The 3 mudstone formations

There are three different mudstone formations found in the study area.

Remind yourself how underwater basins were filled with sediments.

Kinderscout Grits

These mudstones are deltaic deposits.
The rocks occur in large, wide horizontal sheets.
This sandstone with little mud composition, indicates a delta origin as shows no signs of meandering streams or incised valleys in the rock.
Therefore, wide, braided channels were once dominant here.
Kinderscout grits are coarse grained because their origins are from the delta mouth, where fluvial systems terminate and drop their heavier load.

These grits were formed by deposits of a major braided river channel.
Much of the deposition of Millstone Grits in Derbyshire originate from large turbidity currents slowing down channels in underwater fans.
Fast moving currents caused by excess density, carried a large sediment load.
As currents slowed, the sedimentary load was dropped as the water comes to rest.
This resulted in long, thin beds of sediment forming at river slow-points - leaving long, thin beds of Millstone Grit rocks

These Grit formations are sand-rich.
They originate from deep-water systems, where turbidity currents issuing from submarine fan channels filled the Central Pennines Basin.
Because they are deep water deposits, they are found today in valley bottoms (e.g. Longdendale, below Torside Reservoir) and other low points.

Rift events during valley infill stages also affected sediment thickness and facies across them.
Fault lines are shown on the transect diagrams as dashed lines (- - - -). Their effect on the rock formation can be clearly seen.
The patterns are caused by sudden changes in rock either side of the fault where one side has slipped sideways or been moved upwards.
Regional subsidence caused by seismic occurrences may also have affected the sediment accumulation within the basins.