General Fold Info:
Folds at Wikipedia - includes some photos, some general descriptions, mediocre
Folding of Rocks - some examples of fold types, with diagrams, good
Definition: A fold in which the axial plane is horizontal.
Definition: A fold in which the limbs are parallel.
Definition: A sheath fold is a conical fold in which the conical surface is completely closed in the neighbourhood of the cone's apex.
Sheath Folds and more:
Alsop, G.I., and Holdsworth, R.E., 2002, The geometry and kinematics of sheath folds [abs]: Geological Society of America Abstracts with Programs, v. 34, no. 6, p.561.
Alsop, G. I., Holdsworth, R. E., and McCaffrey, K.J.W., 2007, Scale invariant sheath folds in salt, sediments and shear zones: Journal of Structural Geology, 2007, v. 29, no. 10, p. 1585-1604; doi:10.1016/j.jsg.2007.07.012.
Kuiper, Y.D., 2006 ,The usefulness of non-cylindrical (sheath) folds in monoclinic and triclinic shear zones [abs]: Geological Society of America Abstracts with Programs, v. 38, no. 7, p. 19.
Moore, J., C., (unknown date), Shear Zones Ductile and Semi-brittle Zones of Distributed Deformation Around Faults, Especially Strike-slip Faults: "15ShearZones" page from University of California, Santa Cruz, Earth Sciences 150.
Searle, M.P, and Alsop, G.I., 2007, Eye-to-eye with a mega–sheath fold: A case study from Wadi Mayh, northern Oman Mountains: Geology, v. 35, no. 11, p. 1043-1046; doi: 10.1130/G23884A.1.
How to make a sheath fold:
1) Photo of sheath fold exposure (click "click here" for the diagrams).
2) How to make a sheath fold part 1 (then click "continue").
3) How to make a sheath fold part 2 (click "example" to return to the photo).
—Copyright: Dr R. Butler, School of Earth and Environment, Leeds University
—HTML by C. Gordon
(This post continues my ongoing project of cleaning out my drafts folder, which largely consists links collected while doing research of various sorts.)