Lu-Hf analyses of zircon from the Makoppa Dome and Amalia-Kraaipan area: implications for evolution of the Kimberley and Pietersburg blocks of the Kaapvaal Craton

Abstract Previously dated zircon crystals from the Amalia-Kraaipan granite-greenstone belts and Makoppa Dome were analysed for their Lu-Hf isotopic characteristics to refine the geological evolution of these areas. Samples from the Makoppa Dome, belonging to the Pietersburg Block, largely fall within the epsilon Hf-age range for granitoids from the eastern part of the block. However, the oldest 3.01 to 3.03 Ga trondhjemitic gneisses show that reworking of juvenile mafic crust started earlier in the western than the eastern part of the block, suggesting a diachronous tectonic evolution. The three granitoids from the Amalia-Kraaipan area fall within the field for Pietersburg and Kimberley block granitoids. Contribution from older crustal material is seen in a 3.08 Ga schist, likely derived from a volcanic protolith, from the Madibe Belt, in the far east of the Kimberley Block, with a mantle extraction age of 3.25 to 3.45 Ga. The data suggest that the Kimberley Block, like the Pietersburg Block, also contains (minor) ancient crustal components, derived from a depleted mantle source prior to 3.1 Ga. The new data suggest that the Kimberley and Pietersburg blocks underwent a very similar Paleo- to Mesoarchean crustal evolution, with a major crust formation event at 3.1 to 3.0 Ga followed by successive crust reworking until 2.77 Ga. Lavas of the Ventersdorp Supergroup, for which zircon grains from a ca. 2.75 lapilli tuff give εHfi of +2, are the first evidence of a juvenile source, after 300 Myr of crustal reworking.

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New zircon radiometric U-Pb ages and Lu-Hf isotopic data from the ultramafic-mafic sequences of Ranau and Telupid (Sabah, eastern Malaysia): Time to reconsider the geological evolution of Southeast Asia?

Geology ◽

10.1130/g48126.1 ◽

2021 ◽

Author(s):

Basilios Tsikouras ◽

Chun-Kit Lai ◽

Elena Ifandi ◽

Nur’Aqidah Norazme ◽

Chee-Hui Teo ◽

...

Keyword(s):

Ultramafic Rocks ◽

Crustal Material ◽

Isotopic Data ◽

Backarc Basin ◽

Crustal Component ◽

Sulu Sea ◽

Potential Source ◽

Depleted Mantle ◽

Geological Evolution ◽

Mantle Reservoir

New zircon U-Pb geochronology from a peridotite suite near Ranau and the Telupid ophiolite in Sabah, eastern Malaysia, contradict previous studies, which assumed that the Sabah mafic-ultramafic rocks are largely ophiolitic and Jurassic–Cretaceous in age. We show that these rocks formed during a magmatic episode in the Miocene (9.2–10.5 Ma), which is interpreted to reflect infiltration of melts and melt-rock reaction in the Ranau subcontinental peridotites during extension, and concurrent seafloor spreading forming the Telupid ophiolite further south. Older zircons from the Ranau peridotites have Cretaceous, Devonian, and Neoproterozoic ages. Zircon Lu-Hf isotopic data suggest their derivation from a depleted mantle. However, significant proportions of crustal components have been incorporated in their genesis, as evidenced by their less-radiogenic Hf signature compared to a pristine mantle reservoir. The involvement of a crustal component is consistent with our interpreted continental setting for the Ranau peridotite and formation in a narrow backarc basin for the Telupid ophiolite. We infer that the Sulu Sea, which was expanding throughout much of the Miocene, may have extended to the southwest into central Sabah. The Telupid oceanic strand formed during the split, collapse, and rollback of the Sulu arc due to the subduction of the Celebes Sea beneath Sabah. Incorporation of the Sulu arc in the evolving Miocene oceanic basin is a potential source to explain the involvement of crustal material in the zircon evolution of the Telupid ophiolite.

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Circa 2.5 Ga granitoids in the eastern North China craton: Melting from ca. 2.7 Ga accretionary crust

Geological Society of America Bulletin ◽

10.1130/b35091.1 ◽

2019 ◽

Vol 132 (3-4) ◽

pp. 817-834 ◽

Cited By ~ 1

Author(s):

Yilong Li ◽

Jianping Zheng ◽

Wenjiao Xiao ◽

Guoqing Wang ◽

Fraukje M. Brouwer

Keyword(s):

Continental Crust ◽

Mantle Plume ◽

North China Craton ◽

North China ◽

Crustal Material ◽

Crustal Accretion ◽

The North ◽

Depleted Mantle ◽

Granitoid Rocks ◽

Crustal Reworking

Abstract The Neoarchean crust-mantle interaction and crustal evolution of the North China craton are controversial and are instructive of the processes of continental crust growth and cratonic evolution. We present here a systematic study of the petrology, geochemistry, and geochronology of Neoarchean granitoids from the eastern North China craton to elucidate their petrogenesis and tectonic setting. The rocks were collected from the Jielingkou, Anziling, and Qinhuangdao plutons, and an amphibole-monzoporphyry dike in the Qinhuangdao pluton. Samples from the Jielingkou pluton, consisting dominantly of monzodiorite and diorite with minor monzonite and granodiorite, contain 52.2–64.4 wt% SiO2, 2.46–4.52 wt% MgO (Mg# = 0.41–0.54), 3.76–5.77 wt% Na2O, and K2O/Na2O ratios of 0.29–0.71. The Anziling pluton samples, comprising syenite and monzonite, display slightly higher SiO2 (60.9–66.7 wt%) and K2O/Na2O ratios (0.70–1.11), but lower MgO (1.54–2.33 wt%) and Mg# (0.40–0.47) values, compared to the Jielingkou rocks. The Qinhuangdao pluton samples, consisting mainly of granite and minor syenite and granodiorite, with some diorite and monzoporphyry dikes, are characterized by the highest SiO2 values (75.7–76.9 wt%) and K2O/Na2O ratios (0.73–1.41) and lowest MgO content (0.14–0.32 wt%) among the studied samples. The amphibole-monzoporphyry dike has intermediate SiO2 (56.3 wt%), high MgO (3.79 wt%), Na2O (5.55 wt%), and Mg# (0.45), and low K2O/Na2O ratio (0.66). Zircon U-Pb laser-ablation–inductively coupled plasma–mass spectrometry dating showed that all plutons have a ca. 2.5 Ga crystallization age. Zircon crystals have mildly positive εHf(t) values (+0.24 to +5.45) and a depleted mantle model age (TDM1) of ca. 2.7 Ga. We interpret the granitoid rocks as sanukitoid-related, Closepet-type granites, potassium-rich adakites, and potassium-rich granitoid rocks that crystallized in the late Neoarchean (2.5 Ga) and were derived from partial melting of mantle peridotite that was metasomatized with the addition of slab melt, thickened alkali-rich juvenile lower crust and juvenile metamorphosed tonalitic rocks. Mantle plume activity ca. 2.7 Ga is thought to have been responsible for the early Neoarchean tectono-thermal event in the eastern North China craton. This activity resulted in a major crustal accretion period in the craton, with subordinate crustal reworking at its margins. A steep subduction regime between ca. 2.55 Ga and ca. 2.48 Ga led to the remelting of older crustal material, with subordinate crustal accretion by magma upwelling from a depleted mantle source resulting in late Neoarchean underplating. This crustal reworking and underplating resulted in the widespread ca. 2.5 Ga plutons in the eastern North China craton. Continental crust growth in the North China craton thus occurred in multiple stages, in response to mantle plume activity, as well as protracted subduction-related granitoid magmatism during the Neoarchean.

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Plate-Tectonic Evolution of the Far East: ABSTRACT

AAPG Bulletin ◽

10.1306/c1ea5599-16c9-11d7-8645000102c1865d ◽

1978 ◽

Vol 62 ◽

Author(s):

Maurice J. Terman

Keyword(s):

Tectonic Evolution ◽

Far East ◽

Plate Tectonic ◽

The Far East

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Military Service and Adventures in the Far East

10.1017/cbo9781139178747 ◽

2009 ◽

Author(s):

Daniel Henry Mackinnon

Keyword(s):

Military Service ◽

Far East ◽

The Far East

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Is there a regional culture in Russia? Opportunities of using a sociocultural approach in economics

Voprosy Ekonomiki ◽

10.32609/0042-8736-2020-7-108-126 ◽

2020 ◽

pp. 108-126 ◽

Cited By ~ 1

Author(s):

V. A. Bryzgalin ◽

Е. N. Nikishina

Keyword(s):

Far East ◽

Cross Cultural ◽

Regional Culture ◽

Russian Regions ◽

Geographical Patterns ◽

Cross Cultural Differences ◽

The Far East ◽

Sociocultural Approach ◽

Critical Issues ◽

Russian Universities

The paper investigates cross-cultural differences across Russian regions using the methodology of G. Hofstede. First, it discusses the most common approaches in measuring culture and the application of the Hofstede methodology in subnational studies. It identifies the critical issues in measuring culture at the regional level and suggests several strategies to address them. Secondly, the paper introduces subregional data on individualism and uncertainty avoidance using a survey of students across 27 Russian universities. The data allow to establish geographical patterns of individualism in Russia. It is demonstrated that collectivism is most prevalent in the Volga region, while individualism characteristic becomes stronger towards the Far East. The findings are robust to the inclusion of various controls and different specifications of the regression model. Finally, the paper provides a discussion about the potential of applying the sociocultural approach in economics.

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