Differential rotations of north Kyushu Island related to middle Miocene clockwise rotation of SW Japan
Differential rotations of north Kyushu Island related to middle Miocene clockwise rotation of SW Japan
复制标题
北九州岛的差分旋转与日本西南部中中新世顺时针旋转有关
DOI：
10.1029/97jb01343
复制
发表时间：
1997
影响因子：
--
通讯作者：
N. Ishikawa
中科院分区：
文献类型：
--
作者：
N. Ishikawa
对九州岛北部白垩纪花岗岩和第三纪沉积岩样品进行了古地磁测量，以阐明15 Ma时日本西南部构造块体顺时针（CW）旋转的运动学。北九州岛北方渐新世沉积岩的古地磁方向显示该地区相对于东亚有明显的顺时针旋转（R=35.9°±11.0°），而北九州岛西部渐新世至早中新世沉积岩的古地磁方向则没有明显的构造位移。北九州岛西南部始新世沉积岩的原位二次磁化方向和白垩纪花岗岩的稳定剩磁提供了衰减的CW偏转。这些古地磁数据与以前的研究结果相结合，表明北九州岛（主九州）的主体在30 ~ 14 Ma之间相对于东亚发生了顺时针（36°）旋转，而西部（西九州）自20 Ma以来没有发生明显的构造位移。考虑到区域地质构造，古地磁结果表明，西日本构造块体的西部范围经历了中中新世CW旋转被截断的主九州以西。古地磁数据还表明，30 ~ 14 Ma期间，九州本岛相对于日本西南部主要地区逆时针旋转（28° ± 13°）。这一结果意味着，在整个块体的CW旋转期间，日本西南块体的最西部（主九州）没有经历像其主体部分那样多的旋转。
Paleomagnetic measurements were made on samples of Cretaceous granites and Tertiary sedimentary rocks from north Kyushu Island in order to clarify the kinematics of clockwise (CW) rotation of the SW Japan tectonic block at 15 Ma. A paleomagnetic direction from Oligocene sedimentary rocks in the northern part of north Kyushu Island indicates a significant CW rotation of the region (R=35.9°±11.0°) relative to eastern Asia, while the direction from Oligocene to early Miocene sedimentary rocks in the western part of north Kyushu Island shows no significant tectonic displacement. In situ directions of secondary magnetization from Eocene sedimentary rocks in the southwestern part of north Kyushu Island, and stable remanences from Cretaceous granites, provide CW deflections of declination. These paleomagnetic data, combined with those previously reported, suggest that the main part of north Kyushu Island (Main Kyushu) was rotated CW (36°) between 30 and 14 Ma relative to eastern Asia, whereas no significant tectonic displacement has taken place since 20 Ma in the western part (Western Kyushu). Considering regional geological structures, the paleomagnetic results indicate that the western extent of the SW Japan tectonic block which experienced middle Miocene CW rotation is truncated west of Main Kyushu. The paleomagnetic data also suggest that Main Kyushu rotated counterclockwise (28° ± 13°) relative to the main part of SW Japan between 30 and 14 Ma. This result implies that the westernmost part of the SW Japan block (Main Kyushu) did not experience as much rotation as its main part during CW rotation of the whole block.
DOI：
10.1098/rspa.1953.0064
发表时间：
1953-01-01
影响因子：
--
作者：
FISHER, R
通讯作者：
FISHER, R