TY - JOUR

T1 - Callovian Ostracods of Central Dagestan

T2 - Biostratigraphy, Paleoecology, and Chorology

AU - Tesakova, E. M.

AU - Glinskikh, L. A.

PY - 2020/7/1

Y1 - 2020/7/1

N2 - Analysis of the distribution of ostracods from the Armkhi Formation (Callovian) of the Tsudakhar section (Central Dagestan) enabled the identification of a stratigraphic sequence of six assemblages determined by paleoecological conditions and the first ostracod-based biostratigraphic zonation of the Callovian of Dagestan. Beds with Pleurocythere khapissovi and the Neurocythere cruciata intermedia Zone of the European ostracod scales were identified in the middle Callovian; this facilitated the interregional correlation for ostracods. Paleoecological analysis demonstrated the formation of the lower part of the section (beds with P. khapissovi and the N. cruciata intermedia Zone) in the coastal zone of the upper subtidal with normal marine salinity, good aeration, and low sedimentation rates. Sediments of the upper part of the section (paleoecological intervals with Schuleridea translucida–Cytherella perennis and with C. perennis) accumulated in the lower zone of the upper subtidal with a high sedimentation rate, high (and constantly increasing) eutrophication, and lowered pH values. Analysis of the paleogeographic distribution of the species studied revealed the connections of the Caucasus Sea to Western and Eastern Europe and to Central Asia.

AB - Analysis of the distribution of ostracods from the Armkhi Formation (Callovian) of the Tsudakhar section (Central Dagestan) enabled the identification of a stratigraphic sequence of six assemblages determined by paleoecological conditions and the first ostracod-based biostratigraphic zonation of the Callovian of Dagestan. Beds with Pleurocythere khapissovi and the Neurocythere cruciata intermedia Zone of the European ostracod scales were identified in the middle Callovian; this facilitated the interregional correlation for ostracods. Paleoecological analysis demonstrated the formation of the lower part of the section (beds with P. khapissovi and the N. cruciata intermedia Zone) in the coastal zone of the upper subtidal with normal marine salinity, good aeration, and low sedimentation rates. Sediments of the upper part of the section (paleoecological intervals with Schuleridea translucida–Cytherella perennis and with C. perennis) accumulated in the lower zone of the upper subtidal with a high sedimentation rate, high (and constantly increasing) eutrophication, and lowered pH values. Analysis of the paleogeographic distribution of the species studied revealed the connections of the Caucasus Sea to Western and Eastern Europe and to Central Asia.

KW - biostratigraphy

KW - Callovian

KW - Central Dagestan

KW - chorology

KW - Middle Jurassic

KW - ostracods

KW - paleoecology

UR - http://www.scopus.com/inward/record.url?scp=85089032932&partnerID=8YFLogxK

U2 - 10.1134/S0869593820040097

DO - 10.1134/S0869593820040097

M3 - Article

AN - SCOPUS:85089032932

VL - 28

SP - 402

EP - 415

JO - Stratigraphy and Geological Correlation

JF - Stratigraphy and Geological Correlation

SN - 0869-5938

IS - 4

ER -