Editing Quaternary geology and geomorphology of the area around Kisdon, upper Swaledale - an excursion

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=== Locality 4. Continue along the track to Ramps Holme Bridge across the River Swale [SD 9105 9860] ===
 
=== Locality 4. Continue along the track to Ramps Holme Bridge across the River Swale [SD 9105 9860] ===
  
Well-developed river terraces can be seen adjacent to both the east [SD 9100 9995]–[SD 9090 9965] and west [SD 9065 0045]–[SD 9085 0035] banks of the Swale sloping at an angle steeper than that of the present river. Several poor sections show that these are formed of rounded boulders in a gravel and sand matrix. These terraces formed as fans at the mouth of the Swale gorge but have been dissected as the river eroded upstream as far as Kisdon Force. A small fan is developed at [SD 908 992] where Arn Gill changes gradient from the steep hillside to the low angle valley bottom. The river between Hartlakes and Ramps Holme Bridge shows well-developed active braiding and adjacent low terraces. These very coarse-grained bedforms have developed here due to the introduction of mining waste into the river. Progressive formation and dissection of these features results in small terraces, which like all the other terraces in the region are of local significance only.
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Well-developed river terraces can be seen adjacent to both the east [SD 9100 9995]–[SD 9090 9965] and west [SD 9065 0045]–[SD 9085 0035] banks of the Swale sloping at an angle steeper than that of the present river. Several poor sections show that these are formed of rounded boulders in a gravel and sand matrix. These terraces formed as fans at the mouth of the Swale gorge but have been dissected as the river eroded upstream as far as Kisdon Force. A small fan is developed at [SD 908 992] where Am Gill changes gradient from the steep hillside to the low angle valley bottom. The river between Hartlakes and Ramps Holme Bridge shows well-developed active braiding and adjacent low terraces. These very coarse-grained bedforms have developed here due to the introduction of mining waste into the river. Progressive formation and dissection of these features results in small terraces, which like all the other terraces in the region are of local significance only.
  
 
=== Locality 5. Take the footpath to Muker [SD 9100 9790] ===
 
=== Locality 5. Take the footpath to Muker [SD 9100 9790] ===
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=== Locality 6. Take the footpath to Thwaite [SD 8930 9820] via a short section of road at Usha Gap [SD 902 979] ===
 
=== Locality 6. Take the footpath to Thwaite [SD 8930 9820] via a short section of road at Usha Gap [SD 902 979] ===
  
Part of Muker and the eastern section of the path are on a kame terrace [SD 9090 9790]–[SD 9050 9800] which was formed when a lake was dammed between ice lobes in the Swale and Muker Beck valleys. The gradient of this terrace is less than the adjacent rivers reflecting sediment supply from both ice sources. While the kame terrace formed, Kisdon acted as a '''nunatak'''. West and south of the kame terrace the land is at a lower level, originating as an ice-tongue hollow (around [SD 904 979]). This is now infilled with low-level river terraces formed in response to high flood events, such as that of 1883, when the Swale reached a level of 9.4  at Keld. At Usha Gap the nose of the massive debris flow extends across the north side of the valley (around [SD 901 981]), having originated from a scar just below Kisdon Farm (around [SD 902 984]). Between Usha Gap and Thwaite the footpath passes a classic nickpoint [SD 8985 9815] formed at the limit of incision by Skeb Skeugh into the fan of Thwaite Beck. At this point the active floodplain of Skeb Skeugh becomes a fossil terrace. At the south side of Thwaite Beck small kames can be seen surrounded by river gravels (around [SD 896 980]). These kames must have been formed in the valley bottom during ice stagnation, then, following ice-wastage they have been almost buried by river sedimentation.
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Part of Muker and the eastern section of the path are on a kame terrace [SD 9090 9790]–[SD 9050 9800] which was formed when a lake was dammed between ice lobes in the Swale and Muker Beck valleys. The gradient of this terrace is less than the adjacent rivers reflecting sediment supply from both ice sources. While the kame terrace formed, Kisdon acted as a nunatak. West and south of the kame terrace the land is at a lower level, originating as an ice-tongue hollow (around [SD 904 979]).
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This is now infilled with low-level river terraces formed in response to high flood events, such as that of 1883, when the Swale reached a level of 9.4 m at Keld. At Usha Gap the nose of the massive debris flow extends across the north side of the valley (around [SD 901 981]), having originated from a scar just below Kisdon Farm (around [SD 902 984])
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 +
Between Usha Gap and Thwaite the footpath passes a classic nickpoint [SD 8985 9815] formed at the limit of incision by Skeb Skeugh into the fan of Thwaite Beck. At this point the active floodplain of Skeb Skeugh becomes a fossil terrace. At the south side of Thwaite Beck small kames can be seen surrounded by river gravels (around [SD 896 980])
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These kames must have been formed in the valley bottom during ice stagnation, then, following ice-wastage they have been almost buried by river sedimentation.
  
 
=== Locality 7. Continue along the footpath through Skeb Skeugh to the road at [SD 8890 9940], then along the road to Angram [SD 8875 9975] ===
 
=== Locality 7. Continue along the footpath through Skeb Skeugh to the road at [SD 8890 9940], then along the road to Angram [SD 8875 9975] ===

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