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Partitioned Pathways, Unified Sibumasu Depocenter: Gondwanan Tectono-Climatic Rerouting From West Malaya's Detrital Record
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DOI:10.1029/2025TC009062.png)
Abstract
En 中文
Peripheral terranes are often assumed to mirror adjacent continental detrital zircon sources. However, the peri-Gondwanan Sibumasu terrane exhibits two distinct zircon signatures-traditionally interpreted as separate basins fed by different sedimentary pathways (Australia or India). This conceptual shortcut bypasses the labyrinthine reality of source-sink relationships, necessitating refined sediment dispersal reconstructions. Crucially, West Malaya-strategically located in the middle of Sibumasu terrane-provides key insights into resolving this structural conundrum. Two Cambrian samples in West Malaya reveal coeval detrital contributions from India and Australia. But by mid-Paleozoic, Northwestern domain strata are dominated by 1.0-0.7 Ga Indian zircons, contrasting with the Southeastern domain 1.3-1.0 Ga Australian sources. Volcaniclastic sediments with Early Ordovician (480-460 Ma) zircon population demarcate these provenance shifts. The distinct source of these diverging transport pathways mid-Paleozoic are further corroborated by dissimilar TDM2 (Hf) model ages (2.1 vs. 1.8 Ga) and dissimilar normalized alpha-dose values (Ectasian to Stenian and Ediacaran to Cambrian age populations) between the Northwestern and Southeastern domains. The abrupt mid-Paleozoic provenance disparity following Cambrian mixing suggests an absence of local structural or geomorphic controls within Sibumasu and implies a single, cohesive sink region. Rather than fragmentation into sub-basins, these shifts record evolving Gondwanan tectonic dynamics and paleoclimate that progressively redirected two distinct sediment dispersal systems from their continental sources (India and Australia) into a unified depocenter.
Keywords:
detrital zircon
U-Pb geochronology
East Gondwana
southeast Asia
sediment transport
Paleozoic
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