Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite

Abstract The origin of sedimentary dolomite and the factors that control its formation within the geological record remain speculative. In most models, dolomite formation is linked to evaporative conditions, high water temperature, increasing Mg/Ca ratio, increasing alkalinity, and high amounts of b...

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Main Authors: J. McCormack, T. R. R. Bontognali, A. Immenhauser, O. Kwiecien
Format: Article
Language:English
Published: Wiley 2018-04-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2018GL077344
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author J. McCormack
T. R. R. Bontognali
A. Immenhauser
O. Kwiecien
author_facet J. McCormack
T. R. R. Bontognali
A. Immenhauser
O. Kwiecien
author_sort J. McCormack
collection DOAJ
description Abstract The origin of sedimentary dolomite and the factors that control its formation within the geological record remain speculative. In most models, dolomite formation is linked to evaporative conditions, high water temperature, increasing Mg/Ca ratio, increasing alkalinity, and high amounts of biomass. Here we challenge these archetypal views, by documenting a case example of Quaternary dolomite which formed in Lake Van at constantly low temperature (<4°C) and without direct control of the latter conditions. Dolomite occurs within highstand sediments related to suborbital climate variability (Dansgaard‐Oeschger cycles). We propose that dolomite precipitation is a product of a microbially influenced process, triggered by ecological stress, resulting from reventilation of the water‐sediment interface. Independently from the validity of this hypothesis, our results call for a reevaluation of the paleoenvironmental conditions often invoked for early diagenetic dolomite‐rich intervals within sedimentary sequences and for caution when interpreting time series of subrecent lacustrine carbonates.
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institution Kabale University
issn 0094-8276
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series Geophysical Research Letters
spelling doaj-art-087dfe1413a543e5b09fd71fea7921ef2025-08-20T03:47:32ZengWileyGeophysical Research Letters0094-82761944-80072018-04-014583625363410.1002/2018GL077344Controls on Cyclic Formation of Quaternary Early Diagenetic DolomiteJ. McCormack0T. R. R. Bontognali1A. Immenhauser2O. Kwiecien3Sediment and Isotope Geology Ruhr University Bochum Bochum GermanyDepartment of Earth Sciences ETH Zurich Zurich SwitzerlandSediment and Isotope Geology Ruhr University Bochum Bochum GermanySediment and Isotope Geology Ruhr University Bochum Bochum GermanyAbstract The origin of sedimentary dolomite and the factors that control its formation within the geological record remain speculative. In most models, dolomite formation is linked to evaporative conditions, high water temperature, increasing Mg/Ca ratio, increasing alkalinity, and high amounts of biomass. Here we challenge these archetypal views, by documenting a case example of Quaternary dolomite which formed in Lake Van at constantly low temperature (<4°C) and without direct control of the latter conditions. Dolomite occurs within highstand sediments related to suborbital climate variability (Dansgaard‐Oeschger cycles). We propose that dolomite precipitation is a product of a microbially influenced process, triggered by ecological stress, resulting from reventilation of the water‐sediment interface. Independently from the validity of this hypothesis, our results call for a reevaluation of the paleoenvironmental conditions often invoked for early diagenetic dolomite‐rich intervals within sedimentary sequences and for caution when interpreting time series of subrecent lacustrine carbonates.https://doi.org/10.1002/2018GL077344dolomitecarbonate precipitationDansgaard‐Oeschger cyclesLake Vandiagenesispaleoclimate
spellingShingle J. McCormack
T. R. R. Bontognali
A. Immenhauser
O. Kwiecien
Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite
Geophysical Research Letters
dolomite
carbonate precipitation
Dansgaard‐Oeschger cycles
Lake Van
diagenesis
paleoclimate
title Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite
title_full Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite
title_fullStr Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite
title_full_unstemmed Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite
title_short Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite
title_sort controls on cyclic formation of quaternary early diagenetic dolomite
topic dolomite
carbonate precipitation
Dansgaard‐Oeschger cycles
Lake Van
diagenesis
paleoclimate
url https://doi.org/10.1002/2018GL077344
work_keys_str_mv AT jmccormack controlsoncyclicformationofquaternaryearlydiageneticdolomite
AT trrbontognali controlsoncyclicformationofquaternaryearlydiageneticdolomite
AT aimmenhauser controlsoncyclicformationofquaternaryearlydiageneticdolomite
AT okwiecien controlsoncyclicformationofquaternaryearlydiageneticdolomite