Calc alkaline volcanism-aided phytoplankton growth and organic matter production of the Cenomanian-Turonian Eagle Ford Formation of South Texas.
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| Title: | Calc alkaline volcanism-aided phytoplankton growth and organic matter production of the Cenomanian-Turonian Eagle Ford Formation of South Texas. |
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| Authors: | Chakrabarty, Puloma1,2,3 (AUTHOR) pulomac@g.ucla.edu, Basu, Asish R.1 (AUTHOR) |
| Source: | International Geology Review. May2026, Vol. 68 Issue 10, p1185-1206. 22p. |
| Subject Terms: | *Phytoplankton, *Volcanism, *Organic compounds, *Geological time scales, *Anoxic waters, *Black shales |
| Geographic Terms: | Texas |
| Abstract: | The kerogen-rich Eagle Ford (EF) black shales of south Texas formed in the Late Cretaceous, overlapping the Cenomanian-Turonian (C-T) boundary and the Oceanic Anoxic Event 2 (OAE2). This study proposes a continuous calc-alkaline volcanogenic model of oil-generation for the EF by petrographic, geochemical, and geochronological studies of sub-surface and surface EF shale cores. Biotite, alkali feldspar phenocrysts, andesitic rock fragments and swelling clays observed, and X-ray diffraction (XRD) analyses of bulk samples indicate continuous volcanism during EF deposition. Zircons yield U-Pb ages of 93.2 ± 1.66 Ma, 94.13 ± 1.25 Ma and 93.7 ± 1.9 Ma, consistent with the C-T age of deposition. The εHf(i) of zircons averaged at +1.23, indicating a crustal component in the arc volcanism. In the 187Os/188Osinitial at 93 Ma, the time of EF deposition is 2.47–5.11 indicating a continental-crustal origin of the osmium (Os). Continuous arc volcanism during the EF deposition of volcanic-silicic sediments and carbonates was simultaneously a part of the Cretaceous global continental arc flare-ups, responsible for greenhouse conditions and anoxia during black shales deposition. We conclude that the black shale of the EF is dominated by lamalginites (unicellular solitary or colonial phytoplankton), produced during algal blooms falling as 'marine snow' augmented by calc-alkaline volcanism at the C-T boundary. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: enr DbLabel: Energy & Power Source An: 193598879 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Calc alkaline volcanism-aided phytoplankton growth and organic matter production of the Cenomanian-Turonian Eagle Ford Formation of South Texas. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Chakrabarty%2C+Puloma%22">Chakrabarty, Puloma</searchLink><relatesTo>1,2,3</relatesTo> (AUTHOR)<i> pulomac@g.ucla.edu</i><br /><searchLink fieldCode="AR" term="%22Basu%2C+Asish+R%2E%22">Basu, Asish R.</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22International+Geology+Review%22">International Geology Review</searchLink>. May2026, Vol. 68 Issue 10, p1185-1206. 22p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Phytoplankton%22">Phytoplankton</searchLink><br />*<searchLink fieldCode="DE" term="%22Volcanism%22">Volcanism</searchLink><br />*<searchLink fieldCode="DE" term="%22Organic+compounds%22">Organic compounds</searchLink><br />*<searchLink fieldCode="DE" term="%22Geological+time+scales%22">Geological time scales</searchLink><br />*<searchLink fieldCode="DE" term="%22Anoxic+waters%22">Anoxic waters</searchLink><br />*<searchLink fieldCode="DE" term="%22Black+shales%22">Black shales</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22Texas%22">Texas</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The kerogen-rich Eagle Ford (EF) black shales of south Texas formed in the Late Cretaceous, overlapping the Cenomanian-Turonian (C-T) boundary and the Oceanic Anoxic Event 2 (OAE2). This study proposes a continuous calc-alkaline volcanogenic model of oil-generation for the EF by petrographic, geochemical, and geochronological studies of sub-surface and surface EF shale cores. Biotite, alkali feldspar phenocrysts, andesitic rock fragments and swelling clays observed, and X-ray diffraction (XRD) analyses of bulk samples indicate continuous volcanism during EF deposition. Zircons yield U-Pb ages of 93.2 ± 1.66 Ma, 94.13 ± 1.25 Ma and 93.7 ± 1.9 Ma, consistent with the C-T age of deposition. The εHf(i) of zircons averaged at +1.23, indicating a crustal component in the arc volcanism. In the 187Os/188Osinitial at 93 Ma, the time of EF deposition is 2.47–5.11 indicating a continental-crustal origin of the osmium (Os). Continuous arc volcanism during the EF deposition of volcanic-silicic sediments and carbonates was simultaneously a part of the Cretaceous global continental arc flare-ups, responsible for greenhouse conditions and anoxia during black shales deposition. We conclude that the black shale of the EF is dominated by lamalginites (unicellular solitary or colonial phytoplankton), produced during algal blooms falling as 'marine snow' augmented by calc-alkaline volcanism at the C-T boundary. [ABSTRACT FROM AUTHOR] |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=enr&AN=193598879 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1080/00206814.2026.2627317 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 22 StartPage: 1185 Subjects: – SubjectFull: Phytoplankton Type: general – SubjectFull: Volcanism Type: general – SubjectFull: Organic compounds Type: general – SubjectFull: Geological time scales Type: general – SubjectFull: Anoxic waters Type: general – SubjectFull: Black shales Type: general – SubjectFull: Texas Type: general Titles: – TitleFull: Calc alkaline volcanism-aided phytoplankton growth and organic matter production of the Cenomanian-Turonian Eagle Ford Formation of South Texas. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Chakrabarty, Puloma – PersonEntity: Name: NameFull: Basu, Asish R. IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 05 Text: May2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 00206814 Numbering: – Type: volume Value: 68 – Type: issue Value: 10 Titles: – TitleFull: International Geology Review Type: main |
| ResultId | 1 |
