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Cretaceous-Paleogene paleoenvironmental changes in the Yezo basin, Northeast Japan.

日本东北部虾夷盆地白垩纪-古近纪古环境变迁。

基本信息

批准号：
17540441
负责人：
ANDO Hisao
金额：
$ 2.37万
依托单位：
Ibaraki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

During 2005 to 2007 the Lower Cretaceous to Paleocene Yezo Group in Hokkaido and the Lower Cretaceous Miyako and Upper Cretaceous Kuji groups in the Pacific side of Tohoku, have been surveyed from viewpoints of sedimentary facies, megafossil and pollen biostratigraphy, biofacies and others.Our survey revealed that six depositional sequences showing shallow-marine coarsening-and showing show-upward facies successions, are traceable in the Campanian Hakobuchi Formation over the Nakagawa area, northern Hokkaido. In the uppermost Albian to Turonian Mikasa Formation distributed in central Hokkaido, a total of 12 fourth-order depositional sequences can be observed in the eastern limb of the Ikushunbetsu- Sorachi anticline area. Each of sequences 20 to 100 m thick constitutes inner to outer shelf bioturbated sandy mudstone in the lower part and shoreface fine/medium massive/hummocky to trough cross-stratified sandstone in the upper. Furthermore, three third-order depositional sequence sets fo … More r both of the Hakobuchi and Mikasa formations, can be identified through stacking patterns of the sequences. Those sequences and sequence sets seem to have formed by repetitive relative sea-level changes influenced by global eustacy, as typically exemplified in the Western Interior Cretaceous in North America. The high-resolution sequence stratigraphic framework enables reconstructing sedimentary history and paleogeography in the western margin of the Yezo basin. Molluscan fossil occurrences and their composition such as ammonoids, inoceramids and other bivalves within each sequence indicate the taphonomic relation between fossil habitats and depositional environments.In the Santonian to Campanian Kuji Group exposed along the north Sanriku Coast, the stratigraphic variation in pollen flora shows a hinterland paleovegetational change represented by increase of bisaccate pollen. The lateral variation suggests that distribution of plant communities would have been analogous to present-day vegetational variation in several tens kilometer scale. The integrated approach of palynology and sedimentary facies analysis illustrates detailed paleovegetation and fine-scale paleoclimatic fluctuations during Late Cretaceous. Less

2005 - 2007年，对北海道下白垩统-古新统鹿佐群、东北太平洋侧下白垩统宫古群和上白垩统久治群进行了沉积相、巨化石和花粉生物地层学、生物相等方面的研究，发现6个沉积层序表现为浅海变粗和显示向上的相序，在北方北海道中川地区的Campanian Hakobuchi组中可找到。在北海道中部分布的Albian至Turonian米卡萨组的最上部，在Ikushunbetsu- Sorachi背斜地区的东翼共可观察到12个四级沉积层序。每个20 - 100 m厚的层序下部由内到外陆架生物扰动桑迪泥岩组成，上部由滨面细/中块状/丘状到槽状交错层状砂岩组成。在此基础上，建立了三个三级沉积层序组， ...更多信息通过层序的叠加样式可以识别出箱渊组和米卡萨组。这些层序和层序组似乎是由受全球海平面升降影响的重复性相对海平面变化形成的，典型的例子是北美白垩纪西部内陆。高分辨率层序地层格架的建立，为重建耶佐盆地西缘的沉积历史和古地理提供了可能。每个层序中的软体动物化石产出及其组成（如菊石、介虫和其他双壳类）表明了化石生境与沉积环境之间的埋藏关系。在沿着北三陆海岸出露的Santonian至Campanian Kuji群中，花粉植物群的地层变化显示了以双囊花粉增加为代表的腹地古植被变化。横向变化表明，植物群落的分布与当今几十公里范围内的植被变化类似。孢粉学和沉积相分析的综合方法，详细说明了古植被和精细尺度的古气候波动在晚白垩世。少

项目成果

期刊论文数量（0）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Shallow to offshore marine bio? and lithofacies changes along basin transect and Cenomanian-Turonian oceanic anoxice vent in Cretaceous Yezo forearc basin, central Hokkaido

浅海到近海海洋生物？

DOI：
发表时间：
2006
期刊：
Field Excursion Guidebook for 17th International Sedimentological Congress, Fukuoka.
影响因子：
0
作者：
Ando;H.;・Hasegawa;T.;・Hikida;Y.・Hirano;H.
通讯作者：
H.

香川県東部地域に分布する上部白亜系和泉層群北縁相における堆積の層序的・地理的変化

香川县东部上白垩统和泉群北缘相沉积地层与地理变化