Early Cretaceous

System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
Paleogene Paleocene Danian younger
Cretaceous Upper/
Late
Maastrichtian 66.0 72.1
Campanian 72.1 83.6
Santonian 83.6 86.3
Coniacian 86.3 89.8
Turonian 89.8 93.9
Cenomanian 93.9 100.5
Lower/
Early
Albian 100.5 ~113.0
Aptian ~113.0 ~125.0
Barremian ~125.0 ~129.4
Hauterivian ~129.4 ~132.9
Valanginian ~132.9 ~139.8
Berriasian ~139.8 ~145.0
Jurassic Upper/
Late
Tithonian older
Subdivision of the Cretaceous system
according to the ICS, as of 2017.[1]

The Early Cretaceous (geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 146 Ma to 100 Ma.

Geology[]

A large igneous province on the Liaodong Peninsula, China, c. 131–117 Ma lasted for 10 million years. It was the result of the subduction of the Kula and Pacific plates, which was probably caused by a superplume.[2]

During the opening of the South Atlantic the Paraná–Etendeka large igneous province produced 1.5 million km³ of basalts and rhyolites per year beginning 133 Ma and lasting for a million years.[3]

Evolution[]

During this time many new types of dinosaur appeared or came into prominence, including ceratopsians, spinosaurids, carcharodontosaurids and coelurosaurs, while survivors from the Late Jurassic continued to persist.

Angiosperms (flowering plants) appeared for the first time during the Early Cretaceous.[4] This time also saw the evolution of the first members of the Neornithes (modern birds).[5]

A 125 Ma-old boreosphenidan mammal found in the Yixian Formation, China, is one of the oldest mammal fossils found. The fossil location indicates early mammals began to diversify from Asia during the Early Cretaceous. It was related closer to metatherians (marsupials) than eutherians (placentals) and had feet adapted from climbing trees.[6]

See also[]

References[]

  1. ^ Super User. "ICS - Chart/Time Scale". www.stratigraphy.org.
  2. ^ Wu, F. Y.; Lin, J. Q.; Wilde, S. A.; Zhang, X. O.; Yang, J. H. (2005). "Nature and significance of the Early Cretaceous giant igneous event in eastern China". Earth and Planetary Science Letters. 233 (1–2): 103–119. doi:10.1016/j.epsl.2005.02.019.
  3. ^ Renne, P. R.; Ernesto, M.; Pacca, I. G.; Coe, R. S.; Glen, J. M.; Prévot, M.; Perrin, M. (1992). "The age of Paraná flood volcanism, rifting of Gondwanaland, and the Jurassic-Cretaceous boundary". Science. 258 (5084): 975–979. doi:10.1126/science.258.5084.975.
  4. ^ Sun, G., Q. Ji, D.L. Dilcher, S. Zheng, K.C. Nixon & X. Wang 2002. Archaefructaceae, a New Basal Angiosperm Family. Science 296(5569): 899–904.
  5. ^ Lee, Michael SY; Cau, Andrea; Naish, Darren; Dyke, Gareth J. (May 2014). "Morphological Clocks in Paleontology, and a Mid-Cretaceous Origin of Crown Aves" (PDF). Systematic Biology. Oxford Journals. 63 (1): 442–449. doi:10.1093/sysbio/syt110. PMID 24449041.
  6. ^ Luo, Z. X.; Ji, Q.; Wible, J. R.; Yuan, C. X. (2003). "An Early Cretaceous tribosphenic mammal and metatherian evolution" (PDF). Science. 302 (5652): 1934–1940. doi:10.1126/science.109071. Retrieved 16 July 2019.