Using the kink band method of section construction

[@geologicalWORLD7956]

you use a bisector , but I don't know at what measurement I placed it to draw the arc.

[@robbutler2095]

Project an orthogonal line from pairs of dip sites - where they intersect defines the place, then bisect the angle and draw in this bisector. This define the abrupt fold axial surface and the limbs are defined as panels of constant dip. Does that work for you as explanation?

[@konstantinkuhn3050]

But how do you know that the fold is chevron like in the underground and not with round hinges? I mean, if you have very poor outcrop quality and don‘t see that its a chevron like fold in the outcrop, the chevron assuption might be wrong, right?

[@robbutler2095]

The method REQUIRES abrupt hinges (chevron/kinky) - but, as you note - this might not be appropriate ... this is the nature of all construction/interpretation methods - and a key decision facing an interpreter is to select the appropriate method... see the kink vs Busk film for an illustration of this...

[@konstantinkuhn3050]

@@robbutler2095 Thanks! And btw. currently I‘m in my master in geology and your videos are very interesting and helpful👌

[@robbutler2095]

@@konstantinkuhn3050 Good luck with your studies - enjoy!!

[@m.acr_01]

Nice