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The 2022 Winter Olympics will be held in the Beijing-Zhangjiakou area, which is located in the eastern North China Craton (NCC) and contains a comprehensive geological record from the Archaean to Cenozoic. In this paper, we first review the geology of the Beijing-Zhangjiakou area, then, combined with data from the rest of the NCC, we discuss the geological evolution of the area in the context of the NCC. The geological and tectonic evolution of the Beijing-Zhangjiakou area can be regarded as a proxy or analogue for the geological history of the whole of the NCC. Six stages have been divided as follows: 1) Neoarchean massive continental crust growth; 2) Paleoproterozoic cratonization; 3) Meso-Neoproterozoic multi-stage rifting; 4) Palaeozoic marginal orogeny; 5) Mesozoic craton destruction; and 6) Cenozoic intra-plate extension. We hope this paper will be helpful to both geologists and non-geologists who will attend the 2022 Beijing-Zhangjiakou Winter Olympics and may be interested in rocks and geology around the Winter Olympic sites. [ABSTRACT FROM AUTHOR]

Based on a brief introduction of the spatial distribution, rock types and formation ages of the late Mesoarchean-early Neoarchean (2.6~3.0 Ga) rocks in some key areas of the North China Craton, this paper summarizes the ages and geochemical and Nd-Hf-O isotopic compositions of the granitoids all over the craton. The late Mesoarchean-early Neoarchean basement shows the following features: (1) The late Mesoarchean-early Neoarchean magmatism is almost continuous, with a peak period of 2.70~2.75 Ga; (2) The late Mesoarchean-early Neoarchean rocks widely occur in the North China Craton, mainly in the Eastern Ancient Terrane, the Central Ancient Terrane and the Southern Ancient Terrane; (3) The intrusive rocks are mainly tonalite in composition, with trondhjemite, granodiorite, K-rich granite and gabbro-diorite; (4) The supracrustal rocks are commonly small in scale and scatter in granitoids. The rock types are mainly meta-basaltic rocks. In some areas, there are meta-komatiites, meta-andesitic-dacitic rocks and meta-clastic sedimentary rocks; (5) 2.6 Ga can be regarded as the boundary between the early and late Neoarchean in the North China Craton; (6) TTG rocks show large Sr/Y and La/Yb variations, plotting in the high-, medium- and low-pressure TTG areas in the Sr/Y-Y and La/Yb-Yb diagrams. Except for a few K-rich granites, the late Mesoarchean-early Neoarchean rocks are commonly depleted in Nd-Hf isotope compositions, with the magmatic zircon being similar in O isotope composition to that of the Archean magmatic zircon worldwide; (7) Many regions have similar geological characteristics, but some regions show great uniqueness. The research futher supports the understanding that, similar to many other typical cratons worldwide, the late Mesoarchean-early Neoarchean is the most important period of continental accretion in the North China Craton, and the main difference is that the North China Craton underwent a strong and widespread magmatotectonothermal event at the end of the Neoarchean. [ABSTRACT FROM AUTHOR]

The Neoarchean basement rocks of the Qixingtai region in the northwest of western Shandong, eastern North China Craton are divided into western and eastern domains, separated by a ductile shear zone. The western domain is mainly composed of early Neoarchean tonalitic and supracrustal rocks, and the eastern domain is composed of late Neoarchean crustally‐derived granite with diverse early Neoarchean enclaves up to several kilometres long of supracrustal and gneissic TTG‐diorite rocks. This study reports an integrated field, whole‐rock geochemistry and zircon U–Pb‐Hf study on the granites and their enclaves in the eastern domain. The supracrustal enclaves are mainly composed of meta‐basaltic and meta‐ultramafic rocks and are the same in lithological association and formation time as the 2,750–2,700 Ma Liuhang "Formation" in the western area. The TTG‐diorite enclaves can be divided into early and late groups. Magmatic zircons from early TTG‐diorite samples have U–Pb ages of 2,731 ± 17 to 2,748 ± 13 Ma and εHf(t) values of +2.7 to +9.5, whereas trondhjemite samples of the late group have U–Pb zircon ages of 2,588 ± 18 to 2,606 ± 12 Ma and εHf(t) values of +0.6 to +6.5. The Hf isotopic signatures on magmatic zircon from the >2,700 Ma diorite‐tonalites indicate that they are predominantly juvenile crustal additions, probably with minor involvement of older crust in their genesis, as given by tDM (Hf) ages ranging back to 2.92 Ga. The eastern granites range from monzogranite to syenogranite in composition and commonly have negative Eu anomalies, indicating residual plagioclase in the source region. Magmatic zircons from two granite samples have U–Pb ages of 2,516 ± 24 and 2,527 ± 18 Ma and εHf(t) values of +1.0 to +7.0. A fine‐grained syenogranite dyke contains inherited early Neoarchean zircons with εHf(t) values of +1.6 to +7.4. The isotopic signatures of the late Neoarchean granites that dominate the eastern domain show that they were derived from partial melting recycling of older continental crust recognized in the region – early Neoarchean rocks formed as a result of juvenile crustal additions. This is a common signature for late Archean crustal evolution throughout much of the North China Craton, and is the hallmark of some other Archean terranes, such as the Dharwar Craton of south India. The geodynamic explanations for the formation globally of vast amounts of crustally‐derived late Neoarchean granite are discussed. [ABSTRACT FROM AUTHOR]

Voluminous Neoarchean plutonic and supracrustal rocks are well developed in the Western Shandong Province of the North China Craton, which has been divided into a late Neoarchean crustally-derived granite belt, a middle to early Neoarchean ancient rock belt and a late Neoarchean juvenile rock belt. Earlier studies provided reconnaissance evidence for ∼2.60 Ga metamorphism in some areas. This study presents SHRIMP zircon U–Pb dating and O isotope analysis on nine metamorphosed igneous rock samples (gneissic tonalite, gneissic trondhjemite, gneissic quartz diorite and meta-gabbro) from the ancient rock belt. Magmatic zircons vary in age from 2.74 Ga to 2.60 Ga, whereas metamorphic and anatectic zircons vary in age from 2.63 Ga to 2.59 Ga, with an age peak of 2.61 Ga. In this study, we identified 2.69–2.67 Ga metamorphic zircons for the first time. Most of zircons, whether magmatic or metamorphic, have δ 18 O values of +4.5‰ to +6.5‰ (V-SMOW). However, the oldest tonalite sample with a protolith age of 2735 Ma has zircons showing low δ 18 O (V-SMOW) values, particularly in recrystallized domains and overgrowths. This suggests at least in local crustal extension and influx of meteoric water during the evolution of the rocks. Combined with data from earlier studies, we draw the conclusion that the Western Shandong Province experienced a regional tectono-thermal event at ∼2.60 Ga, as a result of high heat flow and crustal extension, perhaps caused by a mantle plume or mantle overturn activity. Therefore we conclude that 2.60 Ga can be regarded the break between early and late Neoarchean crustal accretion. The O isotope study indicates that in some cases, trondhjemitic leucosome was not derived from nearby gneissic tonalite, although they show a close relationship in outcrop. [ABSTRACT FROM AUTHOR]

The western Shandong Province (WSP) is one of the typical Neoarchaean granite-greenstone belts in the Eastern Block of the North China Craton (NCC) and is an important region to investigate the early Precambrian evolutionary history of the NCC. The Taishan association, consisting of a ~2.7 Ga komatiite-tholeiite sequence and a ~2.5 Ga felsic volcano-sedimentary sequence, is the major lithological assemblage in the WSP. In the Qixingtai area, the felsic volcano-sedimentary sequence, partly subjected to anatexis, is composed of hornblende gneiss, voluminous fine-grained biotite gneiss and biotite plagioclase gneiss. SHRIMP zircon dating shows that the protolith of the biotite plagioclase gneiss formed after ca. 2.53 Ga. The tonalite intrusion into the volcanic protoliths of the fine-grained biotite gneiss and biotite plagioclase gneiss occurred at 2.52 Ga. Our age data constrain the time of formation of the felsic volcano-sedimentary sequence in the Taishan area as 2.53-2.52 Ga. The majority of zircons from the felsic volcano-sedimentary rocks have intermediate εHf(t) values (−1.2 to +2.1). The whole rock Nd isotopes of the Taishan felsic volcano-sedimentary rocks yield the εNd(t = 2522 Ma) values of +2.6 to −1.8 and TDM2 ages 3.03-2.68 Ga. These values indicate the pre-existing crust was reworked at the end of the Neoarchaean (~2.5 Ga). The Taishan felsic volcano-sedimentary rocks are rhyodacite-dacite and andesite in composition. These rocks and the tonalite display similar high SiO2 (65-72 wt.%) and low MgO (1-2 wt.%) content. In contrast, the minor andesites in the area have lower SiO2 (61-62 wt.%) and higher MgO (5.3-6.3 wt.%), suggesting more mantle contribution during their petrogenesis. However, the Mg-rich andesites have identical rare earth element and multi-element patterns with the rhyodacite-dacites and distinguish them from the Taishan sanukitoids. We suggest that the 2.53-2.52 Ga felsic volcanics of the Taishan association are the products of partial melting of a subducted oceanic crust. The andesites were produced by minor modification of the ascending tonalite-trondhjemite-granodiorite-type magma by the mantle wedge. Our study indicates that (1) the tectonic regime of the WSP greenstone belt was dominated by an arc-subduction system at ~2.52 Ga and (2) the 2.53-2.52 Ga felsic volcano-sedimentary rocks and intrusive tonalite are the products of crustal reworking. The felsic volcano-sedimentary sequence of the Taishan association and other ~2.5 Ga arc-like assemblages in the NCC provide important clues to understand the nature of the tectonothermal events at the end of the Neoarchaean. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Nhlangano granite-gneiss in south-west Swaziland, dated at 2.98 Ga, forms an elliptical dome of remobilised, migmatitic crust. Strongly deformed supracrustal rocks wrap around or form synformal keels infolded with subdomes of Nhlangano Gneiss and represent Mesoarchaean Pongola Supergroup strata at amphibolite- to granulite-facies metamorphic grade. Amphibolites represent the metamorphosed equivalents of Nsuze Group basalts and andesites on the basis of similar trace element and Nd isotope data. Garnetiferous Mahamba Gneiss, dated at c. 2.96 Ga, represents the metamorphosed equivalents of felsic to intermediate volcanic rocks and minor pelitic interflow sedimentary units of the Nsuze Group. Quartzites and associated metamorphosed iron formations are part of the lower Mozaan Group (Sinceni Formation) as indicated by the presence of detrital zircons as young as 3.07 Ga and matching geochemical provenance characteristics. Ar-Ar analysis of hornblende separates dates amphibolite-facies metamorphism and associated dome emplacement at c. 2.72 Ga. Exhumation took place during NW-SE crustal extension and was facilitated by partial melting of the mid-crustal rocks. Exhumation took place below a southeastward-dipping detachment fault, giving rise to NW-SE oriented elliptical gneiss domes due to vertical and lateral flow of partially molten rocks. The Nhlangano gneiss dome has features in common with migmatite-cored metamorphic core complexes. Its emplacement points to tectonic instability of the eastern part of the Kaapvaal Craton in the Neoarchaean. [ABSTRACT FROM AUTHOR]

Western Shandong is the only area in the North China Craton where abundant supracrustal rocks of the early and late Neoarchean are developed. This study presents an integrated geological investigations, whole-rock geochemistry and SHRIMP U Pb zircon dating investigation of the supracrustal rocks at Yanlingguang, one of the most typical areas of Neoarchean supracrustal rocks in western Shandong. The original Yanlingguan 'formation' is now subdivided into three belts: the Northeastern, Central and Southwestern belts, which are all in tectonic contact. The Northeastern and Southwestern belts are mainly composed of meta-komatiitic and basaltic rocks. Four granitic dykes intruding these belts have magmatic zircon ages of 2731–2530 Ma, supporting the conclusion that the supracrustal rocks were formed in the early Neoarchean. Meta-basalt with pillow structures has been identified in several locations, with the largest being ~35 m in thickness. The meta-komatiitic rocks are Al-undepleted komatiites and have ∑REE and (La/Yb) n of 2.30–26.21 ppm and 0.29–2.35, respectively, whereas the meta-basaltic rocks have ∑REE and (La/Yb) n of 16.45–53.26 ppm and 0.67–1.78, respectively, and ε Nd (t) values of 3.36–4.76, being similar to N-MORB. Eleven samples of meta-sedimentary rocks (including meta-sandstones-siltstones and meta-conglomerates) from the Central Belt have zircon U Pb ages extending from 2760 to 2520 Ma, providing evidence for the first time that they were deposited during the late Neoarchean, rather than the early Neoarchean as previously thought. The meta-sandstones-siltstones show large variations in major element contents, but have low ∑REE (49.17–102.30 ppm) and (La/Yb) n (1.53–7.00) ratios, with negligible to weakly negative or positive Eu anomalies (Eu/Eu* = 0.60–1.17), and record ε Nd (t) values of 0.96–3.21. Combined with regional geological investigations, we conclude that the early Neoarchean supracrustal rocks were formed in an oceanic environment. It is also suggested that the sandstones-siltstones of the late Neoarchean were derived from the early Neoarchean basement, and that the conglomerates were derived from two separate source regions; one of early, and the other of late Neoarchean age. The identification of basal conglomerates is consistent with the arc model established in early studies. We suggest that the criteria employed in this study can be used for determining whether or not an Archean greenstone belt is of oceanic affinity. • Yanlingguang in western Shandong contains three greenstone belts that differ in age. • The Northwestern and Southwestern belts are early Neoarchean. • The Central belt is late Neoarchean. • Early Neoarchean ultramafic and mafic rocks formed at 2.75 Ga in an oceanic setting. • Late Neoarchean metasedimentary rocks formed at 2.52 Ga in an island arc setting. [ABSTRACT FROM AUTHOR]

Western Shandong Province is a typical area of the North China Craton (NCC) where Neoarchean plutonic and supracrustal rocks are widely distributed. Early studies documented that ∼2.7 Ga and ∼2.5 Ga magmato-tectono-thermal events are well developed in the area. Here we report SHRIMP U–Pb ages and Hf-in-zircon isotopic data from ten samples of different magmatic rock types including hornblendite, gneissic tonalite, gneissic trondhjemite and gneissic granite. Magmatic zircon grains have 207 Pb/ 206 Pb ages ranging from 2667 to 2598 Ma. Some rocks contain ∼2.5 Ga metamorphic rims and ∼2.7 Ga zircon cores. The magmatic zircon grains have ɛ Hf ( t ) values and Hf crustal model ages of −1.1 to +11.3 and 3.02–2.4 Ga, respectively. Combined with an earlier study, our main conclusions are that the middle Neoarchean rocks mainly occur together with early Neoarchean rocks in the northeastern portion of the central belt. Juvenile additions to continental crust and crustal recycling played important roles in the middle Neoarchean of western Shandong Province, and the entire Neoarchean tectonic evolution can be divided into middle to early Neoarchean (2.75–2.6 Ga) and late Neoarchean (2.6–2.5 Ga) events. [ABSTRACT FROM AUTHOR]