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TitleCampanian-Maastrichtian clay-rich sequences along North Pacific margin: early cooling history of Cretaceous Greenhouse
AuthorHasegawa, T; Moriya, K; Haggart, J
SourceJapan Geoscience Union Annual Meeting, abstracts; 2014 p. 1
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20140037
PublisherJapan Geoscience Union
MeetingJapan Geoscience Union, Annual Meeting; Yokohama; JP; April 28 - May 2, 2014
Mediapaper; on-line; digital
File formatpdf
ProvinceWestern offshore region
AreaNorth Pacific; Japan; Russian Federation; Canada; United States
Lat/Long WENS-163.0000 167.0000 59.0000 32.0000
Subjectspaleontology; geochronology; stratigraphy; Upper Cretaceous; Campanian; Cenomanian; Coniacian; Maastrichtian; biostratigraphy; carbon isotopes; fossil assemblages; fossil distribution; Yezo Group; Nanaimo Group; Mesozoic; Cretaceous
ProgramFrontier basin analysis, Geoscience for New Energy Supply (GNES)
AbstractCretaceous shelf and fore-arc basin sandstone and mudstone are preserved in the coastal regions of Japan, Far East Russia, and the Pacific coast of Canada and USA. Several of these sequences have been variously assessed in terms of their biostratigraphy and chemostratigraphy, and correlated to the Aptian through Maastrichtian. In addition to macro- and microfossil biostratigraphy, carbon isotope (d13C) stratigraphy has also identified some important event horizons within these successions, such as OAE2. Owing to the clay-rich nature of the strata, parts of the sequences yield excellently preserved calcareous fossils available for oxygen isotope thermometry (Moriya et al., 2003). This study examines the Campanian-Maastrichtian interval. Its chronostratigraphy, including detailed d13C stratigraphy, has been summarized recently (Voigt et al., 2012) and it records the initial phase of global cooling of the Cretaceous greenhouse Earth (Moriya, 2011; Friedrich et al., 2012). As the northern paleo-Pacific Ocean had a large heat capacity, its paleoceanography should provide insights for understanding the subsequent environmental transition from greenhouse to ice house Earth. The Yezo Group and its equivalent in Hokkaido (Japan) and Sakhalin (Russian Far East), as well as the Nanaimo Group of the Canadian Pacific coast (British Columbia), are examined in this study. From the Yezo Group, a clear negative d13C excursion as large as 1.4?2 permil has been identified. On Sakhalin, its Campanian-Maastrichtian boundary age is constrained by local bio- and magnetostratigraphy, and the excursion is thus identified as the Campanian Maastrichtian Boundary Event (CMBE), associated with some subevents. Carbon isotopic event, CMBE, suggested from magneto- and biostratigraphy (Haggart et al., 2011; Ward et al., 2012) of the Nanaimo Group near the top of the Northumberland Formation is well observed at the expected mudstone-dominated interval of the formation with negative 1.5 permil excursion. These progresses of stratigraphic correlational potential enable us to correlate CMBE interval between NW and NE Pacific with higher resolution.
Summary(Plain Language Summary, not published)
This contribution is an abstract of a presentation at a scientific conference. The authors have developed a potential new method for determining the temperature of ocean waters of the Late Cretaceous period of geologic time, approximately 80 million years ago. Determining the variation in ocean water temperatures can be used to help assess the organic richness of the mudstone deposits, which is important in helping identify potential petroleum-bearing rocks of Canada.