Origin of ooidal ironstones in relation to warming events: Cretaceous-Eocene Bakchar deposit, south-east Western Siberia

Maxim Rudmin, Aleksey Mazurov, Santanu Banerjee

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

An integrated study involving petrographical, mineralogical and geochemical investigations proposes the origin of the Bakchar ironstone deposit by upward migration of a mixture of Fe-rich brine and hydrothermal fluid through marine sediments. Trace element concentrations of the ironstone deposits rule out continental derivation of Fe, while high REE concentrations indicate mixed hydrogeneous and hydrothermal source. Three main types of ironstone within the Bakchar deposit are characterized by distinct mineralogical assemblage of authigenic minerals corresponding to oxic, methanic and weakly sulfidic dysoxic conditions. Changing redox conditions of the depositional environment, methane seepage in warm seawater and availability of iron influx possibly determined the final mineralogy of three varieties of ironstones. The association of siderite with ferrimagnetic sulfides like greigite and pyrrhotite in type-1 ore indicate anaerobic oxidation of methane with limited bacterial sulfate reduction. The ironstone deposits of Narym, Kolpashevo and Bakchar are contemporaneous with geological events like ocean anoxic event 3 (OAE-3), Cretaceous-Paleogene (K-Pg) boundary and Palaeocene-Eocene Thermal Maximum (PETM), respectively, all corresponding to warm seawater conditions.

Original languageEnglish
Pages (from-to)309-325
Number of pages17
JournalMarine and Petroleum Geology
Volume100
DOIs
Publication statusPublished - 1 Feb 2019

Fingerprint

ironstone
Siberia
Eocene
warming
deposits
Cretaceous
heating
methane
minerals
siderites
seepage
pyrrhotite
greigite
seawater
mineralogy
authigenic mineral
trace elements
Hypsithermal
availability
siderite

Keywords

  • Bakchar deposit
  • Geochemistry
  • Mineralogy
  • Ooidal ironstones
  • Western Siberia

ASJC Scopus subject areas

  • Oceanography
  • Geophysics
  • Geology
  • Economic Geology
  • Stratigraphy

Cite this

@article{01acfe092a54428d853a688215e27110,
title = "Origin of ooidal ironstones in relation to warming events: Cretaceous-Eocene Bakchar deposit, south-east Western Siberia",
abstract = "An integrated study involving petrographical, mineralogical and geochemical investigations proposes the origin of the Bakchar ironstone deposit by upward migration of a mixture of Fe-rich brine and hydrothermal fluid through marine sediments. Trace element concentrations of the ironstone deposits rule out continental derivation of Fe, while high REE concentrations indicate mixed hydrogeneous and hydrothermal source. Three main types of ironstone within the Bakchar deposit are characterized by distinct mineralogical assemblage of authigenic minerals corresponding to oxic, methanic and weakly sulfidic dysoxic conditions. Changing redox conditions of the depositional environment, methane seepage in warm seawater and availability of iron influx possibly determined the final mineralogy of three varieties of ironstones. The association of siderite with ferrimagnetic sulfides like greigite and pyrrhotite in type-1 ore indicate anaerobic oxidation of methane with limited bacterial sulfate reduction. The ironstone deposits of Narym, Kolpashevo and Bakchar are contemporaneous with geological events like ocean anoxic event 3 (OAE-3), Cretaceous-Paleogene (K-Pg) boundary and Palaeocene-Eocene Thermal Maximum (PETM), respectively, all corresponding to warm seawater conditions.",
keywords = "Bakchar deposit, Geochemistry, Mineralogy, Ooidal ironstones, Western Siberia",
author = "Maxim Rudmin and Aleksey Mazurov and Santanu Banerjee",
year = "2019",
month = "2",
day = "1",
doi = "10.1016/j.marpetgeo.2018.11.023",
language = "English",
volume = "100",
pages = "309--325",
journal = "Marine and Petroleum Geology",
issn = "0264-8172",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Origin of ooidal ironstones in relation to warming events

T2 - Cretaceous-Eocene Bakchar deposit, south-east Western Siberia

AU - Rudmin, Maxim

AU - Mazurov, Aleksey

AU - Banerjee, Santanu

PY - 2019/2/1

Y1 - 2019/2/1

N2 - An integrated study involving petrographical, mineralogical and geochemical investigations proposes the origin of the Bakchar ironstone deposit by upward migration of a mixture of Fe-rich brine and hydrothermal fluid through marine sediments. Trace element concentrations of the ironstone deposits rule out continental derivation of Fe, while high REE concentrations indicate mixed hydrogeneous and hydrothermal source. Three main types of ironstone within the Bakchar deposit are characterized by distinct mineralogical assemblage of authigenic minerals corresponding to oxic, methanic and weakly sulfidic dysoxic conditions. Changing redox conditions of the depositional environment, methane seepage in warm seawater and availability of iron influx possibly determined the final mineralogy of three varieties of ironstones. The association of siderite with ferrimagnetic sulfides like greigite and pyrrhotite in type-1 ore indicate anaerobic oxidation of methane with limited bacterial sulfate reduction. The ironstone deposits of Narym, Kolpashevo and Bakchar are contemporaneous with geological events like ocean anoxic event 3 (OAE-3), Cretaceous-Paleogene (K-Pg) boundary and Palaeocene-Eocene Thermal Maximum (PETM), respectively, all corresponding to warm seawater conditions.

AB - An integrated study involving petrographical, mineralogical and geochemical investigations proposes the origin of the Bakchar ironstone deposit by upward migration of a mixture of Fe-rich brine and hydrothermal fluid through marine sediments. Trace element concentrations of the ironstone deposits rule out continental derivation of Fe, while high REE concentrations indicate mixed hydrogeneous and hydrothermal source. Three main types of ironstone within the Bakchar deposit are characterized by distinct mineralogical assemblage of authigenic minerals corresponding to oxic, methanic and weakly sulfidic dysoxic conditions. Changing redox conditions of the depositional environment, methane seepage in warm seawater and availability of iron influx possibly determined the final mineralogy of three varieties of ironstones. The association of siderite with ferrimagnetic sulfides like greigite and pyrrhotite in type-1 ore indicate anaerobic oxidation of methane with limited bacterial sulfate reduction. The ironstone deposits of Narym, Kolpashevo and Bakchar are contemporaneous with geological events like ocean anoxic event 3 (OAE-3), Cretaceous-Paleogene (K-Pg) boundary and Palaeocene-Eocene Thermal Maximum (PETM), respectively, all corresponding to warm seawater conditions.

KW - Bakchar deposit

KW - Geochemistry

KW - Mineralogy

KW - Ooidal ironstones

KW - Western Siberia

UR - http://www.scopus.com/inward/record.url?scp=85056796332&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85056796332&partnerID=8YFLogxK

U2 - 10.1016/j.marpetgeo.2018.11.023

DO - 10.1016/j.marpetgeo.2018.11.023

M3 - Article

AN - SCOPUS:85056796332

VL - 100

SP - 309

EP - 325

JO - Marine and Petroleum Geology

JF - Marine and Petroleum Geology

SN - 0264-8172

ER -