Dikes are tabular or sheet-like bodies of magma that cut through and across the layering of adjacent rocks. They form when magma rises into an existing fracture, or creates a new crack by forcing its way through existing rock, and then solidifies. Hundreds of dikes can invade the cone and inner core of a volcano, sometimes preferentially along zones of structural weakness.

A
B
C
D
E

F
G
H
I
K
L
M
O
P

Q
R
S
T
U
V