Paleo-Asian oceanic subduction-related modification of the lithospheric mantle under the North China Craton: Evidence from peridotite xenoliths in the Datong basalts

Recycling of Paleo-Asian Ocean carbonates and its influence on the lithospheric composition of the North China Craton

“…The difference between these two types of mantle metasomatism lies in two aspects: one is that the metasomatic mantle domain caused by recycling of Paleoproterozoic carbonates should be distributed in the north-south direction, while the metasomatic mantle domain caused by the southward subduction of the PAO plate should be distributed in the east-west direction; the other is that the re-cycled Paleoproterozoic carbonates and thus the metasomatized mantle is characterized by a relatively low 87 Sr/ 86 Sr ratio (Veizer and Mackenzie, 2003;Castillo, 2015). Recent studies have shown that the high 87 Sr/ 86 Sr mantle caused by carbonate metasomatism is along the east-west trending in the northern margin of the NCC (Xu et al, 2003;Zhang H F et al, 2012;Wang et al, 2016;Wu et al, 2017), while it is featured by north-south zoning in the interior of the NCC . This indicates that the metasomatic carbonate melts were mostly derived from recycled sedimentary carbonates related to the subduction of the PAO plate (Wang et al, 2016;Wu et al, 2017).…”

“…The occurrence of a large number of late Paleozoic and early Mesozoic granitoid intrusions in the northern margin of the NCC indicates that the subduction of the PAO slab could have strongly influenced the lithosphere of the NCC (Zhang et al, 2009a(Zhang et al, , 2009b. Therefore, although lithospheric thinning mainly occurred in the eastern part of the NCC and is considered to have been triggered by the subduction of the Pacific plate (Zhu et al, 2011), the subduction of the PAO slab transported abundant marine and continental sediments into the lithospheric mantle and undoubtedly contributed to the lithospheric mantle transformation of the NCC (Xu, 2002;Liu et al, 2010b;Chen et al, 2016Wang et al, 2016Wang et al, , 2019Wu et al, 2017).…”

“…The Sr isotopic compositions of clinopyroxenes with low Ti/ Eu and high (La/Yb) N can be divided into two groups (Figure 6b). The mantle metasomatism caused by recycled carbonatederived melts could be related to the Paleoproterozoic subduction associated with the amalgamation of the eastern and western blocks of the NCC (Xu C et al, 2017;Xu et al, 2018;Xu et al, 2019) and/or the Paleozoic subduction of the PAO plate (Wang et al, 2016;Wu et al, 2017). The difference between these two types of mantle metasomatism lies in two aspects: one is that the metasomatic mantle domain caused by recycling of Paleoproterozoic carbonates should be distributed in the north-south direction, while the metasomatic mantle domain caused by the southward subduction of the PAO plate should be distributed in the east-west direction; the other is that the re-cycled Paleoproterozoic carbonates and thus the metasomatized mantle is characterized by a relatively low 87 Sr/ 86 Sr ratio (Veizer and Mackenzie, 2003;Castillo, 2015).…”

“…Recent studies have shown that the high 87 Sr/ 86 Sr mantle caused by carbonate metasomatism is along the east-west trending in the northern margin of the NCC (Xu et al, 2003;Zhang H F et al, 2012;Wang et al, 2016;Wu et al, 2017), while it is featured by north-south zoning in the interior of the NCC . This indicates that the metasomatic carbonate melts were mostly derived from recycled sedimentary carbonates related to the subduction of the PAO plate (Wang et al, 2016;Wu et al, 2017).…”

“…There are two main views on the final closure time of the PAO, either the late Devonian (Xu et al, 2013) or the end of Permian (~250 Ma; Xiao et al, 2003;Windley et al, 2007). A large amount of marine carbonates were deposited in the PAO (Volkova and Budanov, 1999;Lü et al, 2013;Schertl and Sobolev, 2013;Zhao et al, 2013), some of which were carried into the mantle through subduction during the PAO closure (Liu et al, 2015;Chen et al, 2016), resulting in physical and chemical modification of the lithospheric mantle in the NCC (Liu et al, 2010b;Wang et al, 2016;Chen et al, , 2018Liu et al, 2019;He et al, 2020b), the South Mongolian microblock (Wiechert et al, 1997;Kononova et al, 2002) and the Tarim Craton (Cheng et al, 2018). Therefore, the study of the subducted sedimentary carbonates is significant to help reconstruct the history of the PAO and decipher the influence of the carbonate cycle on the cratonic mantle.…”