0 a deep, narrow crack, especially in rock or the earth --
1 a deep crack, esp. one in rock or ice or in the ground --
In the model under consideration, the width of the fissure is much smaller than the dimension of the adjacent block.
These changes opened up a series of structural fissures and internal conflicts.
However, a significant amount of extension is still represented by the sediment-filled fissures.
Some smaller cavities, or larger cavities with restricted access to the unconformity, were apparently filled by sediment that trickled down into the fissure system.
The reptiles and mammals found in the fissure deposits are found, most frequently, in the form of numerous disarticulated skeletal elements.
Some fissure-fills contain angular fragments of wall-rock that can be matched to the adjacent margin.
For some permeability ratios and fissure widths, the large-scale description is achieved by introducing the so-called double porosity model.
But this attempt fizzled, undermined by internal fissures and regional pressures that still preclude a strong central state.