Long-term ENSO-like events represented in the Middle Pleistocene shelf successions, Boso Peninsula, Japan
Long-term ENSO-like events represented in the Middle Pleistocene shelf successions, Boso Peninsula, Japan
复制标题
日本房总半岛中更新世陆架序列中的长期类 ENSO 事件
DOI：
10.1016/s0031-0182(03)00685-0
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Makoto Ito
中科院分区：
文献类型：
--
作者：
K. Horikawa;Makoto Ito
从日本博索半岛中更新世一地组和Kakinokidai组（约0.7 Ma）的海侵陆架序列描述了千禧年、世纪和十年尺度的地层旋回。一地组（厚度约400 m）是在古黑潮大曲流影响下发育的陆架沙丘杂岩，其东北方向与外陆架Kakinokidai组（厚度约170 m）的泥质沉积相交错。两个组中的大部分被划分为氧同位素第18 ~ 17期冰川隆起时期形成的海侵体系域。海侵陆架沉积中存在三种不同类型的旋回。第一次旋回期（约3000年）以卡奇诺基台组粗化向上单元为代表，与砂岭杂岩向东北伸展有关。每一个向上粗化单元的下部比上部有更多的暴风穿插。第二次旋回（持续时间约250年）是由砂砾岩沉积中的主层理面定义的，解释为砂砾岩复合体的前兆侧向迁移形成的。第三次旋回（持续时间约几十年或更短）被定义为大型槽状交错层状砂岩单元内以活化面为界的单元。这三种不同类型的周期被解释为记录了古黑潮的路径和速度的波动，以响应大的曲流。现代黑潮大曲流的振荡每隔几至10年被解释为对ENSO （El Niño-Southern振荡）事件的响应，也与西太平洋台风频率的减少有关。如果我们的地层学解释是正确的，那么古黑潮-洋流控制的陆架序列记录了古气候的高频振荡对中更新世西太平洋长期enso类事件的响应。
Millennial-, century-, and decadal-scale stratigraphic cyclicities are described from transgressive shelf successions of the Middle Pleistocene Ichijiku and Kakinokidai Formations (ca. 0.7 Ma) in the Boso Peninsula, Japan. The Ichijiku Formation (ca. 400 m thick) represents a shelf sandridge complex developed under the influence of the large meanders of the paleo-Kuroshio Current, and intertongues with outer shelf muddy deposits of the Kakinokidai Formation (ca. 170 m thick) to the northeast. Most of the two formations are classified as a transgressive systems tract formed during the rise in glacioeustasy from oxygen isotope stages 18 to 17. Three different types of cyclicities are identified in the transgressive shelf deposits. The first cyclicity (ca. 3000 years duration) is represented by coarsening-upward units of the Kakinokidai Formation associated with the northeastward extension of the sandridge complex. Lower parts of each coarsening-upward unit are characterized by intercalations of tempestites more than the upper parts. The second cyclicity (ca. 250 years duration) is defined by master bedding surfaces within sandridge deposits, interpreted as formed in response to lateral migration of foresets of the sandridge complex. The third cyclicity (ca. a few decades or shorter duration) is defined as the units bounded by reactivation surfaces within large-scale trough cross-bedded sandstone units. The three different types of cyclicities are interpreted to document fluctuations in the paths and speeds of the paleo-Kuroshio Current in response to the large meanders. Oscillations of the large meanders of the modern Kuroshio Current every few to 10 years are interpreted to be in response to ENSO (El Niño-Southern Oscillation) events, and are also associated with the decrease in frequency of typhoons in the western Pacific. If our stratigraphic interpretation is true, the paleo-Kuroshio-Current-controlled shelf successions document high-frequency oscillations in paleoclimates responding to the long-term ENSO-like events in the western Pacific during the Middle Pleistocene.
DOI：
10.1007/bf02107107
发表时间：
1975-07
期刊：
Journal of the Oceanographical Society of Japan
影响因子：
--
作者：
H. Nitani
通讯作者：
H. Nitani