Dating lacustrine carbonate strata with detrital zircon U-Pb geochronology

Emily S Finzel; Justin A Rosenblume

doi:10.1130/G48070.1

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Dating lacustrine carbonate strata with detrital zircon U-Pb geochronology

Journal article

Peer reviewed

Dating lacustrine carbonate strata with detrital zircon U-Pb geochronology

Emily S Finzel and Justin A Rosenblume

Geology (Boulder), Vol.49(3), pp.294-298

11/04/2020

DOI: 10.1130/G48070.1

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Abstract

Carbonate lacustrine strata in nonmarine systems hold great potential for refining depositional ages through U-Pb dating of detrital zircons. The low clastic sediment flux in carbonate depositional environments may increase the relative proportion of zircons deposited by volcanic air fall, potentially increasing the chances of observing detrital ages near the true depositional age. We present U-Pb geochronology of detrital zircons from lacustrine carbonate strata that provides proof of concept for the effectiveness of both acid-digestion recovery and resolving depositional ages of nonmarine strata. Samples were collected from Early Cretaceous foreland basin fluvial sandstone and lacustrine carbonate in southwestern Montana (USA). Late Aptian-early Albian (ca. 115-110 Ma) maximum depositional ages young upsection and agree with biostratigraphic ages. Lacustrine carbonate is an important component in many types of tectonic basins, and application of detrital zircon U-Pb geochronology holds considerable potential for dating critical chemical and climatic events recorded in their stratigraphy. It could also reveal new information for the persistent question about whether the stratigraphic record is dominated by longer periods of background fine-grained sedimentation versus short-duration coarse-grained events. In tectonically active basins, lacustrine carbonates may be valuable for dating the beginning of tectonic subsidence, especially during periods of finer-grained deposition dominated by mudrocks and carbonates.

absolute age

carbonate rocks

Cretaceous

deposition

depositional environment

detrital zircon

Geochronology

Kootenai Formation

lacustrine environment

Lower Cretaceous

Mesozoic

Montana

nesosilicates

orthosilicates

sedimentary rocks

sedimentation

separation

silicates

stratigraphic units

Stratigraphy

tectonics

U/Pb

United States

Western U.S

zircon

zircon group

Details

Title: Subtitle: Dating lacustrine carbonate strata with detrital zircon U-Pb geochronology
Creators: Emily S Finzel - University of Iowa
Justin A Rosenblume - University of Iowa
Resource Type: Journal article
Publication Details: Geology (Boulder), Vol.49(3), pp.294-298
Publisher: Geological Society of America (GSA)
DOI: 10.1130/G48070.1
ISSN: 0091-7613
eISSN: 1943-2682
Language: English
Date published: 11/04/2020
Academic Unit: Earth and Environmental Sciences
Record Identifier: 9984229292902771

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