Paleo-Asian oceanic slab under the North China craton revealed by carbonatites derived from subducted limestones
Foley, Stephen F.
Ducea, Mihai N.
AffiliationDepartment of Geosciences, University of Arizona
MetadataShow full item record
PublisherGEOLOGICAL SOC AMER, INC
CitationPaleo-Asian oceanic slab under the North China craton revealed by carbonatites derived from subducted limestones 2016, 44 (12):1039 Geology
Rights© Geological Society of America
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AbstractIt is widely accepted that the lithospheric mantle under the North China craton (NCC) has undergone comprehensive refertilization due to input from surrounding subducted slabs. However, the possible contribution from the Paleo-Asian oceanic slab to the north is poorly constrained, largely because of the lack of convincing evidence for the existence of this slab under the NCC. We report here carbonatite intruding Neogene alkali basalts in the Hannuoba region, close to the northern margin of the NCC. Trace element patterns with positive Sr and U anomalies, negative high field strength elements (Nb, Ta, Zr, Hf, and Ti) and Ce anomalies, high Sr-87/Sr-86 ratios (0.70522-0.70796), and high delta O-18(SMOW) (standard mean ocean water) values (22.2%-23%) indicate that this carbonatite had a limestone precursor. However, the presence of coarse-grained mantle-derived clinopyroxene, orthopyroxene, and olivine, and chemical features of the carbonates suggest that the carbonate melts were derived from the mantle. The carbonates have high Nd-143/Nd-144 ratios (0.51282-0.51298) and show negative correlation between CaO and Ni contents, resulting from reaction between carbonate melt and peridotite. Considering the regional tectonic setting, the carbonatite probably formed by melting of subducted sedimentary carbonate rocks that formed part of the Paleo-Asian oceanic slab, and thus could provide the first direct evidence for the presence of the Paleo-Asian oceanic slab beneath the NCC.
Note12 month embargo; first published online October 2016.
VersionFinal accepted manuscript
SponsorsNational Science Foundation of China [41530211, 41125013, 90914007]; Ministry of Science and Technology of China [2013CB429806]; State Administration of Foreign Expert Affairs of China [B07039]; Specialized Research Fund for the Doctoral Program of Higher Education ; Ministry of Science and Technology Special Funds of the State Key Laboratory of Geological Processes and Mineral Resources (China University of Geosciences)