, ▁relatively ▁young ▁ge omorph ological ▁features . ▁Most ▁f elsen me ers ▁formed ▁during ▁or ▁since ▁the ▁last ▁ice ▁age ▁( appro xim ately ▁ 2 0 , 0 0 0 ▁years ▁ago ). ▁O thers ▁may ▁be ▁pre - g la cial ▁features ▁that ▁surv ived ▁gla ci ation ▁beneath ▁cold - based ▁gla ci ers . ▁Their ▁specific ▁age ▁can ▁be ▁determined ▁using ▁surface ▁expos ure ▁d ating , ▁a ▁technique ▁that ▁works ▁best ▁on ▁materials ▁which ▁have ▁been ▁exposed ▁to ▁cos mic ▁ray s ▁with ▁little ▁inter ference ▁from ▁trees ▁or ▁so ils . ▁ ▁See ▁also ▁Stone ▁run ▁We ather ing ▁ ▁References ▁ ▁Category : R ock ▁form ations ▁Category : Ge omorph ology ▁Category : Ge ot op es <0x0A> </s> ▁The ▁B red en ey ▁Lad ies ▁Open ▁is ▁a ▁tournament ▁for ▁professional ▁female ▁tennis ▁players ▁played ▁on ▁out door ▁cl ay ▁courts . ▁The ▁event ▁is ▁class ified ▁as ▁a ▁$ 2 5 , 0 0 0 ▁I TF ▁Women ' s ▁Circ uit ▁tournament ▁and ▁has ▁been ▁held ▁in ▁Ess en , ▁Germany , ▁since ▁ 2 0 1 3 . ▁ ▁Past ▁final s ▁ ▁Singles ▁ ▁Dou bles ▁ ▁External ▁links ▁▁ ▁I TF ▁search ▁ ▁Official ▁Website ▁▁ ▁Category : IT F ▁Women ' s ▁Circ uit ▁Category : Cl ay ▁court ▁tennis ▁tournament s ▁Category : T ennis ▁tournament s ▁in ▁Germany ▁Category : Rec urr ing ▁sport ing ▁events ▁established ▁in ▁ 2 0 1 3 ▁Category :