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Middle Turonian trace fossils from the Bystrzyca and Długopole sandstones in the Nysa Kłodzka Graben (Sudetes, SW Poland)

100%

Chrząstek A.

2013

tom Vol. 57, No. 3

443–-466

The Middle Turonian sediments of the Nysa Kłodzka Graben (Bystrzyca Sandstone in the Stara Bystrzyca outcrop and the Długopole Sandstone in Długopole Górne Quarry) contain trace fossils, which include Curvolithus simplex, ?Macaronichnus isp., Ophiomorpha nodosa, Ophiomorpha isp., Palaeophycus tubularis, Thalassinoides cf. paradoxicus, T. suevicus and Thalassinoides isp. The assemblage of trace fossils points to the proximal Cruziana ichnofacies, that characterizes the distal lower shoreface and the archetypal Cruziana ichnofacies, typical of upper offshore settings. The trace fossils evidence implies that sedimentation took place in a shallow basin with periods of a sudden sediment input, good oxygenation and normal salinity. The Bystrzyca and Długopole sandstones are deposits of the shallow epicontinental sea that were deposited between the fair-weather and storm-wave base, in the distal lower shoreface–upper offshore setting. The Bystrzyca Sandstone is recognized as storm-originated deposits, whereas the Długopole Sandstone is probably the part of prograding “accumulation terrace”. The source of material for the sandstone was the East Sudetic Island and probably also the Orlica–Bystrzyca Uplift. The studied sandstones are related to a regression that started in the early/middle Middle Turonian and caused a relative uplift of the surrounding land.

Jurassic tetrapod footprint ichnofaunas and ichnofacies of the Western Interior, USA

84%

Lockley M. , Gierlinski G.

tom Vol. 12, no. 2

133-150

The Jurassic tetrapod track record of the Western Interior, USA, is one of the most diverse, complete and well-studied in the world, spanning a relatively continuous representation of Lower, Middle and Upper Jurassic formations. Although a few of these formations, notably the Morrison Formation, have yielded abundant body fossils, the majority lack abundant skeletal remains and, while trackrich, are in some cases completely barren of body fossils. Thus, the track record assumes great importance as the most complete and representative record of changing tetrapod faunas through time in a region where the body fossil record is often sparse or absent. In the Lower and Middle Jurassic, many distinctive assemblages are associated with eolian units (Wingate, Navajo and Entrada) that are almost devoid of body fossils. However, the former two units are rich in synapsid tracks characterized as the Brasilichnium ichnofacies. In the Middle Jurassic, fluctuating sea-levels exerted important controls on the distribution of theropod and pterosaur-dominated ichnofaunas associated with coastal plain and marginal marine settings. The Morrison ichnofauna is a reliable reflection of the body fossil record of that formation. Ongoing efforts to group and classify the various tetrapod ichnofaunas into tetrapod ichnofacies and tetrapod biochron categories have, in some cases, provoked stimulating, if sometimes inconclusive, debate.