Ultrahigh-temperature metamorphism under isobaric heating: New evidence from the North China Craton

Yang, Qiong-Yan; Santosh, M.; Tsunogae, Toshiaki

doi:10.1016/j.jseaes.2014.01.018

Cited by 55 publications

(65 citation statements)

References 70 publications

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“…As mentioned above, metamorphic ages obtained from pelitic granulites and minor granitoids in the Jining Group can be divided into three populations: (i) >1.95 Ga (Li et al ., ); (ii) c . 1.93–1.91 Ga (Santosh et al ., , ; Cai et al ., ); (iii) 1.89–1.84 Ga (Wan et al ., ; Li et al ., ; Jiao et al ., ; Yang et al ., ). These ages were controversially interpreted to represent two separate orogenic events or a protracted orogenic process with slow cooling and uplift.…”

Section: Discussionmentioning

confidence: 97%

“…() are the weighted mean ages of 1.89–1.81 Ga and 1.93–1.87 Ga respectively, and the timing of the UHT metamorphism of 1.88 Ga in Yang et al . () is the weighted mean age of 1.96–1.79 Ga. Long age spectrums are also common in other areas. For example, Zhang et al .…”

Section: Discussionmentioning

confidence: 97%

“…Zircon in MP pelitic granulites yielded metamorphic ages of 1.98–1.96 Ga (Li et al ., ), c . 1.91 Ga (Cai et al ., ) and 1.89–1.84 Ga (Wan et al ., ; Li et al ., ; Jiao et al ., ) while zircon in UHT granulites yielded metamorphic ages of 1.93–1.92 Ga (Santosh et al ., , ) and 1.88 Ga (Yang et al ., ). S‐type granites with a crystallization age of 1.92–1.90 Ga (Zhong et al ., ) as well as gabbronorites with intrusion age of c .…”

Section: Geological Settingmentioning

confidence: 99%

“…The U–Pb data have revealed several age groups including magmatism at c . 1.93 Ga (Peng et al ., ) and 1.92–1.90 Ga (Zhong et al ., ) and metamorphism at 1.98–1.96 Ga (Li et al ., ), 1.93–1.91 Ga (Santosh et al ., , ; Cai et al ., ) and 1.89–1.84 Ga (Wan et al ., ; Li et al ., ; Jiao et al ., ; Yang et al ., ). It still remains unknown why so many ages/events were recorded in the rocks of the Jining Group, especially whether the younger ages of 1.89–1.84 Ga were the result of a separate thermal overprint due to the collision between the Western and Eastern Blocks at c .…”

Section: Introductionmentioning

confidence: 99%

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Phase equilibria modelling and zircon age dating of pelitic granulites in Zhaojiayao, from the Jining Group of the Khondalite Belt, North China Craton

Wei

2016

Journal Metamorphic Geology

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The Jining Group occurs as the eastern segment of the Khondalite Belt, North China Craton and is dominated by a series of granulite facies rocks involving ‘normal’ pelitic granulites recording peak temperatures of ~850 °C and ultrahigh‐temperature (UHT) pelitic granulites recording peak temperatures of 950–1100 °C. The P–T paths and ages of these two types of granulites are controversial. Three pelitic granulite samples in the Jining Group comprising two sillimanite–garnet gneiss samples (J1208 and J1210) and one spinel–garnet gneiss sample (J1303) were collected from Zhaojiayao, where ‘normal’ pelitic granulites occur, for determination of their metamorphic evolution and ages. Samples J1208 and J1210 are interpreted to record cooling paths from the Tmax stages with P–T conditions respectively of ~870–890 °C/7–8 kbar and >840 °C/>7.5 kbar constrained from the stability fields of the observed mineral assemblages and the isopleths of plagioclase, garnet and biotite compositions in pseudosections. Sample J1303 is interpreted to record pre‐Tmax decompression from the kyanite‐stability fields to the Tmax stage of 950–1020 °C/8–9 kbar and a post‐Tmax cooling path revealed mainly from the stability field of the observed mineral assemblage, the plagioclase zoning and the biotite composition isopleth in pseudosections. The post‐Tmax cooling stage can be divided into suprasolidus and subsolidus stages. The suprasolidus cooling may not result in an equilibrium state at the solidus in a rock. Therefore, different minerals may record different P–T conditions along the cooling path; the inferred maximum temperature is commonly higher than the solidus as well as different solidi being recorded for different samples from the same outcrop but experiencing different degrees of melt loss. Plagioclase compositions, especially its zoning in plagioclase‐rich granulites, are predicted to be useful for recording the higher temperature conditions of a granulite's thermal history. The three samples studied seem to record the temperature range covering those of the ‘normal’ and UHT pelitic granulites in the Jining Group, suggesting that UHT conditions may be reached in ‘normal’ granulites without diagnostic UHT indicators. LA‐ICP‐MS zircon U–Pb data provide a continuous trend of concordant 207Pb/206Pb ages from 1.89 to 1.79 Ga for sample J1210, and from 1.94 to 1.80 Ga for sample J1303. These continuous and long age spectrums are interpreted to represent a slow cooling and exhumation process corresponding to the post‐Tmax cooling P–T paths recorded by the pelitic granulites, which may have followed the exhumation of deeply buried rocks in a thickened crust region resulted from a collision event at c. 1.95 Ga as suggested by the pre‐Tmax decompression P–T path.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 97%

Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Phase equilibria modelling and zircon age dating of pelitic granulites in Zhaojiayao, from the Jining Group of the Khondalite Belt, North China Craton

Wei

2016

Journal Metamorphic Geology

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“…The Khondalite Belt is characterized by the occurrence of both high‐pressure (HP) and medium‐pressure (MP) granulite facies rocks in the west (Yin et al., ; Zhao et al., , ), and sapphirine‐bearing ultrahigh‐temperature metamorphic rocks in the east (Guo et al., , ; Santosh, Tsunogae, et al., ). LA–ICP–MS and SHRIMP zircon U–Pb dating showed that the age of metamorphism was broadly 1.96–1.83 Ga (Dan et al., ; Jiao, Guo, Harley, & Peng, ; Jiao, Guo, Wang, & Peng, ; Jiao, Fitzsimons, & Guo, ; Santosh, Liu, Shi, & Liu, ; Santosh, Sajeev, Li, Liu, & Itaya, ; Santosh, Wilde, & Li, ; Wan et al., ; Yang, Santosh, & Tsunogae, ; Yin et al., , ; Zhao et al., ). Minor occurrences of TTG gneisses, garnet–cordierite S‐type granites, charnockites, and mafic granulites, have also been reported within the belt (Guo et al., ; Liu et al., ; Peng et al., ; Wan, Xie, et al., ; Yin et al., ; Zhai, ).…”

Section: Geological Settingmentioning

confidence: 99%

Ultrahigh‐temperature metamorphism in the Helanshan complex of the Khondalite Belt, North China Craton: Petrology and phase equilibria of spinel‐bearing pelitic granulites

Gou

Liu

et al. 2018

Journal Metamorphic Geology

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To better understand the formation of ultrahigh‐temperature (UHT) metamorphic rocks, we present a detailed petrological study of the recently discovered spinel‐bearing garnet–sillimanite granulites in the Helanshan complex of the Khondalite Belt in the North China Craton. In calculated P–T pseudosections, isopleths of grossular content in the peak assemblage field of garnet+K‐feldspar+sillimanite+spinel+ilmenite+quartz+melt suggest that the metamorphic peak occurred at ∼960–1,030°C and 6.3–7.3 kbar. Using ternary feldspar thermometry, a minimum temperature limit of the peak metamorphic conditions is calculated to be ∼910–955°C at 6.5 kbar, with a weighted mean of ∼940°C. Thus, all these results point to a very steep geothermal gradient well into the UHT field. In addition, a clockwise P–T evolution is determined, which involves pre‐Tmax decompression followed by nearly isobaric cooling. Based on these newly discovered UHT pelitic granulites, which do not contain index minerals typically considered diagnostic of UHT metamorphism, and the high‐P pelitic granulites exposed in the Helanshan and Qianlishan complexes, we propose that the Khondalite Belt is an ultrahot metamorphic orogen formed by collision between the Yinshan and Ordos Terranes. The style of this continental collision was rather different from Phanerozoic collisions, but was similar to the two‐sided hot collision model during the Proterozoic. Two‐sided hot collision involves shallow slab breakoff during collision, which leads to extension and the development of a wide plateau‐like orogen, which is underlain by melt‐bearing mantle that maintains a hot environment at the collision zone.

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Metamorphic evolution and tectonic significance of ultrahigh‐temperature mafic granulites in the southern part of the Shiguai area, Daqingshan, China

et al. 2019

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Ultrahigh-temperature (UHT) mafic granulites in the southern part of the Shiguai area in Daqingshan, China, crop out within the Shanheyuan Gneiss of the Khondalite Belt (KB), a Paleoproterozoic tectonic belt in the Western Block of the North China Craton (NCC). The UHT mafic granulites occur within hypersthene-bearing dioritic-granitic gneiss as irregular lenses and deformed dike swarms. Four metamorphic generation assemblages (M 1 -M 4 ) are recognized in the studied samples. M 1 is defined by the enclosed orthopyroxene and clinopyroxene within the "red eye" corona of the garnet, representing the prograde metamorphic stage. M 2 (UHT granulite-facies) is marked by the appearance of "red eye" corona of the garnet, with mineral assemblages of grt-cpx-opx-pl-ilm-q. M 3 is defined by spinel-rich symplectites between garnet and orthopyroxene, including grt-opx-pl-spl-mt-ilm. M 4 (amphibolite facies) is featured by the development of amphibole. Phase equilibrium modelling and some critical thermobarometers are combined to constrain the P-T evolution of the studied samples. The P-T conditions for the M 1 -M 4 are respectively estimated at~8 kbar/ 771-852°C,~9.4-10.0 kbar/~930-965°C,~5.0-5.4 kbar/~865-910°C,~5.0-5.2 kbar/~675-682°C, which define a clockwise P-T path, involving nearisothermal decompression following the peak metamorphism. The P-T path indicates that the rocks underwent a sequence of tectonothermal processes that started with crustal thickening (M 1 -M 2 ), followed by rapid crustal uplift (M 3 ) and cooling (M 4 ). This process is inferred that the metamorphism of the UHT mafic granulites was associated with rapid exhumation and uplift that followed the continent-continent collision and amalgamation of the Yinshan and Ordos blocks. This amalgamation formed the Paleoproterozoic KB in the Western Block of the NCC.

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Ultrahigh-temperature metamorphism under isobaric heating: New evidence from the North China Craton

Cited by 55 publications

References 70 publications

Phase equilibria modelling and zircon age dating of pelitic granulites in Zhaojiayao, from the Jining Group of the Khondalite Belt, North China Craton

Phase equilibria modelling and zircon age dating of pelitic granulites in Zhaojiayao, from the Jining Group of the Khondalite Belt, North China Craton

Ultrahigh‐temperature metamorphism in the Helanshan complex of the Khondalite Belt, North China Craton: Petrology and phase equilibria of spinel‐bearing pelitic granulites

Metamorphic evolution and tectonic significance of ultrahigh‐temperature mafic granulites in the southern part of the Shiguai area, Daqingshan, China

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