caa a22 4500 467934096 CHVBK 20180406152952.0 cr unu---uuuuu 170328e20061101xx s 000 0 eng 10.1007/s10347-006-0082-0 doi (NATIONALLICENCE)springer-10.1007/s10347-006-0082-0 Ichnology of Lower Jurassic beach deposits in the Shemshak Formation at Shahmirzad, southeastern Alborz Mountains, Iran [Elektronische Daten] [Franz Fürsich, Markus Wilmsen, Kazem Seyed-Emami] A 19m thick package of well-sorted lowermost Jurassic (Hettangian-Lower Sinemurian?) sandstones within the Shemshak Formation of the southeastern Alborz Mountains displays features characteristic of foreshore to upper shoreface environments such as tabular bedding, low-angle lamination, trough cross-stratification, parting lineation, and oscillation ripples. In contrast to most other beach successions recorded in the literature the sandstones contain a trace fossil assemblage characterised by low abundance but comparatively high diversity. The assemblage, comprising 14 ichnotaxa, is dominated by Palaeophycus heberti, Rhizocorallium irregulare, Gyrochorte comosa, and Parahaentzschelinia surlyki. Contrary to predictions, which assume a dominance of suspension-feeders in such high-energy environments, the trace fossil assemblage represents a variety of ethological groups ranging from suspension-feeders to deposit-feeders, detritus-feeders, scavengers, and a possible trap constructor (Ctenopholeus), whereby deposit-feeders predominate. This anomaly is explained by a high amount of organic detritus in the sediment, indicated by abundant plant material, and a position of the beach in the vicinity of a river mouth. Springer-Verlag, 2006 Jurassic nationallicence Shemshak Formation nationallicence Alborz Mountains nationallicence Trace fossils nationallicence Beach nationallicence Fürsich Franz Institut für Paläontologie der Universität Würzburg, Pleicherwall 1, 97070, Würzburg, Germany aut Wilmsen Markus Institut für Paläontologie der Universität Würzburg, Pleicherwall 1, 97070, Würzburg, Germany aut Seyed-Emami Kazem School of Mining Engineering, University College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran, Iran aut Facies Springer-Verlag 52/4(2006-11-01), 599-610 0172-9179 52:4<599 2006 52 10347 https://doi.org/10.1007/s10347-006-0082-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10347-006-0082-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fürsich Franz Institut für Paläontologie der Universität Würzburg, Pleicherwall 1, 97070, Würzburg, Germany aut NATIONALLICENCE 700 1- Wilmsen Markus Institut für Paläontologie der Universität Würzburg, Pleicherwall 1, 97070, Würzburg, Germany aut NATIONALLICENCE 700 1- Seyed-Emami Kazem School of Mining Engineering, University College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran, Iran aut NATIONALLICENCE 773 0- Facies Springer-Verlag 52/4(2006-11-01), 599-610 0172-9179 52:4<599 2006 52 10347 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer