An Intra-Oceanic Subduction System Influenced by Ridge Subduction in the Diyanmiao Subduction Accretionary Complex of the Xar Moron Area, Eastern Margin of the Central Asian Orogenic Belt

Abstract

This study focuses on the geology, geochemistry, Sr-Nd isotopes and their tectonic settings of three types of basalts in Diyanmiao ophiolite in the Xar Moron area located on the eastern margin of the Central Asian Orogenic Belt. Type I basalts are oceanic tholeiites with a depleted light rare earth element (LREE) pattern, which are similar to the typical N-mid-oceanic ridge basalt (MORB) and suggests that they were formed at a mid-oceanic ridge. The initial ⁸⁷Sr/⁸⁶Sr ratios of Type I basalts range from 0.703 966 to 0.705 276 and the ε _Nd(t) values are from 16.49 to 17.15, indicating that they were derived from a depleted mantle source. Type II basalts belong to the medium-potassium calc-akaline series and have the geochemical characteristics of Nb-enriched basalt (NEB) with high Nb content (14.5 ppm) and strong enrichment in LREEs, implying that they were created by the partial melting of mantle wedge peridotite that previously metasomatized by slab melts. Type III basalts are high-Al basalt (HAB) with high-Al contents (Al₂O₃=16.75 wt.%–18.00 wt.%), distinct Nb depletion and high Th/Yb ratios. Thus they were likely generated in a normal island-arc setting. Therefore, the association of MORB, NEB, and HAB in the study area may be due to the subduction of a mid-oceanic ridge, and the Diyanmiao ophiolite is proposed to be formed in the forearc setting of a mid-oceanic ridge subduction system.

Keywords

mid-oceanic ridge basalt / Nb-enriched basalt / high-Al basalt / ridge subduction / Diyanmiao ophiolite / Inner Mongolia

References

[1] Breitsprecher K, Thorkelson D J. Neogene Kinematic History of Nazca-Antarctic-Phoenix Slab Windows beneath Patagonia and the Antarctic Peninsula. Tectonophysics, 2009, 464(1): 10-20. 2/3/4

[2] Brophy J G, Marsh B D. On the Origin of High-Alumina Arc Basalt and the Mechanics of Melt Extraction. Journal of Petrology, 1986, 27(4): 763-789.

[3] Cheng Y, Xiao Q H, Li T D, . Magmatism and Tectonic Background of the Early Permian Intra-Oceanic Arc in the Diyanmiao Subduction Accretion Complex Belt in the Eastern Margin of the Central Asian Orogenic Belt. Earth Science, 2019, 44(10): 1-15. (in Chinese with English Abstract)

[4] Cole R B, Nelson S W, Layer P W, . Eocene Volcanism above a Depleted Mantle Slab Window in Southern Alaska. Geological Society of America Bulletin, 2006, 118(1): 140-158. 2

[5] Crawford A J, Falloon T J, Eggins S. The Origin of Island Arc High-Alumina Basalts. Contributions to Mineralogy and Petrology, 1987, 97(3): 417-430.

[6] Defant M J, Drummond M S. Derivation of Some Modern Arc Magmas by Melting of Young Subducted Lithosphere. Nature, 1990, 347(6294): 662-665.

[7] Defant M J, Drummond M S. Mount St. Helens: Potential Example of the Partial Melting of the Subducted Lithosphere in a Volcanic Arc. Geology, 1993, 21(6): 547-550.

[8] Defant M J, Jackson T E, Drummond M S, . The Geochemistry of Young Volcanism throughout Western Panama and Southeastern Costa Rica: An Overview. Journal of the Geological Society, 1992, 149(4): 569-579.

[9] Dickinson W R, Snyder W S. Geometry of Subducted Slabs Related to San Andreas Transform. The Journal of Geology, 1979, 87(6): 609-627.

[10] Elliott T, Plank T, Zindler A, . Element Transport from Slab to Volcanic Front at the Mariana Arc. Journal of Geophysical Research: Solid Earth, 1997, 102(B7): 14991-15019.

[11] Fan Y X, Li T D, Xiao Q H, . Zircon U-Pb Ages, Geochemical Characteristics of Late Permian Granite in West Ujimqin Banner, Inner Mongolia, and Tectonic Significance. Geological Review, 2019, 65(1): 248-266. (in Chinese with English Abstract)

[12] Geng H Y, Sun M, Yuan C, . Geochemical, Sr-Nd and Zircon U-Pb-Hf Isotopic Studies of Late Carboniferous Magmatism in the West Junggar, Xinjiang: Implications for Ridge Subduction?. Chemical Geology, 2009, 266(3): 364-389. 4

[13] Green T H. Island Arc and Continent-Building Magmatism—A Review of Petrogenic Models Based on Experimental Petrology and Geochemistry. Tectonophysics, 1980, 63(1): 367-385. 2/3/4

[14] Hart S R, Erlank A J, Kable E J D. Sea Floor Basalt Alteration: Some Chemical and Sr Isotopic Effects. Contributions to Mineralogy and Petrology, 1974, 44(3): 219-230.

[15] Hastie A R, Kerr A C, Pearce J A, . Classification of Altered Volcanic Island Arc Rocks Using Immobile Trace Elements: Development of the Th-Co Discrimination Diagram. Journal of Petrology, 2007, 48(12): 2341-2357.

[16] Hofmann A W, Jochum K P, Seufert M, . Nb and Pb in Oceanic Basalts: New Constraints on Mantle Evolution. Earth and Planetary Science Letters, 1986, 79(1): 33-45. 2

[17] Hollings P, Kerrich R. An Archean Arc Basalt-Nb-Enriched Basalt-Adakite Association: The 2.7 Ga Confederation Assemblage of the Birch-Uchi Greenstone Belt, Superior Province. Contributions to Mineralogy and Petrology, 2000, 139(2): 208-226.

[18] Humphris S E, Thompson G. Hydrothermal Alteration of Oceanic Basalts by Seawater. Geochimica et Cosmochimica Acta, 1978, 42(1): 107-125.

[19] Jahn B M. The Central Asian Orogenic Belt and Growth of the Continental Crust in the Phanerozoic. Geological Society, London, Special Publications, 2004, 226(1): 73-100.

[20] Jahn B M, Wu F Y, Chen B. Granitoids of the Central Asian Orogenic Belt and Continental Growth in the Phanerozoic. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 2000, 91(1): 181-193. 2

[21] Janney P E, Castillo P R. Basalts from the Central Pacific Basin: Evidence for the Origin of Cretaceous Igneous Complexes in the Jurassic Western Pacific. Journal of Geophysical Research: Solid Earth, 1996, 101(B2): 2875-2893.

[22] Jian P, Liu D Y, Kröner A, . Time Scale of an Early to Mid-Paleozoic Orogenic Cycle of the Long-Lived Central Asian Orogenic Belt, Inner Mongolia of China: Implications for Continental Growth. Lithos, 2008, 101(3): 233-259. 4

[23] Johnston A D. Anhydrous P-T Phase Relations of Near-Primary High-Alumina Basalt from the South Sandwich Islands. Contributions to Mineralogy and Petrology, 1986, 92(3): 368-382.

[24] Kelemen P B, Hanghj K, Greene A R. One View of the Geochemistry of Subduction-Related Magmatic Arcs, with an Emphasis on Primitive Andesite and Lower Crust. Treatise on Geochemistry, 2003, 3: 1-70.

[25] Kepezhinskas P K, Defant M J, Drummond M S. Progressive Enrichment of Island Arc Mantle by Melt-Peridotite Interaction Inferred from Kamchatka Xenoliths. Geochimica et Cosmochimica Acta, 1996, 60(7): 1217-1229.

[26] Klein E M, Karsten J L. Ocean-Ridge Basalts with Convergent-Margin Geochemical Affinities from the Chile Ridge. Nature, 1995, 374(6517): 52-57.

[27] Kusky T M, Windley B F, Safonova I, . Recognition of Ocean Plate Stratigraphy in Accretionary Orogens through Earth History: A Record of 3.8 Billion Years of Sea Floor Spreading, Subduction, and Accretion. Gondwana Research, 2013, 24(2): 501-547.

[28] Kusky T M, Young C P. Emplacement of the Resurrection Peninsula Ophiolite in the Southern Alaska Forearc during a Ridge-Trench Encounter. Journal of Geophysical Research: Solid Earth, 1999, 104(B12): 29025-29054.

[29] Li G Z, Wang Y J, Li C Y, . Discovery of Early Permian Radiolarian Fauna in the Solon Obo Ophiolite Belt, Inner Mongolia and Its Geological Significance. Chinese Science Bulletin, 2017, 62(5): 400-406.

[30] Li J Y. Permian Geodynamic Setting of Northeast China and Adjacent Regions: Closure of the Paleo-Asian Ocean and Subduction of the Paleo-Pacific Plate. Journal of Asian Earth Sciences, 2006, 26(3): 207-224. 4

[31] Li Y J, Wang G H, Santosh M, . Subduction Initiation of the SE Paleo-Asian Ocean: Evidence from a Well Preserved Intra-Oceanic Forearc Ophiolite Fragment in Central Inner Mongolia, North China. Earth and Planetary Science Letters, 2020, 535: 116087

[32] Liu J F, Li J Y, Chi X G, . A Late-Carboniferous to Early Early-Permian Subduction-Accretion Complex in Daqing Pasture, Southeastern Inner Mongolia: Evidence of Northward Subduction beneath the Siberian Paleoplate Southern Margin. Lithos, 2013, 177 285-296.

[33] Liu J F, Li J Y, Sun L X, . Zircon U-Pb dating of the Jiujingzi ophiolite in Bairin Left Banner, Inner Mongolia: Constraints on the formation and evolution of the Xar Moron River suture zone. Geology in China, 2016, 43(6): 1947-1962. (in Chinese with English Abstract)

[34] Liu X J, Xu J F, Wang S Q, . Geochemistry and Dating of E-MORB Type Mafic Rocks from Dalabute Ophiolite in West Junggar, Xinjiang and Geological Implications. Acta Petrologica Sinica, 2009, 25(6): 1373-1389. (in Chinese with English Abstract)

[35] Liu X J, Xiao W J, Xu J F, . Geochemical Signature and Rock Associations of Ocean Ridge-Subduction: Evidence from the Karamaili Paleo-Asian Ophiolite in East Junggar, NW China. Gondwana Research, 2017, 48: 34-49.

[36] Liu X J, Xu J F, Hou Q Y, . Geochemical Characteristics of Karamaili Ophiolite in East Junggar, Xingjiang: Products of Ridge Subduction. Acta Petrologica Sinica, 2007, 23(7): 1591-1602. (in Chinese with English Abstract)

[37] Moores E M, Kellogg L H, Dilek Y. Tethyan Ophiolites, Mantle Convection, and Tectonic “Historical Contingency”: A Resolution of the “Ophiolite Conundrum”. Special Paper of the Geological Society of America, 2000, 349: 3-12.

[38] Papanastassiou D A, Depaolo D J, Wasserburg G J. Rb-Sr and Sm-Nd Chronology and Genealogy of Mare Basalts from the Sea of Tranquility. Proceedings of Lunar Science Conference, 1977, 8: 1639-1672.

[39] Pearce J A. Supra-Subduction Zone Ophiolites: The Search for Modern Analogues. Special Paper of the Geological Society of America, 2003, 373: 269-293.

[40] Pearce J A, Norry M J. Petrogenetic Implications of Ti, Zr, Y, and Nb Variations in Volcanic Rocks. Contributions to Mineralogy and Petrology, 1979, 69(1): 33-47.

[41] Pearce J A, Peate D W. Tectonic Implications of the Composition of Volcanic ARC Magmas. Annual Review of Earth and Planetary Sciences, 1995, 23(1): 251-285.

[42] Plank T, Langmuir C H. The Chemical Composition of Subducting Sediment and Its Consequences for the Crust and Mantle. Chemical Geology, 1998, 145(3): 325-394. 4

[43] Polat A, Kerrich R. Magnesian Andesites, Nb-Enriched Basalt-Andesites, and Adakites from Late-Archean 2.7 Ga Wawa Greenstone Belts, Superior Province, Canada: Implications for Late Archean Subduction Zone Petrogenetic Processes. Contributions to Mineralogy and Petrology, 2001, 141(1): 36-52.

[44] Pu W, Gao J F, Zhao K D, . The Separation of Rb-Sr and Sm-Nd Using DATA and HIBA. Acta Geoscientica Sinica, 2005, 26(S1): 54 (in Chinese with English Abstract)

[45] Rollinson H. Second Hutton Symposium on the Origin of Granites and Related Rocks. Journal of Structural Geology, 1993, 15 6 812-813.

[46] Rollinson H R, Lowry D. Early Basic Magmatism in the Evolution of the Northern Marginal Zone of the Archean Limpopo Belt. Precambrian Research, 1992, 55(1): 33-45. 2/3/4

[47] Safonova I Y, Santosh M. Accretionary Complexes in the Asia-Pacific Region: Tracing Archives of Ocean Plate Stratigraphy and Tracking Mantle Plumes. Gondwana Research, 2014, 25(1): 126-158.

[48] Sajona F G, Maury R C, Bellon H, . Initiation of Subduction and the Generation of Slab Melts in Western and Eastern Mindanao, Philippines. Geology, 1993, 21(11): 1007-1010.

[49] Sajona F G, Maury R C, Bellon H, . High Field Strength Element Enrichment of Pliocene—Pleistocene Island Arc Basalts, Zamboanga Peninsula, Western Mindanao (Philippines). Journal of Petrology, 1996, 37(3): 693-726.

[50] Şengör A M C, Natal’in B A, Burtman V S. Evolution of the Altaid Tectonic Collage and Palaeozoic Crustal Growth in Eurasia. Nature, 1993, 364(6435): 299-307.

[51] Shen P, Pan H D, Xiao W J, . An Ordovician Intra-Oceanic Subduction System Influenced by Ridge Subduction in the West Junggar, Northwest China. International Geology Review, 2014, 56(2): 206-223.

[52] Shen X M, Zhang H X, Wang Q, . Late Devonian-Early Permian A-Type Granites in the Southern Altay Range, Northwest China: Petrogenesis and Implications for Tectonic Setting of “A2-Type” Granites. Journal of Asian Earth Sciences, 2011, 42(5): 986-1007.

[53] Sisson, V. B., Pavlis, T. L., Roeske, S. M., et al., 2003, Introduction: An Overview of Ridge-Trench Interactions in Modern and Ancient Settings, In: Sisson, V. B., Roeske, S. M., Pavlis, T. L., eds., Geology of a Transpressional Orogen Developed during Ridge-Trench Interaction along the North Pacific Margin, Boulder, Colorado. Geological Society of America, 371(Special Paper): 1–18

[54] Song S, Wang M M, Xu X, . Ophiolites in the Xing’an-Inner Mongolia Accretionary Belt of the CAOB: Implications for Two Cycles of Seafloor Spreading and Accretionary Orogenic Events. Tectonics, 2016, 34(10): 2221-2248.

[55] Stern R J, Morris J, Bloomer S H, . The Source of the Subduction Component in Convergent Margin Magmas: Trace Element and Radiogenic Isotope Evidence from Eocene Boninites, Mariana Forearc. Geochimica et Cosmochimica Acta, 1991, 55(5): 1467-1481.

[56] Sun M, Long X P, Cai K D, . Early Paleozoic Ridge Subduction in the Chinese Altai: Insight from the Abrupt Change in Zircon Hf Isotopic Compositions. Science in China Series D: Earth Sciences, 2009, 52(9): 1345-1358.

[57] Sun S S, McDonough W F. Chemical and Isotopic Systematics of Oceanic Basalts: Implications for Mantle Composition and Processes. Geological Society, London, Special Publications, 1989, 42(1): 313-345.

[58] Tang G J, Wang Q, Wyman D A, . Ridge Subduction and Crustal Growth in the Central Asian Orogenic Belt: Evidence from Late Carboniferous Adakites and High-Mg Diorites in the Western Junggar Region, Northern Xinjiang (West China). Chemical Geology, 2010, 277(3): 281-300. 4

[59] Thorkelson D J. Subduction of Diverging Plates and the Principles of Slab Window Formation. Tectonophysics, 1996, 255(1): 47-63. 2

[60] Thorkelson D J, Madsen J K, Sluggett C L. Mantle Flow through the Northern Cordilleran Slab Window Revealed by Volcanic Geochemistry. Geology, 2011, 39(3): 267-270.

[61] Thorkelson D J, Taylor R P. Cordilleran Slab Windows. Geology, 1989, 17(9): 833-836.

[62] Tilley C E. Some Aspects of Magmatic Evolution. Quarterly Journal of the Geological Society, 1950, 106(1): 37-61. 2/3/4

[63] Wang J F, Li Y J, Li H Y, . Discovery of Early Permian Intra-Oceanic Arc Adakite in the Meilaotewula Ophiolite, Inner Mongolia and Its Evolution Model. Acta Geologica Sinica, 2017, 91(8): 1776-1795. (in Chinese with English Abstract)

[64] Wang Y J, Fan Z Y. Discovery of Permian Radiolariansin Ophiolite Belt on Northern Side of Xar Moron River, Inner Mongolia and Its Geological Significance. Acta Palaeontologica Sinica, 1997, 36(1): 58-69. (in Chinese with English Abstract)

[65] Wilhem C, Windley B F, Stampfli G M. The Altaids of Central Asia: A Tectonic and Evolutionary Innovative Review. Earth-Science Reviews, 2012, 113(3): 303-341. 4

[66] Winchester J A, Floyd P A. Geochemical Discrimination of Different Magma Series and Their Differentiation Products Using Immobile Elements. Chemical Geology, 1977, 20: 325-343.

[67] Windley B F, Alexeiev D, Xiao W J, . Tectonic Models for Accretion of the Central Asian Orogenic Belt. Journal of the Geological Society, 2007, 164(1): 31-47.

[68] Wood D A. The Application of a Th-Hf-Ta Diagram to Problems of Tectonomagmatic Classification and to Establishing the Nature of Crustal Contamination of Basaltic Lavas of the British Tertiary Volcanic Province. Earth and Planetary Science Letters, 1980, 50(1): 11-30.

[69] Wood D A, Joron J L, Treuil M. A Re-Appraisal of the Use of Trace Elements to Classify and Discriminate between Magma Series Erupted in Different Tectonic Settings. Earth and Planetary Science Letters, 1979, 45(2): 326-336.

[70] Xiao W J, Han C M, Yuan C, . Middle Cambrian to Permian Subduction-Related Accretionary Orogenesis of Northern Xinjiang, NW China: Implications for the Tectonic Evolution of Central Asia. Journal of Asian Earth Sciences, 2008, 32(2): 102-117. 3/4

[71] Xiao W J, Windley B F, Hao J, . Accretion Leading to Collision and the Permian Solonker Suture, Inner Mongolia, China: Termination of the Central Asian Orogenic Belt. Tectonics, 2003, 22(6): 1069

[72] Xu W T. Contrastive Research of Ophiolite Mélange Belts in the Central-East of Xing’an-Mongolian Orogenic Belt, 2017, Beijing: China University of Geosciences (in Chinese with English Abstract)

[73] Yin D F. The Formation Age, Genesis and Its Geological Significance of the Xingshuwa Tectonic Mélange in Inner Monglia, 2018, Beijing: China University of Geosciences (in Chinese with English Abstract)

[74] Yogodzinski G M, Lees J M, Churikova T G, . Geochemical Evidence for the Melting of Subducting Oceanic Lithosphere at Plate Edges. Nature, 2001, 409 6819 500-504.

[75] Zhang J E, Xiao W J, Han C M, . Magmatism of Mid-Oceanic Ridge Subduction during Carboniferous in Western Junggar: Evidence from Maliya Ophiolite. Acta Petrologica Sinica, 2010, 26(11): 3272-3282. (in Chinese with English Abstract)