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Paragneiss zircon geochronology and trace element geochemistry, North Qaidam HP/UHP terrane, western China

Journal of Asian Earth Sciences

By:
, , , and
DOI: 10.1016/j.jseaes.2008.12.007

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Abstract

In the southeastern part of the North Qaidam terrane, near Dulan, paragneiss hosts minor peridotite and UHP eclogite. Zircon geochronology and trace element geochemistry of three paragneiss samples (located within a ???3 km transect) indicates that eclogite-facies metamorphism resulted in variable degrees of zircon growth and recrystallization in the three samples. Inherited zircon core age groups at 1.8 and 2.5 Ga suggest that the protoliths of these rocks may have received sediments from the Yangtze or North China cratons. Mineral inclusions, depletion in HREE, and absence of negative Eu anomalies indicate that zircon U-Pb ages of 431 ?? 5 Ma and 426 ?? 4 Ma reflect eclogite-facies zircon growth in two of the samples. Ti-in-zircon thermometry results are tightly grouped at ???660 and ???600 ??C, respectively. Inclusions of metamorphic minerals, scarcity of inherited cores, and lack of isotopic or trace element inheritance demonstrate that significant new metamorphic zircon growth must have occurred. In contrast, zircon in the third sample is dominated by inherited grains, and rims show isotopic and trace element inheritance, suggesting solid-state recrystallization of detrital zircon with only minor new growth. ?? 2009 Elsevier Ltd.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Paragneiss zircon geochronology and trace element geochemistry, North Qaidam HP/UHP terrane, western China
Series title:
Journal of Asian Earth Sciences
DOI:
10.1016/j.jseaes.2008.12.007
Volume
35
Issue:
3-4
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Asian Earth Sciences
First page:
298
Last page:
309