!"#$%&'()*+,-*./0,&/1*2%&)-* * * 3*4&'-5*+%6&*7*7*7*7*7** 9:(19+%(-9*%5*+,-*>)??2&#/012&+@4)+0-%+,-.#>:?+,-.&7* 8,-*&'>-&*9'1-9*5:$$*4:0G*:(1*+,-*)&%6(1*'9*5%&;-1*4/*:(* !"#8,-*90&:;4$-*1%<(*5&%;*+,-*&%:1*+%*+,-*;%6+,*%5*+,-* :99%&+;-(+*%5*$%%9-*4%6$1-&9*:(1*9,'()$-*4:(G97** ./0,&/1*;͚ƚŚĞŽŶĨůƵĞŶĐĞ͛=*'9*%>-&*9+--#$/*+'$+-1*4-19*%5*+,-* * $%%&'#()*&+,-.&#/012&+*ʹ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ig:99%&+;-(+*%5*$%%9-*4%6$1-&9*:(1*9,'()$-*4:(G97* A: Upper Limestone Shales at the confluence* # ./0,&/1*;͚ƚŚĞŽŶĨůƵĞŶĐĞ͛=*'9*%>-&*9+--#$/*+'$+-1*4-19*%5*+,-* * $%%&'#()*&+,-.&#/012&+!"#$%&'()*+,-**ʹ*:$+-&(:+'()*4-19*%5*$';-9+%(-*./0,&/1*2%&)-* A"#L(*+,-*(%&+,-:9+*9'1-*%5*+,-*&'>-&*M+&6-*&'),+*4:(G=B*(-:&* Fig C: Lime waste# :(1*;619+%(-?9,:$-7* * 3"#@(*+,-*4-1*%5*+,-*A-$$+-B*'5*+,-*<:+-&*5$%<*'9*$%<B*+,-* * +,-*:00-99*+&:0GB*:*<,'+-N)&-/*1-#%9'+*0:(*4-*9--(*'(*:* SWOAPG Sychryd Gorge 3*4&'-5*+Area* Resources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͚ƚŚĞŽŶĨůƵĞŶĐĞ͛=*'9*%>-&*9+--#$/*+'$+-1*4-19*%5*+,-* * &'>-&*:(1*'9*0$-:&$/*0%()$%;-&:+'0*'-*0%(+:'(9*#-44$-9B* ͚ZŽŽƚƐdƌĂǀĞƌƐĞ͛=B*:*+,'(*%6+0&%#*%5*9:(19+%(-*9+&-+0,-9* $%%&'#()*&+,-.&#/012&+*ʹ*:$+-&(:+'()*4-19*%5*$';-9+%(-* +,-*+%#*%5*+,-*4:(G7* Exploring the Geology of the Sychryd Gorge A Brief Tour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n the bed of the Mellte, '(*0%(+&:9+*+%*+,-*-:&$'-&*$';-9+%(-B*+,'9*9:(19+%(-*'9* if the water flow is low, the 1'##'()*9%6+,<:&197* 1. The scramble down from the contact between the Upper * * ** road to the mouth of the Limestone Shales and the * Sychryd (‘the Confluence’) is over Basal Grit can be seen. The steeply 9lted beds of the Upper Basal Grit here forms the Limestone Shales – alternang bed of the river and is * beds of limestone and mudstone/ Fig A: Upper Limestone Shales at the clearly conglomerac ie confluence# shale. * contains pebbles, almost all Fig A: Upper Limestone Shales at the confluence# * are quartz. * 3"#@(*+,-*4-1*%5*+,-*A-$$+-B*'5*+,-*<:+-&*5$%<*'9*$%<B*+,-* Fig C: Lime waste # !"#$%&'()*+,-*./0,&/13"#@(*+,-*4-1*%5*+,-*A-$$+-B*'5*+,-*<:+-&*5$%<*'9*$%<B*+,-*0%(+:0+*4-+<--(*+,-*2%&)-* *$%%&'#()*&+,-.&#/012&+*:(1*+,-*Fig C: 41+12#Lime waste# * * *0%(+:0+*4-+<--(*+,-*$%%&'#()*&+,-.&#/012&+*:(1*+,-*41+12# * Fig B: Basal Grit in the bed of the M ellte:# 5'),*0:(*4-*9--(7*8,-*C:9:$*2&'+*,-&-*5%&;9*+,-*4-1*%5*+,-*5'),*0:(*4-*9--(7*8,-*C:9:$*2&'+*,-&-*5%&;9*+,-*4-1*%5*+,-* B"#3+*+,-*&'>-&*4-(1B*(-:&*+,-*+&--*<'+,*-"#%9-1*&%%+9*M!"#! 3*4&'-5*+%6&*7*7*7*7*7** 9:(19+%(-9*%5*+,-*>)??2&#/012&+@4)+0-%+,-.#>:?+,-.&7* B"#3+*+,-*&'>-&*4-(1B*(-:&*+,-*+&--*<'+,*-"#%9-1*&%%+9# *M!"#! 8,-*&'>-&*9'1-9*5:$&'>-&*:(1*'9*0$-:&$/*0%()$%;-&:+'0*'-*&'>-&*:(1*'9*0$-:&$/*0%()$%;-&:+'0*'-*$*4:0G*:(1*+,-*)&%6(1*'9*5%&;-1*4/*:(*0%(+:'(9*#-44$-9B*0%(+:'(9*#-44$-9B*͚ZŽŽƚƐdƌĂǀĞƌƐĞ͛=B*:*+,'(*%6+0&%#*%5*9:(19+%(-*9+&-+0,-9*͚ZŽŽƚƐdƌĂǀĞƌƐĞ͛=B*:*+,'(*%6+0&%#*%5*9:(19+%(-*9+&-+0,-9* !"#8,-*90&:;4$-*1%<(*5&%;*+,-*&%:1*+%*+,-*;%6+,*%5*+,-* :$;%9+*:$$*:&-*D6:&+E7* :99%&+;-(+*%5*$%%9-*4%6$1-&9*:(1*9,'()$-*4:(G97*:$;%9+*:$$*:&-*D6:&+E7* * :0&%99*+,-*&'>-&7*8,-9-*9:(19+%(-96":0&%99*+,-*&'>-&7*8,-9-*9:(19+%(-9#F-:1'()*6#*+,-*(:&&%<*)%&)-*%5*+,-*./0,&/1*/%6*:$;%9+**:&-*+/#'0:$*%5*+,-# *:&-*+/#'0:$*%5*+,-# %&#!",!/./,4$,)4!/4+*!;͚ůƵĞ^ƚĂůDŝŶĞ͛7!+,*$!*0)!'()(*!+,-.! ./0,&/1*;͚ƚŚĞŽŶĨůƵĞŶĐĞ͛=*'9*%>-&*9+--#$/*+'$+-1*4-19*%5*+,-*3. Heading up the narrow gorge of the Sychryd you almost immediately enter the * 4. Upstream of the high arch of the road bridge, the gorge quickly widens out. This is because it 4)+0-%+,-.#>:?+,-.&#=-'*1,)-.H*+,-*$:&)-&*#:&+*'9*5%&;-1* * * ';;-1':+-$/*-(+-&*+,-*;:'(*4%1/*%5*+,-*4)+0-%+,-.#>:?+,-.&#=-'*1,)-.H*+,-*$:&)-&*#:&+*'9*5%&;-1*71'8-.)9&'-:+# $%%&'#()*&+,-.&#/012&+*ʹ*:$+-&(:+'()*4-19*%5*$';-9+%(-*main body of the Carboniferous Limestone – a very hard rock but one which is crosses the 5&%;*;619+%(-9*46+*%00:9'%(:$*9:(19+%(-9*:##-:&7*8,-/*Dinas Fault beyond which are the easily eroded mudstones and thin sandstones of $,!*0)!($2*01*#2)!9)-*!./,&!+(!-9$$4)4:! A"#L(*+,-*(%&+,-:9+*9'1-*%5*+,-*&'>-&*M+&6-*&'),+*4:(G=B*(-:&* ()*&+,-.&5&%;*;619+%(-9*46+*%00:9'%(:$*9:(19+%(-9*:##-:&7*8,-/**ʹ*:*>-&/*,:&1*&%0G*46+*%(-*<,'0,*'9*9%$64$-*'(* :(1*;619+%(-?9,:$-7* soluble in even mildly acidic water. The Sychryd has cut a passage through this band the Middle Shales/Bishopston Mudstone&-9'9+*-&%9'%(*&:+,-&*4-++-&*+,:(*+,-*;619+%(-97*O%+-*+,:+B*%&#!",!/./,4$,)4!/4+*!. The river sides fall back and the ground is formed by ;͚ůƵĞ^ƚĂůDŝŶĞ͛7!+,*$!*0)!'()(*!+,-.! Fig! D: erosion resistant sandstone within mudstones# +,-*:00-99*+&:0GB*:*<,'+-N)&-/*1-#%9'+*0:(*4-*9--(*'(*:* '(*0%(+&:9+*+%*+,-*-:&$'-&*$';-9+%(-B*+,'9*9:(19+%(-*'9* * of limestone; its flow has moulded the shapes of the gorge sides with potholes and an assortment of loose boulders and shingle banks.$,!*0)!($2*01*#2)!9)-*!./,&!+(!-9$$4)4:->-(*;'$1$/*:0'1'0*<:+-&7*8,-*./0,&/1*,:9*06+*:*#:99:)-*&-9'9+*-&%9'%(*&:+,-&*4-++-&*+,:(*+,-*;619+%(-97*O%+-*+,:+B*! # >-)-+:+-1*4:(G7*8,'9*'9*:*;:(N;:1-*1-#%9'+H*<:9+-*2)*&* 1'##'()*9%6+,<:&197* +,&%6),*+,'9*4:(1*%5*$';-9+%(-H*'+9*5$%<*,:9*;%6$1-1*+,-*'(*0%(+&:9+*+%*+,-*-:&$'-&*$';-9+%(-B*+,'9*9:(19+%(-*'9* scallop markings. The thick beds of limestone dip northwards ie towards the Mellte 1:+'()*5&%;*+,-*1:/9*<,-(*:*$';-G'$(*<:9*'(*%#-&:+'%(*:+* * ! C"#C$:0G*0%$%6&-1*;619+%(-*0:(*4-*9--(*'(*#$:0-9*'(*+,-* * ** * 1'##'()*9%6+,<:&197* at around 30degrees. +,-*+%#*%5*+,-*4:(G7* 9,:#-9*%5*+,-*)%&)-*9'1-9*<'+,*#%+,%$-9*:(1*90:$$%#* 4:(G9*%5*+,-*&'>-&H*+,-*4$:0G-&*+,-*0%$%6&B*+,-*,'),-&*'+9* ;:&G'()97* *8,-*+,'0G*4-19*%5*$';-9+%(-*1'#*(%&+,<:&19*'-* * ** * * 0:&4%(*0%(+-(+7*8,%9-*<'+,*,'),-9+*0:&4%(*0%(+-(+*;'),+* 5. On the northeast side of the 6. At the river bend, near +%<:&19*+,-*A-$$+-*:+*:&%6(1*IJ1-)&--97* 4-*0%(9'1-&-1*1'&+/*0%:$97*8,-*0:&4%(*'9*:$$*+,:+*'9*$-5+*%5* river (true right bank), near the the tree with exposed roots * >-)-+:+'%(*<,'0,*1'-1*:(1*<:9*0%;#:0+-1*:(1*<,'0,B*%>-&* access track, a white-grey deposit (the ‘Roots Traverse’), a ;"#K#9+&-:;*%5*+,-*,'),*:&0,*%5*+,-*&%:1*4&'1)-B*+,-*)%&)-* can be seen in a vegetated bank. thin outcrop of sandstone ;'$$'%(9*%5*/-:&9B*+6&(-1*+%*9+%(-7*8,-&-*'9*9%;-*'&%(N This is a man-made deposit; Fig B: Basal Grit in the bed of the M ellte:# stretches across the river. D6'0G$/*<'1-(9*%6+7*8,'9*'9*4-0:69-*'+*0&%99-9*+,-*<).1+#=1:2,* 9+:'('()*M&69+N0%$%6&=*:(1*:*/-$$%<*0%$%&:+'%(*%(*9%;-*&%0G* waste lime dang from the days # These sandstones are 4-/%(1*<,'0,*:&-*+,-*-:9'$/*-&%1-1*;619+%(-9*:(1*+,'(** 96&5:0-9*<,'0,*'9*2)*-.),&#M5')*!=7#* when a limekiln was in operaon 6"#F-:1'()*6#*+,-*(:&&%<*)%&)-*%5*+,-*./0,&/1*/%6*:$;%9+*typical of the Bishopston Fig E: Iron within mudstones at the top of the bank. ';;-1':+-$/*-(+-&*+,-*;:'(*4%1/*%5*+,-*Fig E: Iron within mudstones! 71'8-.)9&'-:+# Mudstone FormaCon ; the ! ()*&+,-.&! Fig B*ʹ:*:*>-&/*,:&1*&%0G*46+*%(-*<,'0,*'9*9%$64$-*'(* Basal Grit in the bed of the M ellte:larger part is formed from # Fig D: erosion resistant! sandstone within mudstones# ->-(*;'$1$/*:0'1'0*<:+-&7*8,-*./0,&/1*,:9*06+*:*#:99:)-* * # "#!"!#$%&'!()%*+$,!$-!./,&!$,!*0)!,$#*01*#2)!#+30*!(+4)!$-!# mudstones but occasional "#!"!#$%&'!()%*+$,!$-!./,&!$,!*0)!,$#*01*#2)!#+30*!(+4)!$-! Fig A: Upper Limestone Shales at the confluence# +,&%6),*+,'9*4:(1*%5*$';-9+%(-H*'+9*5$%<*,:9*;%6$1-1*+,-*"# C"#C$:0G*0%$%6&-1*;619+%(-*0:(*4-*9--(*'(*#$:0-9*'(*+,-* *0)!#+5)#!6!"#$! $%&$͚>ŽǁĞƌƌŝĚŐĞdƌĂǀĞƌƐĞ͛Žƌ͚%&'()*+,-$sandstones appear. They "# * 9,:#-9*%5*+,-*)%&)-*9'1-9*<'+,*#%+,%$-9*:(1*90:$$%#*6"#F-:1'()*6#*+,-*(:&&%<*)%&)-*%5*+,-*./0,&/1*/%6*:$;%9+*4:(G9*%5*+,-*&'>-&H*+,-*4$:0G-&*+,-*0%$%6&B*+,-*,'),-&*'+9**0)!#+5)#!6!"#$! $%&$͚>ŽǁĞƌƌŝĚŐĞdƌĂǀĞƌƐĞ͛Žƌ͚%&'()*+,-$ ;:&G'()97ŽƌŶĞƌ͛7!*4+(89/'(!/!3)$9$3+%/9!-/29*:!;0+(!+(!$,)!$-!/!(</#=!$-!8,-*+,'0G*4-19*%5*$';-9+%(-*1'#*(%&+,<:&19*'-* resist erosion rather beQer 3"#@(*+,-*4-1*%5*+,-*A-$$+-B*'5*+,-*<:+-&*5$%<*'9*$%<B*+,-* Fig C';;-1':+-$/*-(+-&*+,-*;:'(*4%1/*%5*+,-*: Lime waste# 71'8-.)9&'-:+#0:&4%(*0%(+-(+7*8,%9-*<'+,*,'),-9+*0:&4%(*0%(+-(+*;'),+* +%<:&19*+,-*A-$$+-*:+*:&%6(1*IJ1-)>>?@AAB!/9+3,)4!-/29*(!<0+%0!#2,!*0#$230!*&--97* 0)!%$/9-+)94!/,4!than the mudstones.