Assessing the relationships of the Hell Creek–Fort Union contact, Cretaceous-Paleogene boundary, and Chicxulub impact ejecta horizon at the Hell Creek Formation lectostratotype, Montana, USA
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Published:January 01, 2014
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CiteCitation
Jason R. Moore, Gregory P. Wilson, Mukul Sharma, Hannah R. Hallock, Dennis R. Braman, Paul R. Renne, 2014. "Assessing the relationships of the Hell Creek–Fort Union contact, Cretaceous-Paleogene boundary, and Chicxulub impact ejecta horizon at the Hell Creek Formation lectostratotype, Montana, USA", Through the End of the Cretaceous in the Type Locality of the Hell Creek Formation in Montana and Adjacent Areas, Gregory P. Wilson, William A. Clemens, John R. Horner, Joseph H. Hartman
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The interval spanning the uppermost Hell Creek Formation to the overlying lowermost Fort Union Formation in north-central Montana encompasses a marked paleoenvironmental change (associated with the formational contact), the Chicxulub impact event, and the Cretaceous-Paleogene boundary. We have examined the record of this transition at the Hell Creek Formation lectostratotype to determine the placement of these events using a series of lithological, geochemical, palynological, and 40Ar/39Ar geochronological analyses. The claystone derived from the Chicxulub impact is identified based on lithological criteria, enrichment of iridium and osmium, and osmium isotope ratios. The impact claystone also contains a Cyathidites...
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Through the End of the Cretaceous in the Type Locality of the Hell Creek Formation in Montana and Adjacent Areas

GeoRef
- absolute age
- Ar/Ar
- biostratigraphy
- Cenozoic
- Chicxulub Crater
- clastic rocks
- claystone
- Cretaceous
- dates
- deposition
- ejecta
- Fort Union Formation
- Garfield County Montana
- Hell Creek Formation
- iridium
- K-T boundary
- lower Paleocene
- Mesozoic
- metals
- Mexico
- microfossils
- Montana
- North Dakota
- osmium
- Paleocene
- Paleogene
- palynomorphs
- platinum group
- reworking
- sampling
- sedimentary rocks
- stratigraphic boundary
- Tertiary
- United States
- Upper Cretaceous
- north-central Montana
- Flag Butte