Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Annales Societatis Geologorum Poloniae

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Ichnotaxonomy

Sortuj według:

Ogranicz wyniki do:

Pioneer colonization, evidenced by Rhizocorallium in the Middle Triassic of Poland

Stachacz Michał

Annales Societatis Geologorum Poloniae

2023

Vol. 93, No. 4

363--379

A large collection of the trace fossil Rhizocorallium from the Middle Triassic of the Polish part of the Germanic Basin (Peri-Tethys) is analysed and their ichnotaxonomical classification presented. Special attention is given to the deep form of Rhizocorallium with a vertical retrusive spreite, filled with faecal pellets, with detailed documentation of this structure, based on isolated specimens and serial sections. This analysis also reveals ∩-shaped and deep, protrusive structures. A former interpretation of Rhizocorallium as a rapidly formed fugichnion is not followed here; instead, an interpretation of the trace fossil as a complex fodinichnion is proposed. Scavengers and their relation to crinoid meadows, as well as predators, are indicated as potential tracemakers of some Rhizocorallium. Although Rhizocorallium is common throughout the Middle Triassic, unusual forms and the domination of substrates by Rhizocorallium in general mostly occur in the transgressive system of the lowermost Muschelkalk, and in regressive, marginal facies of the lower Keuper. Such a distribution of unusual forms of Rhizocorallium is interpreted as representing opportunistic, pioneer burrow assemblages that developed during the long-term benthic recovery after the P-T crisis, or in unfavourable conditions generally. Moreover, dynamic conditions with mixed clastic-carbonate sedimentation and rapidly varying salinity promoted smooth transitions from Rhizocorallium to Diplocraterion. Similar successions of dominant trace-fossil assemblages, of comparable sizes, occur in many sections around the world and demonstrate the record of slow recovery that continued through the Middle Triassic. The illustrated record of evolution of the Middle Triassic Rhizocorallium assemblages in Poland documents the last two stages of benthos recovery after the P-T boundary. A similar situation is observed around the world and, in many cases, great abundance of Rhizocorallium seems to be an indication of pioneer burrowing in dynamic, unfavourable environments.

Synaptichnium tracks from the middle Muschelkalk (Middle Triassic, Anisian) Bernburg site (Saxony-Anhalt, Germany)

Marchetti Lorenzo, Klein Hendrik, Falk Daniel, Wings Oliver

Annales Societatis Geologorum Poloniae

2020

Vol. 90, No. 3

321--330

The Solvay Quarry of Bernburg is one of the most important ichnosites from the Muschelkalk of the Germanic Basin. Extensive surfaces with long chirotheriid trackways have been discovered and assigned to Chirotherium and Isochirotherium. Some undescribed step cycles from this site are analysed here and assigned to Synaptichnium isp. These footprints belong to a “thick-digit” Synaptichnium morphotype recognised at several Middle Triassic sites of Pangaea that seems to differ from the currently valid Synaptichnium ichnospecies. This is the first occurrence of Synaptichnium from this site and the only including step cycles one from the track-bearing Muschelkalk successions of N Germany and the Netherlands. A comparison between the tetrapod ichnoassociations of marginal marine and alluvial units of the Muschelkalk of the Germanic Basin reveals a similar ichnofaunal composition but different relative proportions between ichnotaxa. Rhynchosauroides and Procolophonichnium occur more often in tidal units, whereas the alluvial units show a higher abundance of chirotheriid tracks and an overall greater track diversity.