Detrital zircon U-Pb dating and Hf isotope analyses of the Kabwelumu Formation, northeastern Zambia

被引：0

作者：

Xing S. ^{[1
]}

Ji S. ^{[1
]}

Wang J. ^{[2
]}

Ren J. ^{[2
]}

Liu Z. ^{[1
]}

Gu A. ^{[2
]}

Sun H. ^{[2
]}

Zhang J. ^{[1
]}

Liu C. ^{[1
]}

Zhang D. ^{[1
]}

机构：

[1] No. 5 Geological Team, Bureau of Geologic Exploration and Mineral Development of Hebei Province, Tangshan

[2] Tianjin Centre, China Geological Survey, Tianjin

来源：

Dizhi Xuebao/Acta Geologica Sinica | 2021年 / 95卷 / 04期

关键词：

Detrital zircon; Kabwelumu Formation; Northeastern Zambia; Provenance analysis; U-Pb dating and Hf isotope;

D O I：

10.19762/j.cnki.dizhixuebao.2021023

中图分类号：

学科分类号：

摘要：

As a stable sedimentary sequence coveringthe crystalline basement in northeastern Zambia, the Kabwelumu Formation is widely exposed in the center of Mporokoso basin. Therefore, its depositional age, provenance and sedimentary environment can provide important information for understanding of the crustal evolution. Based on our new detailed field geological mapping results, this paper reports geological profile characteristics, detrital zircons LA-ICP-MS U-Pb ages, and Hf isotope analysis of the Kabwelumu Formation. We show that theKabwelumu Formation is a set of sedimentary sequences that settled slowly under stable hydrodynamic conditions. The lower part is mainly characterized by braided river, meanderstream, river, or lacustrine delta facies, while the upper was gradually transformed into far shore deep-water lacustrine facies. The obtained detrital zircons range in age from 2228±20 to 1712±22Ma. The youngest detrital zircons and previously reported detrital zircons from the Kasama Group together define the sedimentary time limit of the Kabwelumu Formation, which may be between 1712±22Ma to 1434±14Ma, belonging to the Meso-Proterozoic. The detrital zircons of the Kabwelumu Formation show obvious proximal features and are mostly magmatic in origin, indicating that the provenance area is the proximal magmatic rock. The detrital zircon age of the Kabwelumu Formation and the sedimentary cover display two peaks at 2100 ~ 1960 Ma, 1900 ~ 1740 Ma, which is in agreement with the Usagaran stage and the Ubendian stage tectonic thermal events in the Ubendian regional tectonicbelt. The main provenance may be paleoproterozoic magmatic rocks, granitic gneiss and volcanic rock of Bangweulu Block. εHf(t) values are -8.9~+5.1 with corresponding TDM2 ages of 2.3~3.0 Ma, indicating that the basement complex of the Bangweulu block is mostly derived from re-melting and recycling of the ancient continental crust (~ 2.7Ga), and an accretion occurred at 2.4Ga, which is later than the Tanzania Craton. © 2021, Science Press. All right reserved.

引用

页码：1191 / 1211

页数：20

共 44 条

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