Sketching cross-sections - Isle of Wight

Interpreting a simplified geological map of this classic area - drawing a sketch cross-section to build understanding of the geological structure. Part of "The Shear Zone" video channel. A copy of the map is available on the Shear Zone website (see link from Channel home page).

[@markfishersolosailing7033]

It's a real shame that the KT boundary has been eroded away and not visible, especially in Alum bay where it would be great to see.

[@robbutler2095]

Yes - not really any KT boundary sections to play with there ... need to go to Italy!

[@user-ij3qo6xl9s]

Thanks. Very clear. I think the map can be divided into two areas, strike-slip region to thrust and fold region, according to your teaching.

[@robbutler2095]

Not sure I understand your reasoning. The Isle of Wight displays a simple fold pair/monocline. Incidentally - check out the video Basin Inversion - a short visit to Purbeck, which shows the adjacent area and setting.

[@user-ij3qo6xl9s]

Thanks a lot. I understand the inversion system series. This systems including an asymmetric fold in N-S profile, indicating about NS σH=σ1, but σv=σ3; and another asymmetric fold horizontally distributed in southwest of the map, , indicating about NS σH=σ1, but σv=σ2. The two structural systems may be related in a process of tectonic inversion and nowdays they are governing different areas the the region. @@robbutler2095

[@user-ij3qo6xl9s]

@@robbutler2095 I also find some banded base quartzofeldspar metamorphic rocks show strongly folding structure, or thrust related folds (e.g. axis is EW direction). But regionaly structure is normal faulting with a strike of NS (below that is granitoid). According to inversion thought, this can also be thought to be a regional extension cause a type of ductile reverse shearing in area of local but the shallower outer wall layer above the granitoid.