March 2013 LIP of the Month

Printer-friendly versionPrinter-friendly version

1330~1320 Ma Yanliao mafic sill province of the North China Craton*

Shuan-Hong Zhang, Yue Zhao

MLR Key Laboratory of Paleomagnetism and Tectonic Reconstruction, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China

E-mail: tozhangshuanhong@163.com (Dr. S.-H. Zhang)

*This report is extracted from the following papers:

Zhang, S.-H., Zhao, Y., Yang, Z.-Y., He, Z.-F., Wu, H., 2009. The 1.35 Ga diabase sills from the northern North China Craton: implications for breakup of the Columbia (Nuna) supercontinent. Earth and Planetary Science Letters, 288, 588–600. DOI: 10.1016/j.epsl.2009.10.023.

Zhang, S.-H., Zhao, Y., Santosh, M., 2012. Mid-Mesoproterozoic bimodal magmatic rocks in the northern North China Craton: Implications for magmatism related to breakup of the Columbia supercontinent. Precambrian Research, 222–223, 339–367. DOI: 10.1016/j.precamres.2011.06.003.

Abstract

Large volumes of diabase sills (named as the Yanliao mafic sill province) occurred within the latest Paleoproterozoic to Mesoproterozoic sedimentary rocks and extended over 500 km from west to east in the northern part of the North China Craton (NCC). Recent zircon and baddeleyite U-Pb dating results indicate simultaneous emplacement of these diabase sill swarms in the Mid-Mesoproterozoic at around 1330~1320 Ma. Zircon LA-ICP-MS U-Pb dating of the Shangdu-Huade granitic pluton in the northern NCC yielded similar emplacement ages ranging from 1331±11 Ma to 1313±17 Ma. The Mid-Mesoproterozoic magmatic rocks in the northern NCC constitute a typical bimodal magmatic suite. The geochemical and Nd-Hf isotopic data suggest that the diabasic rocks were generated by partial melting of the depleted asthenosphere mantle coupled with slight crustal assimilation in a continental rift setting; however, the granitic rocks were generated mainly through partial melting of the ancient continental crust, probably induced by the upwelling of hot asthenosphere mantle during continental rifting processes. The recognition of these bimodal magmatic rocks indicates that the northern NCC experienced a Mid-Mesoproterozoic rifting event that is considered to have led to the final breakup of the Columbia (Nuna) supercontinent. The carbonatite rocks and rare earth element-niobium mineralization in the giant Bayan Obo ore deposit in the northern NCC were also probably related to this continental rifting event in the Mid-Mesoproterozoic.

1. Introduction

The assembly of the Columbia (Nuna) supercontinent has been recorded in the North China Craton (NCC) by the 2.0–1.8 Ga collisional orogenic belts (e.g., Zhao et al., 2003a, 2004; Santosh, 2010). However, whether the NCC was involved in the breakup of the Paleo-Mesoproterozoic supercontinents is still controversial (e.g., Zhai et al., 2000; Lu et al., 2008; Rogers and Santosh, 2002; Zhao et al., 2003a; Li et al., 2008), mainly due to lack of reliable isotopic ages for the Mesoproterozoic (1.6–1.0 Ga) magmatism and tectonism in the NCC. Many paleogeographic reconstructions for the Columbia and Rodinia supercontinents during the Meso-Neoproterozoic time have excluded the NCC (e.g., Hoffman, 1991; Dalziel, 1991; Rogers and Santosh, 2002; Pesonen et al., 2003) or put it far away from other continents (e.g., Li et al., 2008). The recently indentified 1330~1320 Ma Yanliao mafic sill province in the northern part of the NCC (Zhang et al., 2009, 2012a; Li et al., 2009) provide important evidence for reconstruction of the NCC within the Columbia supercontinent.

2. Spatial distribution of the Yanliao mafic sill province and the associated felsic magmatism

Diabase sills are widespread within the latest Paleoproterozoic to Mesoproterozoic sedimentary rocks in the northern NCC and extended over 500 km from west to east (Figs. 1 and 2). They are especially common near Chaoyang, Lingyuan, Pingquan, Xiabancheng, Kuancheng, Huailai and western Beijing (Figs. 2 and 3). These sills have thickness of several meters up to several hundard meters. Their intrusive contacts are very clear and thin baked zones or thermal recrystallization can be observed near the boundaries of the sills (Fig. 4). These diabase sills are particularly common within the Xiamaling and Wumishan Formations; also locally within the Chuanlinggou, Gaoyuzhuang, Hongshuizhuang and Tieling Formations (Fig. 5). Usually, three to five layers of diabase sills can be observed within the Xiamaling Formation from western Bejing to Chaoyang in the northern NCC (Fig. 6). Large volumes of diabase sills are very common within the Wumishan Formation near Chaoyang and are several tens of meters to several hundred meters thick, many of them running a few kilometers or even up to several tens of kilometers (Fig. 3). All the sills emplaced within the latest Paleoproterozoic to Mesoproterozoic sedimentary rocks display typical diabasic texture with similar mineral compositions of pyroxene (35–60 vol.%), plagioclase (40–55 vol.%), magnetite (3–10 vol.%) and hornblende (0–5 vol.%).


Figure 1 Sketch map showing late Paleoproterozoic-Mesoproterozoic continental rifting in the NCC


Figure 2 Sketch geological map of the northern NCC showing distribution of the latest Paleoproterozoic to Meso-Neoproterozoic sedimentary rocks in the northern NCC


Figure 3 Geological map showing distribution of the diabase sills within the Mesoproterozoic sedimentary rocks near Chaoyang in western Liaoning Province


Figure 4 Field photograph showing occurrence of the Yanliao mafic sill swarms in the northern NCC


Figure 5 Subdivision and zircon U-Pb age constraints on latest Paleoproterozoic to Meso-Neoproterozoic strata in the northern NCC


Figure 6 Representative geological sections showing the diabase sills within the Mesoproterozoic Xiamaling Formation

A Mid-Mesoproterozoic granitic pluton recently identified is located between the Shangdu and Huade counties in the northern margin of the NCC (Figs. 2 and 7). It is emplaced into the Mesoproterozoic Jixian System of Bayan Obo Group composed mainly of sedimentary rocks subjected to low-grade metamorphism in the east edge of the Zha'ertai-Bayan Obo-Huade rift zone (Fig. 1). Rocks from the granite pluton display a coarse-medium grained porphyritic texture with a broadly uniform mineral composition of K-feldspar (40–60 vol.%), plagioclase (5–30 vol.%), quartz (25–35 vol.%), biotite (5–10 vol.%), hornblende (0–5 vol.%) and accessory magnetite, titanite, apatite and zircon, and secondary (<5 vol.%) sericite, muscovite and epidote.


Figure 7 Geological map of Mid-Mesoproterozoic Shangdu-Huade granite pluton in the northern margin of the NCC

3. Geochronology of the Yanliao mafic sill province and the associated felsic magmatism

Our new SHRIMP and LA-ICP-MS U-Pb zircon ages from two diabase samples (Fig. 8A–B) and SIMS baddeleyite dating of four diabase samples (Fig. 9A–D) emplaced into the Wumishan, Tieling and Xiamaling Formations yield similar emplacement ages ranging from 1325±5 Ma to 1316±37 Ma. These results indicate that the emplacement of the diabase sills within Wumishan, Tieling and Xiamaling Formations occurred simultaneously at around 1.33–1.32 Ga.


Figure 8 U-Pb concordia diagrams for zircons from Mid-Mesoproterozoic magmatic rocks. Data-point error crosses are 2σ.


Figure 9 U-Pb concordia diagrams for baddeleyites from Mid-Mesoproterozoic diabase sills. Data-point error crosses are 2σ.

Zircon LA-ICP-MS U-Pb dating on four samples from the Shangdu-Huade granite pluton in the northern NCC yielded emplacement ages from 1331±11 Ma to 1313±17 Ma (Fig. 9C–F). These ages are similar to those obtained from the diabase sills in the northern NCC, indicating coeval emplacement of these bimodal intrusive rocks in the Mid-Mesoproterozoic at around 1.33 to 1.31 Ga.

4. Geochemical and isotopic characteristics of the Yanliao mafic sill province and the associated felsic magmatism

The Mid-Mesoproterozoic diabase sills within the late Paleoproterozoic to Mesoproterozoic sedimentary rocks exhibit very similar petrological and geochemical compositions with low contents of SiO2, high contents of TiO2, Fe2O3T and MgO. They are classified as gabbro-gabbroic diorite or subalkaline basalt on total alkali (K2O+Na2O) vs. silica (SiO2) and Nb/Y vs. Zr/TiO2 diagrams (Fig. 10A–B) and exhibit tholeiitic compositions on the AFM diagram (Fig. 10C). These petrological and geochemical features indicate that the diabase rocks were generated from mantle-derived basaltic magma. Slight LREE-enrichment on chondrite-normalized REE patterns, positive Pb anomaly and slight negative Nb-Ta anomalies on primitive mantle-normalized spidergrams suggest crustal assimilation during magma processes (Wilson, 1989). The whole-rock Nd and zircon and baddeleyite Lu-Hf isotopic data provide important constraints on the source characteristics. All the diabase samples exhibit very similar Nd and Hf isotopic compositions with positive whole-rock εNd(t) and zircon and baddeleyite εHf(t) values (Fig. 11). On εNd(t) vs. emplacement age and εHf(t) vs. U-Pb age of zircons and baddeleyites, the rocks plot in the area between evolution lines of chondrite and depleted mantle (Fig. 11). These Nd and Hf isotopic systematics are very different from those of the 1.74–1.69 Ga Damiao anorthosite complex in the northern NCC that was considered to be derived from partial melting of an enriched lithospheric mantle (Xie, 2005; Zhang et al., 2007). Partial melting of the subcontinental lithospheric mantle cannot account for the high positive εNd(t) and εHf(t) values of the diabase sills, and the primary basaltic magmas of these rocks were likely derived from a depleted deep asthenosphere mantle source during the continental rifting stage. The Mid-Mesoproterozoic diabase sills in the northern NCC were likely generated by partial melting of the depleted asthenosphere mantle coupled with slight crustal assimilation in a continental rifting environment.




Figure 10 Geochemical classification diagrams for Mid-Mesoproterozoic magmatic rocks from the northern part of the NCC.



Figure 11 εNd(t) vs. emplacement age and εHf(t) vs. U-Pb age of zircons and baddeleyites from Mid-Mesoproterozoic magmatic rocks from the northern part of the NCC.

Rocks from the Mid-Mesoproterozoic granitic pluton are characterized by high contents of SiO2, K2O+Na2O, low TiO2, Fe2O3T and MgO and classified as granite or rhyodacite/dacite in geochemical classification diagrams. These felsic intrusive rocks can be produced either by fractional crystallization of a basaltic magma or by partial melting of the ancient continental crust. The Mid-Mesoproterozoic granitic rocks are characterized by low negative whole-rock εNd(t) and zircon εHf(t) values and old Nd and Hf isotopic model ages (Fig. 11). Their Nd-Hf isotopic compositions are very different from those of the diabase sills, indicating different source areas for these mafic and felsic intrusive rocks. On εNd(t) vs. emplacement age and εHf(t) vs. U-Pb age of zircons, they fall into an area near the 2.4–2.6 Ga evolutionary trend line of ancient crust of the NCC (Fig. 11), indicating their derivation from ancient crustal material. Therefore, the Mid-Mesoproterozoic granitic rocks in the northern NCC were mainly produced by partial melting of the older continental crust. The crustal anatexis in the northern NCC in the Mid-Mesoproterozoic was likely induced by upwelling hot asthenosphere mantle during continent rifting processes.

5. Implications for reconstruction of the Columbia supercontinent

Although it is well recognized that the NCC was involved in the global assembly of the Columbia supercontinent during Paleoproterozoic time (e.g., Condie, 2002; Wilde et al., 2002; Zhao et al., 2003a; Kusky et al., 2007; Santosh, 2010), the position of this craton within the Columbia supercontinent is not well constrained because of the lack of reliable paleomagmatic and geochronological data. Models on the paleo-position of the NCC within the Columbia supercontinent in the Paleo-Mesoproterozoic are diverse, and proposals include the connection of the NCC to Siberia (Condie, 2002), Baltica (Wilde et al., 2002), India (Zhao et al., 2003b; Zhang et al., 2012b) or a juxtaposition between Baltica, South America and Africa (Kusky et al., 2007). Since the evidence for Meso-Neoproterozoic (1.6–0.5 Ga) magmatism and tectonism was lacking in the NCC, most researchers believe that the NCC was not involved in the final breakup of the Columbia supercontinent during 1.35 to 1.20 Ga (e.g., Rogers and Santosh, 2002; Hou et al., 2008) nor the assembly and breakup of the Rodinia supercontinent in the late Mesoproterozoic to Neoproterozoic (e.g., Lu et al., 2008). Thus, many paleogeographic reconstructions for the Columbia and Rodinia supercontinents during Meso-Neoproterozoic time have excluded the NCC (e.g., Hoffman, 1991; Dalziel, 1991; Rogers and Santosh, 2002; Pesonen et al., 2003).

The major Mid-Mesoproterozoic continental rift magmatism in the northern NCC documented in our study therefore provides important constraints for the reconstruction of the Columbia supercontinent and the timing of breakup of the NCC from the Columbia supercontinent. A comparison of the paleomagnetic data from the NCC with those of the Laurentia and Siberia (Zhang et al., 2009), combined with the distribution of the Mid-Mesoproterozoic (1.4–1.2 Ga) dyke (sill) swarms, and the 2.1–1.8 Ga orogens indicates that the NCC was a member of the Nena amalgam including Laurentia, Siberia and Baltica cratons in the Columbia supercontinent. The NCC was probably located between the North America (Laurentia) and Siberia cratons in the late Paleoproterozoic to Mid-Mesoproterozoic (Zhang et al., 2009). The breakup of the NCC from the Columbia supercontinent is recorded by the 1.33–1.31 Ga bimodal magmatism in the northern NCC and supported by paleomagmatic data (Halls et al., 2000; Wu et al., 2005; Pei et al., 2006; Zhang et al., 2006, 2012b; Li et al., 2008; Chen et al., 2013).

6. Implications for genesis of the giant Bayan Obo REE-Nb-Fe ore deposit

The giant Bayan Obo REE-Nb-Fe ore deposit in northern NCC is among the world’s largest known rare earth ore reserves and has attracted considerable attention since its discovery. However, mineralization ages, tectonic setting and genesis of the deposits have been the subject of much debate for many years (e.g., Ren et al., 1994; Liu et al., 2004; Wu, 2008). Although the ages of mineralization obtained from the REE-Nb deposit range from the Mesoproterozoic to Early Paleozoic, many results show that the Mid-Mesoproterozoic (1.4–1.2 Ga) is a very important period for REE-Nb mineralization (e.g., Nakai et al., 1989; Conrad and Mckee, 1992; Wang et al., 1994; Zhang et al., 1994, 2001). Both field relations and geochemical evidence show a close petrogenetic link between the carbonatites and the Bayan Obo REE-Nb mineral deposit (e.g., Bai and Yuan, 1985; Le Bas et al., 1992, 2007; Yuan et al., 1992; Wang et al., 2002; Yang et al., 2003, 2009). Although the carbonatite rocks in the Bayan Obo REE-Nb-Fe ore deposit have not be precisely dated, their Sm-Nd isochron and zircon U-Pb ages are mainly around 1.4–1.2 Ga (e.g., Zhang et al., 2001; Fan et al., 2006; Le Bas, 2006; Le Bas et al., 2007; Yang et al., 2010), indicating their emplacement in the Mid-Mesoproterozoic. Therefore, emplacement of the carbonatite rocks and REE-Nb mineralization in the Bayan Obo deposit were probably coeval with those of the diabase and granite rocks in the Yanliao and Zha'ertai-Bayan Obo-Huade rift zones in the northern NCC.

Global giant or large REE deposits are usually related to carbonatite complexes in continental rift zones and their geochemical features show that sources for the large-scale REE mineralization is closely related to input from anomalous subcontinental mantle during rifting processes (e.g., Lehmann et al., 1994; Bai et al., 1996; Xu et al., 2004; Ernst and Bell, 2010). Although many workers proposed the formation of the Bayan Obo REE-Nb-Fe ore deposit in a continental rift environment (e.g., Drew et al., 1990; Cao et al., 1994; Bai et al., 1996), whether the continental rift was still active in the northern NCC in the Mid-Mesoproterozoic (1.4–1.2 Ga) remains uncertain, mainly due to lack of reliable geochronological data on contemporaneous rift-related magmatism. The Mid-Mesoproterozoic bimodal magmatism in continental rift setting within the northern NCC reported in this study provides critical constraints for the formation of the giant Bayan Obo REE-Nb-Fe ore deposit in a continental rift environment related to the breakup of the Columbia supercontinent in the Mid-Mesoproterozoic.

Acknowledgement

The authors greatly appreciate Prof. Richard E. Ernst for the invitation to provide this report.

References

Bai, G., Yuan, Z., 1985. Carbonatites and related mineral resources. Bulletin of the Institute of Mineral Deposits, Chinese Academy of Geological Sciences 13, 107–140 (in Chinese with English abstract).

Bai, G., Yuan, Z., Wu, C. 1996. Geotectonic setting of the Bayan Obo deposit, Inner Mongolia. Acta Geoscientia Sinica 17(Supp.), 1–8 (in Chinese with English abstract).

Cao, R.L., Zhu, S.H., Wang, J.W., 1994. Source materials and genesis of the Bayan Obo Fe-REE ore deposit. Science in China (Ser. B) 24, 1298–1307 (in Chinese).

Chen, L., Huang, B., Yi, Z., Zhao, J., Yan, Y., 2013. Paleomagnetism of ca. 1.35 Ga sills in northern North China Craton and implications for paleogeographic reconstruction of the Mesoproterozoic supercontinent Precambrian Research 228, 36–47.

Condie, K.C., 2002. Breakup of a Paleoproterozoic Supercontinent. Gondwana Research 5, 41–43

Conrad, I.E., Mckee, E.H., 1992. 40Ar/39Ar dating of vein amphibole from the Bayan Obo iron-rare earth element-niobium deposit, China: constraints on mineralization and deposition of the Bayan Obo Group. Economic Geology 87, 185–188.

Dalziel, I.W.D., 1997. Neoproterozoic–Paleozoic geography and tectonics: review, hypothesis, environmental speculation. Geological Society of America Bulletin 108, 16–42

Drew, L.J., Meng, Q., Sun, W., 1990. The Bayan Obo iron–rare-earth–niobium deposit, Inner Mongolia, China. Lithos 26, 46–65.

Ernst, R.E., Bell, K., 2010. Large igneous provinces (LIPs) and carbonatites. Mineralogy and Petrology 98, 55–76.

Fan, H.R., Hu, F.F., Chen, F.K., Yang, K.F., Wang, K.Y., 2006. Intrusive age of No.1 carbonatite dyke from Bayan Obo REE-Nb-Fe deposit, Inner Mongolia: with answers to comment of Dr. Le Bas. Acta Petrologica Sinica 22, 519–520 (in Chinese with English abstract).

Hoffman, P.F., 1991. Did the breakout of Laurentia turn Gondwanaland inside-out? Science 252, 1409–1412

Hou, G., Santosh, M., Qian, X., Lister, G.S., Li, J. 2008. Tectonic constraints on 1.3~1.2 Ga final breakup of Columbia supercontinent from a giant radiating dyke swarm. Gondwana Research 14, 561–566.

Kusky T., Li J., Santosh M., 2007. The Paleoproterozoic North Hebei Orogen: North China craton's collisional suture with the Columbia supercontinent. Gondwana Research 12, 4–28.

Le Bas, M.J., 2006. Re-interpretation of zircon date in a carbonite dyke at the Bayan Obo giant REE-Fe-Nb deposit, China. Acta Petrologica Sinica 22, 517–518.

Le Bas, M.J., Keller, J., Tao, K.J., Wall, F., Williams, C.T., Zhang, P.S., 1992. Carbonatite Dykes at Bayan Obo, Inner Mongolia, China. Mineralogy and Petrology 46, 195–228.

Le Bas, M.J., Xueming, Y., Taylor, R.N., Spiro, B., Milton, J.A., Peishan, Z., 2007. New evidence from a calcite-dolomite carbonatite dyke for the magmatic origin of the massive Bayan Obo ore-bearing dolomite marble, Inner Mongolia, China. Mineralogy and Petrology 90, 223–248.

Lehmann, B., Nakai, S., Höhndorf, A., Brinckmann, J., Dulski, P., Hein, U.F., Masuda, A., 1994. REE mineralization at Gakara, Burundi: Evidence for anomalous upper mantle in the western Rift Valley. Geochimica et Cosmochimica Acta 58, 985–992.

Li, Z.X., Bogdanova, S.V., Collins, A.S., Davidson, A., De Waele, B., Ernst, R.E., Fitzsimons, I.C.W., Fuck, R.A., Gladkochub, D.P., Jacobs, J., Karlstrom, K.E., Lu, S., Natapov, L.M., Pease, V., Pisarevsky, S.A., Thrane, K., Vernikovsky, V., 2008. Assembly, configuration, and break-up history of Rodinia: a synthesis. Precambrian Research 160, 179–210.

Li, H.K., Lu, S.N., Li, H.M., Sun, L.X., Xiang, Z.Q., Geng, J.Z., Zhou, H.Y., 2009. Zircon and baddeleyite U-Pb precision dating of basic rock sills intruding Xiamaling Formation, North China. Geological Bulletin of China 28, 1396–1404 (in Chinese with English abstract).

Lu, S.N., Zhao, G.C., Wang, H.C., Hao, G.J., 2008. Precambrian metamorphic basement and sedimentary cover of the North China Craton: A review. Precambrian Research 160, 77–93.

Nakai, S., Masuda, A., Shimizu, H., Qi, L., 1989. La-Ba dating and Nd and Sr isotope studies on Baiyun Obo rare earth element ore deposits, Inner Mongolia, China. Economic Geology 84, 2296–2299.

Pesonen, L.J., Elming, S.-A., Mertanen, S., Pisarevsky, S., D’Agrella-Filho, M.S., Meert, J.G., Schmidt, P.W., Abrahamsen, N., Bylund, G., 2003. Palaeomagnetic configuration of continents during the Proterozoic. Tectonophysics 375, 289–324.

Ren, Y.C., Zhan, Y.C., Zhang, Z.Q., 1994. Study on heat events of ore-forming Bayan Obo deposit. Acta Geoscientia Sinica 15, 95–101 (in Chinese with English abstract).

Rogers, J.J.W., Santosh, M., 2002. Configuration of Columbia, a Mesoproterozoic supercontinent. Gondwana Research 5, 5–22.

Santosh, M., 2010. Assembling North China Craton within the Columbia supercontinent: The role of double-sided subduction. Precambrian Research 178, 149–167.

Wang, J., Tatsumoto, M., Li, X., Premo, W.R., Chao, E.C.T., 1994. A precise 232Th-208Pb chronology of fine grained monazite: Age of the Bayan Obo REE-Fe-Nb ore deposit, China. Geochimica et Cosmochimica Acta 58, 3155–3169.

Wang, X., Hao, Z., Li, Z., Xiao, G., Zhang, T., 2002. A typical alkaline rock-carbonatite complex in Bayan Obo, Inner Mongolia. Acta Geologica Sinica 76, 501–524 (in Chinese with English abstract).

Wilde, S.A., Zhao, G.C., Sun, M., 2002. Development of the North China Craton during the Late Archaean and its final amalgamation at 1.8 Ga; some speculations on its position within a global Palaeoproterozoic supercontinent. Gondwana Research 5, 85–94.

Wilson, M., 1989. Igneous Petrogenesis: A Global Tectonic Approach. Chapman & Hall, London. p. 466

Wu, C., 2008. Bayan Obo controversy: carbonatites versus iron oxide-Cu-Au-(REE-U). Resource Geology 58, 348–354.

Xie, G.H., 2005. Petrology and geochemistry of the Damiao anorthosite and the Miyun rapakivi granite. Science Press, Beijing, p. 195 (in Chinese).

Xu, C., Zhang, H., Huang, Z.L., Liu, C.Q., Qi, L., Li, W.B., Guan, T., 2004. Genesis of the carbonatite-syenite complex and REE deposit at Maoniuping, Sichuan Province, China: Evidence from Pb isotope geochemistry. Geochemical Journal 38, 67–76.

Yuan, Z., Bai, G., Wu, C., Zhang, Z., Ye, X., 1992, Geological features and genesis of the Bayan Obo REE ore deposit, Inner Mongolia, China. Applied Geochemistry 7, 429–442.

Yang, X.M., Yang, X.Y., Zheng, Y.F., Le Bas, M.J., 2003. A rare earth element-rich carbonatite dyke at Bayan Obo, Inner Mongolia, North China. Mineralogy and Petrology 78, 93–110.

Yang, X.Y., Sun, W.D., Zhang, Y.X., Zheng, Y.F., 2009. Geochemical constraints on the genesis of the Bayan Obo Fe-Nb-REE deposit in Inner Mongolia, China. Geochimica et Cosmochimica Acta 73, 1417–1435.

Yang, K.F., Fan, H.R., Hu, F.F., Wang, K.Y., 2010. Intrusion sequence of carbonatite dykes and REE accumulation mechanism in Bayan Obo district. Acta Petrologica Sinica 26, 1523–1529 (in Chinese with English abstract).

Zhai, M.G., Bian, A.G., Zhao, T.P., 2000. The amalgamation of the supercontinent of North China craton at the end of the Neoarchaean, and its break-up during the late Palaeoproterozoic and Mesoproterozoic. Science in China (Ser. D) 43 (Supp.), 219–232.

Zhang, Z.Q., Tang, S.H., Wang, J.H., Yuan, Z.X., Bai, G., 1994. New data for ore-forming age of the Bayan Obo REE ore deposit. Acta Geoscientia Sinica 15, 85–94 (in Chinese with English abstract).

Zhang, Z.Q., Tang, S.H., Yuan, Z.X., Bai, G., Wang, J.H., 2001. The Sm-Nd and Rb-Sr isotopic systems of the dolomite in the Bayan Obo ore deposit, Inner Mongolia, China. Acta Petrologica Sinica 17, 637–642 (in Chinese with English abstract).

Zhang, S.H., Liu, S.W., Zhao, Y., Yang, J.H., Song, B., Liu, X.M., 2007. The 1.75–1.68 Ga anorthosite-mangerite-alkali granitoid-rapakivi granite suite from the northern North China Craton: magmatism related to a Paleoproterozoic orogen. Precambrian Research 155, 287–312.

Zhang, S.-H., Zhao, Y., Yang, Z.-Y., He, Z.-F., Wu, H., 2009. The 1.35 Ga diabase sills from the northern North China Craton: implications for breakup of the Columbia (Nuna) supercontinent. Earth and Planetary Science Letters, 288, 588–600.

Zhang, S.-H., Zhao, Y., Santosh, M., 2012a. Mid-Mesoproterozoic bimodal magmatic rocks in the northern North China Craton: Implications for magmatism related to breakup of the Columbia supercontinent. Precambrian Research, 222–223, 339–367.

Zhang, S., Li, Z.-X., Evans, D.A.D., Wu, H., Li, H., Dong, J., 2012b. Pre-Rodinia supercontinent Nuna shaping up: A global synthesis with new paleomagnetic results from North China. Earth and Planetary Science Letters, 353–354, 145–155.

Zhao, G.C., Sun, M., Wilde, S.A., Li, S.Z., 2003a. Assembly, accretion and breakup of the Paleo-Mesoproterozoic Columbia Supercontinent: Records in the North China Craton. Gondwana Research 6, 417–434.

Zhao, G.C., Sun, M., Wilde, S.A., 2003b. Correlations between the Eastern Block of the North China Craton and the South Indian Block of the Indian Shield: An Archean to Paleoproterozoic link. Precambrian Research 122, 201–233.

Zhao, G.C., Sun, M., Wilde, S.A., Li, S., 2004. A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup. Earth-Science Reviews 67, 91–123.