Triassic Lacustrine Sedimentation from the Tanzhuang Formation, Jiyuan-Yima Basin, Southeastern China

• Autores: María Gabriela Mángano, Luis Alberto Buatois, Wu Xiantao, Sun Junmin, Zhang Guocheng
• Localización: Lake basins through space and time / coord. por Elizabeth H. Gierlowski-Kordesch, K. Kelts, 2000, ISBN 0891810528, págs. 133-139
• Idioma: inglés
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• Resumen

  • The Tanzhuang Formation represents the uppermost Triassic unit in the Iiyuan-Yima basin. It is well exposed southwest of Jiyuan City, western HenanProvince, central China (Figure 1). The Jiyuan-Yimabasin, which is part of the Ordos megabasin, containsabout 1500 m of Middle Triassic-Middle Jurassic continentalsediments. This basin is divided into two subbasins, Jiyuan and Yima, located north and southof the Yellow River, respectively. Stratigraphy and paleontologic content of the deposits have beensummarized by Zhou and Li (1980), Kang et a1.(1984, 1985), and Hu (1991) (Figure 2). Sedimentologic and stratigraphic evidence suggest that Jurassic sedimentation took place in a pull-apart basin(Buatois et aI., 1994a, this volume); however, the Triassictectonic framework is still poorly understood.Triassic deposits of the northern Jiyuan area andsouthern Yima area show significant changes in facies associations. These facies variations may have resulted from asymmetry of the basin. Triassic lacustrine sediments were most likely developed within apost-collisional intracratonic downwarp basin that formed as a result of early Indo-Sinian tectonic movements during the Middle Triassic. Strike-slip tectonismoccurred in the study area coincident with the Triassic-Jurassic boundary (cf. Wang, 1985; Manganoet aI., 1994; Buatois et aI., 1994a).