Here it can be clearly seen how the cave was formed along a bedding plane, the horizontal line marking the boundary between two layers of limestone, but the direction the cave has taken is determined by more complex factors. Why does Black Keld resurge where it does, when the dip of the limestone (the angle of the bedding plane) leads the caves higher up, away from it? One answer might be that the dip is not constant over the whole locality (and is relatively shallow anyway.) Since the cave lies on the base of the limestone there may be local unconformities of the underlying rock as well, which would channel the water. There is definitely evidence of joint controlling direction (vertical cracks in the rock). Further in to the cave, faults may also be a factor. |
