Elkahatchee Creek area contains multiple
intrusions into a quartz-diorite. The intrusions
include numerous dikes, veins, and pegmatites.
The class mapped the surface expression of these
intrusions to determine age relationships based
on cross-cutting relationships.
(1) Xenoliths fell into
the magma chamber and were compressed during an
orogeny. (2) Massive quartzite viens were
emplaced, that were later foliated. (3) A final
series of quartzite veins were injected, followed
by a series of felsic dikes.
of principal stresses changed over time. During
the Acadian orogeny the maximum principal stress
was directed in a east-west direction. During the
Alleghanian orogeny the maximum principal stress
was directed in a northwest-southeast direction.
Shearing upon the area caused
small-and-large-scale deformations within the
picture shows two dikes on the outcrop. The
intrusion on the left (outlined in blue) has not
been compressed as the dike on the right
(outlined in black) has. After the dike on the
right had cooled, it was compressed from end to
end, giving it the kinked layout it now has.
blue outlined areas on the left side of the
photograph are small-scale shear indicators. Here
they indicate right lateral shear.