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 Unpublished MSc.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
Return to MS Theses completed in the Geological
Sciences Program, University at Albany