Hello all
I believe the term transform fault concept was introduced by J.Tuzo
Wilson: 1965, A new class of faults and their bearing
on continental drift, Nature, v. 207, p. 343-347.
The original concept was that a plate boundary was
"transformed" from divergent (or convergent) to strike-slip
motion at a point called a 'transform". Hence a
"transform fault" was a fault linking two transforms.
This sense, and the original meaning of "transform" to refer to
a point, was progressively lost as "transform fault" became
abbreviated to just "transform".
The Pengiun Dictionary definition seems to be referring to the original
concept of 'transforms' when it talks about the "ends of
constructive and destructive plate margins".
Although Wilson's work was mainly on mid-ocean ridge systems, it's pretty
clear that the intent was to define a transform fault as any strike-slip
fault that is also what we would now call a plate boundary. Hence
faults like the San Andreas that cut portions of continental lithosphere
are definitely included.
This is the sense in which the term is used in most in most subsequent
undergraduate books on plate tectonics (e.g. Cox & Hart: Plate
Tectonics How It Works 1986) and in most introductory textbooks
too.
John Waldron
At 07:43 AM 2006/6/9, you wrote:
Googling 'Transform Fault' gives
all sorts of confusing definitions
for the term — and Philip Kearey's 1996 'New Penguin Dictionary of
Geology' gives the following:
"transform fault: A special form of strike-slip fault which joins
the
ends of constructive and destructive plate margins." What on earth
is
a student to make of that?
John Waldron, Department of Earth & Atmospheric Sciences, 1-26
Earth Sciences Building, University of Alberta, Edmonton, AB Canada T6G
2E3
-------------------------------------------------------------
University spam filters may reject some sources of mail. If this
happens, try me at [log in to unmask]