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  • 1
    Electronic Resource
    Electronic Resource
    Hadean diamonds in zircon from Jack Hills, Western Australia (2007)
    [s.l.] : Nature Publishing Group
    Nature 448 (2007), S. 917-920 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Detrital zircons more than 4 billion years old from the Jack Hills metasedimentary belt, Yilgarn craton, Western Australia, are the oldest identified fragments of the Earth’s crust and are unique in preserving information on the earliest evolution of the Earth. Inclusions of quartz, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature06083
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  • 2
    Electronic Resource
    Electronic Resource
    Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago (2001)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 409 (2001), S. 175-178 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] No crustal rocks are known to have survived since the time of the intense meteor bombardment that affected Earth between its formation about 4,550 Myr ago and 4,030 Myr, the age of the oldest known components in the Acasta Gneiss of northwestern Canada. But evidence of an ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35051550
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  • 3
    Electronic Resource
    Electronic Resource
    Zircon U–Pb ages and tectonic implications of ‘Early Paleozoic’ granitoids at Yanbian, Jilin Province, northeast China (2004)
    Melbourne, Australia : Blackwell Science Pty
    The @island arc 13 (2004), S. 0 
    Details
    ISSN: 1440-1738
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Abstract  The Yanbian area is located in the eastern part of the Central Asian Orogenic Belt (CAOB) of China and is characterized by widespread Phanerozoic granitic intrusions. It was previously thought that the Yanbian granitoids were mainly emplaced in the Early Paleozoic (so-called ‘Caledonian’ granitoids), extending east–west along the northern margin of the North China craton. However, few of them have been precisely dated; therefore, five typical ‘Caledonian’ granitic intrusions (the Huangniling, Dakai, Mengshan, Gaoling and Bailiping batholiths) were selected for U–Pb zircon isotopic study. New-age data show that emplacement of these granitoids extended from the Late Paleozoic to Late Mesozoic (285–116 Ma). This indicates that no ‘Caledonian’ granitic belt exists along the northern margin of the North China craton. The granitoids can be subdivided into four episodes based on our new data: Early Permian (285 ± 9 Ma), Early Triassic (249–245 Ma), Jurassic (192–168 Ma) and Cretaceous (119–116 Ma). The 285 ± 9 Ma tonalite was most likely related to subduction of the Paleo-Asian Oceanic Plate beneath the North China craton, followed by Triassic (249–245 Ma) syn-collisional monzogranites, representing the collision of the CAOB orogenic collage with the North China craton and final closure of the Paleo-Asian Ocean. The Jurassic granitoids resulted from subduction of the Paleo-Pacific plate and subsequent collision of the Jiamusi–Khanka Massif with the existing continent, assembled in the Triassic. The Early Cretaceous granitoids formed in an extensional setting along the eastern Asian continental margin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1738.2004.00442.x
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  • 4
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    The Precambrian Khondalite Belt in the Daqingshan area, North China Craton: evidence for multiple metamorphic events in the Palaeoproterozoic era (2009)
    In:  Geological Society Special Publication 323: 73-97.
    Details
    Publication Date: 2009-09-08
    Description: High-grade pelitic metasedimentary rocks (khondalites) are widely distributed in the northwestern part of the North China Craton and were named the Khondalite Belt'. Prior to the application of zircon geochronology, a stratigraphic division of the supracrustal rocks into several groups was established using interpretative field geology. We report here SHRIMP U-Pb zircon ages and Hf-isotope data on metamorphosed sedimentary and magmatic rocks at Daqingshan, a typical area of the Khondalite Belt. The main conclusions are as follows: (1) The early Precambrian supracrustal rocks belong to three sequences: a 2.56-2.51 Ga supracrustal unit (the previous Sanggan group'), a 2.51-2.45 Ga supracrustal unit (a portion of the previous upper Wulashan group') and a 2.0-1.95 Ga supracrustal unit (including the previous lower Wulashan group', a portion of original upper Wulashan group' and the original Meidaizhao group') the units thus do not represent a true stratigraphy; (2) Strong tectono-thermal events occurred during the late Neoarchaean to late Palaeoproterozoic, with four episodes recognized: 2.6-2.5, 2.45-2.37, 2.3-2.0 and 1.95-1.85 Ga, with the latest event being consistent with the assembly of the Palaeoproterozoic supercontinent Columbia; (3) During the late Neoarchaean to late Palaeoproterozoic (2.55-2.5, 2.37 and 2.06 Ga) juvenile, mantle-derived material was added to the crust.
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  • 5
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    The Khanka Block, NE China, and its significance for the evolution of the Central Asian Orogenic Belt and continental accretion (2010)
    In:  Geological Society Special Publication 338: 117-137.
    Details
    Publication Date: 2010-09-28
    Description: Sensitive high-resolution ion microprobe and inductively coupled plasma mass spectrometry U-Pb dating of zircons from granitoids and paragneiss in the Chinese segment of the Khanka Block reveals that granite magmatism occurred at 518{+/-}7 Ma and was followed shortly after by high-grade metamorphism at c. 500 Ma (timing ranging from 491{+/-}4 Ma in medium-grained granitoid, through 499{+/-}10 Ma in porphyritic granite, to 501{+/-}8 Ma in paragneiss). Such a scenario has previously been established on similar lithologies in the Jiamusi Block to the west, with identical ages. This suggests that the Khanka and Jiamusi blocks form part of a single terrane and that the Dunhua-Mishan Fault, which was previously considered to separate two unique terranes, cannot be a terrane boundary fault. Previous suggestions of a link between the Khanka Block and the Hida Block in Japan are not supported following a comparison of the new zircon data with published ages for the Japanese terranes. A granitoid with an age of 112{+/-}1 Ma in the Khanka Block probably records the effect of Pacific plate subduction, as such ages are common further south in the extreme eastern part of the North China Craton, where they have been related to post-collisional extension and lithospheric thinning in the Jiaodong Peninsula. The presence of such young granitoids, and the previous dating of blueschist-facies metamorphism as late Early Jurassic in the Heilongjiang Complex of the Jiamusi Block, supports the view that the current location of the Jiamusi-Khanka terrane is a product of circum-Pacific accretion rather than it being a microcontinental block that was trapped by the northward collision of the North China Craton with Siberia as part of the assembly of the main Central Asian Orogenic Belt.
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  • 6
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    Determining Precambrian crustal evolution in China: a case-study from Wutaishan, Shanxi Province, demonstrating the application of precise SHRIMP U-Pb geochronology (2007)
    In:  Geological Society Special Publication 226: 5-25.
    Details
    Publication Date: 2007-10-08
    Description: SHRIMP U-Pb zircon analyses from eight samples of metamorphosed intermediate to felsic volcanic rocks from the lower, middle and upper subgroups' of the Wutai sequence in the North China Craton define a weighted mean 207Pb/206Pb age of 2523 {+/-} 3 Ma. Although individual rock ages range from 2533 {+/-} 8 Ma to 2513 {+/-} 8 Ma, all overlap within the error of the mean and do not support a stratigraphic interpretation for the sequence, since variations within individual previously assigned formations' in the sequence match the total age range. Contrary to previous interpretations, there is no correlation in age with metamorphic grade. These features highlight the need to reformulate stratigraphic schemes when defining the Precambrian geology of the North China Craton. The similarity in age between volcanic rocks of the Wutai Complex and higher-grade gneisses of the adjacent Fuping and Hengshan complexes supports the view that all three complexes represent portions of a Late Archaean arc complex that was tectonically dismembered and then re-assembled. There is no Fuping or Wutai orogeny in this, its type area: all three complexes were deformed and metamorphosed during collision of the eastern and western blocks of the North China Craton in the Luliang orogeny c. 1.8 Ga ago.
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  • 7
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    Late Archaean to Palaeoproterozoic evolution of the Trans-North China Orogen: insights from synthesis of existing data from the Hengshan-Wutai-Fuping belt (2007)
    In:  Geological Society Special Publication 226: 27-55.
    Details
    Publication Date: 2007-10-08
    Description: The Hengshan-Wutai-Fuping mountain belt constitutes the middle segment of the Trans-North China Orogen, which separates the North China Craton into the Eastern and Western Blocks. The belt consists of the high-grade Hengshan and Fuping complexes, and the intervening low- to medium-grade Wutai Complex. Previous tectonic models assumed that the high-grade complexes were an older basement (Archaean to Palaeoproterozoic) to the low-grade Wutai Complex. However, new geochronological data show that the emplacement of granitoid rocks and eruption of volcanic rocks in the Wutai Complex occurred essentially coeval with or slightly earlier than intrusion of the tonalitic-trondhjemitic-granodioritic (TTG) suites in the Hengshan and Fuping complexes. New isotopic data also reveal the widespread presence of Palaeoproterozoic granitoid rocks in these complexes. Structural and metamorphic data demonstrate similar tectonothermal histories for the three complexes, which are characterized by peak medium- to high-pressure metamorphism accompanied by the development of thrusting, isoclinal folding (F2) and penetrative foliations, followed by near-isothermal decompression and cooling and retrogression associated with the formation of large-scale ductile shear zones and asymmetrical folds (F3) with nearly vertical axial planes. These geochronological, structural and metamorphic data suggest that the tectonic evolution of the Hengshan-Wutai-Fuping mountain belt may not be related to local interaction of the three complexes, as suggested in earlier models, either through closure of a Wutai rift or collision between a Wutai arc and the Hengshan and Fuping micro-continental blocks. Instead, they may represent elements of a single Late Archaean to Early Palaeoproterozoic magmatic arc that was subsequently incorporated into the Trans-North China Orogen along which the Eastern and Western blocks amalgamated to form the North China Craton at around 1.85 Ga.
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  • 8
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    Polymetamorphism of mafic granulites in the North China Craton: textural and thermobarometric evidence and tectonic implications (2001)
    In:  Geological Society Special Publication 184: 323-341.
    Details
    Publication Date: 2001-01-01
    Description: The basement of the North China Craton can be divided into the Archaean Eastern and Western Blocks, separated by major Palaeoproterozoic terrane boundaries that roughly correspond with the limits of a 100-300 km wide zone, named the Trans-North China Orogen. Some mafic granulites from the orogen and adjoining areas in the Eastern and Western Blocks preserve textural evidence for two granulite facies events involving contrasting P-T paths. The first event is characterized by three distinct mineral assemblages, M1a to M1c. M1a is represented by fine-grained orthopyroxene + clinopyroxene + plagioclase {+/-} quartz, which is surrounded by the M1b garnet + quartz symplectite, which itself is mantled by the M1c plagioclase + biotite symplectite. These assemblages and their P-T estimates define an anticlockwise P-T path, with peak metamorphism of 7.0-8.0 kbar and 800-850{degrees}C (M1a) followed by isobaric cooling to 700-750{degrees}C (M1b) and pressure-decreasing cooling to 630-700{degrees}C (M1c). The second event also includes three mineral assemblages, M2a to M2c. M2a represents growths of garnet porphyroblasts and matrix orthopyroxene + plagioclase + clinopyroxene + quartz; M2b consists of orthopyroxene + plagioclase {+/-} clinopyroxene symplectites or coronas; and M2c is represented by plagioclase + hornblende symplectites. These assemblages and their P-T estimates define a clockwise P-T path, with peak metamorphism of 9.2-9.8 kbar and 820-850{degrees}C (M2a), followed by near-isothermal decompression (M2b) of 7.0-7.6 kbar and 760-810{degrees}C and cooling (M2c) to 690-760{degrees}C. The isobaric cooling, anticlockwise, P-T path of the first granulite facies event is similar to the P-T paths inferred for the c.2.5 Ga metamorphosed mafic granulites from the Eastern and Western Blocks, whereas the near-isothermal decompression, clockwise, P-T path of the second granulite facies event is similar to the P-T paths inferred for the c. 1.8 Ga metamorphosed khondalite series in the Western Block and some mafic granulites in the Trans-North China Orogen. These relations suggest that the polymetamorphic granulites were derived from the reworking of the 2.5 Ga metamorphosed granulites during the 1.8 Ga collision between the Eastern and Western Blocks that resulted in the final amalgamation of the North China Craton.
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  • 9
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    First Direct Dating of Alteration of Paleo-Oil Pools Using Rubidium-Strontium Pyrite Geochronology (2020)
    Molecular Diversity Preservation International
    Details
    Publication Date: 2020-07-04
    Description: Direct dating of petroleum systems by hydrocarbon or associated authigenic minerals is crucial for petroleum system analysis and hydrocarbon exploration. The precipitation of authigenic pyrite in petroliferous basins is commonly genetically associated with hydrocarbon generation, migration, accumulation, or destruction. Pyrite rubidium-strontium (Rb-Sr) isotope dilution thermal ionization mass spectrometry (ID-TIMS) is a well-developed technique, and its successful application for high-temperature ore systems suggests that this dating method has the potential to directly date key processes in the low-temperature petroleum systems. Rb-Sr data for pyrites in two Ordovician carbonate rock specimens collected from ~4952 m in the YD-2 well in the Yudong region, northern Tarim Basin (NW China), yield two identical isochron ages within analytical uncertainties: 206 ± 13 (2σ) and 224 ± 28 Ma (2σ). SEM investigations demonstrate that Rb and Sr atoms mainly reside in the crystal lattice of the pyrites due to the absence of fluid and mineral inclusions. The rigorous Rb-Sr isochron relations documented in the samples indicate that such residency can result in sufficient Rb/Sr fractionation and initial Sr isotopic homogenization for geochronology. In addition, the closure temperature (227–320 °C) for the Rb-Sr isotope system in pyrite is higher than the precipitation temperature for pyrite in petroleum-related environments (below 200 °C), suggesting that the Rb-Sr age of pyrite was not overprinted by post-precipitation alteration. Integrating the lead-strontium-sulfur isotopes of the pyrites with burial history analysis, the ages are interpreted as the timing of alteration of the paleo-oil pool by a hydrothermally-triggered thermochemical sulfate reduction process. This study, for the first time, demonstrates that Rb-Sr pyrite geochronology, combined with radiogenic and stable isotopic analyses, can be a useful tool to evaluate the temporal evolution of oil pools. This approach bears great potential for dating of petroleum systems anywhere else in the world.
    Electronic ISSN: 2075-163X
    Topics: Geosciences
    Published by Molecular Diversity Preservation International
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  • 10
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    Metallic lead nanospheres discovered in ancient zircons (2015)
    National Academy of Sciences
    Details
    Publication Date: 2015-04-06
    Description: Zircon (ZrSiO4) is the most commonly used geochronometer, preserving age and geochemical information through a wide range of geological processes. However, zircon U–Pb geochronology can be affected by redistribution of radiogenic Pb, which is incompatible in the crystal structure. This phenomenon is particularly common in zircon that has experienced ultra-high temperature metamorphism, where ion imaging has revealed submicrometer domains that are sufficiently heterogeneously distributed to severely perturb ages, in some cases yielding apparent Hadean (〉4 Ga) ages from younger zircons. Documenting the composition and mineralogy of these Pb-enriched domains is essential for understanding the processes of Pb redistribution in zircon and its effects on geochronology. Using high-resolution scanning transmission electron microscopy, we show that Pb-rich domains previously identified in zircons from East Antarctic granulites are 5–30 nm nanospheres of metallic Pb. They are randomly distributed with respect to zircon crystallinity, and their association with a Ti- and Al-rich silica melt suggests that they represent melt inclusions generated during ultra-high temperature metamorphism. Metallic Pb is exceedingly rare in nature and previously has not been reported in association with high-grade metamorphism. Formation of these metallic nanospheres within annealed zircon effectively halts the loss of radiogenic Pb from zircon. Both the redistribution and phase separation of radiogenic Pb in this manner can compromise the precision and accuracy of U–Pb ages obtained by high spatial resolution methods.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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