Ichnological and Sedimentological analisis of Meso-Cenozoic sediments of the Central Segment of Achara-Trialeti zone

Author: Zurab Lebanidze
Co-authors: Kakha Koiava, Otar Djaparidze
Annotation:

From paleoichnological viewpoint in Central segment of Achara-Trialeti fold zone has been interesting only Middle Eocene sedimentary series so far. Though during field trip 2013 in the paleocene part of “Borjomi suite” (Dabiskhevi subsuite) were for the first time defined two types of bioturbation – representatives of ichnogenera Chondrites Sternberg and Helicodromites Berger. Combination of Helicodromites and Chondrites traces are characteristic for distal marly and silty turbidites of fine-grained turbidite systems. At the same time, Chondrites are common especially in low-oxygen environments. In Middle Eocene ichnocomplexe we have determined complicated, spiral and meandering and combined traces, which belong to following ichnogenera: Helmintoida, Spiroraphe, Cosmoraphe, Taphrhelmintopsis, Spirophycus. The latter two are common for Eocene in Spain. Such complicated traces are related to facies, which correspond to biotops with stable environment and poor feeding supplies (deep sea bottom). All in all, the mentioned area of Paleocene-Lower Eocene basin of Borjomi district used to be a distal part of fine-grained turbidite system and was characterized by low-oxygen mode of sedimentation (Chondrites ichnofacies). In Middle Eocene this area, based on gained ichnological data, was a bottom of the deep sea. This coincides with supposition, that in Middle Eocene took place maximum rifting of Achara-Trialeti.

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აჭარა–თრიალეთის ზონის ცენტრალური სეგმენტის მეზო–კაინოზოური ნალექების იქნოლოგიური და სედიმენტოლოგიური ანალიზი [ka]