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

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F19%3APU136093" target="_blank" >RIV/00216305:26620/19:PU136093 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0016703718306185" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0016703718306185</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.gca.2018.10.032" target="_blank" >10.1016/j.gca.2018.10.032</a>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/LQ1601" target="_blank" >LQ1601: CEITEC 2020</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Geochimica et cosmochimica acta

ISSN

0016-7037

e-ISSN

1872-9533

Svazek periodika

245

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

18

Strana od-do

222-239

Kód UT WoS článku

000453771600013

EID výsledku v databázi Scopus

—