Folds Anticlines and synclines - Now that you undertand simple inclinel planes, Plunging folds- Younger layers of which simulate limbs of folds, let's tackle folds in their entirety. Figure 14.5 rock overlie older layers of rock (like shows two bacic types of folds an anticline (arch-shaped) and a syncline (trough-. layers in a cake). In the structural shaped). Both are shown in block diagram (lefi) and in map view (right). examples presented thos far it has been obvious which rock layers overlie which. However, not all fold axes are horizontal. Some folds are tilted so that their axes are said to plunge (i.e., slope downward as in Figure 14-6), You might say that these structures "dip." (Imagine in Figure 14-6A that you are tipping a hog trough and spilling its contents in the direction of plange.) In such cases the relative ages of rock layers are less obvious. Hint As a guide to which of two contigueus layers is older, just look to see which overlies which along any vertical line on any sile of the block diagram. Figure 14-5 A. An anticlitie, B. A syocline. (Map vicws so the right) A fold axis runs along the crest of a fold and bisects it into two limbs. A fold axis ean be considered here as synonymous with the term hingeline, which runs along the line of maximam curvature of a fold. (Hingeline is: analogous to the pin in a door hinge. with the plates of the hinge simulating the limbs of the fold.) Figure 14-6. Planging folds. A. A fold: plunging toward you. Note the inclined axis (arrow) R. A fold plunging away from you. The map patteras for the two are ilbe saine, but the armangeminens of layen differ. Q14-5. In Figure 14-6/, what basic type of fold is illustrated (Le. anticline or syncline)? Which layer is the oldest (a,b, c,d, or e)? Q14-6. In Figure 14-68, what basic. type of fold is ifiustrated (i.e, anticline or syncline)? Which layer is the oldest (a, b,c,d, or e)?.

1. Folds Anticlines and synclines - Now that you undertand simple inclinel planes, Plunging folds-
Younger layers of which simulate limbs of folds, let's tackle folds in their entirety. Figure 14.5 rock
overlie older layers of rock (like shows two bacic types of folds an anticline (arch-shaped) and a
syncline (trough-. layers in a cake). In the structural shaped). Both are shown in block diagram
(lefi) and in map view (right). examples presented thos far it has been obvious which rock layers
overlie which. However, not all fold axes are horizontal. Some folds are tilted so that their axes are
said to plunge (i.e., slope downward as in Figure 14-6), You might say that these structures "dip."
(Imagine in Figure 14-6A that you are tipping a hog trough and spilling its contents in the direction
of plange.) In such cases the relative ages of rock layers are less obvious. Hint As a guide to
which of two contigueus layers is older, just look to see which overlies which along any vertical line
on any sile of the block diagram. Figure 14-5 A. An anticlitie, B. A syocline. (Map vicws so the
right) A fold axis runs along the crest of a fold and bisects it into two limbs. A fold axis ean be
considered here as synonymous with the term hingeline, which runs along the line of maximam
curvature of a fold. (Hingeline is: analogous to the pin in a door hinge. with the plates of the hinge
simulating the limbs of the fold.) Figure 14-6. Planging folds. A. A fold: plunging toward you. Note
the inclined axis (arrow) R. A fold plunging away from you. The map patteras for the two are ilbe
saine, but the armangeminens of layen differ. Q14-5. In Figure 14-6/, what basic type of fold is
illustrated (Le. anticline or syncline)? Which layer is the oldest (a,b, c,d, or e)? Q14-6. In Figure
14-68, what basic. type of fold is ifiustrated (i.e, anticline or syncline)? Which layer is the oldest (a,
b,c,d, or e)?