High-Frequency Oolitic Tidal Cycles and Their Geochemical Signatures in the Upper Ediacaran Qigebulake Formation, NW Tarim Basin (China)
Year: 2025
Type: article
Abstract: The Qigebulake Formation in the northwestern Tarim Basin records high-frequency oolitic tidal flat cycles formed during the Upper Ediacaran, a period marked by tectonic, volcanic, and hydrothermal events. This study presents a detailed petrographic and geochemical characterization of these cycles, focusing on their lithofacies development and implications for regional geological processes. Seven microfacies were identified, ranging from oolitic dolostone and dolothrombolite to siliciclastic dolomudstone and mudstone. Elemental trends indicate a systematic decline in SiO2, Al2O3, and TiO2 content with decreasing siliciclastic input, suggesting a shallowing-upward sequence. Volcaniclastic quartz grains, exhibiting embayed textures and bright-blue cathodoluminescence, are reported here for the first time in the Ediacaran of Tarim, supporting synsedimentary volcanic input. Positive δEu anomalies, coupled with low Al/(Al+Fe+Mn) and elevated Fe2O3/TiO2 and MnO/TiO2 ratios, reveal hydrothermal influence in upper-cycle dolostones. These signatures, combined with regional stratigraphy, suggest that the Qigebulake tidal flat records the interplay between deposition, volcanism, and fluid migration during the late Ediacaran. The findings provide new constraints on the evolution of peritidal environments and inform deep carbonate reservoir assessments in Tarim and similar cratonic basins.
Source: Minerals
DOI: 10.3390/min15060613
Authors: Yan Hao, Shaonan Zhang
Institutions: Sinopec (China), Southwest Petroleum University
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
OpenAlex ID: W4411092791