Minor and trace element variations in chromite from the Songshugou dunites, North Qinling Orogen: Evidence for amphibolite-facies metamorphism

Lithos ◽  
2019 ◽  
Vol 328-329 ◽  
pp. 146-158 ◽  
Author(s):  
Hong Yu ◽  
Hong-Fu Zhang ◽  
Hai-Bo Zou ◽  
Yue-Heng Yang
Keyword(s):  
Trace Element ◽  
Amphibolite Facies ◽  
Qinling Orogen ◽  
Facies Metamorphism ◽  
North Qinling

Geochronology of the transition of eclogite to amphibolite facies metamorphism in the North Qinling orogen of central China

Lithos ◽  
2011 ◽  
Vol 125 (3-4) ◽  
pp. 969-983 ◽  
Author(s):  
Hao Cheng ◽  
Chao Zhang ◽  
Jeffrey D. Vervoort ◽  
Xianhua Li ◽  
Qiuli Li ◽  
...  
Keyword(s):  
Amphibolite Facies ◽  
Central China ◽  
Qinling Orogen ◽  
The North ◽  
Facies Metamorphism ◽  
North Qinling

Zircon geochronology and trace element characteristics of eclogites and granulites from the Orlica-Śnieżnik complex, Bohemian Massif

2009 ◽  
Vol 147 (3) ◽  
pp. 339-362 ◽  
Author(s):  
MICHAEL BRÖCKER ◽  
REINER KLEMD ◽  
ELLEN KOOIJMAN ◽  
JASPER BERNDT ◽  
ALEXANDER LARIONOV
Keyword(s):  
Trace Element ◽  
Bohemian Massif ◽  
Trace Element Analysis ◽  
Amphibolite Facies ◽  
Zircon Geochronology ◽  
Metamorphic Zircon ◽  
Element Analysis ◽  
Large Variability ◽  
Facies Metamorphism ◽  
Eclogite Facies

AbstractU–Pb zircon geochronology and trace element analysis was applied to eclogites and (ultra)high-pressure granulites that occur as volumetrically subordinate rock bodies within orthogneisses of the Orlica-Śnieżnik complex, Bohemian Massif. Under favourable circumstances such data may help to unravel protolith ages and yet-undetermined aspects of the metamorphic evolution, for example, the time span over which eclogite-facies conditions were attained. By means of ion-probe and laser ablation techniques, a comprehensive database was compiled for samples collected from prominent eclogite and granulite occurrences. The 206Pb/238U dates for zircons of all samples show a large variability, and no single age can be calculated. The protolith ages remain unresolved due to the lack of coherent age groups at the upper end of the zircon age spectra. The spread in apparent ages is interpreted to be mainly caused by variable and possibly multi-stage Pb-loss. Further complexities are added by metamorphic zircon growth and re-equilibration processes, the unknown relevance of inherited components and possible mixing of different aged domains during analysis. A reliable interpretation of igneous crystallization ages is not yet possible. Previous studies and the new data document the importance of a Carboniferous metamorphic event at c. 340 Ma. The geological significance of this age group is controversial. Such ages have previously either been related to peak (U)HP conditions, the waning stages of eclogite-facies metamorphism or the amphibolite-facies overprint. This study provides new arguments for this discussion because, in both rock types, metamorphic zircon is characterized by very low total REE abundances, flat HREE patterns and the absence of an Eu anomaly. These features strongly suggest contemporaneous crystallization of zircon and garnet and strengthen interpretations proposing that the Carboniferous ages document late-stage eclogite-facies metamorphism, and not amphibolite-facies overprinting.

scholarly journals Rutile in Amphibolite Facies Metamorphic Rocks: A Rare Example from the East Qinling Orogen, China

2021 ◽  
Vol 11 (18) ◽  
pp. 8756
Author(s):  
Changming Wang ◽  
Shicheng Rao ◽  
Kangxing Shi ◽  
Leon Bagas ◽  
Qi Chen ◽  
...  
Keyword(s):  
Thin Layers ◽  
Amphibolite Facies ◽  
Central China ◽  
Metamorphic Rocks ◽  
Qinling Orogen ◽  
Critical Metal ◽  
Icp Ms ◽  
North Qinling ◽  
Increasing Demand ◽  
Zr In Rutile

Rutile is an important ore mineral to meet the increasing demand of critical metal Ti in various sectors. Here we report a rare example of rutile deposits hosted within the Baishugang–Wujianfang amphibolite-facies metamorphic rocks in the East Qinling Orogen, central China. The rutiles are mostly located within or along the margins of biotite and show 94.6 to 99 wt% TiO2. Rutiles occur as chains, thin layers along the foliation, and dense clusters. The grains are coexisted with magnetite. Based on Zr-in-rutile thermometer the estimated crystallisation temperature is at 630 °C at 7.0 kba. Based on Cr/Nb ratio, the source of the rutile is correlated with Ti-bearing silicate minerals such as biotite from aluminous sedimentary protoliths. The rutile deposit formed during lower amphibolite-facies metamorphism, and is distinct from the eclogite- and granulite-related types elsewhere in the orogen. The LA-ICP-MS U–Pb analyses of rutiles from the deposit yield lower intercept 238U/206Pb ages of 386 ± 16 Ma at the Baishugang–Wujianfang district. These ages correspond to a Devonian arc–continent collisional event between the South and North Qinling domains in the East Qinling Orogen.

DIVING DEEPER INTO THE PICURIS OROGEN: UPPER AMPHIBOLITE FACIES METAMORPHISM AND BRITTLE DEFORMATION ALONG THE PLOMO SHEAR ZONE

2020 ◽  
Author(s):  
Adrian E. Castro ◽  
◽  
Chloe Bonamici ◽  
Christopher G. Daniel ◽  
Danielle Shannon Sulthaus
Keyword(s):  
Shear Zone ◽  
Amphibolite Facies ◽  
Brittle Deformation ◽  
Facies Metamorphism

scholarly journals Metamorphic evolution and U-Pb zircon SHRIMP geochronology of the Belizário ultramafic amphibolite, Encantadas Complex, southernmost Brazil

2003 ◽  
Vol 75 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Léo A. Hartmann ◽  
João O.S. Santos ◽  
Jayme A.D. Leite ◽  
Carla C. Porcher ◽  
Neal J. Mcnaughton
Keyword(s):  
Ultramafic Rock ◽  
Greenschist Facies ◽  
Amphibolite Facies ◽  
Rio De La Plata ◽  
Metamorphic Evolution ◽  
Río De La Plata ◽  
La Plata ◽  
Shrimp Geochronology ◽  
Facies Metamorphism ◽  
Magnesian Basalt

The integrated investigation of metamorphism and zircon U-Pb SHRIMP geochronology of the Belizário ultramafic amphibolite from southernmost Brazil leads to a better understanding of the processes involved in the generation of the Encantadas Complex. Magmatic evidence of the magnesian basalt or pyroxenite protolith is only preserved in cores of zircon crystals, which are dated at 2257 ± 12 Ma. Amphibolite facies metamorphism M1 formed voluminous hornblende in the investigated rock possibly at 1989 ± 21 Ma. This ultramafic rock was re-metamorphosed at 702±21 Ma during a greenschist facies eventM2; the assemblage actinolite + oligoclase + microcline + epidote + titanite + monazite formed by alteration of hornblende. The metamorphic events are probably related to the Encantadas Orogeny (2257±12 Ma) and Camboriú Orogeny (~ 1989 Ma) of the Trans-Amazonian Cycle, followed by an orogenic event (702±21 Ma) of the Brasiliano Cycle. The intervening cratonic period (2000-700 Ma) corresponds to the existence of the Supercontinent Atlantica, known regionally as the Rio de la Plata Craton.

scholarly journals Zircon U–Pb Dating and Lu-Hf Isotope of the Retrograded Eclogite from Chicheng, Northern Hebei Province, China

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xu Kong ◽  
Xueyuan Qi ◽  
Wentian Mi ◽  
Xiaoxin Dong
Keyword(s):  
Regional Metamorphism ◽  
Granulite Facies ◽  
Amphibolite Facies ◽  
Metamorphic Event ◽  
Isotopic Data ◽  
Metamorphic Condition ◽  
Eu Anomaly ◽  
Facies Metamorphism ◽  
Eclogite Facies ◽  
Plagioclase Gneiss

We report zircon U–Pb ages and Lu-Hf isotopic data from two sample of the retrograded eclogite in the Chicheng area. Two groups of the metamorphic zircons from the Chicheng retrograded eclogite were identified: group one shows characteristics of depletion in LREE and flat in HREE curves and exhibit no significant Eu anomaly, and this may imply that they may form under eclogite facies metamorphic condition; group two is rich in HREE and shows slight negative Eu anomaly indicated that they may form under amphibolite facies metamorphic condition. Zircon Lu-Hf isotopic of εHf from the Chicheng eclogite has larger span range from 6.0 to 18.0, which suggests that the magma of the eclogite protolith may be mixed with partial crustal components. The peak eclogite facies metamorphism of Chicheng eclogite may occur at 348.5–344.2 Ma and its retrograde metamorphism of amphibolite fancies may occur at ca. 325.0 Ma. The Hongqiyingzi Complex may experience multistage metamorphic events mainly including Late Archean (2494–2448 Ma), Late Paleoproterozoic (1900–1734 Ma, peak age = 1824.6 Ma), and Phanerozoic (495–234 Ma, peak age = 323.7 Ma). Thus, the metamorphic event (348.5–325 Ma) of the Chicheng eclogite is in accordance with the Phanerozoic metamorphic event of the Hongqiyingzi Complex. The eclogite facies metamorphic age of the eclogite is in accordance with the metamorphism (granulite facies or amphibolite facies) of its surrounding rocks, which implied that the tectonic subduction and exhumation of the retrograded eclogite may cause the regional metamorphism of garnet biotite plagioclase gneiss.

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