People | George
Davis
Active Tectonics as Integrative Capstone in
Teaching Structural Geology
Though the sequence of presentation varies widely
from instructor to instructor, fundamental topics covered in the
teaching of undergraduate structural geology are basic descriptions
of structures, displacement and strain, deformation mechanisms, material
behavior, force and stress, structural associations, and tectonics.
It might be argued that “the
making of structures” has historically been a relative weakness
in the pedagogy of structural geology.
Most examples used in the classical teaching
of structural geology have focused on ancient structures in ancient
mountain belts because of factors related both to history of geology
and geologic history, including investigations of oil and mineral
provinces. But without
illuminating examples of structures forming today, there can be too
great a gap between stress analysis or strain analysis or experimental
metaphors and the creation of structures. Even though the
origin of structures resides so commonly in plate tectonics, plate
tectonics may not necessarily be covered at all in structural geology
classes, for a whole variety of practical reasons and false assumptions.
Active tectonics can illuminate “the making of structures” in
real time. GPS “tracking” of plate motions
calls out whole fields of displacement vectors and deformation paths,
including rates of motions. “Deformation” can
be “seen” through comparison of initial and final locations
of individual points, changes in orientation of bodies, and changes
in shapes of whole regions. Individual structures, and systems
of structures, can be viewed in the context of actively deforming milieu
of which they are a tiny part. Relationships between, e.g., folding
and faulting can be grasped through the integration of geodetic measurements
of changing topography, focal mechanisms for earthquakes, and 3D mapping
of earthquake storms of seismic action. In situ stress orientation
data, and well chosen seismic reflection profiles, help to round out
the picture. Opportunities for creative pedagogy abound. For
example, the sequencing of examples of ‘active tectonics’ will
vary considerably from instructor to instructor: active tectonic
scenarios (theatre!) can be interspersed along the way, or can ‘cap
off’ the course in ways the reveal the ‘punch line’ of
what is forcing structures to form.
[Davis, G.H., and Reynolds, S.J., 2004, Active tectonics
as integrative capstone in teaching
Structural geology: Geological Society of America Abstracts with
Programs, v. 36, no. 5, p. 348.]
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