Due to spreading of Helan and Qinling rift valleys during the Ordovician period, a L-shaped swell belt formed in the western and south - ern parts of the basin.

奥陶纪由于西边贺兰裂谷和南面秦岭裂谷发生扩张裂离，在盆地西缘和南缘产生裂谷肩翘升，形成l形隆起带。

youdao

On the bas is of the regional depositional environment of the ophiolite zone, it indicates a short-term spreading, the ocean-land transform is not complete, and developed on the interarc rift basin .

结合区域沉积环境确定该蛇绿岩带的构造环境为扩张历史暂短、洋陆转换不彻底、发育于消减带上的弧间裂谷盆地。

youdao

"What's different about them is that spreading ridges on the Earth typically spread symmetrically about a rift, " he said.

BBC: Enceladus has 'spreading surface'