,! ,butt}ton-,swynn}ton dykes "<or "s"ts s+ul>ly1 ! ,butt}ton dyke"> >e an assemblage ( igne|s 9tru.ns : ext5d 9 a r|<ly nor?-nor?we/ to s|?-s|?1/ align;t "? ,/af=d%ire 9 ! ,5gli% ,midl&s4
,! dykes 7 f/ id5tifi$ 9 ! #ahdjs by ,*>les ,d>w9 & sep>ately by ,james ,kirkby4 ,2ss _! surface |tcrop1 geophysical te*niques "<grav;y & magnetic surveys"> h all{$ _! c|rse to 2 mapp$ 9 "s detail ov} a #ae km l;g corridor :1 9 ! case ( p>allel 9tru.ns1 is up to #gejm wide 9 places4 ,! dykes : >e ne>-v}tical ?|< _h+ to ! we/ at up to #ae~j1 v>y f ab #am to a maximum ( #bgm 9 wid?4 ,! dykes >e ( v>iable composi;n b >e g5}ally ( ! alkal9e-basalt type4 ,! ea/,-we/ tr5d+ ,swynn}ton fault (fsets ! dyke 9 a s9i/ral mann}4 ,sph}oidal w1!r+ ( expos$ sec;ns ( ! dykes has focuss$ on cool+ jo9ts pres5t )9 ! body ( 9trusive rock4
,radiometric dat+ ( ! dykes has return$ ages ( >.d #eb million ye>s = _! emplace;t ?|< an old} age ( >.d #fa million ye>s has al be5 su7e/$ by m1sure;ts4 ,small scale 3tact metamorphism ( ! c.try rocks 9to : ! dykes 7 9trud$ has be5 not$ at s"eal localities4
,o!r dykes ( ? g5}al age 9 nor!rn ,5gl& h be5 associat$ ) volcanism : took place at ! ,isle ( ,mull igne|s c5tre 9 we/}n ,scotl& dur+ ! e>ly ,palaeog5e ,p}iod at a "t ( regional cru/al t5.n associat$ ) ! op5+ ( ! nor? ,atlantic ,oc1n & : result$ 9 ! 9tru.n ( 9num}able dykes4