Publication detail

A Paleoproterozoic mantle source modified by subducted sediments under the North China craton

XU, C. CHAKHMOURADIAN, A. KYNICKÝ, J. LI, YX. SONG, W. CHEN, W.

Original Title

A Paleoproterozoic mantle source modified by subducted sediments under the North China craton

Type

journal article in Web of Science

Language

English

Original Abstract

Subduction is an effective mechanism for deep recycling of supracrustal rocks and mantle refertilization. However, the timing of the onset of modern-style deep subduction is debated. Here we report geochronogical and geochemical data for an intrusive suite of ultramafic, syenitic and carbonatitic rocks, a carbonatite-hosted peridotite xenolith, and granulites from the Paleoproterozoic Trans-North China orogen in the North China craton (NCC). The xenolith differs in composition from typical cratonic mantle peridotites. It equilibrated at T approximate to 1100 degrees C and P approximate to 29 kbar, i.e. under hotter conditions than cratonic mantle xenoliths worldwide. The carbonatites and associated alkaline rocks were emplaced at 1810 +/- 3 Ma and are related to the Paleoproterozoic collision between the Western and Eastern segments of the NCC. These intrusions show Sr-Nd isotope compositions consistent with an enriched mantle source [(Sr-87/Sr-86)(i) = 0.7027-0.7039; epsilon Nd-(t) = -4 to -6], and contain zircon characterized by unradiogenic Hf isotope compositions [epsilon Hf-(t) = -5 to -9] and high delta O-18(smow) values (7.9-9.5 parts per thousand). In contrast, basement granulites and wall-rock granites are enriched in radiogenic Nd and Hf isotopes, but low in O-18. These differences rule out the possibility of crustal contamination. Our results thus suggest that modern-style plate tectonics dates back at least to the Paleoproterozoic Era, and the post-collisional Paleoproterozoic alkaline magmatism in the NCC tapped mantle sources modified by deep sediment recycling.

Keywords

Paleoproterozoic alkaline rocks; Carbonatites; Orogenic belt; Mantle sources; Subducted sediments; Modern plate tectonics

Authors

XU, C.; CHAKHMOURADIAN, A.; KYNICKÝ, J.; LI, YX.; SONG, W.; CHEN, W.

Released

15. 1. 2019

ISBN

0016-7037

Periodical

Geochimica et cosmochimica acta

Year of study

245

Number

1

State

United States of America

Pages from

222

Pages to

239

Pages count

18

URL

https://www.sciencedirect.com/science/article/pii/S0016703718306185

BibTex

@article{BUT163439,
  author="XU, C. and CHAKHMOURADIAN, A. and KYNICKÝ, J. and LI, YX. and SONG, W. and CHEN, W.",
  title="A Paleoproterozoic mantle source modified by subducted sediments under the North China craton",
  journal="Geochimica et cosmochimica acta",
  year="2019",
  volume="245",
  number="1",
  pages="222--239",
  doi="10.1016/j.gca.2018.10.032",
  issn="0016-7037",
  url="https://www.sciencedirect.com/science/article/pii/S0016703718306185"
}