拗拉槽，也称裂堑、裂陷槽、拗拉谷、大陆裂谷，板块构造理论认为：大陆三叉裂谷系形成初期，由于地幔柱的上升，产生了由正断层组成的三叉断裂系统，随着地幔柱的不断隆起，初始的断裂体系开始扩张，根据同一力学体系应力优先释放原理，三叉断裂体系必然有一支断裂系得不到充分的发展。其中2支继续发展成为新的大洋，另一支没有得到充分发展的断裂系就成为拗拉槽。因此，由地幔柱上隆引发的拗拉槽是面对大洋且尾端伸进大陆内部，长期发育、充填沉积的陆内裂谷或地堑。其基本的地质特征是：

拗拉槽是对术语"aulacogen"的音译。出自希腊语aulax (垄沟)。由苏联地质学家尼古拉·沙特茨基于1946年提出.

In geology, an aulacogen or aulocogen is a failed arm of a triple junction of a plate tectonics rift system. A triple junction beneath a continental plate initiates a three way breakup of the continental plate. As the continental break-up develops one of the three spreading ridges typically fails or stops spreading. The resulting failed rift is called an aulacogen and becomes a filled graben system within the continent.