▁preserved . ▁During ▁this ▁late ▁stage , ▁smooth ▁pla ins ▁materials ▁were ▁depos ited ▁in ▁bas ins , ▁cr aters , ▁and ▁local ised ▁low ▁areas ▁and ▁have ▁low ▁cr ater ▁density . ▁The ▁young est ▁cr aters ▁are ▁sharp ▁rim med ▁with ▁bright ▁ray s . ▁ ▁The ▁small ▁size ▁of ▁Mercur y , ▁its ▁lack ▁of ▁atmosphere , ▁and ▁the ▁cr ater ed ▁nature ▁of ▁its ▁surface ▁inv ite ▁comparison ▁with ▁the ▁Moon . ▁The ▁ge olog ic ▁histor ies ▁of ▁the ▁two ▁bodies ▁are ▁similar . ▁Both ▁surfaces ▁record ▁a ▁decre asing ▁impact ▁flux . ▁The ▁cr ater ing ▁history ▁of ▁Mercur y ▁was ▁concurrent ▁with ▁episodes ▁of ▁la va ▁flo oding ▁( cr ater ed ▁pla ins ) ▁that ▁may ▁have ▁ob liter ated ▁some ▁bas ins ▁and ▁flo oded ▁large ▁areas ▁in ▁a ▁manner ▁similar ▁to ▁the ▁mare ▁filling ▁on ▁the ▁Moon . ▁Bright - rayed ▁cr aters , ▁such ▁as ▁K ui per , ▁mark ▁the ▁young est ▁events ▁similar ▁to ▁Cop ern ican ▁cr aters ▁on ▁the ▁Moon ; ▁some ▁dark ▁patch es ▁along ▁the ▁west ▁margin ▁of ▁the ▁quad rangle ▁may ▁represent ▁late ▁vol can ism . ▁ ▁Some ▁differences ▁between ▁the ▁Moon ▁and ▁that ▁part ▁of ▁Mercur y ▁observed ▁in ▁this ▁quad rangle ▁may ▁be ▁more ▁apparent ▁than ▁real . ▁Appar ent ▁differences ▁may ▁be ▁the ▁result ▁of ▁resolution ▁of ▁the ▁imag ing ▁system , ▁and ▁small ▁view ing ▁and ▁ill um ination ▁angles ▁that ▁do ▁not ▁allow ▁ins pection ▁of ▁the ▁surface ▁under