The Hahajima Seamount is located at the junction between the Izu–Bonin and Mariana forearc slopes in the northwest Pacific Ocean, and between the Philippine Sea Plate and the Ogasawara Plateau on the Pacific Plate. Despite numerous previous studies, the origin of the Hahajima Seamount remains controversial. Here we constrain its origin based on sedimentological and chronological analyses of shallow‐water carbonates collected from the eastern slope of the seamount. The carbonates are dominated by floatstones with numerous mollusks. Gravel‐sized bioclasts include mollusks (e.g. nerineids and rudists) and local calcareous spines and minor amounts of corals. Sand‐sized components include bioclasts of benthic foraminifers and dasycladalean algae, and non‐skeletal grains of intraclasts and peloids, with no ooids. Most of the bioclasts are bioeroded and coated with micrite envelopes. The Sr isotope ages of the samples fell into two ranges: Berriasian or Aptian (140.3 Ma or 118.3–113.2 Ma, respectively) and Coniacian to Campanian (86.5–77.2 Ma). Shallow‐water carbonates on the Hahajima Seamount are similar in lithology and Sr isotope ages to those on the Ogasawara Plateau located to the east, on the opposite side of the Izu–Bonin Trench (i.e. on the Pacific Plate). This indicates that the shallow‐water carbonates on the eastern slope of the Hahajima Seamount were not deposited in situ, but instead originated from the Ogasawara Plateau. The eastern section of this seamount can thus be interpreted as an accretionary wedge.

中文翻译：

---

菲律宾海板块伊豆-波宁弧与太平洋板块小gas原高原碰撞带哈哈马海山东坡碳酸盐岩的构造意义

Hahajima海山位于西北太平洋伊豆-波宁和马里亚纳前臂斜坡之间的交界处，以及菲律宾海板块与太平洋板块的小gas原高原之间的交界处。尽管进行了许多先前的研究，但Hahajima Seamount的起源仍存在争议。在这里，我们根据从海山东坡收集的浅水碳酸盐岩的沉积学和年代学分析，来限制其起源。碳酸盐以具有大量软体动物的浮石为主。砾石大小的生物碎屑包括软体动物（例如，神经氨酸盐和红血球）和当地的钙质棘和少量的珊瑚。沙粒大小的成分包括底栖有孔虫和达斯克拉达兰藻类的生物碎屑，以及碎屑和类胶质的非骨骼颗粒，没有阿片类物质。大多数生物破骨细胞都经过了生物侵蚀，并涂有微晶石包膜。样品的Sr同位素年龄分为两个范围：Berriasian或Aptian（分别为140.3 Ma或118.3-113.2 Ma）和Coniacian到Campanian（86.5-77.2 Ma）。Hahajima海山上的浅层碳酸盐岩的岩性和Sr同位素年龄与伊豆–Bonin海沟对面（即太平洋板块）东部的小gas原高原的浅层碳酸盐岩相似。这表明Hahajima海山东坡上的浅水碳酸盐不是原地沉积的，而是源自小gas原高原。因此，该海山的东部可以解释为增生楔。分别）和科尼亚西至坎帕尼亚（86.5-77.2 Ma）。Hahajima海山上的浅层碳酸盐岩的岩性和Sr同位素年龄与伊豆–Bonin海沟对面（即太平洋板块）东部的小gas原高原的浅层碳酸盐岩相似。这表明Hahajima海山东坡上的浅水碳酸盐不是原地沉积的，而是源自小gas原高原。因此，该海山的东部可以解释为增生楔。分别）和科尼亚西至坎帕尼亚（86.5-77.2 Ma）。Hahajima海山上的浅层碳酸盐岩的岩性和Sr同位素年龄与伊豆–Bonin海沟对面（即太平洋板块）东部的小gas原高原的浅层碳酸盐岩相似。这表明Hahajima海山东坡上的浅水碳酸盐不是原地沉积的，而是源自小gas原高原。因此，该海山的东部可以解释为增生楔。这表明Hahajima海山东坡上的浅水碳酸盐不是原地沉积的，而是源自小gas原高原。因此，该海山的东部可以解释为增生楔。这表明Hahajima海山东坡上的浅水碳酸盐不是原地沉积的，而是源自小gas原高原。因此，该海山的东部可以解释为增生楔。