magma may be derived from partial melting of EM-I heated by the upwelling asthenospheric mantle or asthenospheric diapirism.

Authors:

• Yung-Tan Lee
• Ren-Yi Huang
• Ju-Chin Chen
• Jyh-Yi Shih
• Meng-Lung Lin
• Hsiao-Ling Yu
• Yen-Tsui Hu
• Chih-Cheng Chen

Keywords:

• Geochemistry
• Jiangsu Province
• Cenozoic basalts
• Fractional crystallization.

References:

[1] D. G. Chen, H. T. Chou, C. T. Yang and Y. S. Wang, "Petrogenesis of
Cenozoic volcanic rocks and isotopic characteristics of mantle sources in
Shandong, Anhwei and Jiangsu provinces. The Characteristics and
dynamics of upper mantle of China." Seismic Press, Beijing, pp. 124-131 ,
1990.(in Chinese)
[2] C. K. Brooks and T. F. D. Nielsen, "The East Greenland continental
margin: a transition between oceanic and continental magmatism." J.
Geol. Soc. London 39,pp.265-275, 1982.
[3] X. L. Huang, Y. G. Xu and D. Y. Liu, "Geochronology, petrology and
geochemistry of the granulite xenolith from Nushan, east China:
Implication for a heterogeneous lower crust beneath the Sino-Korean
Craton." Acta Geochimica et Cosmochimica, 68, pp.127-149, 2004.
[4] B. M. Jahn, B. Auvray, J. Cornichet, Y. L. Bai, Q. H. Shen and D. Y.
Liu, " 3.5 Ga old amphibolites from eastern Hebei province, China: field
occurrence, petrography, Sm-Nd isochron age and REE geochemistry."
Precambrian Research, 34, pp.311-346, 1987.
[5] B. M. Jahn, "Origin of granulites: Geochemical constraints from archean
granulite facies rocks of the Sino-Korean craton, China." In Vielzeuf , D.
and Vidal, Ph. (eds), Granulites and Crustal Evolution. Kluwer Academic
Publishers, Netherlands, pp. 471-492, 1990.
[6] R. X. Liu, W. J. Chen, J. Z. Sun and D. M. Li, "The K-Ar age and tectonic
environment of Cenozoic volcanic rocks in China." In Liu, R. X., ed. The
age and geochemistry of Cenozoic volcanic rocks in China. The Seismic
Press, Beijing, pp. 1-43, 1992. (In Chinese).
[7] A. I. Okay and A. M. C. Sengör, "Evidence for intracontinental
thrust-related exhumation of the ultra-high-pressure rocks in China."
Geology, 20, pp.411-414, 1992.
[8] A. Yin and S. Y. Nie, "An indentation model for the North and South
China collision and the development of the Tan-Lu and Honam fault
systems, eastern Asia." Tectonics, 12, pp. 801-813, 1993.
[9] S. L. Chung, "Trace element and isotope characteristics of Cenozoic
basalts around the Tanlu fault with implications for the eastern plate
boundary between North and South China." Journal of Geology,
107,pp.301-312, 1999.
[10] Z. X. Li, "Collision between the North and South China blocks: a
crustal-detachment model for suturing in the region east of the Tanlu
fault." Geology, 22, pp.739-742, 1994.
[11] J. F. Ying, H. F. Zhang, N. Kita, Y. Morishita and, G. Shimoda, "Nature
and evolution of Late Cretaceous lithospheric mantle beneath the eastern
North China Craton: Constraints from petrology and geochemistry of
peridotitic xenoliths from J├╝nan, Shandong Province, China." Earth and
Planetary Science Letters, 244, pp.622-638, 2006.
[12] H. Zou, A. Zindler, X. Xu and Q. Qi, "Major, trace element, and Nd, Sr
and Pb isotope studies of Cenozoic basalts in SE China: mantle sources,
regional variations, and tectonic significance." Chemical Geology, 171,
pp.33-47, 2000.
[13] D. Chen and Z. Peng, "K-Ar ages and Pb and Sr isotopic characteristics of
Cenozoic volcanic rocks in Shandong, China." Geochimica, 5,
pp.293-303, 1985. (in Chinese)
[14] J. Dostal, C. Dupuy, M. Z. Zhai and X. C. Zhi, "Geochemistry and origin
of Pliocene alkali basaltic lavas from Anhui-Jiangsu, eastern China."
Geochemical Journal, 22, pp.165-176, 1988.
[15] L. Wu, M. Zhai, X. Zheng, R. Yang and Z. Huang, "Cenozoic volcanic
rocks in eastern China." Acta Petrologica Sinica, 1, pp.1-23, 1985. (in
Chinese)
[16] Y. G. Xu and J. L. Bodinier, "Contrasting enrichments in high and low
temperature xenoliths from Nushan, Eastern China: Results of a single
metasomatic event during lithospheric accretion?" Journal of Petrology,
45, pp.321-341, 2004.
[17] T. N. Irvine and W. R. A. Baragar, " A guide to the chemical classification
of the common rocks." Can. J. Earth Sci. 8, pp. 523-548, 1971.
[18] F. A. Frey and M. Prinz, "Ultramafic inclusions from San Carlos,
Arizona: petrological and geochemical data bearing on their
petrogenesis." Earth and Planetary Science Letters, 38, pp.129-176,
1978.
[19] J. F. G. Wilkinson and R. W. Le Maitre, "Upper mantle amphiboles and
micas and TiO2, K2O, and P2O5 abundances and 100Mg/(Mg+Fe+2)
ratios of common basalts and andesites: implications for modal mantle
metasomatism and undepleted mantle compositions." Journal of
Petrology, 28, pp.37-73, 1987.
[20] S. S. Sun and W. F. McDonough, "Chemical and isotopic systematics of
oceanic basalts: implications for mantle composition and processes."
Journal Geological Society of London Special Publication,
42,pp.313-345, 1989.
[21] X. C. Zhi, Y. Song, F. A. Frey, J. Feng and M Zhai, "Geochemistry of
Hannuoba basalts, eastern China: constraints on the origin of continental
alkali and tholeiitic basalts." Chemical Geology, 88, pp.1-33, 1990.
[22] K. Tu, M. F. Flower, R. W. Carlson, M. Zhang and G. H. Xie, "Sr, Nd, and
Pb isotopic compositions of Hainan basalts (south China): implications
for a subcontinental lithosphere Dupal source." Geology, 19, pp.567-569,
1991.
[23] M. F. J. Flower, M. Zhang, C. Y. Chen, K. Tu and G. Xie, "Magmatism in
the South China Basin, 2. Post-spreading Quaternary basalts from Hainan
Island, South China." Chemical Geology, 97, pp.65-87, 1992.
[24] S. L. Chung, S. S. Sun, K. Tu, C. H. Chen and C. Y. Lee, "Late Cenozoic
basaltic volcanism around the Taiwan Strait, SE China: product of
lithosphere-asthenosphere interaction during continental extension."
Chemical Geology, 112, pp.1-20, 1994.
[25] C. Q. Liu, A. Masuda and G. H. Xie, "Major- and trace-element
compositions of Cenozoic basalts in eastern China: petrogenesis and
mantle source." Chemical Geology, 114, pp.19-42, 1994.
[26] J. L. Bodinier, C. Merlet, R. M Bedini., F. Simien, R. Remaid and C. J.
Carrido, "The distribution of niobium, tantalum, and other highly
incompatible trace elements in the lithospheric mantle: the spinel
paradox." Acta Geochimica et Cosmochimica, 60, pp.545-550, 1996.
[27] D. A. Ionov and A. W. Hofmann, "Nb-Ta-rich mantle amphiboles and
micas: implications for subduction-related metasomatic trace element
fractionations." Earth and Planetary Science Letters, 131, pp.341-356,
1995.
[28] F. Kalfoun, D. A. Ionov and C. Merlet, "HFSE residence and Nb-Ta ratios
in metasomatised, rutile-bearing mantle peridotites." Earth and
Planetary Science Letters, 199, pp.49-65, 2002.
[29] A. W. Hofmann, K. P. Joohum, M. Seufert and W. M. White, "Nb and Pb
in oceanic basalts: new constraints on mantle evolution." Earth Planet.
Sci. Lett. 79,pp.33-45, 1986.
[30] Y. Chen, Y Zhang., D. Graham, S. Su and J. Deng, "Geochemistry of
Cenozoic basalts and mantle xenoliths in Northeast China." Lithos, 96,
pp.108-126, 2007.
[31] A. Zindler and S. R. Hart, "Chemical geodynamics." Annual Review of
Earth and Planetary Science, 14, pp.493-571, 1986.
[32] H. L. Zhao, "Neogene-Quaternary continental rifting volcanism and deep
process in the southeast coast of China." China Geosciences University
Press. (in Chinese)
[33] S. R. Hart, "Heterogeneous mantle domains: signatures, genesis and
mixing chronologies." Earth Planet. Sci. Lett. 90, pp.273-296, 1988.
[34] B. L. Weaver, "The origin of oceanic island basalt endmember.
Compositions: trace element and isotopic constraints." Earth and
Planetary Science Letters, 104, pp.381-397, 1991.
[35] M. Meschede, "A method of discriminating between different types of
Mid-ocean ridge basalts and continental tholeiites with the Nb-Zr-Y
diagram." Chem. Geol. 56,pp.207-218, 1986.