The high-pressure metamorphosed Gridino dyke swarm comprises a major group of Mesoarchean 2.87-2.82 Ga mafic dykes intruded within the Mesoarchean continental crust of the Kola craton(the Belomorian tectonic province
Two eclogite associations have been recognized within Belomorian TTG gneisses:(1)the subduction-type Salma association and(2)Gridino eclogitized mafic dykes.Protoliths of the Salma eclogites represent a sequence
The Southern Granulite Terrane(Dharwar Craton),South India,is a key unit for understanding the origin of charnockite.New U-Pb and Lu-Hf analyses in zircon crys-tals from 16 samples representing a wide variety of litho...The Southern Granulite Terrane(Dharwar Craton),South India,is a key unit for understanding the origin of charnockite.New U-Pb and Lu-Hf analyses in zircon crys-tals from 16 samples representing a wide variety of litho-types from the quarries in Kabbaldurga reveal a complex geological history in the Archean and early Paleoprotero-zoic.Magmatic protoliths predominantly record Paleoar-chean ages between 3.4 and 3.2 Ga.Combined U-Pb and Lu-Hf signatures indicate a history of recurrent crustal anatexis,juvenile magmatic input,and felsic injections.Mesoarchaean magmatic charnockites were generated mainly from hornblende-dehydration melting of Paleoar-chaean mafic rocks.In addition,Peninsular Gneissic Com-plex of the Dharwar Craton,commonly described as TTG suites,are likely generated by melting of hydrated basalt.The new data are consistent with the idea of a convecting magmatic cycle and also support the proposal that the southern Dharwar Craton comprises a tilted cross-sec-tion through the Archaean crust.Paleoproterozoic high-temperature event is documented here as a complex unit involving juvenile mafic magmatism,granulite facies imprints and crustal anatexis as well as felsic injections,occurring within a short time period around 2.5 Ga.展开更多
The Gawler Craton preserves a complex and prolonged tectonic history spanning the interval c.3200–1500 Ma.Reworking of Paleoarchean,c.3400–3250 Ma crust led to the formation of c.3150 Ma granites now exposed within ...The Gawler Craton preserves a complex and prolonged tectonic history spanning the interval c.3200–1500 Ma.Reworking of Paleoarchean,c.3400–3250 Ma crust led to the formation of c.3150 Ma granites now exposed within a narrow belt in the eastern Gawler Craton.Following this,there is no known record of significant tectonic activity until the onset of bimodal magmatism during the Neoarchean to earliest Paleoproterozoic,c.2560–2470 Ma.This magmatism was terminated by high temperature metamorphism and deformation during the 2465–2410 Ma Sleafordian Orogeny.Magmatic events associated with widespread sedimentation over the interval c.2000–1740 Ma largely sources this older crust.The c.1730–1690 Ma Kimban Orogeny reworked these Paleoproterozoic basins and the Neoarchean basement in a pre-dominantly transpressional orogenic system.Juvenile mantle input followed by widespread crustal melting occurred over the interval c.1620–1570 Ma.This period of intense magmatism initiated with emplacement of the relatively juvenile c.1620–1608 Ma St Peter Suite.This was followed by the economically significant c.1600–1570 Ma Gawler Range Volcanics/Hiltaba Suite magmatic event,which resulted from widespread mid-crustal melting.Synchronous deformation and high temperature metamorphism accompanied the Gawler Range Volcanics/Hiltaba Suite magmatic event indicating it occurred in an orogenic environment.Far field stress was distributed around a central core zone of largely undisturbed Gawler Range Volcanics with deformation localised in the northern and southern Gawler Craton.The Gawler Range Volcanics/Hiltaba Suite magmatic event resulted in formation of a province of major economic significance that includes the giant Olympic Dam Cu-Au-U ore body.展开更多
The Dharwar Craton(DC)in India consists of three distinct Archean blocks.Previous research suggests that the Central Dharwar Block(CDB)experienced a geological history(3.3-2.5 Ga)comparable to the Western Dharwar Crat...The Dharwar Craton(DC)in India consists of three distinct Archean blocks.Previous research suggests that the Central Dharwar Block(CDB)experienced a geological history(3.3-2.5 Ga)comparable to the Western Dharwar Craton(WDC).However,3.0-2.7 Ga geological records are missed in the CDB.This study identified the 2.85 Ga gabbroic xenoliths within the Closepet batholith in the CDB.The~2.85 Ga inherited zircons and zircon Hf model ages in CDB further provide evidence for this significant magmatic event.The gabbroic xenoliths are characterized by E-MORB REE patterns and Nb,Ta,and Ti depletions,together with high radiogenic isotopic signatures,including zircon Hf(ε_(Hf)(t)_(min)=-3.2),whole-rock Nd(ε_(Nd)(t)=-0.8-0.7),and Pb isotopes(κ=4.9-7.9),indicating derivation from a slightly enriched mantle source.Additionally,they have high Nb(4.41 to 4.73 ppm),low Ti/V(23.4 to 22.5),and elevated Th/Yb(0.38 to 0.61).All these suggest a subduction-related back-arc basin setting.Coupled with widespread early Neoarchean subduction-related igneous rocks in the DC,the 2.85 Ga gabbroic magmatism signifies that the DC had transitioned into a tectonic stage dominated by lateral movement of continental blocks around 2.85 Ga,corresponding to global~2.85 Ga magmatic events.展开更多
文摘The high-pressure metamorphosed Gridino dyke swarm comprises a major group of Mesoarchean 2.87-2.82 Ga mafic dykes intruded within the Mesoarchean continental crust of the Kola craton(the Belomorian tectonic province
文摘Two eclogite associations have been recognized within Belomorian TTG gneisses:(1)the subduction-type Salma association and(2)Gridino eclogitized mafic dykes.Protoliths of the Salma eclogites represent a sequence
基金funded by the India-Brazil bilateral co-operation Project:INT/BRAZIL/P-02/2013by Indian Statistical Institute,Geoscience Institute of São Paulo University,Brazil and Department of Geology,University of Calcutta.M.Hueck thanks FAPESP for a post-doctoral fellowship(grant 2019/06838-2).
文摘The Southern Granulite Terrane(Dharwar Craton),South India,is a key unit for understanding the origin of charnockite.New U-Pb and Lu-Hf analyses in zircon crys-tals from 16 samples representing a wide variety of litho-types from the quarries in Kabbaldurga reveal a complex geological history in the Archean and early Paleoprotero-zoic.Magmatic protoliths predominantly record Paleoar-chean ages between 3.4 and 3.2 Ga.Combined U-Pb and Lu-Hf signatures indicate a history of recurrent crustal anatexis,juvenile magmatic input,and felsic injections.Mesoarchaean magmatic charnockites were generated mainly from hornblende-dehydration melting of Paleoar-chaean mafic rocks.In addition,Peninsular Gneissic Com-plex of the Dharwar Craton,commonly described as TTG suites,are likely generated by melting of hydrated basalt.The new data are consistent with the idea of a convecting magmatic cycle and also support the proposal that the southern Dharwar Craton comprises a tilted cross-sec-tion through the Archaean crust.Paleoproterozoic high-temperature event is documented here as a complex unit involving juvenile mafic magmatism,granulite facies imprints and crustal anatexis as well as felsic injections,occurring within a short time period around 2.5 Ga.
文摘The Gawler Craton preserves a complex and prolonged tectonic history spanning the interval c.3200–1500 Ma.Reworking of Paleoarchean,c.3400–3250 Ma crust led to the formation of c.3150 Ma granites now exposed within a narrow belt in the eastern Gawler Craton.Following this,there is no known record of significant tectonic activity until the onset of bimodal magmatism during the Neoarchean to earliest Paleoproterozoic,c.2560–2470 Ma.This magmatism was terminated by high temperature metamorphism and deformation during the 2465–2410 Ma Sleafordian Orogeny.Magmatic events associated with widespread sedimentation over the interval c.2000–1740 Ma largely sources this older crust.The c.1730–1690 Ma Kimban Orogeny reworked these Paleoproterozoic basins and the Neoarchean basement in a pre-dominantly transpressional orogenic system.Juvenile mantle input followed by widespread crustal melting occurred over the interval c.1620–1570 Ma.This period of intense magmatism initiated with emplacement of the relatively juvenile c.1620–1608 Ma St Peter Suite.This was followed by the economically significant c.1600–1570 Ma Gawler Range Volcanics/Hiltaba Suite magmatic event,which resulted from widespread mid-crustal melting.Synchronous deformation and high temperature metamorphism accompanied the Gawler Range Volcanics/Hiltaba Suite magmatic event indicating it occurred in an orogenic environment.Far field stress was distributed around a central core zone of largely undisturbed Gawler Range Volcanics with deformation localised in the northern and southern Gawler Craton.The Gawler Range Volcanics/Hiltaba Suite magmatic event resulted in formation of a province of major economic significance that includes the giant Olympic Dam Cu-Au-U ore body.
基金financially supported by the National Natural Science Foundations of China(41890831,41421002)the MOST Special Fund from the State Key Laboratory of Continental Dynamics,Northwest University(201210133)。
文摘The Dharwar Craton(DC)in India consists of three distinct Archean blocks.Previous research suggests that the Central Dharwar Block(CDB)experienced a geological history(3.3-2.5 Ga)comparable to the Western Dharwar Craton(WDC).However,3.0-2.7 Ga geological records are missed in the CDB.This study identified the 2.85 Ga gabbroic xenoliths within the Closepet batholith in the CDB.The~2.85 Ga inherited zircons and zircon Hf model ages in CDB further provide evidence for this significant magmatic event.The gabbroic xenoliths are characterized by E-MORB REE patterns and Nb,Ta,and Ti depletions,together with high radiogenic isotopic signatures,including zircon Hf(ε_(Hf)(t)_(min)=-3.2),whole-rock Nd(ε_(Nd)(t)=-0.8-0.7),and Pb isotopes(κ=4.9-7.9),indicating derivation from a slightly enriched mantle source.Additionally,they have high Nb(4.41 to 4.73 ppm),low Ti/V(23.4 to 22.5),and elevated Th/Yb(0.38 to 0.61).All these suggest a subduction-related back-arc basin setting.Coupled with widespread early Neoarchean subduction-related igneous rocks in the DC,the 2.85 Ga gabbroic magmatism signifies that the DC had transitioned into a tectonic stage dominated by lateral movement of continental blocks around 2.85 Ga,corresponding to global~2.85 Ga magmatic events.
