Asian land mammal age

Geologic timescale for prehistoric Asian fauna From Wikipedia, the free encyclopedia

The Asian land mammal ages, acronym ALMA, establish a geologic timescale for prehistoric Asian fauna, from the Paleocene to the Pleistocene.[1] These periods are referred to as ages, stages, or intervals and were established using geographic place names where fossil materials where obtained. Many of the ALMAs are based on corresponding faunas found in the Erlian Basin in Inner Mongolia, China.[2]

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.

Ages

Direct radiometric dating of all ALMAs has not proven possible.[3] Few absolute dates have been proposed, and those that have been are approximate and based on correlations to faunas in other parts of the world.

More information Age, Lower boundary ...
Age Lower boundary Upper boundary Correlation Correlation (NALMA)
Nihewanian Pleistocene[1]
Youhean Late Pliocene[1] Late Blancan[1]
Jinglean Early Pliocene[1] Late Hemphillian–early Blancan[1]
Baodean Late Miocene[1] Late Clarendonian–early Hemphillian[1]
Bahean ~11.1 Ma[4] Middle–late Miocene[1] Clarendonian[1]
Tunggurian ~11.1 Ma[4] Early–middle Miocene[1] Barstovian[1]
Shanwangian ~19.5 Ma[4] Early Miocene[1] Late Hemingfordian[1]
Xiejian ~23.03 Ma[4] ~19.5 Ma[4] Early Miocene[4]
Tabenbulakian ~31 Ma[2]/30.6 Ma[5] ~23.03 Ma[4] Late Oligocene[1] late Whitneyan[2]–early Hemingfordian[1]
Hsandagolian ~33.9 Ma[2]/33.3 Ma[5] ~31 Ma[2]/30.6 Ma[5] Early–middle Oligocene[2] (early Rupelian)[2] Orellan–middle Whitneyan[2]
Kekeamuan Early–middle Oligocene[1] Late Orellan–early Whitneyan[1]
Houldjinian Early Oligocene[1] Early Orellan[1]
Ergilian ~37.8 Ma[2] ~33.9 Ma[2] Late Eocene[1] (Priabonian[2]) Chadronian[1]
Ulangochuian ~39.9 Ma[6] ~37.8 Ma[2] Late Eocene[2] (late Bartonian[2]) Duchesnean[2]
Sharamurunian ~42.7 Ma[2] ~39.9 Ma[6] Middle–late Eocene[1][2] (Late Lutetian–early Bartonian[2][7]) Late Uintan (Ui3)[2]
Irdinmanhan ~47.8 Ma[2] ~42.7 Ma[2] Middle Eocene[1][2] (Early–Middle Lutetian[2]) Early–middle Uintan (Ui1–Ui2)[2]
Arshantan ~52.1 Ma[2] ~47.8 Ma[2] Early Eocene[2] (late Ypresian[2]) Bridgerian[2]
Bumbanian ~56.0 Ma[2] ~52.1 Ma[2] Early Eocene[1][2] (early Ypresian[2]) Wasatchian[2]
Gashatan ~56.0 Ma[2] Late Paleocene[1][2] Late Clarkforkian[2]
Nongshanian Late Paleocene[1] Tiffanian–early Clarkforkian[1]
Shanghuan Early Paleocene[1] Puercan–Torrejonian[1]
Close

Other continental ages

See also

References

Related Articles

Wikiwand AI