Sedimentology of the distal fan and lake deposits of the Tianshui-Qinan Basin (Central China): evidences against a possible eolian origin

• Autores: Ana María Alonso Zarza, C.H. Song, Jian Zhang, X. Wang, Yingchao Zhang
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 9, 2006 (Ejemplar dedicado a: VI Congreso del Grupo Español del Terciario), págs. 21-24
• Idioma: inglés
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• Resumen

  • In this paper we analyze twu sections within the Tianshui-Qinan, a closed basin in Central China. The deposits are Miocene and Pliocene in age and in recent times they have been considered as loess. The preliminary sedimentological study indicates a closed lacustrine basin, with a very flat topography in the inner parts. Periodical desiccation and subaerial exposure periods of both mudflats and shallow lakes caused important reworking of the sediments. The lake margins were ramp-like with different energy levels. Low energy lake margins are represented by marls, intraclastic and palustrine limestones, whereas higher energetic levels are indicated by rippled sands and silts.