Geochemistry of the Upper Jurassic–Lower Cretaceous limestone of the Bilecik Formation in the Dümrek area (Eskişehir, western Central Anatolia): implications for depositional environment and paleotemperature.
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| Title: | Geochemistry of the Upper Jurassic–Lower Cretaceous limestone of the Bilecik Formation in the Dümrek area (Eskişehir, western Central Anatolia): implications for depositional environment and paleotemperature. |
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| Authors: | KAHYA, Asuman1 asuman27@gmail.com, BAĞCI, Metin2 |
| Source: | Turkish Journal of Earth Sciences. 2026, Vol. 35 Issue 2, p108-128. 21p. |
| Subjects: | Limestone, Geochemistry, Sedimentation & deposition, Cretaceous Period, Temperature, Jurassic Period |
| Geographic Terms: | Eskisehir (Turkey), Turkey |
| Abstract: | Upper Jurassic–Lower Cretaceous limestones of the Bilecik Formation are exposed near the village of Dümrek (Eskişehir Province) within the Sakarya Zone. Mineralogical analyses reveal that these limestones are predominantly composed of calcite and include intraclasts, fossil shell fragments, ooids, and peloids, cemented by sparry and micritic calcite. The U/Th, Ni/Co, V/(V+Ni), V/ Cr, and Ce/Ce* ratios indicate that these carbonates were deposited in an oxic environment. Furthermore, the Mn/Sr ratios imply no diagenetic alteration, indicating preservation of the original geochemical signature. The PAAS-normalized REE+Y patterns of these limestones display depletion in light rare earth elements, a pronounced positive La anomaly (La/La* = 2.13–6.2), a distinct negative Ce anomaly (Ce/Ce* = 0.18–1.76), a slight positive Eu anomaly (Eu/Eu* = 1–1.41), and an enrichment in Y, all pointing to a well-oxygenated depositional environment with negligible detrital input. Stable isotope data show that the average δ13C (V-PDB) value is 2.47‰, while the average δ18O (V-PDB) value is –2.10‰. The δ18O values display slight alteration with negative values, which are interpreted as evidence of early marine diagenesis. Based on these oxygen isotope values, the estimated paleotemperature during carbonate precipitation was approximately 26.15 °C. The calculated paleosalinity index (Z) of 131.40, obtained using the average δ18O and δ13C values, corroborates a marine origin for the carbonates. Furthermore, the paleoclimate proxy ratio ∑(Fe + Mn + Cr + Ni + V + Co)/∑(Ca + Mg + Sr + Ba + K + Na) ranges between 0.087 and 0.09, indicative of an arid climate during limestone formation. The δ13C (V-PDB) ‰ versus δ18O (V-PDB) ‰ bivariate diagram confirms the marine character of the limestone. [ABSTRACT FROM AUTHOR] |
| Copyright of Turkish Journal of Earth Sciences is the property of Scientific and Technical Research Council of Turkey and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 192447956 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Geochemistry of the Upper Jurassic–Lower Cretaceous limestone of the Bilecik Formation in the Dümrek area (Eskişehir, western Central Anatolia): implications for depositional environment and paleotemperature. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22KAHYA%2C+Asuman%22">KAHYA, Asuman</searchLink><relatesTo>1</relatesTo><i> asuman27@gmail.com</i><br /><searchLink fieldCode="AR" term="%22BAĞCI%2C+Metin%22">BAĞCI, Metin</searchLink><relatesTo>2</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Turkish+Journal+of+Earth+Sciences%22">Turkish Journal of Earth Sciences</searchLink>. 2026, Vol. 35 Issue 2, p108-128. 21p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Limestone%22">Limestone</searchLink><br /><searchLink fieldCode="DE" term="%22Geochemistry%22">Geochemistry</searchLink><br /><searchLink fieldCode="DE" term="%22Sedimentation+%26+deposition%22">Sedimentation & deposition</searchLink><br /><searchLink fieldCode="DE" term="%22Cretaceous+Period%22">Cretaceous Period</searchLink><br /><searchLink fieldCode="DE" term="%22Temperature%22">Temperature</searchLink><br /><searchLink fieldCode="DE" term="%22Jurassic+Period%22">Jurassic Period</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22Eskisehir+%28Turkey%29%22">Eskisehir (Turkey)</searchLink><br /><searchLink fieldCode="DE" term="%22Turkey%22">Turkey</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Upper Jurassic–Lower Cretaceous limestones of the Bilecik Formation are exposed near the village of Dümrek (Eskişehir Province) within the Sakarya Zone. Mineralogical analyses reveal that these limestones are predominantly composed of calcite and include intraclasts, fossil shell fragments, ooids, and peloids, cemented by sparry and micritic calcite. The U/Th, Ni/Co, V/(V+Ni), V/ Cr, and Ce/Ce* ratios indicate that these carbonates were deposited in an oxic environment. Furthermore, the Mn/Sr ratios imply no diagenetic alteration, indicating preservation of the original geochemical signature. The PAAS-normalized REE+Y patterns of these limestones display depletion in light rare earth elements, a pronounced positive La anomaly (La/La* = 2.13–6.2), a distinct negative Ce anomaly (Ce/Ce* = 0.18–1.76), a slight positive Eu anomaly (Eu/Eu* = 1–1.41), and an enrichment in Y, all pointing to a well-oxygenated depositional environment with negligible detrital input. Stable isotope data show that the average δ13C (V-PDB) value is 2.47‰, while the average δ18O (V-PDB) value is –2.10‰. The δ18O values display slight alteration with negative values, which are interpreted as evidence of early marine diagenesis. Based on these oxygen isotope values, the estimated paleotemperature during carbonate precipitation was approximately 26.15 °C. The calculated paleosalinity index (Z) of 131.40, obtained using the average δ18O and δ13C values, corroborates a marine origin for the carbonates. Furthermore, the paleoclimate proxy ratio ∑(Fe + Mn + Cr + Ni + V + Co)/∑(Ca + Mg + Sr + Ba + K + Na) ranges between 0.087 and 0.09, indicative of an arid climate during limestone formation. The δ13C (V-PDB) ‰ versus δ18O (V-PDB) ‰ bivariate diagram confirms the marine character of the limestone. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Turkish Journal of Earth Sciences is the property of Scientific and Technical Research Council of Turkey and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.55730/1300-0985.2009 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 21 StartPage: 108 Subjects: – SubjectFull: Limestone Type: general – SubjectFull: Geochemistry Type: general – SubjectFull: Sedimentation & deposition Type: general – SubjectFull: Cretaceous Period Type: general – SubjectFull: Temperature Type: general – SubjectFull: Jurassic Period Type: general – SubjectFull: Eskisehir (Turkey) Type: general – SubjectFull: Turkey Type: general Titles: – TitleFull: Geochemistry of the Upper Jurassic–Lower Cretaceous limestone of the Bilecik Formation in the Dümrek area (Eskişehir, western Central Anatolia): implications for depositional environment and paleotemperature. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: KAHYA, Asuman – PersonEntity: Name: NameFull: BAĞCI, Metin IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 03 Text: 2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 13000985 Numbering: – Type: volume Value: 35 – Type: issue Value: 2 Titles: – TitleFull: Turkish Journal of Earth Sciences Type: main |
| ResultId | 1 |
