TY - JOUR

T1 - Stratigraphy, Lithology, and Geochemistry of Coastal and Shallow-Sea Sections of the Uppermost Middle Jurassic–the Lowermost Cretaceous Section in the Anabar River Region (Arctic Siberia)

AU - Nikitenko, B. L.

AU - Devyatov, V. P.

AU - Pestchevitskaya, E. B.

AU - Popov, A. Yu

AU - Fursenko, E. A.

AU - Khafaeva, S. N.

N1 - Funding Information: The research was financially supported by the Russian Science Foundation (Grants Nos. 18-17-00038 and 19-17-00091) and the Russian Foundation for Basic Research (Grant No. 18-05-70035, 20-05-00076). Publisher Copyright: © 2022, Novosibirsk State University.

PY - 2022/5

Y1 - 2022/5

N2 - Concepts of the stratigraphy of the coastal and shallow-sea sections of the uppermost Middle Jurassic and Lower Cretaceous, exposed on the right bank of the Anabar River, have radically changed many times. The performed study and analysis of the published data are aimed at refining the bio-and lithostratigraphic subdivision of the section, substantiating its stratigraphic completeness, and describing the identified stratigraphic units in detail. Comprehensive biostratigraphic studies of the uppermost Bathonian — the lowermost Boreal Berriasian reveal a sequence of nine biostratigraphic units with dinocysts and palynoflora in the ranks of zones and local zones. Some of the palynological biostratigraphic units have been identified for the first time. Foraminiferal assemblages of the boreal standard zones are recorded in the sections under study. The obtained biostratigraphic data and analysis of all known ammonite occurrences make it possible to demonstrate the stratigraphic continuity of the section in the Anabar River region, despite the reduced thickness of the stratigraphic units. The stratigraphic position of the boundary between the Sodiemykha and Buolkalakh formations is accurately defined. According to the interpretation proposed, the basal horizon of the Buolkalakh Formation is associated with a beginning of a new major sedimentation stage in the late Oxfordian–early Kimmeridgian, identified as the lower boundary of lithostratigraphic units of different ranks throughout the entire Arctic Region and partially in the Boreal Region. The lithogeochemical parameters of the studied formations are obtained for the first time. The content of Corg in the studied samples does not exceed its Clarke values, and the pyrolytic parameter Tmax indicates that the organic matter is immature and the petroleum potential is low. The considered organic matter of the rocks is characterized by a heavy isotope composition of carbon, suggesting its mostly terrigenous genesis.

AB - Concepts of the stratigraphy of the coastal and shallow-sea sections of the uppermost Middle Jurassic and Lower Cretaceous, exposed on the right bank of the Anabar River, have radically changed many times. The performed study and analysis of the published data are aimed at refining the bio-and lithostratigraphic subdivision of the section, substantiating its stratigraphic completeness, and describing the identified stratigraphic units in detail. Comprehensive biostratigraphic studies of the uppermost Bathonian — the lowermost Boreal Berriasian reveal a sequence of nine biostratigraphic units with dinocysts and palynoflora in the ranks of zones and local zones. Some of the palynological biostratigraphic units have been identified for the first time. Foraminiferal assemblages of the boreal standard zones are recorded in the sections under study. The obtained biostratigraphic data and analysis of all known ammonite occurrences make it possible to demonstrate the stratigraphic continuity of the section in the Anabar River region, despite the reduced thickness of the stratigraphic units. The stratigraphic position of the boundary between the Sodiemykha and Buolkalakh formations is accurately defined. According to the interpretation proposed, the basal horizon of the Buolkalakh Formation is associated with a beginning of a new major sedimentation stage in the late Oxfordian–early Kimmeridgian, identified as the lower boundary of lithostratigraphic units of different ranks throughout the entire Arctic Region and partially in the Boreal Region. The lithogeochemical parameters of the studied formations are obtained for the first time. The content of Corg in the studied samples does not exceed its Clarke values, and the pyrolytic parameter Tmax indicates that the organic matter is immature and the petroleum potential is low. The considered organic matter of the rocks is characterized by a heavy isotope composition of carbon, suggesting its mostly terrigenous genesis.

KW - Anabar River

KW - Arctic Siberia

KW - dinoflagellate cysts

KW - foraminifers

KW - lithogeochemistry

KW - organic geochemistry

KW - spores and pollen

KW - stratigraphy

KW - Upper Jurassic and Lower Cretaceous

UR - http://www.scopus.com/inward/record.url?scp=85140394228&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/84031560-1257-3172-a5c2-8e2499e8f0ab/

U2 - 10.2113/RGG20204262

DO - 10.2113/RGG20204262

M3 - Article

AN - SCOPUS:85140394228

VL - 63

SP - 558

EP - 589

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 5

ER -