Provenance and Paleogeographic Evolution of the Upper Paleozoic–Lower Mesozoic Strata in Northern Laos.
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| Title: | Provenance and Paleogeographic Evolution of the Upper Paleozoic–Lower Mesozoic Strata in Northern Laos. |
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| Authors: | Jin, Jingjie1 (AUTHOR), Qian, Xin1 (AUTHOR) qianx3@mail.sysu.edu.cn, Senebouttalath, Vongpaseuth2 (AUTHOR), Zhang, Yuzhi1 (AUTHOR), Wang, Yuejun1 (AUTHOR) |
| Source: | Journal of Earth Science. Jun2025, Vol. 36 Issue 3, p861-879. 19p. |
| Subject Terms: | *Clastic rocks, *Back-arc basins, *Earth sciences, *Sedimentary rocks, *Watersheds |
| Geographic Terms: | Laos |
| Abstract: | The Late Paleozoic–Early Mesozoic sedimentary system of the Luang Prabang Paleotethyan back-arc basin in northern Laos is important for investigating sedimentary provenance, paleogeographic patterns, and the tectonic evolution of the eastern Paleotethyan Ocean. This study presents systematic stratigraphy, petrology, geochemistry, and detrital zircon U-Pb-Hf isotopic analyses for the Late Carboniferous–Jurassic sedimentary strata on both sides of the Luang Prabang Basin. Based on distinct stratigraphic ages and provenance characteristics, the clastic rock samples can be divided into four groups. The Group 1 Late Carboniferous–Early Permian samples from the western part of the basin yield detrital zircon age-peaks of ∼348 and ∼1 425 Ma, with corresponding εHf(t) values ranging from −2.0 to +15.5 and +1.5 to +14, respectively. The age spectrum of Group 2 Late Carboniferous–Early Permian samples from the eastern part of the basin shows major age-peaks of ∼287 and ∼1 860 Ma, with εHf(t) values of −5.9–−0.9 and −3.6–+4.2, respectively. Group 3 Late Permian–Triassic samples exhibit age-peaks of ∼242 and ∼1 853 Ma, along with εHf(t) values of −0.7–+14.4 and −5.4–−1.8, respectively. Group 4 Middle–Late Jurassic samples yield age-peaks of ∼237, ∼431, ∼813, ∼1 833, and ∼2 460 Ma, lacking Late Devonian (413–345 Ma) detrital zircons. All these data collectively suggest that the Group 1 sample primarily originated from the Sukhothai arc in western Indochina, Group 2 was from the Kontum and Truong Son in eastern Indochina, and Group 3 has a combined provenance of the Sukhothai, Kontum, and Truong Son. Regional comparisons suggest that the Jurassic provenance was mainly derived from South China, which was imported through the northern river system. Our data, combined with the regional angular unconformities between the Jurassic continental strata and pre-Jurassic marine strata, suggest that the Luang Prabang Basin transformed into a superimposed collisional retroforeland basin during the Jurassic, and the closure of the Luang Prabang BAB occurred before the Late Triassic. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
| Abstract: | The Late Paleozoic–Early Mesozoic sedimentary system of the Luang Prabang Paleotethyan back-arc basin in northern Laos is important for investigating sedimentary provenance, paleogeographic patterns, and the tectonic evolution of the eastern Paleotethyan Ocean. This study presents systematic stratigraphy, petrology, geochemistry, and detrital zircon U-Pb-Hf isotopic analyses for the Late Carboniferous–Jurassic sedimentary strata on both sides of the Luang Prabang Basin. Based on distinct stratigraphic ages and provenance characteristics, the clastic rock samples can be divided into four groups. The Group 1 Late Carboniferous–Early Permian samples from the western part of the basin yield detrital zircon age-peaks of ∼348 and ∼1 425 Ma, with corresponding εHf(t) values ranging from −2.0 to +15.5 and +1.5 to +14, respectively. The age spectrum of Group 2 Late Carboniferous–Early Permian samples from the eastern part of the basin shows major age-peaks of ∼287 and ∼1 860 Ma, with εHf(t) values of −5.9–−0.9 and −3.6–+4.2, respectively. Group 3 Late Permian–Triassic samples exhibit age-peaks of ∼242 and ∼1 853 Ma, along with εHf(t) values of −0.7–+14.4 and −5.4–−1.8, respectively. Group 4 Middle–Late Jurassic samples yield age-peaks of ∼237, ∼431, ∼813, ∼1 833, and ∼2 460 Ma, lacking Late Devonian (413–345 Ma) detrital zircons. All these data collectively suggest that the Group 1 sample primarily originated from the Sukhothai arc in western Indochina, Group 2 was from the Kontum and Truong Son in eastern Indochina, and Group 3 has a combined provenance of the Sukhothai, Kontum, and Truong Son. Regional comparisons suggest that the Jurassic provenance was mainly derived from South China, which was imported through the northern river system. Our data, combined with the regional angular unconformities between the Jurassic continental strata and pre-Jurassic marine strata, suggest that the Luang Prabang Basin transformed into a superimposed collisional retroforeland basin during the Jurassic, and the closure of the Luang Prabang BAB occurred before the Late Triassic. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 1674487X |
| DOI: | 10.1007/s12583-024-0011-6 |
