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Schematic cross section through the present-day Earth outlining differences in composition (left) and rheology (right) between layers. Not to scale.

Schematic cross section through the present-day Earth outlining differences in composition (left) and rheology (right) between layers. Not to scale.

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The Earth as a planetary system has experienced significant change since its formation c. 4.54 Gyr ago. Some of these changes have been gradual, such as secular cooling of the mantle, and some have been abrupt, such as the rapid increase in free oxygen in the atmosphere at the Archean-Proterozoic transition. Many of these changes have directly affe...

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... in their mantles can exhibit a variety of geodynamic regimes at their surfaces, which may readily transition between different states over the thermal lifetime of the parent body ( Petersen et al., 2015). All discussion of 'plates' in this work and related literature refers specifically to discrete masses of a planet's lithosphere (Barrell, 1914: Fig. 2), which defines the uppermost solid layer of the Earth, and is distinguished from the underlying asthenosphere by changes in the dominant mode of heat flow, chemical composition, and/or rheology at the interface (Anderson, 1995;Fischer et al., 2010;Green et al., 2010). From a thermal perspective, heat flow through the lithosphere is ...
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... and Jordan, 2003). The lithosphere may alternatively be referred to as a "lid" as it represents a strong thermal boundary layer separating hot planetary interiors from the cold hydrosphere and surrounding vacuum of space. Finally, it should be emphasized that discussion in this study refers only to rocky planets with silicate crusts and mantles ( Fig. 2), although lithosphere-asthenosphere nomenclature may be equally applied to ice-rich bodies with solid outer shells situated above subsurface liquid oceans (e.g. Roberts and Nimmo, 2008). Two fundamental end-member geodynamic regimes may exist on large silicate bodies, such as the Earth: mobile and stagnant lids. Mobile lids are ...
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... voluminous subducted materials during ocean closure associated with supercontinent assembly temporarily accumulate in the mantle transition zone at 410-660 km depth (Fig. 2), from where they sink to the core-mantle boundary and accumulate as 'slab graveyards' (Fig. 2: Maruyama et al., 2007). Melting of the slab graveyards through heating from the core provides a potential trigger for the formation of superplumes, which ascend from the core-mantle boundary, eventually diverging into hot spots (Condie, 2001) ...
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... voluminous subducted materials during ocean closure associated with supercontinent assembly temporarily accumulate in the mantle transition zone at 410-660 km depth (Fig. 2), from where they sink to the core-mantle boundary and accumulate as 'slab graveyards' (Fig. 2: Maruyama et al., 2007). Melting of the slab graveyards through heating from the core provides a potential trigger for the formation of superplumes, which ascend from the core-mantle boundary, eventually diverging into hot spots (Condie, 2001) and rifting the supercontinent. Plumes rising from the core-mantle boundary facilitate heat and mass transport ...
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... is a high-pressure polymorph of carbon that stabilizes at minimum pressures of ~3.5-4.5 GPa at ~600-1200 °C, equivalent to at least 150-180 km depth within the Earth's upper mantle (Khaliullin et al., 2011; Day, 2012: Figs. 2 and 7). A rarer variety of "superdeep" diamonds are thought to have originated from > 410 km depth, within the mantle transition zone (e.g. Timmerman et al., 2019). As such, during growth, diamonds can trap minerals, fluids, or melts that are stable at various depths within the Earth's interior. Based on their morphology and internal growth ...
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... in their mantles can exhibit a variety of geodynamic regimes at their surfaces, which may readily transition between different states over the thermal lifetime of the parent body ( Petersen et al., 2015). All discussion of 'plates' in this work and related literature refers specifically to discrete masses of a planet's lithosphere (Barrell, 1914: Fig. 2), which defines the uppermost solid layer of the Earth, and is distinguished from the underlying asthenosphere by changes in the dominant mode of heat flow, chemical composition, and/or rheology at the interface (Anderson, 1995;Fischer et al., 2010;Green et al., 2010). From a thermal perspective, heat flow through the lithosphere is ...
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... and Jordan, 2003). The lithosphere may alternatively be referred to as a "lid" as it represents a strong thermal boundary layer separating hot planetary interiors from the cold hydrosphere and surrounding vacuum of space. Finally, it should be emphasized that discussion in this study refers only to rocky planets with silicate crusts and mantles ( Fig. 2), although lithosphere-asthenosphere nomenclature may be equally applied to ice-rich bodies with solid outer shells situated above subsurface liquid oceans (e.g. Roberts and Nimmo, 2008). Two fundamental end-member geodynamic regimes may exist on large silicate bodies, such as the Earth: mobile and stagnant lids. Mobile lids are ...
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... voluminous subducted materials during ocean closure associated with supercontinent assembly temporarily accumulate in the mantle transition zone at 410-660 km depth (Fig. 2), from where they sink to the core-mantle boundary and accumulate as 'slab graveyards' (Fig. 2: Maruyama et al., 2007). Melting of the slab graveyards through heating from the core provides a potential trigger for the formation of superplumes, which ascend from the core-mantle boundary, eventually diverging into hot spots (Condie, 2001) ...
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... voluminous subducted materials during ocean closure associated with supercontinent assembly temporarily accumulate in the mantle transition zone at 410-660 km depth (Fig. 2), from where they sink to the core-mantle boundary and accumulate as 'slab graveyards' (Fig. 2: Maruyama et al., 2007). Melting of the slab graveyards through heating from the core provides a potential trigger for the formation of superplumes, which ascend from the core-mantle boundary, eventually diverging into hot spots (Condie, 2001) and rifting the supercontinent. Plumes rising from the core-mantle boundary facilitate heat and mass transport ...
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... is a high-pressure polymorph of carbon that stabilizes at minimum pressures of ~3.5-4.5 GPa at ~600-1200 °C, equivalent to at least 150-180 km depth within the Earth's upper mantle (Khaliullin et al., 2011; Day, 2012: Figs. 2 and 7). A rarer variety of "superdeep" diamonds are thought to have originated from > 410 km depth, within the mantle transition zone (e.g. Timmerman et al., 2019). As such, during growth, diamonds can trap minerals, fluids, or melts that are stable at various depths within the Earth's interior. Based on their morphology and internal growth ...

Citations

... Thus there must have been reworking and recycling of Archean continental crust in the evolution of the present continental crust, which might have operated during the late Archean. It is suggested that oceanic subduction could have played an important role in the reworking/recycling of the Archean continental crust (Palin et al., 2020;Mole et al., 2021). But, in most Archean cratons, the late Archean also witnessed the final stabilization of the cratonic continental lithosphere (cratonization) through amalgamation of microcontinents (Condie et al., 2009;Zhai et al., 2021). ...
Article
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The late Archean (3.0–2.5 Ga) is a pivotal period, when properties of the continental crust significantly changed and a fundamental shift of geodynamic processes took place. As the major felsic component in early Archean (> 3.0 Ga) crustal records, tonalite-trondhjemite-granodiorite (TTG) suites are compositionally different to the present-day felsic upper continental crust. But it remains unclear how and to what degree the felsic part of the continental crust evolved during the late Archean. The 250 km long Neoarchean Suizhong granitic belt in the North China Craton (NCC) is mainly composed of K-rich granitoids and compositionally distinct to the TTG-dominated early Archean upper continental crust. This belt is a natural laboratory to explore how the early Archean upper continental crust evolved in the late Archean. Combined with our new data (zircon U-Pb ages, bulk-rock geochemistry and zircon Hf isotopes), we provide an overview of the temporal and compositional features of the Neoarchean Suizhong granitic belt. Granitic magmatism in the Suizhong granitic belt mainly took place within 100 Myrs around the end of the Archean, and these rocks are primarily K-rich granitoids with minor TTGs and mafic magmatic enclaves (MMEs). The K-rich granitoids include sanukitoid-like granites and potassic granites; the former are hybrids between melts from Mesoarchean enriched mafic crust and enriched mantle, and the latter are melts from Hadean–Mesoarchean crustal lithologies. The volumetrically minor TTGs were sourced from Mesoarchean low-K mafic crust. MMEs are either cumulates or inclusions of captured enriched mantle melts. Overall, these Neoarchean granitoids are essentially intracrustal reworking products of ancient continental nuclei and are compositionally and temporally similar to syn- and post-collisional magmatism in Phanerozoic collisional orogenic belts. The Neoarchean crustal reworking process was most likely to be induced by amalgamation of micro-continents through collision. Through the collision-induced reworking, a variety of K-rich granitoids were introduced to the Neoarchean upper continental crust. As a result, layering of felsic upper and mafic lower crust was developed, and the maturity of Archean continental crust was significantly enhanced. Collisional orogenesis played a critical role in maturing the Archean continental crust and initial cratonization of the NCC during the late Archean.
... In contrast, plume-driven vertical tectonic activity has been proposed to have been the dominant mode of mantle convection in the Archean (e.g., Bédard et al., 2003;van Kranendonk et al., 2004;Johnson et al., 2014;François et al., 2014). In this interpretation, heat-pipe and squishy-lid tectonic regimes would dominate, due to higher ambient mantle temperatures and differences in crustal rheology (for a relevant review, see Palin et al., 2020). ...
Chapter
The Neoarchean marked an important turning point in the evolution of Earth when cratonization processes resulted in progressive amalgamation of relatively small crustal blocks into larger and thicker continental masses, which now comprise the ancient core of our continents. Although evidence of cratonization is preserved in the ancient continental cores, the conditions under which this geodynamic process operated and the nature of the involved crustal blocks are far from resolved. In the Superior craton, deep-crustal fault systems developed during the terminal stage of Neoarchean cratonization, as indicated by the cratonwide growth of relatively small, narrow, syn-to-late tectonic (ca. 2680–2670 Ma)...
... Plate tectonics is a key feature of our planet, wherein the lithosphere is broken into tessellated fragments that are in continuous, but independent horizontal motion about the axes of rotation called Euler poles (Palin et al., 2020). The inception of plate movement can be traced back at least to 3.2 Ga (Cawood et al., 2018). ...
... The fate of preservation of impact events is highly influenced by the process of plate tectonics. Although the signatures of the tectonic history of the Earth lie on the continental crustal plates (Palin et al., 2020), most of the information about the geological past was obliterated due to several hiatuses in geological records. Moreover, the Earth's crust has undergone a series of evolutionary events since the formation of the first rock material (Brown, Johnson, & Gardiner, 2020). ...
Article
The paradigm of plate tectonics has aided in the identification of the journey of continents on the globe, their assembly into supercontinents, disruption, and re‐assembly. Here, we use meteorite impact craters as proxies for tracking the voyage of lithospheric plates. Employing the provisions in GPlates, an interactive geographic information system‐based plate tectonic reconstruction model, we were able to identify the palaeo‐position, and velocity of the 174 terrestrial impact craters, formed after 1,100 Ma, across the globe. These parameters of craters were evaluated for independent tectonic plates and were correlated with global tectonic events. For example, the similarity in the velocity of Beaverhead (900 Ma) and Holleford (550 Ma) craters since 550 Ma is traced to the connection between the Eastern Basin and North America Craton commencing 1,100 Ma, and through the South Basin and Range. Likewise, the drastic reduction in the velocity of Spider Crater (700 Ma) in Australia after 600 Ma can be attributed to the subduction between east and west Gondwana. The accelerated motion of the Indian Plate at 63 Ma, when the lithosphere was hovering over the Réunion hotspot, is also explained. With the advent of more improved plate tectonic models and the discovery of more impact craters, improvised interpretations will be possible. Voyage of Ramgarh Crater.
... Several age thresholds have been proposed for the onset of plate tectonics over the last several decades. These time windows range from 0.8 Ga (Hamilton, 2011) to 4.2 Ga (Hopkins et al., 2008), with several other models proposing the time span of 2.9 to 3.2 Ga for the onset of Phanerozoic-type rigid plate tectonics (Palin et al., 2020;Dhuime et al., 2015;Condie, 2018;Brennan, 2014;Brenner et al., 2020;Palin and Santosh, 2021). In a more recent review, Condie (2021) has proposed that the Earth experienced two significant transition periods at 2.5-2.0 ...
Article
We present a global synthesis of Cu, Zn, Pb and Ga contents of mafic dike complexes and volcanic rocks associated with 259 ophiolites, ranging in age from Archaean throughout the Phanerozoic. These ophiolites are geochemically classified as subduction-unrelated and subduction-related with various sub-categories, as defined in Dilek and Furnes (2011). The subduction-unrelated ophiolites include Mid-Ocean Ridge (MOR), and Rift, Continental Margin and Plume type ophiolites, collectively grouped as the R/CM/P sub-category. The subduction-related ophiolites include Backarc (BA), Forearc (FA), Backarc to Forearc (BA-FA), and Volcanic Arc (VA) sub-categories. Compositional distribution of these elements in different ophiolite sub-categories show that Zn and Ga patterns are largely uniform and unrelated to the tectonic setting, whereas Cu and Pb patterns show significant variations. Average copper concentrations progressively increase from subduction-related ophiolites to R/CM/P and MOR. Although less pronounced, lead shows a similar increase in average concentrations from subduction zone environments to MOR, with rather irregular patterns for the R/CM/P and VA types. Mafic subunits in analysed ophiolites define similar trends for Cu and Pb. The mafic subunits, comprising alkaline basalts, mid-ocean ridge basalts (MORB), island arc tholeiites (IAT) and boninites, define a progressive shift towards increasing proportions of low concentrations of Cu and Pb in the listed order. To constrain the large variations in the contents of the given elements, we applied petrogenetic modelling of glass analyses. Petrogenetic modelling of the MgO versus Cu, Zn, Pb and Ga distributions in modern MORB show a scatter that can be explained by different degrees of fractional crystallization (20 – 80%) of primitive MORB lavas. In support of previous studies, we find that most erupted MORB lavas are sulphur saturated, whereas primitive boninitic and IAT magmas are S-undersaturated. The trends observed for IAT are in agreement with previous findings that IAT precipitate sulphide only at very high degrees of fractional crystallization, owing to crystallization of magnetite. Boninites are variable and Cu concentration in boninitic glasses indicates that a fraction of them may be S-saturated at relatively low degrees of fractional crystallization. We model two boninitic compositions and achieve S saturation at 15 and 50% fractional crystallization. The observed Pb enrichment in the R/CM/P ophiolites was likely caused by crustal contamination. Mantle sources of mafic magmas of the ophiolites were also enriched in Cu and Pb by a combination of subduction-related processes as reflected in the chalcophile element (Cu and Pb) behavior patterns of various mafic rock types in the ophiolites. Comparing with in-situ oceanic crust, we conclude that the chalcophile element distribution patterns of Cu, Zn, Pb and Ga in mafic lavas and dikes in ophiolites were ca. 80-90% magmatically controlled by their abundances in the mantle melt sources, partial melting episodes, and extents of fractional crystallisation processes. The remaining 10-20% difference we attribute mainly to alteration processes (predominantly loss), as well as types and amounts of subducted sediments, whose melt products contributed to the melt column above subducting slabs.
... Stern 2005), the rock record suggests that a major shift in thermal regime occurred during the Meso-to Neoarchean (Brown 2006;Johnson et al. 2019), and that thermalregime bimodality gradually arose from the Neoarchean to the present day (Holder et al. 2019). This gradual transition was interpreted as possibly registering a shift from an Archean mode of tectonics ( probably stagnant or sluggish lid) to a Proterozoic regime more akin to modern plate tectonics (Brown et al. 2020;Palin et al. 2020;Bruno et al. 2021). ...
... However, Venus' thick CO 2 atmosphere renders observations of its surface challenging. Palin et al. (2020) provided a recent review of how Venus may help us understand the early evolution of Earth, which we summarize and update here. Orbiters mapping Venus with radar instruments have revealed surface features reminiscent of terrestrial tectonic plate margins, such as trench-like landforms that resemble ocean-ocean plate margins, with similar curvatures and asymmetry (Sandwell and Schubert 1992;Schubert and Sandwell 1995), hills along ridges that evoke abyssal hills on mid-oceanic ridges (Head and Crumpler 1987;McKenzie et al. 1992) and transform faults (Ford and Pettengill 1992). ...
Article
As Mars transitioned from an early Earth-like state to the cold desert planet it is today, it preserved a near pristine record of surface environments in a world without plate tectonics and complex life. The records of Mars’ Earth-like surfaces have remained largely untouched for billions of years, enabling space exploration to provide critical insights about the early days of our own planet. Here, we first review what Mars has taught us about volcanic, tectonic, and metamorphic processes in the absence of discrete plates, drawing comparisons to the terrestrial and venusian records. Then, we summarize advances in understanding its early surface environments, including impact cratering, hydrological, sedimentary, and geochemical processes. Altogether, the martian record provides a picture of early environments that were similar to modern terrestrial ones in many respects, with sediment and geochemical cycling, hydrothermal systems capable of hosting life, but with the exception that topography, sediment, and heat sources were provided by volcanoes and impact cratering rather than plate tectonics. Mars thus offers a lens through which one might catch a glimpse of Earth's infancy, provided exploration efforts continue to refine our understanding of the similarities between Earth and Mars as well as the specificities of each planet.
... Archean geodynamic processes and crustal growth mechanisms, particularly the initiation of plate tectonic regimes, remain key scientific issues of debate in the geosciences (Guo and Korenaga, 2020;Hastie and Fitton, 2019;Palin et al., 2020;Turner et al., 2020). Two main mechanisms were dominantly responsible for the early crust of the Earth. ...
Article
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The Anshan-Benxi greenstone belt in the northeastern North China Craton preserves ∼ 3.88 Ga to ∼ 2.5 Ga lithologies that exhibit based secular trends in their geological signatures and hosts large amounts of valuable Neoarchean banded iron formations. However, whether plume or subduction mechanism responsible for those iron deposits remains confusing. This contribution focuses on the metamorphosed volcanic rocks and aims to constrain their geodynamic regime, based on temporal and spatial distributions, petrogenesises and tectonic characteristics. The late Neoarchean metamorphosed volcanic rocks of the Anshan-Benxi greenstone belt are prominently exposed in the Waitoushan-Gongchangling-Benxi area and consist of plagioclase amphibolites, amphibole/mica plagioclase gneisses and amphibole/mica two-feldspar gneisses. All 107 metamorphosed volcanic rock samples may be geochemically and petrographically classified as tholeiites, tholeiitic to calc-alkaline basalts, andesite, and dacite-rhyolite. The tholeiites are characterized by approximately flat REE patterns with negligible Eu anomalies and show negative Nb anomalies on primitive normalized multiple element diagrams, consistent with a back-arc basin basalt origin. The tholeiitic to calc-alkaline basalts have slightly heavy REE-depleted patterns and obvious negative Nb anomalies, which were likely produced by partial melting of mantle peridotites that were metasomatized by subducted slab-released fluids and melts. They may be comparable to island arc basalts. The andesites exhibit notably high MgO, Mg# and transition metal element contents, low FeOT/MgO ratios, fractionated REE patterns and evident negative Nb, Ta and Ti anomalies, which are akin to Phanerozoic high magnesian andesites and are melts of mantle peridotites that were previously metasomatized by subducted slab melts/fluids. The dacite-rhyolites have the highest SiO2 and lowest MgO, Cr and Ni contents and were derived from intracrustal remelting. The zircon U-Pb dating results reveal that the arc tholeiitic to calc-alkaline basalt-andesite-dacite-rhyolite assemblages erupted at ∼ 2.57 Ga – ∼2.52 Ga and back-arc basin basalt lithological association at ∼ 2.55–2.52 Ga. Furthermore, both the arc basalt-andesite-dacite-rhyolite and back-arc basin basalt associations are predominantly exposed within the Waitoushan-Gongchangling-Benxi range of the northeastern Anshan-Benxi greenstone belt. Therefore, we suggest that the Waitoushan-Gongchangling-Benxi area represents a rear-arc to back-arc zone, which was subsequently subjected to consistent NE-SW compression (σ1) and top-to-northeast kinematic features during back arc closure and underwent up to high amphibolite facies metamorphism. However, the Anshan area in the southwestern range of the Anshan-Benxi greenstone belt preserves large amounts of thick-bedded metasedimentary rocks instead of back-arc and arc volcanic rocks, which indicates a stable depositional environment in a typical back arc basin depositional zone. The supracrustal rocks within the back arc basin depositional domain underwent NE-SW compression (σ1) and top-to-southwest kinematic features and mostly experienced greenschist facies metamorphism. These crust-mantle interaction features inferred by metamorphosed volcanic rocks in the Anshan-Benxi greenstone belt, spatial and temporal variations in the lithological assemblages, together with the style of structural deformations, indicate a late Neoarchaean geodynamic evolution from SW-dipping subduction to arc-back-arc development and collisions between ancient continental blocks and arcs.
... The emerging data on the growth of the continental crust and emergence of terrestrial plate tectonics has led to the recognition of supercontinental cycles (Condie, 2018;Stern, 2018;Condie and Puetz, 2019;Palin et al., 2020). The progressive increase in continental crustal area and thickening of the continental crust through the Archean-Paleoproterozoic (PPtz) appears to have peaked around 2.0-1.8 ...
... The secular changes in the Earth system have been modelled based on several lines of evidence (including but not limited to frequency distribution of zircon ages, LIPs, ironformations, anorthosite as well as chemical proxies of sea-water chemistry, atmospheric oxygen levels and mineral stability fields) in the last two decades (Cawood andHawkesworth, 2014, 2019;Condie et al., 2015;Condie, 2018;Stern, 2018;Palin et al., 2020). ...
Article
The present exposures of the (Mesoproterozoic to Neoproterozoic) Purana basins of Peninsular India occupy nearly 1.5 × 10⁵ km² area in the Indian subcontinent, with an equal area being concealed under younger cover or lost to ensuing erosion. These extensional basins evolved on the margins (& with basement) of the existing cratonic blocks during the ‘boring billion years’ of Earth history. They host nearly 0.8 million km³ of epicratonic compacted and lithified sediments derived by weathering and erosion of the adjoining cratonic blocks and deposited on their fringes. The volumetric contents of these basins and their temporal distribution are compiled. The relative distribution and secular variations of sediment contents from these basins appear to synchronise with global Proterozoic supercontinental assembly and dispersal cycles. A comparison of mass-transfer by the erosion of the provenance area and sedimentation in continent margin basins shows that the volumes preserved in the Purana basins are at least 2 magnitudes larger than what can be derived from adjoining cratonic areas within the Indian Subcontinent. Much wider continental masses as well as exhumation (aided by uplift) of km-scale magnitudes of the provenance areas are required to reconcile their volume. Possible linkages with other cratonic blocks within the contemporary supercontinental assemblies are required to resolve this discrepancy.
... Korenaga, 2013;Hawkesworth et al., 2016;Reimink et al., 2021), the decrease in the rate of continental growth (e.g. Belousova et al., 2010;Dhuime et al., 2012Dhuime et al., , 2015Dhuime et al., , 2017Spencer et al., 2017), geochemical data (Cawood et al., 2006;Shirey and Richardson, 2011;Tang et al., 2016;Satkoski et al., 2017), and petrological-thermomechanical numerical modelling (Sizova et al., 2010) indicate an onset of subduction in the Mesoarchean to early Paleoproterozoic (e.g. Brown et al., 2020;Palin et al., 2020). In contrast, some authors argue for an even earlier onset of subduction during late Hadean to early Archean times (e.g. ...
Article
Tracing ultrahigh-pressure (UHP) metamorphism of crustal rocks through the geological record is a key for understanding the evolution of plate tectonics on Earth due to the linkage with deep subduction processes. Until recently, UHP research was almost exclusively based on the investigation of crystalline rocks, but findings of coesite and diamond inclusions in detrital mineral grains demonstrate that the sedimentary record archives mineralogical evidence for UHP metamorphism. We here review previous attempts to link sediments to UHP sources and the recent findings of detrital UHP garnet, and thoroughly discuss the new approach in the search for UHP metamorphism. The indicative UHP minerals were identified by Raman spectroscopy and include monomineralic coesite and bimineralic coesite + quartz inclusions in detrital garnets from the Scandinavian Caledonides of Norway, the D'Entrecasteaux Metamorphic Complex of Papua New Guinea, and the Central European Variscides of Germany, as well as diamond inclusions in the latter. Garnet chemistry and inclusion assemblages are used to gain information about the origin of these mineral grains and to discriminate different UHP sources. Presumably, the value of information will increase in future studies by considering other detrital containers of UHP minerals such as the ultrastable heavy minerals zircon, rutile, and tourmaline, for which also a range of single-grain provenance tools exist. Abundant monomineralic coesite inclusions in detrital minerals allow for investigating coesite preservation factors and potentially elastic thermobarometry in the coesite stability field. Altogether, the method allows for (i) screening large regions systematically for the presence of UHP rocks, (ii) studying the exhumation history of UHP terranes, and (iii) monitoring the former existence of UHP terranes at the Earth's surface.........................................................................................................................................Available for 50 days via https://authors.elsevier.com/a/1ejJk2weQpJ0p
... ;Van Kranendonk, 2010; Bhaskar Rao and Babu, 2011; Bédard et al., 2013;Ernst et al., 2016;Wyman, 2018; Brown et al., 2020;Hawkesworth et al., 2020). The superchondritic εHf values from the Keonjhar detrital zircons indicating a depleted mantle source suggests that unlike the modern-day plate tectonics where the old oceanic crusts subduct into the mantle, re-melt and enrich the mantle, the Archean plates, if existed, did not undergo significantly melting into the mantle during Eoarchean to at least Mesoarchean time.Under this perspective these values can be explained by partial melting of hot mantle beneath a stagnant lid with or without intervention of plume (for generalized review of secular trend in Archean tectonicsPalin et al., 2020;Palin and Santosh, 2021; Fig. 6).Dey et al. (2017) have associated the superchondritic values of the granitic rocks from the Singhbhum Craton to the shallow melting of a juvenile mafic source as well as to the high temperature melting of a heterogeneous, juvenile source consisting of tonalites and proposed a Paleoarchean crustal evolution pattern related to episodic mantle plumes. Sreenivas et al. (2019) advocates that the variation of Hf isotopic compositions from different rock types of distinct ages (e.g., detrital zircon grains from ~2.9 Ga old quartzites and magmatic zircon from a 3.505 Ga old dacite from the Iron Ore Group) of the Singhbhum Craton indicate the presence of both depleted and enriched mantle as distinct sources formed during Paleo-) suggested a mixed magmatic source from near chondritic reservoir considering direct extraction from the mantle immediately before formation of the granitic magma. ...
... Schematic diagram showing secular trend in Archean tectonics from Stagnant lid to Plume-drip and proto-plate tectonics (low-angle subduction) that can explain the juvenile crust emplacement as a mechanism for the growth of early cratons from depleted mantle reservoir that had not undergone any enrichment from the melting of the subducting slab as in the case of modern day plate tectonics (tectonic model outlined after BhaskarRao and Babu, 2011; Ernts et al., 2016;Palin et al., 2020;Palin and Santosh, 2021) ...
Article
The ∼715 m thick matured siliciclastics of the Keonjhar Quartzite, North of the homonymous town, Singhbhum Craton, eastern India, represents one of the best-preserved examples of sedimentation during Mesoarchean time. The LA-ICPMS U-Pb ages with peaks at 3.2 Ga, 3.1 Ga, 3.0 Ga and 2.87 Ga of the detrital zircon grains from the upper part of the Keonjhar Quartzite reveal youngest age population of ∼2.87 Ga. The Hf isotopic compositions have mean initial ¹⁷⁶Hf/¹⁷⁷Hf ratio 0.280897 and low Lu/Hf ratio 0.01. Most of the grains of the zircon population delivered positive εHf (+8.75 to +0.26) values with only two negative values of -0.05 and -3.27. The superchondritic Hf isotopic compositions suggest depleted mantle source, juvenile crustal components and possible role of juvenile crust formation presumably in a stagnant lid to low angle subduction geodynamic regime for the origin of granitoids that sourced the detrital zircon grains.
... In contrast, the tectonic environments and sources of granitic plutonism evolved considerably during the Archean in response to the secular cooling of the Earth's mantle and increasing the shear strength of the crust as inferred by several studies (e.g., Brown et al., 2020;Brown and Johnson, 2018;Cagnard et al., 2011;Capitanio et al., 2019;Cawood et al., 2018;Palin et al., 2020;Poh et al., 2020). The early Archean large-volume intrusions form ovoid, spatially unfocused batholiths that formed through melting of thickened oceanic plateaus and gravity-driven rise of thermal instabilities (diapirs), whereas late Archean intrusions start to resemble modern, subduction-related settings with a tendency to arrange into linear belts (e.g., Yilgarn craton, Superior Province). ...
Article
The Superior Province in Canada represents an excellent natural laboratory to test various models of crustal growth and evaluate tectonic regimes during late Archean. Here, we present new geochemical and geochrono-logical data for ca. 2.8-2.7 Ga plutons intruding different lithotectonic units of the northeastern part of the Superior Province that demonstrate a complex nature and evolution of magma sources in relation to a changing tec-tonic setting. Four distinct plutonic suites were newly identified: (1) sodic tonalite-diorite (TD) with a composition resembling low-pressure TTG-like melts, (2) sodic tonalite-granodiorite-diorite (TGD) with medium/high-pressure TTG-like signatures, (3) Mg-K-rich monzogranite to monzodiorite (sanukitoids; MMD), and (4) K-rich granodiorite-granite-monzogranite (GGM). These suites are interpreted as recording a temporal evolution from plume-assisted melting of lower mafic continental crust through melting of a subducted oceanic slab at different depths to large-scale re-melting of the previously formed and amalgamated crustal units. In this evolutionary scheme, the ∼2730-2700 Ma subduction-related plutonism is the most voluminous addition of the juvenile arc material and thus represents the most significant crustal growth event. Altogether, the above inferences and published data suggest that the late Archean plutonism in the Superior Province formed during a transitional regime from plume-dominated to plate-tectonic over a short time span between ∼2730 and ∼2700 Ma and that this transition was markedly diachronous across the Province.