１　引言俯冲带增生沉积柱中热数据的一个重要的来源系从似海底反射层（ＢＳＲ）深度获得。这些反射层通常发现于水深数百米的下－中大陆坡之下，用于指示甲烷笼状水合物稳定带的温－压场的底部。稳定场与压力仅具中等相关，原始亚底部深度与温度相关。因此，既然压力易于确定 1 Introduction An important source of thermal data in subduction zone accretionary sedimentary columns is derived from depth like seafloor reflector (BSR). These reflectors are commonly found beneath the lower-middle continental slope hundreds of meters deep to indicate the bottom of the temperature-pressure field of the methane-clathrate hydrate stability zone. The stable field is only moderately correlated with pressure, and the original sub-bottom depth is temperature dependent. Therefore, since the pressure is easy to determine