Formation of melt pocket in mantle peridotite xenolith from western Qinling, Central China: Partial melting and metasomatism

Abstract

Two types of melt pockets, closed melt pocket (CMP) and open melt pocket (OMP), are recognized from the peridotite xenoliths entrained in the Cenozoic kamafugites in western Qinling (秦岭), Central China. The Haoti (好梯) CMPs have a mineral assemblage of olivine+ clinopyroxene+amphibole+K-feldspar, whereas the Baiguan (白关) CMPs are composed of olivine+clinopyroxene+ilmenite+carbonate. The components of the OMPs are more complicated. In the Haoti OMPs, there are olivine, clinopyroxene, glass, low modal abundances of amphibole, K-feldspar (Kfs), ilmenite, sulfide, chlorite, perovskite, chromite and phlogopite. The Baiguan OMPs contain olivine, clinopyroxene, glass, chlorite and chromite. Compositionally, olivines in the CMPs and OMPs are both apparently depleted in Ni, and those in the OMPs are also depleted in Fe and Mg, and enriched in Ca compared to the primary ones. Clinopyroxenes display large and systematical compositional variations between the CMPs and OMPs, particularly in Al, Cr, Na, Ca and Ti. Glasses are generally depleted in Si compared to the worldwide glasses in melt pockets, although they still have large variations. Amphiboles and K-feldspars have relatively restricted compositional variations. The petrographical observations and mineral chemistry suggest that the Haoti and Baiguan CMPs were generated by the in-situ decompression melting of orthopyroxenes, olivines and clinopyroxenes, and by the addition of minor external K-rich and Ca-rich melt/fluids. The OMPs formed during the latest metasomatic event in the lithospheric mantle beneath the western Qinling.

Keywords

mantle metasomatism / melt pocket / partial melting / peridotite xenolith / western Qinling

References

Bali E., Falus G., Szabo C., . Remnants of Boninitic Melts in the Upper Mantle beneath the Central Pannonian Basin?. Mineralogy and Petrology, 2007, 90(1–2): 51-72.

Bali E., Szabo C., Vaselli O., . Significance of Silicate Melt Pockets in Upper Mantle Xenoliths from the Bakony-Balaton Highland Volcanic Field, Western Hungary. Lithos, 2002, 61(1–2): 79-102.

Bali E., Zanetti A., Szabo C., . A Micro-scale Investigation of Melt Production and Extraction in the Upper Mantle Based on Silicate Melt Pockets in Ultramafic Xenoliths from the Bakony-Balaton Highland Volcanic Field (Western Hungary). Contributions to Mineralogy and Petrology, 2008, 155(2): 165-179.

Ban M., Witt-Eickschen G., Klein M., . The Origin of Glasses in Hydrous Mantle Xenoliths from the West Eifel, Germany: Incongrunet Break down of Amphibole. Contributions to Mineralogy and Petrology, 2005, 148(5): 511-523.

Bonadiman C., Coltorti M., Beccaluva L., . Mantle Metasomatism vs. Host Magma Interaction: The Ongoing Controversy. Geochimica et Cosmochimica Acta, 2008, 72 12S A95

Carpenter R. L.. Petrology of Mantle Xenoliths Hosted in Tertiary Magmas of the Hessian Depression, Germany: A Comparison to Xenoliths from Quaternary Magmas of the West Eifel: [Dissertation], 1997, Ontario: The University of Western Ontario

Chazot G., Menzies M., Harte B.. Silicate Glasses in Spinel Lherzolites from Yemen: Origin and Chemical Composition. Chemical Geology, 1996, 134(1–3): 159-179.

Dawson J. B.. Kornprobst J.. Contrasting Types of Upper-Mantle Metasomatism?. Kimberlites II: The Mantle and Crust-Mantle Relationships, 1984, Amsterdam: Elsevier Sci. Publ. 289 294

Dong X., Zhao Z. D., Mo X. X., . Geochemistry of the Cenozoic Kamafugites from West Qinling and Its Constraint for the Nature of Magma Source Region. Acta Petrologica Sinica, 2008, 24(2): 238-248.

Embey-Isztin A., Scharbert H. G.. Glasses in Peridotite Xenoliths from the Western Pannonian Basin. Annales Historico-Naturales Musei Nationalis Hungarici, 2000, 92: 5-20.

Francis D.. Mantle-Melt Interaction Recorded in Spinel Lherzolite Xenoliths from the Alligator Lake Volcanic Complex, Yukon, Canada. Journal of Petrology, 1987, 28(3): 569-597.

Franz L., Wirth R.. Thin Intergranular Melt Films and Melt Pockets in Spinel Peridotite Xenoliths from the Rhon Area (Germany): Early Stage of Melt Generation by Grain Boundary Melting. Contributions to Mineralogy and Petrology, 1997, 129(4): 268-283.

Gao S., Zhang B. R., Wang D. P., . Geochemical Evidence for the Proterozoic Tectonic Evolution of the Qinling Orogenic Belt and Its Adjacent Margins of the North China and Yangtze Cratons. Precambrian Research, 1996, 80(1–2): 23-48.

Hibbard M. J., Sjoberg J. J.. Signs of Incongruent Melting of Clinopyroxene in Limbergite, Thetford Hill, Vermont. The Canadian Mineralogist, 1994, 32: 307-317.

Ionov D. A., Dupuy C., O’Reilly S. Y., . Carbonated Peridotite Xenoliths from Spitsbergen: Implications for Trace Element Signature of Mantle Carbonate Metasomatism. Earth and Planetary Science Letters, 1993, 119(3): 283-297.

Ionov D. A., Hofmann A. W., Shimizu N.. Metasomatism-Induced Melting in Mantle Xenoliths from Mongolia. Journal of Petrology, 1994, 35(3): 753-785.

Kloe R., Drury M. R., Van Roermund H. L. M.. Evidence for Stable Grain Boundary Melt Films in Experimentally Deformed Olivine-Orthopyroxene Rocks. Physical and Chemical Minerals, 2000, 27(7): 480-494.

Kuo L. C., Essene E. J.. Petrology of Spinel Harzburgite Xenoliths from the Kishb Plateau, Saudi Arabia. Contributions to Mineralogy and Petrology, 1986, 93(3): 335-346.

Laurora A., Mazzucchelli M., Rivalenti G., . Metasomatism and Melting in Carbonated Peridotite Xenoliths from the Mantle Wedge: The Gobernador Gregores Case (Southern Patagonia). Journal of Petrology, 2001, 42(1): 69-87.

Liang Y., Elthon D.. Geochemistry and Petrology of Spinel Lherzolite Xenoliths from Xalapasco de La Joya, San Luis Potosi, Mexico: Partial Melting and Mantle Metasomatism. Journal of Geophysical Research, 1990, 95(B10): 15859-15877.

Litasov K. D., Sharygin V. V., Litasov Y. D., . Melt Pockets in Mantle Xenoliths from Alkali Basalts of Vitim and Udokan Volcanic Fields, East Siberia. LPI Contribution, 1999, 173 7099

Morgan J. P., Morgan W. J.. Two-Stage Melting and the Geochemical Evolution of the Mantle: A Recipe for Mantle Plum-Pudding. Earth and Planetary Science Letters, 1999, 170(3): 215-239.

Sawyer E. W.. Criteria for the Recognition of Partial Melting. Physics and Chemistry of the Earth (A), 1999, 24(3): 269-279.

Schiano P., Bourdon B.. On the Preservation of Mantle Information in Ultramafic Nodules, Glass Inclusions within Minerals versus Interstitial Glasses. Earth and Planetary Science Letters, 1999, 169(1–2): 173-188.

Shaw C. S. J.. Origin of Sulfide Blebs in Variably Metasomatized Mantle Xenoliths, Quaternary West Eifel Volcanic Field, Germany. The Canadian Mineralogist, 1997, 35: 1453-1463.

Shaw C. S. J.. Dissolution of Orthopyroxene in Basanitic Magma between 0.4 and 2 GPa: Further Implications for the Origin of Si-Rich Alkaline Glass Inclusions in Mantle Xenoliths. Contributions to Mineralogy and Petrology, 1999, 135(2–3): 114-132.

Shaw C. S. J., Eyzaguirre J., Fryer B., . Regional Variations in the Mineralogy of Metasomatic Assemblages in Mantle Xenoliths from the West Eifel Volcanic Field, Germany. Journal of Petrology, 2005, 46(5): 945-972.

Shaw C. S. J., Klügel A.. The Pressure and Temperature Conditions and Timing of Glass Formation in Mantle-Derived Xenoliths from Baarley, West Eifel, Germany: The Case for Amphibole Breakdown, Lava Infiltration and Mineral-Melt Reaction. Mineralogy and Petrology, 2002, 74(2–4): 163-187.

Shaw C. S. J., Thibault Y., Edgar A. D., . Mechanisms of Orthopyroxene Dissolution in Silica-Undersaturated Melts at 1 Atmosphere and Implications for the Origin of Silica-Rich Glass in Mantle Xenoliths. Contributions to Mineralogy and Petrology, 1998, 132(4): 354-370.

Shi L. B., Lin C. Y., Chen X. D.. Composition, Thermal Structures and Rheology of the Upper Mantle Inferred from Mantle Xenoliths from Haoti, Dangchang, Gansu Province, Western China. Seismology and Geology, 2003, 25(4): 525-542.

Stosch H. G., Seck H. A.. Geochemistry and Mineralogy of Two Spinel Peridotite Suites from Dreiser Weiher, West Germany. Geochimica et Cosmochimica Acta, 1980, 44(3): 457-470.

Su B. X., Zhang H. F., Sakyi P. A., . Compositionally Stratified Lithosphere and Carbonatite Metasomatism Recorded in Mantle Xenoliths from the Western Qinling (Central China). Lithos, 2010, 116(1–2): 111-128.

Su, B. X., Zhang, H. F., Tang, Y. J., et al., 2010b. Geochemical Syntheses among the Cratonic, Off-Cratonic and Orogenic Garnet Peridotites and Their Tectonic Implications. International Journal of Earth Sciences, doi:10.1007/s00531-010-0527-0

Su, B. X., Zhang, H. F., Sakyi, P. A., et al., 2010c. The Origin of Spongy Texture of Mantle Xenolith Minerals from the Western Qinling, Central China. Contributions to Mineralogy and Petrology, doi:10.1007/s00410-010-0543-x

Su B. X., Zhang H. F., Wang Q. Y., . Spinel-Garnet Phase Transition Zone of Cenozoic Lithospheric Mantle beneath the Eastern China and Western Qinling and its T-P Conditions. Acta Petrologica Sinica, 2007, 23(6): 1313-1320.

Su B. X., Zhang H. F., Xiao Y., . Characteristics and Geological Significance of Olivine Xenocrysts in Cenozoic Volcanic Rocks from Western Qinling. Progress in Natural Science, 2006, 16(12): 1300-1306.

Su B. X., Zhang H. F., Ying J. F., . Nature and Processes of the Lithospheric Mantle beneath the Western Qinling: Evidence from Deformed Peridotitic Xenoliths in Cenozoic Kamafugite from Haoti, Gansu Province, China. Journal of Asian Earth Sciences, 2009, 34(3): 258-274.

Szabo C., Bodnar R. J., Sobolev A. V.. Metasomatism Associated with Subduction-Related, Volatile-Rich Silicate Melt in the Upper Mantle beneath the Nograd-Gomor Volcanic Field, Northern Hungary/Southern Slovakia: Evidence for Silicate Melt Inclusions. European Journal of Mineralogy, 1996, 8: 881-899.

Tang Y. J., Zhang H. F., Ying J. F., . Refertilization of Ancient Lithospheric Mantle beneath the Central North China Craton: Evidence from Petrology and Geochemistry of Peridotite Xenoliths. Lithos, 2008, 101(3–4): 435-452.

Tracy R. J.. Petrology and Genetic Significance of an Ultramafic Xenoliths Suite from Tahiti. Earth and Planetary Science Letters, 1980, 48(1): 80-96.

Tsuchiyama A.. Melting and Dissolution Kinetics: Application to Partial Melting and Dissolution of Xenoliths. Journal of Geophysical Research, 1986, 91(B9): 9395-9406.

Xu J. F., Castillo P. R., Li X. H., . MORB-Type Rocks from the Paleo-Tethyan Mian-Lueyang Northern Ophiolite in the Qinling Mountains, Central China: Implications for the Source of the Low ²⁰⁶Pb/²⁰⁴Pb and High ¹⁴³Nd/¹⁴⁴Nd Mantle Component in the Indian Ocean. Earth and Planetary Science Letters, 2002, 198(3–4): 323-337.

Xu Y. G., Mercier J. C. C., Menzies M. A., . K-Rich Glass-Bearing Wehrlite Xenoliths from Yitong, Northeastern China: Petrological and Chemical Evidence for Mantle Metasomatism. Contributions to Mineralogy and Petrology, 1996, 125(4): 406-420.

Ying J. F., Zhang H. F., Kita N., . Nature and Evolution of Late Cretaceous Lithospheric Mantle beneath the Eastern North China Craton: Constraints from Petrology and Geochemistry of Peridotitic Xenoliths from Junan, Shandong Province, China. Earth and Planetary Science Letters, 2006, 244(3–4): 622-638.

Yu X. H., Mo X. X., Liao Z. L., . Temperature and Pressure Condition of Garnet Lherzolite and Websterite from West Qinling, China. Science in China (Ser. D), 2001, 31(Suppl.): 128-133.

Yu X. H., Mo X. X., Su S. G., . Discovery and Significance of Cenozoic Volcanic Carbonatite in Lixian, Gansu Province. Acta Petrologica Sinica, 2003, 19(1): 105-112.

Yu X. H., Zhao Z. D., Mo X. X., . Trace Elements, REE and Sr, Nd, Pb Isotopic Geochemistry of Cenozoic Kamafugite and Carbonatite from West Qinling, Gansu Province: Implication of Plume-Lithosphere Interaction. Acta Petrologica Sinica, 2004, 20(3): 483-494.

Zhang G. W., Dong Y. P., Yao A. P.. Some Thoughts on Study of Continental Dynamics and Orogenic Belt. Geology in China, 2002, 29(1): 7-13.

Zhang G. W., Zhang B. R., Yuan X. C., . Qinling Orogenic Belt and Continental Dynamics, 2001, Beijing: Science Press 1 855

Zhang H. F.. Transformation of Lithospheric Mantle through Peridotite-Melt Reaction: A Case of Sino-Korean Craton. Earth and Planetary Science Letters, 2005, 237(3–4): 768-780.

Zhang H. F., Goldstein S. L., Zhou X. H., . Comprehensive Refertilization of Lithospheric Mantle beneath the North China Craton: Further Os-Sr-Nd Isotopic Constraints. Journal of the Geological Society, 2009, 166: 249-259.

Zhang H. F., Nakamura E., Sun M., . Transformation of Subcontinental Lithospheric Mantle through Peridotite-Melt Reaction: Evidence from a Highly Fertile Mantle Xenolith from the North China Craton. International Geology Review, 2007, 49(7): 658-679.

Zhang H. F., Sun M., Zhou M. F., . Highly Heterogeneous Late Mesozoic Lithospheric Mantle beneath the North China Craton: Evidence from Sr-Nd-Pb Isotopic Systematics of Mafic Igneous Rocks. Geological Magazine, 2004, 141: 55-62.

Zheng J. P., Zhang R. Y., Griffin W. L., . Heterogeneous and Metasomatized Mantle Recorded by Trace Elements in Minerals of the Donghai Garnet Peridotites, Sulu UHP Terrane, China. Chemical Geology, 2005, 221(3–4): 243-259.