View source for Morawan Formation

{{Infobox rockunit
| name           = Morawan Formation
| image          =
| caption        =
| type           = [[Formation (stratigraphy)|Formation]]
| age            = [[Chattian]]
| period         = Chattian
| prilithology   =
| otherlithology =
| namedfor       =
| namedby        =
| region         = [[Hokkaido]]
| country        = {{JAP}}
| coordinates    =
| unitof         = [[Kawakami Group]]
| subunits       = unnamed, Kamirawan, Lower Hard Shale, Middle Hard Shales, Upper tuffaceous silstone
| underlies      = [[Kiroro Formation]]
| overlies       = [[Hombetsuzawa Formation]] 
| thickness      = {{convert|500|m|ft|abbr=on}}
| extent         =
| area           =
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}}
The '''Morawan Formation''' is a [[Chattian]] age siliceous marine [[geological formation]] of the [[Oligocene|Oligo]]-[[Miocene]] Japanese [[Kawakami Group]] of eastern [[Hokkaido|Hokkaido prefecture]].<ref name=FossilWorks>{{cite web|title=Fossil Works Morawan Formation|url=http://www.fossilworks.org/cgi-bin/bridge.pl?action=displayStrata&formation=Morawan&group_formation_member=Morawan|website=Fossil Works|access-date=17 December 2021}}</ref><ref name=GSJ>{{cite web|title=Oligo-Miocene Kawakami Group in Eastern Hokkaido - The age and horizon of Ashoro fossil fauna -|url=https://gbank.gsj.jp|website=Geological Survey of Japan|access-date=31 December 2015}}</ref><ref name=Funakawa>{{cite journal|last1=Funakawa|first1=Satoshi|title=Intrageneric variation and temporal change in the internal skeletal structure of plagiacanthids (Radiolaria) from Hokkaido, Japan|journal=Transactions and Proceedings of the Palaeontological Society of Japan |series=New Series|date=30 December 1995|issue=180|pages=208–225}}</ref> The formation is fossil rich and contains source units where toothed baleen whales ([[Aetiocetidae]]) and [[Desmostylia]]ns have been discovered.<ref name=Tsai>{{cite journal|last1=Tsai|first1=Cheng-Hsiu|last2=Ando|first2=Tatsuro|title=Niche Partitioning in Oligocene Toothed Mysticetes (Mysticeti: Aetiocetidae)|journal=Journal of Mammalian Evolution|date=14 April 2015|volume=23|pages=33–41|doi=10.1007/s10914-015-9292-y|s2cid=14470974}}</ref>

The Morawan Formation is a very siliceous unit containing hard platy [[shale]]s interbedded with [[tuff]]aceous [[mudstone]]s and [[sandstone]]s, and some [[pumice]]. The unnamed lower member is a hard platy shale alternating with beds of tuffaceous mudstones and sandstones, the Kamirawan member is a tuffaceous sandstone with pumice, the Lower Hard Shale is a very siliceous hard shale with tuffaceous sandstones and mudstones, and the Middle Hard Shales and the Upper tuffaceous siltstone are similar.<ref name=GSJMap>{{cite journal|last1=Inoue|first1=Eiji|last2=Suzuki|first2=Taisuke|title=Explanatory Text|journal=Geological Map of Japan|date=1961|publisher=Geological Survey of Japan}}</ref>

Fossil species from the Morawan Formation include:
* ''[[Ashorocetus|Ashorocetus eguchii]]''
* ''[[Morawanocetus|Morawanocetus yabukii]]''
* ''[[Aetiocetus|Aetiocetus tomitai]]''
* ''A. polydentatus''

== References ==
{{reflist}}

{{coord missing|Hokkaidō Prefecture}}

[[Category:Geologic formations of Japan]]
[[Category:Paleogene System of Asia]]
[[Category:Paleogene Japan]]
[[Category:Chattian Stage]]
[[Category:Shale formations]]
[[Category:Mudstone formations]]
[[Category:Sandstone formations]]
[[Category:Oligocene paleontological sites]]
[[Category:Paleontology in Japan]]
[[Category:Hokkaido]]