Calcareous microfossil biostratigraphy of the uppermost cenozoic formations distributed in the coast of the Japan Sea. Part 2. Hokuriku Sedimentary Basin.
Calcareous microfossil biostratigraphy of the uppermost cenozoic formations distributed in the coast of the Japan Sea. Part 2. Hokuriku Sedimentary Basin.
复制标题
分布在日本海沿岸最上部新生代地层的钙质微化石生物地层。
DOI：
10.3720/japt.53.9
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
K. Kameo
中科院分区：
文献类型：
--
作者：
T. Takayama;Michio Kato;Tetsuro Kudo;Tokiyuki Sato;K. Kameo
根据第94航次在北大西洋6个站位采集的钙质超微化石组合，在中高纬度第四纪层序中识别出11个钙质超微化石生物层。建立了这些生物层位与磁性地层学的关联，并通过磁性反转之间的内插来估计所有基准面的年龄(Clement和Robinson，1987；Takayama和Sato，1987)。详细描述了富山县Yabuta组、Junicho组和金泽市Omma组的钙质超微化石和有孔虫组合。根据上述结果，雅布塔组、准尼科组和奥玛组的时代分别为上新世晚期、上更新世和更新世。1984年，在奥玛组的上段发现了小型哺乳动物化石--极光剑齿象。这一级别的极光可能指的是钙质超微化石生物层(5)(0.83 Ma)和磁性地层的Brunnes/Matuyama界线(0.73 Ma)之间的地层间隔。OMMA组与Saikawa组不整合。与Omma组不同的是，Saikawa组含有中下新世钙质超微化石。因此，上中新统和上新统的沉积在这两个建造之间完全缺失。
On the basis of calcareous nannofossil assemblages in samples recovered at six sites in the North Atlantic Ocean during DSDP-IPOD Leg 94, eleven calcareous nannofossil biohorizons are recognized in the Quaternary sequences deposited at middle and high latitudes. Correlation of these biohorizons with the magnetostratigraphy is established, and ages of all datums are estimated by interpolations between magnetic reversals (CLEMENT and ROBINSON, 1987; TAKAYAMA and SATO, 1987). The calcareous nannofossil and the foraminiferal assemblages of the Yabuta and the Junicho formations in Toyama Prefecture and the Omma formation at its type locality in Kanazawa City are described in detail. Based on the above mentioned results of DSDP-IPOD Leg 94, the Yabuta, the Junicho and the Omma formations are late Pliocene, Plio-Pleistocene and Pleistocene in age, respectively.In 1984, small mammalian fossil bone of Stegodon aurorae (elephant) was found from the upper Omma formation. This level of S. aurorae is probably referred to the stratigraphic interval between the calcareous nannofossil biohorizon (5) (0.83Ma) and the Brunhes/Matuyama boundary of the magnetostratigraphy (0.73Ma).The Omma formation overlies unconformably the Saikawa formation. In contrast to the Omma formation, the Saikawa formation contains middle to lower Miocene calcareous nannofossils. The upper Miocene and the Pliocene sediments are, therefore, completely missing between these two formations.