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Christopher L. Kirkland - One of the best experts on this subject based on the ideXlab platform.
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conditioned duality of the earth system geochemical tracing of the supercontinent cycle through earth history
Earth-Science Reviews, 2016Co-Authors: Christopher L. Kirkland, Martin J Van KranendonkAbstract:Abstract The balance between constructive versus destructive processes in the formation and Recycling of continental crust over Earth history – or Crustal growth – remains contentious; whereas some advocate continuous continental growth, others suggest episodic growth predominantly during periods of supercontinent assembly. In this paper, we review the geological record and present an analysis of time constrained hafnium and oxygen isotopes in dated zircon crystals, and of incompatible elements (Zr, Th) in dated magmatic rocks, to explore the operation of Earth's supercontinent cycle. This analysis reveals the importance of the supercontinent cycle to continental growth by demonstrating a link between periods of enhanced Crustal Recycling and elevated geochemical proxies of subduction flux. The temporal fluxes in subduction rate suggest a conditioned duality of the Earth system between alternating periods of hot, volatile-rich, and cold, volatile-depleted, mantle relative to an idealised power decrease curve. Hot, volatile-rich mantle periods accompany supercontinent dispersion events and are characterised by mantle superplumes and increased Crustal Recycling during rapid global subduction. Cool, volatile-depleted mantle periods that accompany aggregated supercontinents are interpreted to arise from a combination of the widespread subduction of cold oceanic lithosphere, volatile depletion arising from the preceding voluminous subduction-related magmatism, and core insulation by the slab graveyards that accompanied formation of the supercontinent: these periods are characterised by enhanced mantle influence on magmas but low rates of continental crust production. Pulses of rapid continental growth that accompanied supercontinent assembly led to Crustal oversteps — which can be considered as periods when too much crust had formed relative to the thermal state of the mantle at that time. When combined with the anomalous mantle cooling that accompanied these pulses of rapid crust formation, we postulate that supercontinent assembly led to a stepwise increase in plate size via changes in tessellation during supercontinent dispersal.
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Oxygen isotopes in Pilbara Craton zircons support a global increase in Crustal Recycling at 3.2Ga
Lithos, 2015Co-Authors: Martin J. Van Kranendonk, Christopher L. Kirkland, John B. CliffAbstract:Abstract Oxygen isotopes were measured in zircon crystals from a suite of Paleo- to Mesoarchean igneous and sedimentary rocks from the Pilbara Craton in order to test prevailing models of early Earth tectonic evolution. Our results indicate that igneous zircon crystals older than 3.2 Ga in the Pilbara Craton have mantle-like oxygen isotope signatures, whereas zircon grains younger than c. 3.2 Ga show, on average, isotopically heavier δ 18 O values. Stringent tests on the validity of the isotopically heavy oxygen values – in terms of whether they reflect primary properties of the zircon crystals acquired under magmatic genesis, or the result of later alteration – were conducted in some cases by simultaneous measurement of 16 O 1 H/ 16 O, in conjunction with evaluating more traditional indicators of metamictisation. These data demonstrate that whereas some of the heaviest values are anomalous and due to post-crystallisation alteration via incorporation of water into the zircon structure, others record primary values. The data presented here are used to support a previously documented change in tectonic style in the Pilbara Craton at 3.2 Ga, from early Crustal growth through magmatic accretion above upwelling, hot mantle, to Crustal growth that involved significant amounts of Crustal Recycling arising from the onset of modern-style plate tectonics (steep subduction of old cold oceanic lithosphere). These results align with global datasets of oxygen isotopes, and point to a more general change in the geodynamics of Earth associated with the secular decrease in heat output of our planet.
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orogenic climax of earth the 1 2 1 1 ga grenvillian superevent
Geology, 2013Co-Authors: Christopher L. Kirkland, Martin J Van KranendonkAbstract:The rate of growth of the continental crust is controversial. We present an evaluation of time-constrained analyses of oxygen isotopes in zircon grains and incompatible element (Zr, Th) concentrations in magmatic rocks to test for variations in the degree of Crustal Recycling through geological time. The data indicate a rise in these geochemical proxies from ca. 3.0 Ga to a statistically significant peak at 1.2–1.1 Ga during the amalgamation of supercontinent Rodinia, and a decrease thereafter. When combined with other geological and geophysical observations, the data are interpreted as a consequence of an unprecedented level of Crustal Recycling and sediment subduction during Rodinia assembly, arising from a "Goldilocks" (i.e., just right) combination of larger, thicker plates on a warmer Earth with more rapid continental drift relative to modern Earth. The subsequent decrease in δ 18 O, Zr, and Th measurements is interpreted to reflect decreasing drift rates on a cooling Earth.
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Zircon Lu-Hf isotopes and granite geochemistry of the Murchison Domain of the Yilgarn Craton: Evidence for reworking of Eoarchean crust during Meso-Neoarchean plume-driven magmatism
Lithos, 2012Co-Authors: Tim J. Ivanic, Martin J. Van Kranendonk, Christopher L. Kirkland, Stephen Wyche, Michael T.d. Wingate, Elena BelousovaAbstract:Abstract New in situ Lu–Hf data on zircons from GSWA geochronology samples has provided a unique isotopic dataset with a high temporal resolution for the Murchison Domain of the Yilgarn Craton in Western Australia. These data identify extended periods of juvenile mantle input (positive eHf values) into the crust firstly at c. 2980 Ma and then from c. 2820 Ma to c. 2640 Ma with significant pulses of Crustal Recycling at c. 2750 Ma and c. 2620 Ma (highly negative eHf values). Geochemical data from well-characterised granitic suites of the Murchison Domain provide additional constraints on the Crustal evolution of the area and indicate a prolonged period of Crustal melting and remelting at progressively shallower depths from c. 2750 to c. 2600 Ma. At c. 2760–2753 Ma, widespread calc-alkaline, intermediate to silicic volcanic rocks of the Polelle Group were erupted, accompanied by intrusion of felsic to intermediate melts derived from a variety of Crustal sources that likely formed by partial mixing with basaltic melts. The intrusive rocks include a wide geochemical array of rocks in the Cullculli and Eelya suites that were sourced over a wide range of Crustal depths. At this time a major departure to negative eHf values ( We interpret the driving force for this protracted history of mantle and Crustal melting to be two mantle plumes at 2.81 and 2.72 Ga. These data document the process of cratonization through progressive melt depletion of the lower crust, progressively fractionating and shallower melts, culminating with a final phase of Crustal Recycling (eHf
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Oxygen isotopes in detrital zircons: Insight into Crustal Recycling during the evolution of the Greenland Shield
Lithosphere, 2010Co-Authors: Christopher L. Kirkland, Martin J. Whitehouse, Victoria Pease, M. Van KranendonkAbstract:Insight into the interactions between crust and hydrosphere, through the protracted evolution of the Greenland Shield, can be provided by oxygen isotopes in the mineral remnants of its denuded crust. Detrital zircons with ages of 3900 Ma to 900 Ma found within an arkosic sandstone dike of the Neoproterozoic (?Marinoan) Moraeneso Formation, North Greenland, provide a time-integrated record of the evolution of part of the Greenland Shield. These zircon grains are derived from a wide variety of sources in northeastern Laurentia, including Paleoproterozoic and older detritus from the Committee-Melville orogen, the Ellesmere-Inglefield mobile belt, and the subice continuation of the Victoria Fjord complex. Archean zircon crystals have a more restricted range of δ 18 O SMOW values (between 7.2‰ and 9.0‰ relative to standard mean ocean water [SMOW]) in comparison to Paleoproterozoic 1800–2100 Ma grains, which display significant variation in δ 18 O SMOW (6.8‰–10.4‰). These data reflect differences in Crustal evolution between the Archean and Proterozoic Earth. Through time, remelting or reworking of high δ 18 O materials has become more important, consistent with the progressive emergence of buoyant, cratonized continental lithosphere. A secular increase in the rate of Crustal Recycling is implied across the Archean-Proterozoic boundary. This rate change may have been a response to differences in the composition of sediments and/or the stabilization of continental crust. One Eoarchean oscillatory-zoned zircon grain, free of cracks and with concordant U-Pb systematics, has an elevated δ 18 O SMOW value of 7.8‰. This is interpreted to reflect a primary magmatic signature, supporting the presence of heavy oxygen that may be compatible with a hydrosphere on early Earth, as previously determined only from Jack Hills zircons.
Nicola J Horsburgh - One of the best experts on this subject based on the ideXlab platform.
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sulphur isotopes of alkaline magmas unlock long term records of Crustal Recycling on earth
Nature Communications, 2019Co-Authors: William Hutchison, Ranier Babiel, Adrian A Finch, Michael A W Marks, Gregor Markl, A J Boyce, Eva E Stueken, Henrik Friis, A Borst, Nicola J HorsburghAbstract:Earth’s surface and mantle sulphur reservoirs are connected via subduction, Crustal Recycling and volcanism. Although oceanic hotspot lavas currently provide the best constraints on the deep sulphur cycle, their restricted age range (<200 Ma) means they cannot reveal temporal variations in Crustal Recycling over Earth history. Sulphur-rich alkaline magmas offer the solution because they are associated with recycled sources (i.e. metasomatized lithospheric mantle and plumes) and, crucially, are found throughout the geological record. Here, we present a detailed study of sulphur isotope fractionation in a Mesoproterozoic alkaline province in Greenland and demonstrate that an enriched subduction-influenced source (δ34S of +1 to +5‰) can be reconstructed. A global δ34S compilation reveals secular variation in alkaline magma sources which support changes in the composition of the lithospheric mantle and/or Ga timescales for deep Crustal Recycling. Thus, alkaline magmas represent a powerful yet underutilized repository for interrogating Crustal Recycling through geological time. Sulphur isotopes track Recycling of subducted Crustal material, yet few igneous rocks preserve these signals over Earth history. Here, the authors investigate a billion-year-old alkaline province in Greenland and are able to reconstruct a recycled mantle source, thus alkaline rocks can be used to reveal Crustal Recycling through geological time.
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Sulphur isotopes of alkaline magmas unlock long-term records of Crustal Recycling on Earth.
Nature communications, 2019Co-Authors: William Hutchison, Ranier Babiel, Adrian A Finch, Michael A W Marks, Gregor Markl, A J Boyce, Eva E Stueken, Henrik Friis, A Borst, Nicola J HorsburghAbstract:Earth’s surface and mantle sulphur reservoirs are connected via subduction, Crustal Recycling and volcanism. Although oceanic hotspot lavas currently provide the best constraints on the deep sulphur cycle, their restricted age range (
Kirsty Y. Tomlinson - One of the best experts on this subject based on the ideXlab platform.
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Basement terrane correlations and Crustal Recycling in the western Superior Province: Nd isotopic character of granitoid and felsic volcanic rocks in the Wabigoon subprovince, N. Ontario, Canada
Precambrian Research, 2004Co-Authors: Kirsty Y. Tomlinson, John A. Percival, Greg M. Stott, Denver StoneAbstract:Abstract The western Superior Province represents a collage of Mesoarchean continental (3.2–2.8 Ga) and Neoarchean continental, arc and oceanic (2.8–2.66 Ga) Crustal fragments. Nd isotope data presented here for 89 felsic volcanic and plutonic rocks have been combined with compiled data to generate a data set of over 240 analyses from the Wabigoon and Winnipeg River subprovinces. These samples, from both oceanic and continental environments have been used as Crustal probes, their Nd isotopic character used to investigate the extent of basement terranes, the ancestry of Crustal fragments, their interaction with each other, and the degree of sialic Crustal reworking. The Wabigoon and Winnipeg River subprovinces include three isotopically distinct terranes: (1) The Winnipeg River terrane comprises the Winnipeg River subprovince, the north-central Wabigoon, and the north-eastern Wabigoon subprovince. This region is dominated by Neoarchean granitoid rocks with Mesoarchean vestiges of Previous workers have suggested that the boundary between the western Wabigoon and Winnipeg River terranes represents a cryptic suture resulting from a collision at circa 2.71 Ga. The boundary between the western Wabigoon and Marmion terranes, although obscured by late intrusions, may be a continuation of this suture zone. The boundary between the Winnipeg River and Marmion terranes in the central Wabigoon is also cryptic. Isotopic data suggest that the Marmion terrane is allochthonous with respect to the Winnipeg River terrane. Common magmatism in these two terranes at 2.93–2.87 Ga suggests that they may have collided during this time. In the eastern Wabigoon subprovince this collision zone is speculated to occur at the Humboldt Bay high strain zone. A complex history of Crustal Recycling throughout the Mesoarchean and Neoarchean is revealed, which demonstrates the importance of autochthonous development of granite–greenstone terranes in a continental environment. The data also support models of tectonic accretion during the Archean, indicated by the presence of granite–greenstone terranes of allochthonous origin.
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Mafic to felsic magmatism and Crustal Recycling in the Obonga Lake greenstone belt, western Superior Province: evidence from geochemistry, Nd isotopes and U–Pb geochronology
Precambrian Research, 2002Co-Authors: Kirsty Y. Tomlinson, Donald W. Davis, John A. Percival, David J. Hughes, P. C. ThurstonAbstract:Abstract The central Wabigoon Subprovince of the western Superior Province contains Mesoarchean granitoid and supraCrustal rocks (3.01–2.83 Ga) and 2.78–2.69 Ga granitoid plutons and supraCrustal sequences. It is a key area for understanding the relationship between greenstone belts and surrounding granitoid rocks that may have acted as basement. The Obonga Lake greenstone belt contains two distinct assemblages: (1) a Ta>Nb>Th. They have eNd values of +0.7 to +2.4. A dacitic unit in the northern assemblage has high La/Yb, high Sr/Y, low Nb, Y and heavy REE and is interpreted to represent a mantle-modified slab melt similar to adakites in Cenozoic arcs. The associated enriched basalts may represent melts from the mantle wedge modified by slab melt (adakitic) metasomatism, or they may represent an enriched (OIB-like) asthenospheric source. Rocks of the southern assemblage mostly show Th and light REE enrichment and negative Nb and Ta anomalies. Low eNd values (down to −0.9) can be modelled through contamination of a mafic liquid by 3.3–3.2 Ga sialic crust, although rocks of that age have not been observed. Suggested Mesoarchean basement to the southern assemblage may therefore have had a complex history spanning several hundred million years. The southern assemblage volcanism may have occurred in a continental arc to continental back-arc system where Crustal Recycling played an important role.
Kjell Billström - One of the best experts on this subject based on the ideXlab platform.
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The Variscan gabbros from the Spanish Central System: A case for Crustal Recycling in the sub-continental lithospheric mantle?
Lithos, 2009Co-Authors: David Orejana, Carlos Villaseca, Cecilia Pérez-soba, José A. López-garcía, Kjell BillströmAbstract:The gabbroic intrusions that crop out along the Spanish Central System (SCS) are geochemically heterogeneous, including primitive and evolved rocks. Differentiation is mainly related to fractionation of Cr-spinel and olivine, but mixing with coeval granitic magmas or Crustal assimilation may have also played a role in the evolution of the most differentiated rocks. The most primitive uncontaminated gabbros show arclike trace element chondrite and primitive-mantle normalised patterns, characterised by large ion lithophile elements (LILE)-light rare earth elements (LREE) enrichment, Sr and Pb positive and Nb–Ta–Ti negative anomalies. However, paleogeographic constraints suggest that the SCS was located far from subduction zones, so these geochemical signatures could be better explained by a Recycling of continental Crustal components within the mantle. The most primitive SCS gabbros expand the Sr–Nd isotopic compositional range of the Variscan basic magmatism in the Central Iberian Zone to more depleted values. This reflects a heterogeneous sub-continental lithospheric mantle under central Spain ranging from a depleted mantle (eNd=+3.1, 87Sr/86Sr=0.704) towards an isotopically enriched component (eNd=−1.6, 87Sr/ 86Sr=0.706). Geochemical modelling suggests that mantle enrichment could be explained by minor lower Crustal metapelitic granulite contamination (~2%). Additionally, the Sr–Nd–Pb isotopic ratios of the most primitive gabbros match the composition of the European subcontinental lithospheric mantle recorded in ultramafic xenoliths from western and central Europe.
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The Variscan gabbros from the Spanish Central System: A case for Crustal Recycling in the sub-continental lithospheric mantle?
Lithos, 2009Co-Authors: David Orejana, Carlos Villaseca, Cecilia Pérez-soba, José A. López-garcía, Kjell BillströmAbstract:The gabbroic intrusions that crop out along the Spanish Central System (SCS) are geochemically\ud heterogeneous, including primitive and evolved rocks. Differentiation is mainly related to fractionation of\ud Cr-spinel and olivine, but mixing with coeval granitic magmas or Crustal assimilation may have also played a\ud role in the evolution of the most differentiated rocks. The most primitive uncontaminated gabbros show arclike\ud trace element chondrite and primitive-mantle normalised patterns, characterised by large ion lithophile\ud elements (LILE)-light rare earth elements (LREE) enrichment, Sr and Pb positive and Nb–Ta–Ti negative\ud anomalies. However, paleogeographic constraints suggest that the SCS was located far from subduction\ud zones, so these geochemical signatures could be better explained by a Recycling of continental Crustal\ud components within the mantle. The most primitive SCS gabbros expand the Sr–Nd isotopic compositional\ud range of the Variscan basic magmatism in the Central Iberian Zone to more depleted values. This reflects a\ud heterogeneous sub-continental lithospheric mantle under central Spain ranging from a depleted mantle\ud (εNd=+3.1, 87Sr/86Sr=0.704) towards an isotopically enriched component (εNd=−1.6, 87Sr/\ud 86Sr=0.706). Geochemical modelling suggests that mantle enrichment could be explained by minor lower\ud Crustal metapelitic granulite contamination (~2%). Additionally, the Sr–Nd–Pb isotopic ratios of the most\ud primitive gabbros match the composition of the European subcontinental lithospheric mantle recorded in\ud ultramafic xenoliths from western and central Europe
Robert Kerrich - One of the best experts on this subject based on the ideXlab platform.
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nd isotope systematics of 2 7 ga adakites magnesian andesites and arc basalts superior province evidence for shallow Crustal Recycling at archean subduction zones
Earth and Planetary Science Letters, 2002Co-Authors: Ali Polat, Robert KerrichAbstract:Abstract An association of adakite, magnesian andesite (MA), and Nb-enriched basalt (NEB) volcanic flows, which erupted within ‘normal’ intra-oceanic arc tholeiitic to calc-alkaline basalts, has recently been documented in ∼2.7 Ga Wawa greenstone belts. Large, positive initial ϵNd values (+1.95 to +2.45) of the adakites signify that their basaltic precursors, with a short Crustal residence, were derived from a long-term depleted mantle source. It is likely that the adakites represent the melts of subducted late Archean oceanic crust. Initial ϵNd values in the MA (+0.14 to +1.68), Nb-enriched basalts and andesites (NEBA) (+1.11 to +2.05), and ‘normal’ intra-oceanic arc tholeiitic to calc-alkaline basalts and andesites (+1.44 to +2.44) overlap with, but extend to lower values than, the adakites. Large, tightly clustered ϵNd values of the adakites, together with Th/Ce and Ce/Yb systematics of the arc basalts that rule out sediment melting, place the enriched source in the sub-arc mantle. Accordingly, isotopic data for the MA, NEBA, and ‘normal’ arc basalts can be explained by melting of an isotopically heterogeneous sub-arc mantle that had been variably enriched by Recycling of continental material into the shallow mantle in late Archean subduction zones up to 200 Ma prior to the 2.7 Ga arc. If the late Archean Wawa adakites, MA, and basalts were generated by similar geodynamic processes as their counterparts in Cenozoic arcs, involving subduction of young and/or hot ocean lithosphere, then it is likely that late Archean oceanic crust, and arc crust, were also created and destroyed by modern plate tectonic-like geodynamic processes. This study suggests that Crustal Recycling through subduction zone processes played an important role for the generation of heterogeneity in the Archean upper mantle. In addition, the results of this study indicate that the Nd-isotope compositions of Archean arc- and plume-derived volcanic rocks are not very distinct, whereas Phanerozoic plumes and intra-oceanic arcs tend to have different Nd-isotopic compositions.
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Nd-isotope systematics of ~2.7 Ga adakites, magnesian andesites, and arc basalts, Superior Province: evidence for shallow Crustal Recycling at Archean subduction zones
Earth and Planetary Science Letters, 2002Co-Authors: Ali Polat, Robert KerrichAbstract:Abstract An association of adakite, magnesian andesite (MA), and Nb-enriched basalt (NEB) volcanic flows, which erupted within ‘normal’ intra-oceanic arc tholeiitic to calc-alkaline basalts, has recently been documented in ∼2.7 Ga Wawa greenstone belts. Large, positive initial ϵNd values (+1.95 to +2.45) of the adakites signify that their basaltic precursors, with a short Crustal residence, were derived from a long-term depleted mantle source. It is likely that the adakites represent the melts of subducted late Archean oceanic crust. Initial ϵNd values in the MA (+0.14 to +1.68), Nb-enriched basalts and andesites (NEBA) (+1.11 to +2.05), and ‘normal’ intra-oceanic arc tholeiitic to calc-alkaline basalts and andesites (+1.44 to +2.44) overlap with, but extend to lower values than, the adakites. Large, tightly clustered ϵNd values of the adakites, together with Th/Ce and Ce/Yb systematics of the arc basalts that rule out sediment melting, place the enriched source in the sub-arc mantle. Accordingly, isotopic data for the MA, NEBA, and ‘normal’ arc basalts can be explained by melting of an isotopically heterogeneous sub-arc mantle that had been variably enriched by Recycling of continental material into the shallow mantle in late Archean subduction zones up to 200 Ma prior to the 2.7 Ga arc. If the late Archean Wawa adakites, MA, and basalts were generated by similar geodynamic processes as their counterparts in Cenozoic arcs, involving subduction of young and/or hot ocean lithosphere, then it is likely that late Archean oceanic crust, and arc crust, were also created and destroyed by modern plate tectonic-like geodynamic processes. This study suggests that Crustal Recycling through subduction zone processes played an important role for the generation of heterogeneity in the Archean upper mantle. In addition, the results of this study indicate that the Nd-isotope compositions of Archean arc- and plume-derived volcanic rocks are not very distinct, whereas Phanerozoic plumes and intra-oceanic arcs tend to have different Nd-isotopic compositions.