Study on uplift and erosion history in the Outer Belt of Southwest Japan

我们发现，古地表广泛分布在高海拔地区，它们正在被熊野河切割。熊野河的一条支流中原河(Nakahara River)有一些灯笼，它们逆流而上，侵蚀附近的山坡。尤其是倾斜边坡，由于下切和重力变形而变得不稳定。熊野河上游的Tennokawa河的大部分支流都有灯笼，支流在灯笼上方的古地表内。提示点以上支流的长河剖面向下游延伸，重建了古田野川河的长河剖面。重建后的河床位于当前田野川河河床上方约150米处。我们在古河床上发现了一层砾石层，并通过宇宙核素测年确定了它的年代为30ka。30ka中150m的切削率很高，表明该地区具有稳定的隆升速率。

We found that paleosurfaces are widely distributed in higher elevations and that they are being incised by the Kumano River. The Nakahara River, a tributary of the Kumano River, has knickpoints propagating upstream and undercutting nearby slopes. Dip slopes in particular are destabilized by the undercutting and gravitationally deformed. Most of the tributaries of the Tennokawa River, the upstream portion of the Kumano River, have knickpoints, above which the tributaries are within paleosurfaces. The long river profiles of the tributaries above knickpoints were extended downstream to reconstruct long river profiles of the paleo Tennnokawa River. The reconstructed river bed was about 150 m above the river bed of the current Tennnokawa River. We found a gravel bed on the paleo river bed and dated it 30 ka by cosmogenic nuclide dating. The incision rate of 150 m in 30 ka is very high, suggesting a consistent uplift rate in this area.