Paleontological and magnetostratigraphic data on Upper Cretaceous deposits from borehole no. 8 (Russkaya Polyana District, Southwestern Siberia)

Lebedeva, N. K.; Александрова, Г. Н.; Шурыгин, Б. Н.; Ovechkina, Maria N.; Gnibidenko, Z.N.

doi:10.1134/s086959381301005x

Cited by 25 publications

(8 citation statements)

References 13 publications

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“…1a). This Upper Cretaceous-Palaeogene iron ore deposit occurs in subsurface at depth ranging from 165 m to 230 m (Belous et al 1964;Podobina and Kseneva 2005;Lebedeva et al 2013Lebedeva et al , 2017. The ore-bearing strata in Bakchar deposited in transgressive coastal and shallow marine environments, attaining a maximum thickness of 80 m ( Fig.…”

Section: Geological Settingmentioning

confidence: 99%

Ooidal ironstones in the Meso-Cenozoic sequences in western Siberia: assessment of formation processes and relationship with regional and global earth processes

Rudmin

Banerjee

Abdullayev³

et al. 2020

J. Palaeogeogr.

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This study investigates the process of formation of ooidal ironstones in the Upper Cretaceous-Paleogene succession in western Siberia. The formation of such carbonate-based ironstones is a continuing problem in sedimentary geology, and in this study, we use a variety of data and proxies assembled from core samples to develop a model to explain how the ooidal ironstones formed. Research on pyrite framboids and geochemical redox proxies reveals three intervals of oceanic hypoxia during the deposition of marine ooidal ironstones in the Late Cretaceous to the Early Paleogene Bakchar ironstone deposit in western Siberia; the absence of pyrite indicates oxic conditions for the remaining sequence. While goethite formed in oxic depositional condition, chamosite, pyrite and siderite represented hypoxic seawater. Euhedral pyrite crystals form through a series of transition originating from massive aggregate followed by normal and polygonal framboid. Sediments associated with goethite-chamosite ironstones, encompassing hypoxic intervals exhibit positive cerium, negative europium, and negative yttrium anomalies. Mercury anomalies, associated with the initial stages of hypoxia, correlate with global volcanic events. Redox sensitive proxies and ore mineral assemblages of deposits reflect hydrothermal activation. Rifting and global volcanism possibly induced hydrothermal convection in the sedimentary cover of western Siberia, and released iron-rich fluid and methane in coastal and shallow marine environments. This investigation, therefore, reveals a potential geological connection between Large Igneous Provinces (LIPs), marine hypoxia, rifting and the formation of ooidal ironstones in ancient West Siberian Sea.

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Section: Geological Settingmentioning

confidence: 99%

Ooidal ironstones in the Meso-Cenozoic sequences in western Siberia: assessment of formation processes and relationship with regional and global earth processes

Rudmin

Banerjee

Abdullayev³

et al. 2020

J. Palaeogeogr.

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show abstract

“…The Gan'kino Formation in the Well 8 section con tains abundant organic remains including dinocysts, spores, pollen, nannofossils, bivalves, ammonites, and gastropods [6]. In wells 10 and 2, this unit yields only palynological evidence.…”

Section: A Regional Upper Cretaceous Magnetostratigraphic Section Of mentioning

confidence: 99%

“…In all three sections, the Ipatovo Formation con tains a very impoverished dinocyst assemblage, which allows it to be dated presumably back to the Conia cian-Santonian [6]. Similar to the Pokur Formation, the Kuznetsovo and Ipatovo formations in the sections of wells 8, 10, and 2 are characterized by normal polar ity of the geomagnetic field with three short intervals of reversed magnetization.…”

mentioning

confidence: 92%

“…The marine sediments were dated by correlating them with the dinocyst scale [5] and palynomorph assemblages from reference sections of northwestern Europe. The upper, Maastrichtian part of the Well 8 section contains macrofaunal and nannoplankton remains [6]. The stratigraphic position of palynologi cal assemblages was determined by correlating them with the regional Cretaceous stratigraphic scales of West Siberia [7].…”

mentioning

confidence: 99%

“…The Pokur Formation is dated back to the Albian-Cenomanian with its upper part of the Well 8 belong ing, probably, to the Early Turonian [6]. In all three well sections, the unit is characterized by normal polarity of the geomagnetic field with two intervals of reversed magnetization.…”

mentioning

confidence: 99%

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