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The miniature echinoid trace fossil Bichordites kuzunensis isp. nov. from early Oligocene prodelta sediments of the Mezardere Formation, Gokceada Island, NW Turkey

Demircan H., Uchman A.

Acta Geologica Polonica

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2012

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Vol. 62, no. 2

205-215

EN

The pascichnial trace fossil Bichordites kuzunensis isp. nov. occurs as an epichnial complex structure in early Oligocene prodelta sediments of the Thrace Basin in Gokceada Island, northwest Turkey. It displays characteristics of irregular echinoid burrows such as overall shape and a double meniscate filling with a chevron dorsal suture, in addition to the feature typical of the so far monospecific Bichordites Plaziat and Mahmoudi, 1988, that is a single central core around a single drainage tube. Its miniature size can be related to the small size of the tracemaker (ontogenic feature) or to its dwarfism in a stressed deltaic environment (palaeoecological feature). Its occurrence indicates a period of fully marine conditions during accumulation of the deltaic sediments of the Mezardere Formation.

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Kiss of death of a hunting fish : trace fossil Osculichnus labialis igen. et isp. nov. from late Eocene - early Oligocene prodelta sediments of the Mezardere Formation, Thrace Basin, NW Turkey

Demircan H., Uchman A.

Acta Geologica Polonica

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2010

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Vol. 60, no. 1

29-38

EN

The trace fossil Osculichnus labialis igen. et isp. nov. occurs as hypichnial pairs of uneven bilobate mounds in early Oligocene prodelta sediments of the Thrace Basin. Osculichnus is generally elliptical or crescentic in outline and has two lip-like lobes: a smaller and a larger one, which are separated by an undulate furrow. Herein, it is interpreted as a hunting trace (praedichnion) of a fish penetrating a surficial sand layer and into an underlying mud horizon. The fish hunted for small endobenthic bivalves and perhaps other invertebrates such as polychaetes. Penetration into surficial mud rather than sand resulted in poorly preserved variants of this trace fossil, whose median furrow is commonly not visible. The probability of fish trace makers is supported by experiments.

3

Trace fossils of Miocene deep-sea fan fringe deposits from the Cingöz Formation, southern Turkey

Uchman A., Demircan H.

Annales Societatis Geologorum Poloniae

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1999

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Vol. 69, No. 3-4

125--135

EN

Fan fringe deposits of deep-sea fans are characterised by the Nereites ichnofacies, but in the Miocene Cingöz Formation in southern Turkey they contain 17 ichnospecies typical of the Nereites, Skolithos and Cruziana ichnofacies, including vertical "shallow-water" horn-like forms and Ophiomorpha rudis. Tracemakers of Ophiomorpha rudis have been probably imported by stronger turbidity currents from the inner part of deep-sea fan or occured as a result of gradual colonisation of fan fringe deposits. Similar trace-fossils occurs in related facies of the coeval Marnoso-arenacea Formation in the Northern Apennines. Comparisons with other Cretaceous-Neogene flysch formations show that ichnoassemblages of fan fringe facies are very diverse in general.

PL

Ichnofacja Nereites charakteryzuje utwory otoczenia stożka głębokomorskiego, jednak w utworach otoczenia stożka mioceńskiej formacji Cingöz w południowej Turcji występuje 17 ichnogatunków z ichnofacji Nereites, Skolithos i Cruziana, w tym "płytkowodne" formy w kształcie rogu oraz formy z gatunku Ophiomorpha rudis. Twórcy śladów Ophiomorpha rudis byli prawdopodobnie transportowani przez silniejsze prądy zawiesinowe z wewnętrznej części stożka, lub zasiedlali oni stopniowo środowisko otoczenia stożka. Podobne skamieniałości śladowe występują w pokrewnych facjach równowiekowej formacji Marnoso-arenacea z Apeninów Północnych. Facje otoczenia stożków innych kredowo-paleogeńskich formacji fliszowych charakteryzują się bardzo zróżnicowanymi asocjacjami skamieniałości śladowych.