Columbia Supercontinent Research Articles

Enigmatic Mid‐Proterozoic Orogens: Hot, Thin, and Low

AbstractSince the Archean, secular change in orogenic style is demonstrated through evolution of metamorphic conditions and geochemical proxies. Linked to orogenic style is the amount of crustal thickening and elevation, whereas orogenic vigor is related to the supercontinent cycle. An array of Proterozoic orogens spanned the assembly of supercontinents Columbia and Rodinia, but the vigor of orogenesis is debated, with proposals for both Mesoproterozoic quiescence and climax. We show mid‐Proterozoic orogenesis occurred globally and was broadly continuous; furthermore, orogens exhibit elevated metamorphic thermobaric ratios with large volumes of high‐temperature felsic magmatic rocks. These features reflect higher mantle heat flux leading to increased mid‐crustal flow and lower elevation. In this context, proposals that geochemical proxies for crustal thickness record orogenic quiescence are inconsistent with the geological record. Alternatively, secular change in crustal thickness is attributed to orogenic style, namely the prevalence of hot, thin, and low orogens in the mid‐Proterozoic.

Paleo-Mesoproterozoic magmatism in the Tarim Craton, NW China: Implications for episodic extension to initial breakup of the Columbia supercontinent

The Tarim Craton located in the northwest of China, where the Paleo-Mesoproterozoic extensional magmatism related to the Columbia supercontinent is widely developed. However, the process and time of the extension and initial breakup of the Tarim Craton are still controversial during Paleo-Mesoproterozoic era. In this contribution, we present a systematic petrographic, geochemical, and zircon U-Pb-Hf investigation on Aketashitage granite dykes, Wulan granitic gneisses and Astingbulake metadiabases from the Tarim Craton. Results from our study indicate that the ca. 1.88–1.86 Ga Aketashitage granite dykes belong to I-type granites, which were probably derived from low degree partial melting of thickened Archean crust during early post-collisional setting. The ca. 1.55 Ga Wulan granitic gneisses also show the characteristics of I-type granites, which mainly came from partial melting of mafic lower crust with minor mantle-derived magma input during the rift setting. The ca. 1.55 Ga protoliths of Astingbulake metadiabases show affinity to ocean island basalts and/or continental flood basalts and were produced by partial melting of enriched continental lithospheric mantle under continental rifting setting. In conjunction with previous studies, it can be concluded that the Tarim Craton experienced episodic extension to initial breakup: the South Orogen underwent early post-collisional extension during ca. 1.90–1.85 Ga, followed by late post-collisional extension during ca. 1.80–1.73 Ga; the North Orogen experienced early post-collisional extension at ca. 1.80–1.73 Ga and then entered the late post-collisional extension at ca. 1.67–1.60 Ga; finally, the South Orogen and North Orogen simultaneously entered the initial breakup stage during ca. 1.55–1.47 Ga. Based on a comparison of the global Mesoproterozoic (ca. 1.58–1.45 Ga) magmatic activities as a response to the initial break up of the Columbia supercontinent, we suggest that the Tarim Craton (including the Oulongbuluke Block) and North China Craton were close to India, Australia, Yangtze, Siberia, Congo, São Francisco and West African.

Origin and Precambrian paleogeography of the North Wulan terrane, northwestern China: A coherent model of the Tarim–Qilian–Quanji continent during the Columbia–Rodinia supercontinent cycle

The occurrence of pre-existing crust in orogenic belts has important implications for constraining and testing models of orogenic processes and for making paleogeographic reconstructions. Asynchronous magmatic–metamorphic rocks provide an opportunity to reconstruct the positions and constituent blocks of certain Precambrian fragments. Here we report Neoarchean to Neoproterozoic crustal rocks preserved in the North Wulan Terrane (NWT), northwestern China. Our new zircon geochronological data reveal the ca. 2.57 Ga magmatic and 2.0–1.72 Ga metamorphic events in the NWT, implying its involvement in the formation of Columbia supercontinent. Meanwhile, the NWT also recorded the 1.5–1.3, 1.1, 0.9–0.8 and 0.51–0.48 Ga magmatic-metamorphic activities, corresponding to the involvement of regional Precambrian fragments in cyclic supercontinent-related processes from Columbia to Greater Gondwana. Most of the ca. 2.57 and 0.9–0.8 Ga granites are characterized by enriched zircon εHf(t) values of –5.7 to +0.9 and –5.2 to +7.1. Moreover, some of these granites show fractionated characteristics, with high silica contents (80.3–82.3 wt% and 73.9–75.2 wt%), indicating that these rocks were derived mainly from remelting of 3.6–2.7 Ga mature crustal materials and 1.6–2.0 Ga crustal materials without or with minor contribution of juvenile materials, respectively. On the basis of these new results, regional stratigraphy, and previously determined geochemical data and tectonic signatures, it is concluded that the Quanji Massif and the Central Qilian, Hualong and North Wulan terranes probably formed a coherent Qilian–Quanji block as the southeastern extension of the Tarim Craton initiated from the Neoarchean. We propose that from the Neoarchean to early Paleoproterozoic, the primal Qilian–Quanji block was formed by long-term arc-related magma emplacement and reworking of ancient mature crustal materials in southeastern Tarim Craton. Subsequently, the juvenile Tarim–Qilian–Quanji continent was involved in tectonic cycles during its involvement in the supercontinents of Columbia and Rodinia.

U-Pb ages and Hf isotopic compositions of detrital zircons from the Seochangni Formation of the northeastern Okcheon Metamorphic Belt: Implications to the crustal evolution of the Sino-Korean craton since Paleoproterozoic

The age-unknown Seochangni Formation is distributed in the northeastern part of the Okcheon Metamorphic Belt in central South Korea. It unconformably overlies the Paleoproterozoic Busan gneiss complex exposed as a small dome and is in contact with the Cambrian-Ordovician Joseon Supergroup of the Taebaeksan Basin to the east. We separated detrital zircons from the quartzite units of the Seochangni Formation and used SHRIMP and LA-MC-ICPMS to determine their UPb ages and Hf isotopic compositions. The UPb age distribution of the detrital zircons is divided into two types. In the main type, the ages of Late Paleoproterozoic to Mesoproterozoic are dominant, whereas they have little or no older age components of about 1.87Ga and 2.5Ga, which are characteristic of the Korean peninsula basement rocks. However, the minor type has age components of 0.75 Ga and 1.87 Ga. Age patterns similar to the former type have recently been reported in the western region of the Gyeonggi Massif on the Korean peninsula, as well as in the Sangwon System in North Korea and the southern margin of North China Craton. It suggests a correlation between them and a common crustal evolution within a single craton linked since the Paleoproterozoic. The high positive εHf(t) values of detrital zircons in the Late Paleoproterozoic to Mesoproterozoic period indicate an enhanced input of juvenile materials from the depleted mantle, reflecting the igneous activity associated with the breakup of the supercontinent Columbia.

Zircon and monazite petrochronology studies reveal Mesozoic amphibolite-facies metamorphism overprinting Paleoproterozoic granulite-facies metamorphism: A case study from Rangnim Massif, North Korea

Recent studies have shown similar geological evolution processes between the Precambrian basements in North Korea and North China Craton (collectively called the Sino-Korea Craton). However, the detailed metamorphic evolution of supracrustal rocks in North Korea is still poorly understood. In this study, we investigated the petrology, mineralogy, zircon, and monazite UPb geochronology of five metapelite samples from the Jungsan Group in the Rangnim massif, North Korea, with the aim of better documenting the geodynamic evolution. The mineral assemblages and microtextures recorded two distinct metamorphic events, 1 and 2. Event 1 is characterized by a low-Ca garnet main domain, their abundant sillimanite inclusions, and equilibrium assemblages of sillimanite and biotite in the matrix, with minimum peak P-T conditions estimated at ~ 820 °C and ~ 8 kbar (with a geothermal gradient of ~ 100 °C/kbar). The timing of Event 1 was constrained to ca. 1855 Ma by zircon UPbdating. Event 2 is characterized by a high-Ca garnet narrow chemical band, staurolite, kyanite, biotite, and muscovite in the matrix, with near peak P-T conditions estimated at ~ 610 °C and ~ 7.9 kbar (with a geothermal gradient of ~ 75 °C/kbar). The timing of Event 2 was constrained to ca. 155–110 Ma based on a previous study of titanite and rutile UPb ages, but a subsequent fluid infiltration event at ca. 106 Ma by monazite UPb dating in this study. Our study indicates that supracrustal rocks in North Korea have experienced the same Paleoproterozoic high-grade metamorphism as that in the Jiao-Liao-Ji mobile belt in the North China Craton related to the Columbia Supercontinent; however, there has also been overprinting of a thermal event with mineral assemblages of amphibolite-facies related to extensive Late Jurassic–Cretaceous granitoids intrusion in the region.

Tectono-sedimentary evolution of the Paleoproterozoic succession of the Carajás Basin, southeastern Amazonian Craton, Brazil: Insights from sedimentology, stratigraphy, and U–Pb detrital zircon geochronology

The Carajás Basin, situated in the southeastern Amazonian Craton in northern Brazil, hosts a > 6 km thick pile of volcano-sedimentary rocks deposited from the Neoarchean to the early Paleoproterozoic eras (ca. 2.75–2.06 Ga). It is claimed that this basin started as a rift configuration in which volcanic and banded iron formation strata were deposited during the Neoarchean Era. However, the tectono-sedimentary evolution of this basin through the Paleoproterozoic Era remains unexplored. Based on a sedimentological, stratigraphic, and U–Pb detrital zircon geochronological investigation of a marine to a fluvial succession of this basin, this study suggests that the Carajás Basin evolved in a foreland setting during the early Paleoproterozoic Era. Probably, the Carajás Foreland Basin was sedimented in the underfilled stage (ca. 2.5–2.3 Ga) by deep-marine strata (i.e., glaciogenic submarine fan deposits), likely from the Siderian–Rhyacian Serra Sul Formation. Subsequently, shallow-marine deposits of the Azul Formation were deposited in the filled stage (ca. 2.3–2.1 Ga), followed by deposition of the fluvial to alluvial deposits of the Águas Claras and Gorotire formations during the overfilled stage (ca. 2.1–1.9 Ga). The Azul and Águas Claras formations were supplied mainly by Meso- to Neoarchean source rocks, whereas Paleoproterozoic and Paleoarchean rocks played the role of a subordinate source of sediments. The youngest U–Pb age cluster, at ca. 2.27 Ga, is interpreted as its maximum depositional age. In terms of paleogeography, the occurrence of Rhyacian zircon grains in the Azul Formation deposits suggests, at least partially, a connection between the Carajás Protocontinent with the Bacajá Domain during that period. The integrated data corroborate the hypothesis that the foreland basin was formed in a scenario of collision between the Bacajá Domain and the Carajás Protocontinent during the Transamazonian Cycle. These dramatic upheavals are directly related to the configuration of the Columbia Supercontinent, which initially led to the emergence of the Carajás Foreland Basin, and soon after, the cratonization of proto-Amazonia

Detrital zircon constraints on tectonic evolution of the Liaodong Paleoproterozoic orogenic belt, North China Craton

The Liaodong Paleoproterozoic orogenic belt (LPOB), as part of the eastern North China Craton (NCC), is the result of global collision during the amalgamation of the Columbia supercontinent. Tectonics of the LPOB thus becomes the key to the understanding of the tectonic evolution of the NCC, and may provide important information on the assembly of the supercontinent. Detailed geochronological and geochemical analysis on detrital zircons from the Liaohe group is conducted to unravel the tectonic attribute of the major constituent, i.e., the Liaohe group within the LPOB. The results show that the U-Pb ages of detrital zircons from the Langzishan, Li’eryu, Gaojiayu and Dashiqiao formations at the middle-lower parts of the Liaohe group are mainly characterized by peaks at ~ 2500 and 2200–2100 Ma. However, the ages of detrital zircons from the Gaixian formation at the upper part are peaked at 2100–2000 Ma. The age data indicate that the Archean basement rocks and Paleoproterozoic magmatic activities at 2200–2100 Ma variably provide sources for sediments of the middle-lower Liaohe group. However, sediments of the Gaxian formation at the upper part of the Liaohe group are mainly derived from magmatic activities from the Nangrim and North Gyeonggi blocks at 2100–2000 Ma . The source characteristics of the Liaohe group highlight the importance of back-arc extension in the evolution of the LPOB. The tectonic evolution of the LPOB is, therefore, subdivided into four stages, i.e. early back-arc extension stage (2200–2080 Ma), transitional stage (2080–1940 Ma), main orogenic deformation (1940–1840 Ma) and post-orogenic plutonic emplacement (after 1840 Ma).

An Early Paleoproterozoic back-arc system along the southern margin of the Yinshan Block: Evidence from a newly-defined bimodal volcanic sequence in the Daqingshan Complex, Khondalite Belt

As one of the 2.1 to 1.9 Ga orogenic belts that welded the Columbia supercontinent, the Khondalite Belt in the North China Craton is a typical continent-continent collisional orogen that formed through the collision between the Yinshan and Ordos Blocks. Previous studies mostly focused on the collisional event in the Khondalite Belt but paid little attention to how the subduction system operated before the final closure of the ocean. To address this issue, we identified a series of interlayered meta-mafic and felsic rock assemblages in the Daqingshan Complex and implemented geochemical and geochronological analyses. Petrological and geochemical studies revealed that these rocks are bimodal and include plagioclase amphibolite (Group 1) and biotite plagiogneiss (Group 2). Geochemically, Group 1 samples show tholeiitic affinity, whereas Group 2 samples belong to the high-K calc-alkaline series. Geochemical data indicate that the protolith magma of Group 1 was most likely derived from the partial melting of lithospheric mantle with minor crustal contamination, whereas Group 2 rocks represent highly differentiated magma derived from the partial melting of ancient crustal materials. All the samples show depletion of HFSEs and enrichment of LILEs, indicative of a subduction-related magmatic arc environment. Zircon U-Pb dating results show that the protoliths of Group 1 samples yield crystallization ages of ∼2.47 Ga and metamorphic ages of 1.95 to 1.85 Ga, whereas the protoliths of Group 2 samples yield crystallization ages of ∼2.40 Ga and metamorphic ages of ∼1.85 Ga. Our new results and available geochemical, petrological, and isotopic data demonstrate that the bimodal volcanic sequence of the Daqingshan Complex was developed in a 2.47 to 2.40 Ga back-arc system along the southern margin of Yinshan Block. Subsequent collision between the Ordos and Yinshan Blocks resulted in the formation of the Khondalite Belt and final amalgamation of the Western Block between 1.95 and 1.85 Ga.

Precambrian crustal evolution in Northern Indian Block: Evidence from detrital zircon U-Pb ages and Hf-isotopes

Integrated detrital zircon U–Pb and Lu–Hf isotope analyses were conducted on three siliciclastic sedimentary rock samples from the Vindhyan Supergroup in the Son Valley section of central India. These display two prominent 2.7–2.4 Ga and 1.9–1.5 Ga age groupings along with minor Paleoarchean-Mesoarchean (3.5–2.9 Ga) and late Mesoproterozoic (1.3–1.0 Ga) zircons. These 3.5–1.5 Ga detrital zircons match well with the exposed magmatic and metamorphic rock components within the Bundelkhand and Aravalli cratons of the Northern India Block. Zircon grains of >2.0 Ga mainly produce negative εHf(t) values suggestive of episodic recycling and reworking of old crust components in Northern India Block, whereas zircon grains in the age range of 2.0–1.4 Ga commonly produce positive εHf(t) values, indicating dominant juvenile crust growth in response to assembly and breakup of Columbia supercontinent. Contemporaneous mafic dykes (2.15–2.0 Ga and ca. 1.98 Ga) intruded into the Bundelkhand Igneous Complex present direct lithological evidence for juvenile crustal growth. Similar basement rock compositions and detrital zircon age distributions provide robust evidence that the Bundelkhand craton has possibly been combined with the Aravalli-Banded Gneiss Complex (ABGC) since Paleoproterozoic. 1.3–1.0 Ga old detrital zircons could have sourced from South China or the Central Indian Tectonic Zone or the Eastern Ghats or a pre-existing hidden terrane in India; their dominant negative εHf(t) values suggest reworking of old crustal components in Northern India Block in response to the assembly of Rodinia supercontinent.

Evidence for discrete Archean microcontinents in the Yangtze Craton

It is unclear whether most Archean continents have always existed in their present-day size, or were initially microcontinents or supercratons. The Archean evolution of the Yangtze Craton in South China provides an ideal opportunity to reveal Archean continental architecture. Archean rocks in the Yangtze Craton have been documented in seven separate areas prior to this study. In this paper, we report the first discovery of Archean rocks in a new area in the southern Dabie orogenic belt, which we term the Xishui gneiss. The protolith of the granitic gneiss is strongly peraluminous with high A/CNK ratios of 1.10–1.23 and K2O/Na2O ratios of 0.70–1.72, belonging to the high-K calc-alkaline series. Three samples of the gneiss from different localities yielded protolith ages of 2.51, 2.47, and 2.47 Ga (zircon U–Pb weighted mean ages). Xenocrystic zircons with magmatic texture from the gneiss yielded U–Pb ages of 3.57–2.41 Ga, and records four phases of magmatism and crustal reworking at 3.56, 3.34, 3.18, and 2.51–2.47 Ga. The history of crustal growth recorded by the gneiss can be traced back to ~3.80 Ga, with peaks at 3.8–3.7 and 3.5–3.4 Ga. A comparison of the crustal evolution in the eight exposed Archean terranes of the Yangtze Craton suggests they were independent microcontinents during the Archean and that the present-day Yangtze Craton was amalgamated at 2.0–1.9 Ga during assembly of the Columbia supercontinent.

Meso-Neoproterozoic arc-related sediments of the Xiahe Group in the Qinling block, central China: Implications for the paleogeographic reconstruction of Rodinia

The Meso-Neoproterozoic Rodinia supercontinent formed a coherent large landmass, which was later dispersed over all current major continents and a number of microcontinents. The Qinling block is a Precambrian continental mass, located in the Qinling orogenic belt, which marks the junction of the North China and South China cratons. In this paper, we present a systematic study of the petrology, whole-rock geochemistry and geochronology of metasedimentary rocks from the Xiahe Group, which is a key unit of the Precambrian basement in the Qinling block, to constrain the paleogeographic reconstruction of Rodinia. The studied metasedimentary rocks have detrital zircon ages of 3054–1082 Ma that peak at 1172 Ma and 1582 Ma. The protoliths of the metasedimentary rocks are mainly shales and wackes with maximum depositional ages from 1147 to 1082 Ma, representing a part of a continental arc-related sedimentary sequence. Combining our results with existing data, we propose that their protoliths constituted a sedimentary series including an older sequence of basement and a younger sequence with depositional ages between 1262 and 840 Ma. The detritus that is older than 1266 Ma was sourced from the continental margin of the Indian craton, which was part of the Columbia supercontinent. There was a Paleo-Mesoproterozoic continental nucleus in the Qinling block that split from the margin of the Indian craton during the breakup of Columbia. The source rocks for the younger detritus were arc magmatic rocks in the Qinling block, which formed in a continental arc by oceanic lithosphere subduction during the assembly of Rodinia. A sequence of oceanic subduction beneath the continental nucleus of the Qinling block (1262–981 Ma), arc-continent collision between the continental nucleus and the Indian craton (981–911 Ma), continuous subduction of oceanic crust beneath the block with formation of a mature volcanic arc (929–833 Ma), and continental rifting (833–774 Ma) during the formation of the Qinling block was identified. The block faced the Neoproterozoic ocean during the assembly of Rodinia, and finally rifted off the supercontinent during its breakup to form an isolated arc terrane

Petrogenesis of (meta-) basalts from the North Qilian Orogenic Belt, NW China: implications for the Palaeoproterozoic–Mesoproterozoic tectonic evolution of the North Qilian Block

AbstractThe North Qilian Orogenic Belt is surrounded by the Tarim Craton to the NW and the North China Craton to the NE. The Precambrian continental crust remnants that are distributed in the North Qilian Orogenic Belt are termed the North Qilian Block (NQB), and their tectonic evolution has profound implications for the evolution of the Columbia Supercontinent. Here we present major- and trace-element and Sr–Nd–Hf isotope data for (meta-) basalts from the Beidahe Group (BDHG) and Zhulongguan Group (ZLGG) in the western North Qilian Orogenic Belt, to investigate the tectonic evolution of the NQB during the Proterozoic Eon. The protoliths of Palaeoproterozoic amphibole gneisses and plagioclase amphibolites from the BDHG are calc-alkaline series basalts. These metabasalts show island-arc-basalt affinities with variable Nd and Hf isotopes (ϵNd(t) = −5.0–0.6 and 2.7–4.3;ϵHf(t) = −14.2–2.0 and 6.9–8.8) and were generated by partial melting of the asthenospheric mantle that was metasomatized by aqueous fluid and sediment melt in a continental-arc setting. The early Mesoproterozoic ZLGG basalts show features of shoshonite-series basalts and are geochemically similar to ocean-island basalts. These basalts show variable (87Sr/86Sr)i,ϵNd(t) andϵHf(t) values of 0.70464–0.70699, −1–2.6 and −1.5–5.7, and are products of mantle plume magmatism that participated with subducted oceanic crust in an intracontinental rift setting. This study suggests that the NQB underwent tectonic evolution from palaeo-oceanic subduction to intracontinental rifting during the Palaeoproterozoic–Mesoproterozoic eras. Furthermore, the above tectonomagmatic events were in response to convergence–splitting events of the Columbia Supercontinent during the Palaeoproterozoic–Mesoproterozoic eras.

Discussion on ‘From Pan-African transpression to Cadomian transtension at the West African margin: new U–Pb zircon ages from the Eastern Saghro Inlier (Anti-Atlas, Morocco)’ by Errami et al . 2020 ( SP 503, 209–233)

An important paper has recently been published in Geological Society, London, Special Publications by Errami et al . (2020). On the basis of new U–Pb zircon radiometric data on magmatic and sedimentary rocks in the Saghro Massif, the authors revised the history of magmatic and geodynamic evolution of the Pan-African belts of the Moroccan Anti-Atlas along the northern edge of the West African Craton. The authors focused on the two main accretionary stages widely recognized in the Anti-Atlas (Ennih and Liegeois 2008; Gasquet et al. 2008): (1) a Paleoproterozoic episode, known as the Eburnean Orogeny, characterized by the extensive emplacement of granitoids at c. 2.1 − 2.0 Ga; (2) Neoproterozoic (800–450 Ma) events corresponding to the Pan-African Orogeny. However, in their lithostratigraphic framework of Proterozoic units of the Anti-Atlas, the authors do not account for the magmatic event recently recognized in several inliers in the Anti-Atlas (Fig. 1): Ighrem (Ikenne et al. 2017), Kerdous (Youbi et al. 2019) and Zenaga (Ait Lahna et al. 2020). Sills intrusive into the mixed carbonate–siliciclastic series of the Taghddout and Lkest groups, previously considered as Cryogenian, have been dated at between 1.7 and 1.6 Ga (Fig. 2). These new ages are c . 1 Ga older than previously thought, and call into question the stratigraphic position of the Tagdoute and Lkest groups in the southwestern domain of the Anti-Atlas. These series are now interpreted to be deposited in an intracratonic basin that developed after the assembly of the Nuna–Columbia supercontinent and before the break-up of the Rodinia supercontinent. The previous Cryogenian age for these deposits and their geodynamic setting thus need to be revised. Fig. 1. Geological map of the Anti-Atlas with the locations of the dated sills in the Ighrem, Kerdous and Zenaga inliers shown. SAF, South Atlas Fault; WAC, West African Craton; AVFZ, Ameln Valley Fault Zone; TTFZ, …

Evolution of Neoarchean–Paleoproterozoic basement in the Brunovistulia terrane, S Poland: geological, P-T and geochemical records

Brunovistulia is a composite terrane of Gondwana descent that eventually was accreted to the SW margin of Baltica, central Europe. It is built of metagneous and metasedimentary rocks that originated mainly between 650 and 550 Ma. However in the Upper Silesian part of Brunovistulia, much older fragments have been drilled, which yielded U-Pb zircon ages between 2.75 and 2.0 Ga. They have been interpreted as an “exotic” constituent of the Brunovistulia superterrane, named the Rzeszotary Terrane. Our geological and geochemical studies of the Rzeszotary borehole cores yielded new data on the composition, provenance and evolution of that terrane. Precursors of the Rzeszotary complex were separated from the depleted mantle prior to or around 3.2–3.0 Ga. At 2.75–2.6 Ga, a juvenile magmatic arc edifice formed, beneath which oceanic lithosphere was subducted. Decompression melting of the mantle brought about tholeiite magmas of IAT/MORB composition with LILE additions. Tonalitic and trondhjemitic precursors of gneisses present today were formed at that time, probably due to partial melting of mantle-derived wet basalts at the base of the island arc. Around 2.0 Ga, the arc collided with an unspecified cratonic mass and was subject to orogenic deformation, metamorphism and migmatization. The entire arc edifice was then strongly shortened and forced down to depths equivalent to ~6–12 kbar where the rocks underwent contractional deformation and metamorphism (~500–700°C). Tonalites and trondhjemites were changed to gneisses, and basites to epidote- and garnet amphibolites. These rocks underwent syntectonic migmatization through the mechanism of segregation/differentiation in the presence of fluids and incipient partial melting. Synmetamorphic shortening of the rock pile, which led to folding and heterogeneous development of shear zones with thrust kinematics, terminated with intrusions of K-granites at 2.0 Ga, being followed by some brittle-ductile deformation of unconstrained timing. The 2.0 Ga event may have been connected with the 2.1–1.8 Ga global amalgamation of the Paleoproterozoic supercontinent of Columbia. Later the future Rzeszotary terrane was detached from the Gondwana mainland, reassembled and eventually, in the Neoproterozoic, it became part of the foreland of the Cadomian Orogen in Central Europe.

Paleomagnetic results from the Singhbhum Craton, India: Remagnetization, demagnetization, and complication

We report a complicated magnetic fidelity through time in Singhbhum Craton, India, with new, geographically wide-spread and spatially detailed, paleomagnetic results. The Singhbhum Craton in eastern India is cross-cut by multiple generations of the so-called “Newer Dolerite” dykes. A previously published 1765 Ma paleomagnetic pole represents a useful constraint on the Singhbhum Craton during the amalgamation of the Columbia supercontinent whereas an older ~2763 Ma paleomagnetic pole is problematic. We present additional data from the 1765 Ma dykes that results in a grand mean paleomagnetic pole at 43°N, 320°E (A95 = 10°, K = 17; N = 13). The 1765 Ma pole is supported by a positive baked contact test. Our additional data shows that paleomagnetic results from the 1765 Ma dykes are more complicated by magnetic overprints than originally reported. We also argue that the steep inclination paleomagnetic data from the Singhbhum Craton, previously assumed to represent a Neoarchean signal, are part of a complicated group whose magnetic age is uncertain. We establish a minimum age of 2250 Ma for connecting the Singhbhum and Dharwar cratons on the basis of published geochronology and our interpretation of paleomagnetic data in this paper. Paleomagnetic data from both cratons can be juxtaposed using a simple Euler pole rotation of the Singhbhum Craton relative to Dharwar.

Detrital zircon U-Pb-Hf isotopes from the Yanliao intracontinental rift sediments: Implications for multiple phases of Neoarchean-Paleoproterozoic juvenile crustal growth in the North China Craton

Late Neoarchean-Paleoproterozoic marks a major period of continental growth and recycling, the culmination of which witnessed the assembly of the Columbia supercontinent and its subsequent breakup. The North China Craton (NCC) preserves important records of tectonic activities and crust building and recycling processes during this time. In this study, we carried out U-Pb geochronology and Lu-Hf isotopic analyses of detrital zircon grains from four sedimentary formations of the Changcheng Group in the Yanliao intracontinental rift in NE NCC. Our isotopic ages constrain the timing of initiation of the Yanliao rift as ca. 1680 Ma. The zircon U-Pb data show two major age populations at 2.7–2.5 Ga and 2.2–1.9 Ga, with high and positive εHf(t) values of + 0.1 to + 34.6. Both the Neoarchean and Paleoproterozoic detrital zircon populations were derived from the basement rocks of the NCC. The results from our study indicate major juvenile crust accretion during Neoarchean and Paleoproterozoic associated with the craton building process of the NCC.

Late Neoarchean to Paleoproterozoic arc magmatism in the Shandong Peninsula, North China Craton and its tectonic implications

The transition in tectonic regime of our planet during the late Archean with the initiation broadly modern style subduction system is one of the major topics of interest in earth science. The North China Craton (NCC), one of the oldest cratonic nuclei in the world, preserves important records of Archean and Paleoproterozoic crustal evolution, cratonization and related geodynamic history that are important in understanding the continental growth of the early Earth. Here we investigate a suite of Archean to Paleoproterozoic rocks including hornblendite, amphibolite, gabbro, diorite, basalt, plagiogranite, granite porphyry and greenschist from Shandong Peninsula within the southwestern Jiaoliao block of the eastern NCC using zircon U-Pb geochronology, Lu-Hf isotopes, and whole-rock geochemistry. We aim to understand the timing and petrogenesis of the rock suite and its implications on the geodynamic history of the NCC. Zircon U-Pb data show 207Pb/206Pb ages in the range of 2.68–1.83 Ga, and is divided into three groups of 2.68–2.43, 2.38–1.96 and 1.95–1.83 Ga. Among these, the 2.68–2.43 Ga group confirms with the major magmatic phase during Neoarchean-Paleoproterozoic transition in the eastern NCC, whilst the other groups of 2.38–1.96 and 1.95–1.83 Ga ages might represent the Paleoproterozoic orogenic events in the NCC. Zircon Lu-Hf isotopic data display εHf(t) values ranging from −0.4 to 10.0 and TDMC of 3074–2080 Ma, which are subdivided into one group with U-Pb ages of 2672–2445 Ma characterized by εHf(t) values from −0.4 to 7.0 and TDMC of 3074–2588 Ma and another group (2134–2009 Ma) with εHf(t) values in the range of 2.8–10.0 and TDMC ranging from 2458 to 2080 Ma. These results indicate that the magmas (2672–2445 Ma group) were sourced mainly from Late Mesoarchean to Neoarchean juvenile components with minor input of reworked Mesoarchean crustal components, whereas the 2134–2009 Ma group was derived from Paleoproterozoic juvenile components. Whole-rock geochemical data of the granite porphyry and plagiogranites show typical subduction-related arc signature with the enrichment of LREEs and LILEs and depletion of HREEs and HFSEs (e.g. Nb, Ta, Ti), and mainly belong to I-type granites generated at arc-related setting. The ultramafic–mafic magmatic suite corresponds with tholeiitic to calc-alkaline series which were formed by partial melting of enriched mantle within an island arc setting in an active continental margin. In conjunction with the results from previous studies in the NCC, we correlate the 2.68–2.43 Ga ages with Late Neoarchean amalgamation of microblocks and cratonization of the NCC driven by late Neoarchean oceanic plate subduction, and the 2.38–1.83 Ga ages represent Paleoproterozoic orogenic events including the assembly of major crustal blocks in the NCC within the Paleoproterozoic supercontinent Columbia, and the final collision of these crustal blocks and cratonization.

Finding of Ca. 1.6 Ga Detrital Zircons from the Mesoproterozoic Dagushi Group, Northern Margin of the Yangtze Block

The middle Mesoproterozoic is a crucial time period for understanding the Precambrian tectonic evolutionary history of the northern Yangtze Block and its relationship with the supercontinent Columbia. The Dagushi Group (Gp) is one of the Mesoproterozoic strata rarely found at the northern margin of the Yangtze Block. U–Pb geochronology and Lu–Hf isotopic analyses of detrital zircons were analyzed for three metamorphic quartz sandstone samples collected from the Luohanling and Dangpuling formations of the Dagushi Gp. These metasandstones yielded major zircon populations at ~2.65 Ga and ~1.60 Ga, respectively. The ~1.60 Ga ages first discovered yield a narrow range of ɛHf(t) values from −1.8 to +1.8, which lie above the old crust evolutionary line of the Yangtze Block, suggesting the addition of mantle material. Trace element data indicate that ~1.60 Ga detrital zircons share a basic provenance, whereby they have low Hf/Th and high Nb/Yb ratios. Zircon discrimination diagrams suggest that the ~1.60 Ga detrital zircon source rocks formed in an intra-plate rifting environment. Dagushi Gp provenance studies indicate that the ~1.60 Ga detrital zircon was most likely sourced from the interior Yangtze Block. Thus, we suggest that the late Paleoproterozoic to early Mesoproterozoic continental break-up occurred at the northern margin of the Yangtze Block.

A synthetic geochemical and geochronological dataset of the Mesoproterozoic sediments along the southern margin of North China Craton: Unraveling a prolonged peripheral subduction involved in breakup of Supercontinent Columbia

Controversial issues on the Paleo-Mesoproterozoic tectonic setting of the southern margin of North China Craton (NCC) restricted our understanding of its role in breaking up the Columbia/Nuna Supercontinent. Existing models are still arguing on whether the southern margin was an intra-continental rift or active continental margin. Previous studies mainly focused on the magmatic records in the Paleoproterozoic Xiong’er Group, while the overlain sedimentary series and their depositional nature and the related tectonic environment were not yet well constrained. In this study, we scrutinized the comprehensive geochronological and geochemical dataset for the Mesoproterozoic sedimentary rocks along the southern margin of NCC. Our new results, together with the previous geochemical data show that the interior part of NCC southern margin (e.g. Wufoshan Group of the Song-Ji area) is dominated by the materials from the mature continental crust. Approaching the marginal area of southern NCC (e.g. Gaoshanhe and Guandaokou Groups of the Xiaoqinling-Luanchuan area), sediments are more enriched in magmatic arc fragments and unfractionated materials. Detrital zircon geochronological results revealed a progressive younging tendency from the northern Song-Ji to southern Xiaoqinling-Luanchuan areas. Together with the newly-reported zircon hafnium data, the synthesized dataset in this study favors the hypothesis that the southern NCC during the Paleo-Mesoproterozoic was in an active continental arc setting under a prolonged peripheral subduction regime, which was surrounding the marginal areas of the Columbia/Nuna Supercontinent.

Geochronology of monazite related to REE, Nb–Ta and U–Th bearing minerals from Mesoproterozoic anorogenic magmatism in the E-Colombian Amazonian Craton: Links to mantle plume activity in the Columbia (Nuna) supercontinent

U–Th–Pb geochronology of REE-bearing minerals such as monazite and other phosphates has become a precise tool to date mineralization events through geological time. In the E-Colombian Guainía department, from 3 colluvial sites over western Guiana Shield Mesoproterozoic rocks, Nb–Ta, U–Th and REE bearing minerals probably of pegmatitic origin were sampled including up-to-0.5 cm long monazite crystals. The monazite pan concentrate samples from sites near to the indigenous communities of Barranquilla, San Jose and Chorro Bocón (Espina hills) along the Cuyari, Guainía, and Inírida rivers respectively, were analyzed geochemically and geochronologically using LA-ICP-MS and EPMA. The monazites obtained from the 3 sites are rather similar with an approximate composition Ce0.44La0.16Nd0.16Sm004Y0.03Gd0.02Dy0.01Pr0.05Th0.08Pb0.01Ca0.05Si0.05P0.91O3.94. Their EPMA and LA-ICP-MS ages suggest at least two mineralization events, a first one between 1528 and 1523 Ma in the Barranquilla and San Jose sites, related to the emplacement of rapakivi granites outcropping along the Cuyarí River and the Tabaquen rapakivi granite near the Guainía River, both emplaced ~1545 Ma ago. The second mineralization event from 1390 to 1343 Ma recorded in the Espina-hills is in the age range of the Matraca and Danta rapakivi granites that crystalized between 1400 and 1340 Ma ago. These different anorogenic rapakivi granites were emplaced between 1550 and 1300 Ma into Mesoproterozoic basement rocks and were probably caused by intra-plate processes associated with mantle plume activity within the Columbia (Nuna) supercontinent.