Modification of Archean cratons in southern Africa with foundered segments dropped into the shallow lower mantle

Xi, Jiaji1; Yu, Youqiang1; Zhao, Dapeng2; Hu, Jiashun3

2024-06-01

10.1130/G52023.1

GEOLOGY   影响因子和分区

0091-7613

1943-2682

Subducted slabs have been detected in the lower mantle for almost 30 years, yet the presence of foundered cratonic segments in the lower mantle is still unclear and inadequately investigated. We present the first P-wave radial anisotropy tomography of southern Africa (our model SA-RAnis2024), which reveals a contrasting feature of preserved northwest and modified southeast Kalahari cratonic root. Segments from the modified cratonic lithosphere are inferred to have dropped into the shallow lower mantle where seismic evidence of isolated high-velocity anomalies are observed. We detect such a high-velocity anomaly under the southwest margin of the Kalahari craton, which possibly detached from the southeast Zimbabwe craton at ca. 60 Ma based on plate reconstructions. Foundered segments can be partially brought back up to shallow depths, and contribute to the geochemical heterogeneity of younger lithosphere, through large-scale mantle convection.

SCI ; EI

英语

其他

National Natural Science Foundation of China["42374054","42074052"] ; National Key R&D Program of China[2023YFF0803202] ; Shanghai Rising-Star Program[22QA1409600]

Geology

Geology

WOS:001188289000001

GEOLOGICAL SOC AMER, INC

GEOSCIENCES

Web of Science

1.Tongji Univ, State Key Lab Marine Geol, Shanghai 200092, Peoples R China
2.Tohoku Univ, Grad Sch Sci, Dept Geophys, Sendai 9808578, Japan
3.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Peoples R China

Xi, Jiaji,Yu, Youqiang,Zhao, Dapeng,et al. Modification of Archean cratons in southern Africa with foundered segments dropped into the shallow lower mantle[J]. GEOLOGY,2024,52(6).

Xi, Jiaji,Yu, Youqiang,Zhao, Dapeng,&Hu, Jiashun.(2024).Modification of Archean cratons in southern Africa with foundered segments dropped into the shallow lower mantle.GEOLOGY,52(6).

Xi, Jiaji,et al."Modification of Archean cratons in southern Africa with foundered segments dropped into the shallow lower mantle".GEOLOGY 52.6(2024).