Thermal Structure of a Hot Accretionary Complex: Upper Shimanto Group, Shikoku, Japan

俯冲复合体内部的热结构的大多数模型 预测小地热梯度和低热流的出现。 南海地区地温梯度的计算与实测 然而，槽并不支持这种范式。 而且， 高埋藏温度可能影响了 日本南部的整个新生代时期。 的提升部分 南海增生楔沿日本沿着几条 岛屿;最年轻的这些增生地层（始新世-中新世）是 隶属于上四万十组 该项目将收集样品的热成熟度数据， 这是一个由工作人员研究的四万多增生棱镜， 康奈尔大学和布朗大学 实验室方法包括镜质体 反射率和伊利石结晶度。 目标包括测试 利用热成熟度数据和热成熟度记录的构造模型 历史在复杂的各个单位。 由此产生的数据的重要性将远远超出 具体问题。 数据将提供急需的实证检验 现有的热结构理论模型。 更重要的是， 南海/四万托的例子似乎代表了一个 热态谱。 因此，结果可能会迫使 扩大和完善基本概念框架， 俯冲复合体

Most models of thermal structure within subduction complexes predict the occurrences of small geothermal gradients and low heat flow. Calculated and measured geothermal gradients in the vicinity of Nankai Trough, however, do not support this paradigm. Moreover, abnormally high burial temperatures may have affected the accretionary margin of southern Japan throughout Cenozoic time. Uplifted portions of the Nankai accretionary wedge are well exposed along several of the Japanese Islands; the youngest of these accreted strata (Eocene-Miocene) are assigned to the Upper Shimanto Group. This project will collect thermal-maturity data on samples from the Shimanto accretionary prism, which is being studied by workers at Cornell and Brown Universities. Laboratory methods include vitrinite reflectance and illite crystallinity. Objectives include testing tectonic models using thermal-maturity data and documentation of thermal history within individual units of the complex. The significance of the resulting data will extend well beyond site-specific issues. Data will provide a much-needed empirical check on existing theoretical models of thermal structure. More importantly, the Nankai/Shimanto example appears to represent one end member within a spectrum of thermal regimes. Consequently, results will likely force an expansion and refinement of the fundamental conceptual framework of subduction complexes.