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The '''Miocene''' is the first [[Epoch (geology)|epoch]] of the [[Neogene]] period of the [[Cainozoic]]. It started about 23 million years ago and ended about 5.33 million years ago. The rock beds that mark the start and end are well known, but the exact dates of the start and end of the period are uncertain. The [[biota]] becomes 'modern'.
The '''Miocene''' is the first [[Epoch (geology)|epoch]] of the [[Neogene]] period of the [[Cainozoic]]. It started about 23 million years ago and ended about 5.33 million years ago. The rock beds that mark the start and end are well known, but the exact dates of the start and end of the period are uncertain. The [[biota]] becomes 'modern'.
The Miocene was named by Sir [[Charles Lyell]]. Its name comes from the [[Greek language|Greek]] words {{lang|grc|μείων}} (''{{lang|grc-Latn|meiōn}}'', “less”) and {{lang|grc|καινός}} (''{{lang|grc-Latn|kainos}}'', “new”) and means "less recent", because it has 18% fewer modern sea [[invertebrates]] than the [[Pliocene]].
The Miocene was named by Sir [[Charles Lyell]]. Its name comes from the [[Greek language|Greek]] words {{lang|grc|μείων}} (''{{lang|grc-Latn|meiōn}}'', “less”) and {{lang|grc|καινός}} (''{{lang|grc-Latn|kainos}}'', “new”) and means "less recent", because it has 18% fewer modern sea [[invertebrates]] than the [[Pliocene]].
As the earth cooled, it went from the Oligocene epoch, through the Miocene, and into the Pliocene. The Miocene boundaries are not set at any particular world wide event. They are set at regional boundaries between the warmer Oligocene and the cooler Pliocene epochs.
As the earth cooled, it went from the [[Oligocene]] epoch, through the Miocene, and into the Pliocene. The Miocene boundaries are not set at any particular world wide event. They are set at regional boundaries between the warmer Oligocene and the cooler Pliocene epochs.
The plants and animals of the Miocene were fairly modern. Modern families of [[mammal]]s and birds existed. Whales, seals, and kelp spread. Modern sharks appeared, including the huge ''[[Megalodon]]''. [[Grass]]lands became more common. Mammalian [[browser]]s became less common, and [[grazer]] species became more common. About 100 species of [[ape]] lived at that time, and [[cetacea]]ns were very common in the seas.<ref>{{Cite journal |author=Alton C. Dooley Jr., Nicholas C. Fraser & Zhe-Xi Luo |year=2004 |title=The earliest known member of the rorqual–gray whale clade (Mammalia, Cetacea) |journal=Journal of Vertebrate Paleontology |volume=24 |issue=2 |pages=453–463 |url=http://www.seaturtle.org/PDF/Dooley_2004_JVertPaleo.pdf |format=[[Portable Document Format|PDF]] |doi=10.1671/2401}}</ref> The giganic shark ''[[Carcharodon megalodon]]'' may have preyed on them.
The plants and animals of the Miocene were fairly modern, but familiar present-day species had not yet evolve. Modern families of [[mammal]]s and birds existed. Whales, seals, and kelp spread. Modern sharks appeared, including the huge ''[[Megalodon]]''. [[Grass]]lands became more common. Mammalian [[browser]]s became less common, and [[grazer]] species became more common. About 100 species of [[ape]] lived at that time, and [[cetacea]]ns were very common in the seas.<ref>{{Cite journal |author=Alton C. Dooley Jr., Nicholas C. Fraser & Zhe-Xi Luo |year=2004 |title=The earliest known member of the rorqual–gray whale clade (Mammalia, Cetacea) |journal=Journal of Vertebrate Paleontology |volume=24 |issue=2 |pages=453–463 |url=http://www.seaturtle.org/PDF/Dooley_2004_JVertPaleo.pdf |format=[[Portable Document Format|PDF]] |doi=10.1671/2401}}</ref> The giganic shark ''[[Carcharodon megalodon]]'' may have preyed on them.
== Climate ==
The climate was warm in the Miocene, especially in the first half. The diagram shows that throughout the Oligocene and the first half of the Miocene, climate remained warm.
[[File:Climate sensitivity sea level and atmospheric carbon dioxide. Hansen et al 2013.png|thumb|center|500pxpx|Significant drop off in both temperature and deep sea ocean temperature as measured by delta <sup>18</sup>O after the Middle Miocene Climatic Optimum.]]
This meant that Africa (and elsewhere) was much more forested than today, and that the herbivorous mammals were mainly [[browsers]] rather than [[grazers]]. In the second half of the Miocene temperatures dropped, and grasslands began to expand.
=== Mediterranean ===
Another great event, which undoubtedly affected climate, was the refilling of the [[Mediterranean]] basin. The so-called '''Zanclean flood''' is thought to have refilled the Mediterranean Sea 5.33 million years ago.<ref>{{cite journal| last = Blanc| first = P.-L.| title = The opening of the Plio-Quaternary Gibraltar Strait: assessing the size of a cataclysm| journal = Geodinamica Acta| volume = 15| year = 2002| issue = 15| pages = 303–317| doi = 10.1016/S0985-3111(02)01095-1| bibcode = 2002GeoAc..15..303B }}</ref>
This reconnected the Mediterranean Sea to the [[Atlantic Ocean]]. It is possible that even before the flood there were partial connections to the Atlantic Ocean.
According to this model, water from the [[Atlantic Ocean]] refilled the [[Endorheic basin|dried up basin]] through the modern-day [[Strait of Gibraltar]]. The process took up to two years.<ref>{{cite journal
|authors=M. Roveri|title=A high-resolution stratigraphic framework for the latest Messinian events in the Mediterranean area|journal=Stratigraphy|volume=5|issue=3–4|pages=323–342|year=2008|url=http://160.78.38.2/VM_file/PDF/Roveri_2008_Stratigraphy.pdf|display-authors=etal|url-status=dead|archiveurl=https://web.archive.org/web/20120121052846/http://160.78.38.2/VM_file/PDF/Roveri_2008_Stratigraphy.pdf|archivedate=21 January 2012}}</ref>
The flood may have affected global climate, considering that the much smaller flood triggered when [[Lake Agassiz]] drained did result in a cold period.<ref>Garcia-Castellanos, Daniel ''et al'' 2009. Catastrophic flood of the Mediterranean after the Messinian salinity crisis. ''Nature'' '''462''' (7274): 778–781. [https://www.nature.com/articles/nature08555]</ref>
== Related pages ==
* [[Template:Human timeline|Human timeline]]
== References ==
== References ==
{{Reflist}}
{{Reflist}}
{{Geological history of Earth|state=collapsed}}
{{Geologic History}}
[[Category:Cainozoic]]
[[Category:Cainozoic]]
[[Category:Miocene| ]]