North American land mammal age

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The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when referring to the rock strata of that age) and were established using geographic place names where fossil materials were obtained. [1]

Contents

System

The North American land-mammal-age system was formalized in 1941 as a series of provincial land-mammal ages. [2] The system was the standard for correlations in the terrestrial Cenozoic record of North America and was the source for similar time scales dealing with other continents. The system was revised into a formal chronostratigraphic system. This approach is nominally justified by international stratigraphic codes; it holds that first appearances of individual species in particular sections are the only valid basis for naming and defining the land-mammal ages.

The basic unit of measure is the first/last boundary statement. This shows that the first appearance event of one taxon is known to predate the last appearance event of another. If two taxa are found in the same fossil quarry or at the same stratigraphic horizon, then their age-range zones overlap. [3]

The utility of the system led to its expansion into the Cretaceous (formalized 1986) [4] and the Holocene (formalized 2014). [5] These additions have been used in research related to the Cretaceous–Paleogene extinction event and the ensuing recovery, [6] and to the Anthropocene debate, [5] respectively. However, the ages that stretch into the Cretaceous are sometimes referred to as "North American land vertebrate ages" to reflect the fact that mammals, while still abundant, were not the dominant form of terrestrial life during the Mesozoic. [7]

Ages

Cenozoic land mammal ages

Cretaceous land vertebrate ages

Other continental ages

See also

Related Research Articles

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Hesperocyon is an extinct genus of canids that was endemic to North America, ranging from southern Canada to Colorado. It appeared during the Uintan age, –Bridgerian age (NALMA) of the Mid-Eocene– 42.5 Ma to 31.0 Ma. (AEO). Hesperocyon existed for approximately 11.5 million years.

<i>Daphoenus</i> Extinct genus of carnivores

Daphoenus is an extinct genus of amphicyonids. Daphoenus inhabited North America from the Middle Eocene to the Middle Miocene, 37.2—16.0 Mya, existing for approximately 21 million years.

The Blancan 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 4,750,000 to 1,806,000 years BP, a period of 2.944 million years. It is usually considered to start in the early-mid Pliocene Epoch and end by the early Pleistocene. The Blancan is preceded by the Hemphillian and followed by the Irvingtonian NALMA stages.

The Irvingtonian North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), spanning from 1.9 million – 250,000 years BP. Named after an assemblage of fossils from the Irvington District of Fremont, California, the Irvingtonian is usually considered to overlap the Lower Pleistocene and Middle Pleistocene epochs. The Irvingtonian is preceded by the Blancan and followed by the Rancholabrean NALMA stages.

The Rancholabrean North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from less than 240,000 years to 11,000 years BP, a period of 0.229 million years. Named after the famed Rancho La Brea fossil site in Los Angeles, California, the Rancholabrean is characterized by the presence of the genus Bison in a Pleistocene context, often in association with other extinct Pleistocene forms such as Mammuthus. The age is usually considered to overlap the late Middle Pleistocene and Late Pleistocene epochs. The Rancholabrean is preceded by the Irvingtonian NALMA stage, and it is succeeded by the Santarosean age.

<span class="mw-page-title-main">Barstovian</span> North American faunal stage

The Barstovian 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 16,300,000 to 13,600,000 years BP, a period of 2.7 million years. It is usually considered to overlap the Langhian and Serravallian stages of the Middle Miocene. The Barstovian is preceded by the Hemingfordian and followed by the Clarendonian NALMA stages.

The Orellan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), 34-32 million years ago. It is usually considered to fall within the Early Oligocene. The Orellan precedes the Whitneyan and follows the Chadronian NALMA stages.

The Chadronian age within the North American Land Mammal Ages chronology is the North American faunal stage typically set from 38,000,000 to 33,900,000 years BP, a period of 4.1 million years. It is usually considered to fall within the Eocene epoch. The Chadronian is preceded by the Duchesnean and followed by the Orellan NALMA stages.

The Uintan 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 46,200,000 to 42,000,000 years BP lasting 4.2 million years. It falls within the Eocene epoch, preceded by the Bridgerian and followed by the Duchesnean NALMA stages.

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.

The Clarkforkian 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 56,800,000 to 55,400,000 years BP lasting 1.4 million years.

The Tiffanian 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 60,200,000 to 56,800,000 years BP lasting 3.4 million years.

The Puercan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), spanning the interval from 66,000,000 to 63,300,000 years BP lasting 2.7 million years.

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The Judithian was a North American faunal stage lasting from 83.5 to 70.6 million years ago. It overlaps with the Campanian global stage.

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<i>Ignacius</i> Extinct genus of mammals

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References

  1. ↑ Roberto Díaz Sibaja, Eduardo Jiménez Hidalgo, Ma. Luisa García Zepeda. "Una nueva localidad fosilífera en Oaxaca (México) y el registro más austral de Bison latifrons: Implicaciones paleobiogeográficas, paleoecológicas y paleoambientales" (PDF). Boletín de la Sociedad Geológica Mexicana. 70: 201–222.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ↑ Wood, H. E.; Chaney, R. W.; Clark, J.; Colbert, E. H.; Jepsen, G.L.; Reeside, J. B.; Stock, C. (1941). "Nomenclature and correlation of the North American continental Tertiary". Geological Society of America Bulletin. 52 (1): 1–48. Bibcode:1941GSAB...52....1W. doi:10.1130/gsab-52-1.
  3. ↑ Woodburne, Michael O., ed. (1987). "A prospectus of the North American Mammal Ages". Cenozoic mammals of North America : geochronology and biostratigraphy. Berkeley: University of California Press. pp. 285–290. ISBN   978-0520053922.
  4. ↑ Lillegraven, J. A.; McKenna, M. C. (1986). "Fossil mammals from the" Mesaverde" Formation (late Cretaceous, Judithian) of the Bighorn and Wind River basins, Wyoming: with definitions of late Cretaceous North American land-mammal" ages"". American Museum Novitates (2840): 1–68.
  5. 1 2 3 4 Barnosky, A. D.; Holmes, M.; Kircholtes, R.; Lindsey, E.; Maguire, K. C.; Poust, A. W.; Stegner, M. A.; Sunseri, J.; Swartz, B.; Swift, J.; Villavicencio, N. A. (2014). "Prelude to the Anthropocene: Two new North American land mammal ages (NALMAs)". The Anthropocene Review. 1 (3): 225–242. doi:10.1177/2053019614547433. S2CID   128697655.
  6. ↑ Woodburne, Michael O., ed. (2012). "Mammalian Biochronology of the Latest Cretaceous". Late Cretaceous and Cenozoic mammals of North America biostratigraphy and geochronology. New York: Columbia University Press. pp. 21–43. ISBN   9780231503785.
  7. 1 2 3 4 5 6 Fowler, DW (2017). "Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America". PLOS ONE. 12 (11): e0188426. doi:10.1371/journal.pone.0188426. PMC   5699823 .
  8. ↑ "Rancholabrean age/stage". fossilworks.org.
  9. ↑ Alroy, J. (2000). "New methods for quantifying macroevolutionary patterns and processes". Paleobiology. 26 (4): 707–733. doi:10.1666/0094-8373(2000)026<0707:NMFQMP>2.0.CO;2. S2CID   26470169.
  10. ↑ "Irvingtonian age/stage". fossilworks.org.
  11. ↑ "Blancan age/stage". fossilworks.org.
  12. ↑ "Hemphillian age/stage". fossilworks.org.
  13. ↑ "Clarendonian age/stage". fossilworks.org.
  14. ↑ "Barstovian age/stage". fossilworks.org.
  15. ↑ "Hemingfordian age/stage". fossilworks.org.
  16. ↑ "Harrisonian age/stage". fossilworks.org.
  17. ↑ "Monroecreekian age/stage". fossilworks.org.
  18. ↑ "Geringian age/stage". fossilworks.org.
  19. ↑ "Whitneyan age/stage". fossilworks.org.
  20. ↑ "Orellan age/stage". fossilworks.org.
  21. ↑ "Chadronian age/stage". fossilworks.org.
  22. ↑ "Duchesnean age/stage". fossilworks.org.
  23. ↑ "Uintan age/stage". fossilworks.org.
  24. ↑ "Bridgerian age/stage". fossilworks.org.
  25. ↑ "Wasatchian age/stage". fossilworks.org.
  26. ↑ "Clarkforkian age/stage". fossilworks.org.
  27. ↑ "Tiffanian age/stage". fossilworks.org.
  28. ↑ "Torrejonian age/stage". fossilworks.org.
  29. ↑ "Puercan age/stage". fossilworks.org.
  30. ↑ Ramezani, J.; Beveridge, T.L.; Rogers, R.; Eberth, D.; Roberts, E. (2022). "Calibrating the zenith of dinosaur diversity in the Campanian of the Western Interior Basin by CA-ID-TIMS U–Pb geochronology". Sci Rep. 12: 16026. doi:10.1038/s41598-022-19896-w. PMC   9512893 .
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