Upper Flood Swallet geology photos by Mark Tringham

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Calcite veining, with en-echelon arrays Calcite veining, with en-echelon arrays	Calcite veining, with en-echelon arrays Calcite veining, with en-echelon arrays	En-echelon arrays are formed by shear failure of the host rock, the failure angle generally being at about 30 degrees to the maximum principal stress En-echelon arrays are formed by shear failure of the host rock, the failure angle generally being at about 30 degrees to the maximum principal stress	They form conjugate sets with opposing sense of shear. They form conjugate sets with opposing sense of shear.
The veins themselves form due to secondary extension within the shear zone The veins themselves form due to secondary extension within the shear zone	What looks superficially like a sedimentary conglomerate is in fact cobble sized limestone clasts within a mineral vein. What looks superficially like a sedimentary conglomerate is in fact cobble sized limestone clasts within a mineral vein.	The clasts have a rind of weathering alteration and are enclosed in greyish-white calcite or other white carbonate mineral. The clasts have a rind of weathering alteration and are enclosed in greyish-white calcite or other white carbonate mineral.