Topographic relief in arc-trench systems is thought to be formed by plate subduction; however, few quantitative investigations have so far been reported, with respect to the related mountain building process. This study applies apatite and zircon (U–Th)/He thermochronometry (AHe, ZHe, respectively) to Cretaceous granite rocks in the north part of the northeast (NE) Japan Arc to reveal its cooling/denudation history. Weighted mean AHe ages ranging from 88.6 to 0.9 Ma and ZHe ages from 83.9 to 7.4 Ma were determined for 10 rock samples. Using the AHe data, denudation rates were obtained for each sample. On the fore-arc side, denudation rates of < 0.05 mm/year were calculated, indicating a slow denudation process since the Paleogene. However, in the Ou Backbone Range and on the back-arc side, denudation rates at > 0.1–1.0 mm/year were computed, probably reflecting a recent uplift event since ~ 3–2 Ma. These data indicate a clear contrast in thermal and denudation histories between the tectonic units in this study area, similar to that previously reported from the southern part of NE Japan Arc. A comparison of the thermal/denudation histories between the N- and S- traverses, revealed the arc-parallel trend, the uplift model of the volcanic arc, and some minor variations of thermal/denudation histories in each tectonic unit. This study offers some further insights into the understanding of tectonic processes in an island-arc setting.

中文翻译：

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横跨日本东北弧的 (U–Th)/He 热测时图：了解岛弧环境中的山地建筑

弧形沟系统中的地形起伏被认为是由板块俯冲形成的；然而，迄今为止，关于相关的造山过程的定量调查报告很少。本研究将磷灰石和锆石 (U-Th)/He 热测时法（分别为 AHe、ZHe）应用于日本弧东北部（NE）北部的白垩纪花岗岩，以揭示其冷却/剥蚀历史。10 个岩石样品的加权平均 AHe 年龄范围为 88.6 至 0.9 Ma，ZHe 年龄范围为 83.9 至 7.4 Ma。使用 AHe 数据，获得每个样品的剥蚀率。在前弧侧，计算出<0.05 mm/年的剥蚀率，表明自古近纪以来剥蚀过程缓慢。然而，在 Ou Backbone Range 和弧后侧，计算出的剥蚀率 > 0.1–1.0 mm/year，可能反映了自 ~ 3-2 Ma 以来最近的隆起事件。这些数据表明该研究区构造单元之间的热和剥蚀历史存在明显对比，类似于先前从日本东北弧南部报告的数据。对 N 和 S 横断线之间的热/剥蚀历史进行比较，揭示了弧平行趋势、火山弧的隆起模型以及每个构造单元中的一些热/剥蚀历史的微小变化。这项研究为了解岛弧环境中的构造过程提供了一些进一步的见解。对 N 和 S 横断线之间的热/剥蚀历史进行比较，揭示了弧平行趋势、火山弧的隆起模型以及每个构造单元中的一些热/剥蚀历史的微小变化。这项研究为了解岛弧环境中的构造过程提供了一些进一步的见解。对 N 和 S 横断线之间的热/剥蚀历史进行比较，揭示了弧平行趋势、火山弧的隆起模型以及每个构造单元中的一些热/剥蚀历史的微小变化。这项研究为了解岛弧环境中的构造过程提供了一些进一步的见解。