ABSTRACT
The first-order geologic and morphologic relationships at, along
and
proximal to ridge-transform-ridge plate boundaries are used to
construct
an empirical and speculative tectonic model. The geometry of a
ridge-transform
intersection necessitates the juxtaposition of relatively cold,
thick lithosphere
against the truncated end of an accreting plate boundary. The cold
face
of lithosphere cools the adjacent wedge of asthenosphere rising
beneath
the axis of accretion and restricts the amount of partial melting
thus
attenuating the amount of basaltic melt segregated from the
asthenosphere
per unit time. The manifestation of this cold edge effect is a
thinner
oceanic crust. At depth, upper mantle material is welded against
the cold
edge and creates a shear-couple that results in the progressive
reorientation
of tensile stresses as the ridge-transform intersection is
approached.
The model predicts that the geologic expressions of this cold edge
effect
will become more dramatic with increasing thickness of the
truncating edge.
Field data supporting this model were collected from the
intersection of
the East Pacific Rise with the Tamayo Transform Fault. The field
program
involved both a surface ship (R/V GILLISS) and a manned
submersible (DSRV
ALVIN).
Gallo, D.G., 1984. The influence of Oceanic Transform Boundaries
on
the generation and evolution of Oceanic Lithosphere. Unpublished
MSc. thesis,
State University of New York at Albany. 129pp., +viii
University at Albany Science Library call number: SCIENCE
Oversize
(*) QE 40 Z899 1984 G35
thesis (scanned text) - 5.7MB pdf file
Return to MS Theses completed in the
Geological
Sciences Program, University at Albany