The Wasatchian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 55,400,000 to 50,300,000 years BP lasting 5.1 million years.[1]

It is usually considered to be within the Eocene, more specifically the Early Eocene.

The Wasatchian is preceded by the Clarkforkian and followed by the Bridgerian NALMA stages.

Definition

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The age is named after the Wasatch Formation, a highly fossiliferous stratigraphic unit stretching across six of the United States from Idaho and Montana in the north through Utah and Wyoming to Colorado and New Mexico in the south.

Substages

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The Wasatchian is considered to contain the following substages:

  • Sandcouleean: shares lower boundary with the beginning of the Wasatchian age and shares upper boundary with the base of the Graybullian.
  • Graybullian: shares lower boundary with the end of the Sandcouleean subage and upper boundary with the base of the Lysitean.
  • Lysitean: shares lower boundary with the end of the Graybullian subage and upper boundary with the base of the Lostcabinian.
  • Lostcabinian: shares lower boundary with the end of the Lysitean subage and upper boundary with the beginning of the Bridgerian.

Wasatchian correlations

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Wasatchian correlations in North America
Formation Wasatch DeBeque Claron Indian Meadows Pass Peak Tatman Willwood Golden Valley Coldwater Allenby Kamloops Ootsa Lake Margaret Nanjemoy Hatchetigbee Tetas de Cabra Hannold Hill Coalmont Cuchara Galisteo San Jose Ypresian (IUCS) • Itaboraian (SALMA)
Bumbanian (ALMA) • Mangaorapan (NZ)
Basin Powder River
Uinta
Piceance
Colorado Plateau
Wind River
Green River
Bighorn
Piceance




Colorado Plateau





Wind River





Green River






Bighorn
Williston Okanagan Princeton Buck Creek Nechako Sverdrup Potomac GoM Laguna Salada Rio Grande North Park Raton Galisteo San Juan
Country   United States   Canada   United States   Mexico   United States
Copelemur        
Coryphodon                    
Diacodexis              
Homogalax              
Oxyaena          
Paramys                  
Primates              
Birds          
Reptiles              
Fish              
Insects            
Flora                  
Environments Alluvial-fluvio-lacustrine Fluvial Fluvial Fluvio-lacustrine Fluvial Lacustrine Fluvio-lacustrine Deltaic-paludal Shallow marine Fluvial Shallow marine Fluvial Fluvial
  Wasatchian volcanoclastics

  Wasatchian fauna

  Wasatchian flora
Volcanic Yes No Yes No Yes No Yes No Yes No


References

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