Abstract Calcite grains are plastically deformed at lower temperatures than are quartz grains, which means that investigating the microstructures of both minerals should provide useful information regarding the deformation history of faults. We investigated the conditions of deformation and kinematics of fault rocks within the Hatagawa Fault Zone and the Shajigami Shear Zone, Northeast Japan, using deformation microstructures and crystallographic preferred orientations of quartz and calcite. The Hatagawa Fault Zone trends NNW–SSE, and the associated foliated granite cataclasites show sinistral shear. Limestone mylonite samples showing sinistral shearing display girdles of calcite c-axes close to the YZ plane and Z-maximum, suggesting relatively high and low temperatures of deformation, respectively. The Shajigami Shear Zone trends NE–SW, and quartz microstructures in granodiorite mylonites of the shear zone indicate dislocation creep at temperatures of 400–500 °C. The limestone mylonites have Z-maximum patterns of calcite c-axes. These fault rocks were deformed during the Cretaceous (before the Cenozoic 40° counterclockwise rotation of Northeast Japan) in a kinematic framework characterized by a shortening direction that rotated from N–S to NW–SE. The kinematics and deformation ages of the fault rocks correspond to a change in the direction of motion of the Izanagi Plate at c. 100 Ma.

中文翻译：

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日本东北部畑川断层带和Shajigami剪切带断层岩的变形条件和运动学：方解石和石英微结构的洞察

摘要 方解石颗粒在比石英颗粒更低的温度下发生塑性变形，这意味着研究这两种矿物的微观结构应该提供有关断层变形历史的有用信息。我们使用变形微结构和石英和方解石的晶体择优取向研究了日本东北部畑川断层带和 Shajigami 剪切带内断层岩的变形条件和运动学。畑川断层带呈 NNW-SSE 趋势，相关的叶状花岗岩碎裂岩显示出左旋剪切。显示左旋剪切的石灰岩糜棱岩样品显示出接近 YZ 平面和 Z 最大值的方解石 c 轴的环带，分别表明变形温度相对较高和较低。Shajigami剪切带趋势NE-SW，剪切带花岗闪长岩糜棱岩中的石英微结构表明在 400-500 °C 的温度下位错蠕变。石灰岩糜棱岩具有方解石 c 轴的 Z 最大值模式。这些断层岩在白垩纪期间（日本东北部新生代逆时针旋转 40°之前）在运动学框架中变形，其特征是缩短方向从 N-S 旋转到 NW-SE。断层岩的运动学和变形年龄对应于 c 时伊邪那岐板块运动方向的变化。100 马。这些断层岩在白垩纪期间（日本东北部新生代逆时针旋转 40°之前）在运动学框架中变形，其特征是缩短方向从 N-S 旋转到 NW-SE。断层岩的运动学和变形年龄对应于 c 时伊邪那岐板块运动方向的变化。100 马。这些断层岩在白垩纪期间（日本东北部新生代逆时针旋转 40°之前）在运动学框架中变形，其特征是缩短方向从 N-S 旋转到 NW-SE。断层岩的运动学和变形年龄对应于 c 时伊邪那岐板块运动方向的变化。100 马。