n a t i o n a l a c a d e m y o f s c i e n c e s
R o b e
R t P h i l l i
P s h a
R P
1 9 1 1 – 2 0 0 4
A Biographical Memoir by
c l a
R e n c e R .
a l l e n
Any opinions expressed in this memoir are those of the author
and do not necessarily reflect the views of the
National Academy of Sciences
.
Biographical Memoir
C
opyright
2010
national
aCademy
of
sCienCes
washington
,
d
.
C
.
R o b e
R t P
h i l l i
P
s h a
R P
June 24, 1911–May 25, 2004
b y
c l a
R e n c e
R .
a l l e n
o
ne
of
the
leading
figures
of
american geology,
Robert P.
sharp, died peacefully at age 92 in his home
at
santa
barbara,
california, on
may 25, 2004.
sharp’s
multitude of contributions on the physical processes that
have modified the surface of
earth, as well as
mars, are true
scientific classics.
they have substantially enhanced our
understanding of the unique roles of water, wind, and ice in
modifying planetary surfaces. Virtually an equal contribution
was
sharp’s leadership and vision in geological academia and
his spawning of a generation of students who have become
scientific leaders themselves.
i first met
bob when
i was a graduate student at
caltech
in the late 1940s.
although
i was not under his direct
supervision, he recruited me as a geophysicist into several
of his glaciological field teams in
alaska,
canada, and else
-
where. We subsequently became fellow faculty members at
caltech, and
i coauthored a number of papers with him.
most importantly, however, we became close friends as
fly-fishing and backpacking partners, especially on numerous
trips to
california’s
sierra
nevada and the
yellowstone
region—endeavors that continued well into retirement for
both of us.
4
b i o
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a P h i c a l
m e m o i
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sharp was born in
oxnard,
california, and spent the
greater part of his youth in the local Ventura
county area.
his grandparents on both sides had been regional pioneers,
and the families were mainly involved in agricultural ventures.
sharp grew up closely associated with farm ways and mores,
and throughout his life he invariably arose in the morning
at the first inkling of light in the eastern sky.
it was in his
youth that he developed the highly disciplined ways that
were such hallmarks in his subsequent professional career
and personal life.
sharp’s primary and secondary schooling were not remark
-
able, but two of his youthful activities were especially impor
-
tant to him.
first were the many camping and fishing trips he
took with his father, grandfather, and uncles, particularly to
the
owens Valley and
mono
basin of eastern
california—both
areas to which he returned numerous times in his subsequent
studies.
sharp’s paternal grandfather was particularly influen
-
tial in honing
sharp’s skills in trout fishing, an activity that
bob pursued avidly throughout his life.
a second activity
that, in
bob’s words, “had considerable influence on me,”
was the
boy
scouts, which again had a very strong outdoor
flavor.
much later in life, in 1978, he was honored with the
distinguished
eagle
scout
award by the national
boy
scout
organization.
exactly why
sharp chose to attend the
california
institute
of
technology as an undergraduate is not clear.
neither of
his parents had even graduated from high school, but
bob
was obviously ambitious, curious, and talented.
one of his
close high-school friends was somewhat of a “boy-wonder
scientist” and was so determined to go to
caltech that
bob
also applied to
caltech, perhaps simply out of competitive
spirit.
his friend later washed out, but
bob not only survived
the very difficult freshman year but also gradually gained
confidence and blossomed.
he started out in engineering,
5
R o b e
R t P h i l l i
P s h a
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switched to chemistry, and then to geology after taking an
inspiring introductory course from
caltech’s John
buwalda—a
course in which he first began to understand the intriguing
rocks and land forms that he had tramped over on his earlier
fishing and camping trips.
bob later said that “discovery of the
subject of geology was one of the great good fortunes of my
life.”
he was particularly intrigued by the fact that one might
make a living doing something that was so much fun.
sharp had participated in football, basketball, and track
in high school but had not been an outstanding athlete.
in
college, however, he participated more avidly, primarily in
football and track, and it was clearly an important character-
building experience for him.
in his senior year he was quar
-
terback of the
caltech football team, which was surprisingly
good in its league and even played U
cla
in the
coliseum.
much later
sharp was named by
Sports Illustrated
as one of
25 former gridiron stars who had gone on to very significant
careers.
sharp went on to pursue doctoral work at
harvard,
primarily at the urging of one of his highly respected
caltech
mentors,
ian
campbell.
after the intensely regimented
academic program at
caltech,
bob found the
harvard
atmosphere more relaxing, and he obviously enjoyed the
opportunity to delve into a wider variety of subjects and
activities.
among other things he took up sculling on the
charles River.
sharp essentially chose his own Ph.
d. thesis project and
then persuaded the noted
harvard geomorphologist, Kirk
bryan, to supervise it.
a new topographic map had just been
issued of the Ruby-
east
humboldt Range area of northeastern
nevada, and with this as a base for field mapping,
sharp saw
the opportunity to contribute to the understanding of basin
and range structure, which was then—and still is to this
day—somewhat of an enigma. What is it that controls the
b i o
G R
a P h i c a l
m e m o i
R s
remarkably uniform and repetitive series of north-trending,
equally spaced mountain ranges of the geologic province
that extends from southern
oregon south through
nevada,
and into eastern
california and western
arizona?
sharp
first recognized and documented the episodic, asymmetric
uplift of the Ruby-
east
humboldt Range, which began about
5 million years ago, and he emphasized that the rocks of the
range interior had been highly deformed and modified in
a much earlier history of regional mountain building than
that which controlled the range-bounding faults that define
the mountains today—something that has now been shown
for many ranges of the Great
basin.
he also found that
the summit areas of the range had been extensively glaci
-
ated during the worldwide Pleistocene glacial period, and
his studies of the landforms associated with that glaciation
sparked an interest in glaciers and glaciation that persisted
throughout his subsequent career.
seven major publications
arose from
sharp’s thesis work, at least two of which are now
recognized as true classics.
bob worked alone and enjoyed occasional days off fishing
in the lakes and streams of the remote high country.
he later
warned me that one must not mix fishing and geology: “
you
cannot go into the field dreaming that at 5:00 p.m. you will
lay down your geologic hammer and pick up your fly rod.”
a productive day must be fully devoted to one or the
other.
between the two long summers that
bob worked in
nevada, he received an invitation from his former
caltech
mentor,
ian
campbell, to participate in a two-month geologic
expedition boating down the Grand
canyon from
lees
ferry to what is now
lake
mead.
the expedition was to be
sponsored jointly by
caltech and the
carnegie
institution
of Washington.
the inner gorge of the Grand
canyon was
at that time essentially
terra incognita
in terms of its geology,
7
R o b e
R t P h i l l i
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and
sharp eagerly jumped at the chance to help unravel its
mysteries.
he was worried that
harvard might cut off his
student stipend during the interval, but
harvard not only
allowed him to take leave from his thesis activities but also
gave him a “traveling fellowship” as well.
three senior geolo
-
gists led the 19
7 trip:
ian
campbell, John
maxson, and
J. t. stark.
later,
e. d. mcKee joined the group at the foot
of the
bass
trail.
the only other participants, in addition to
sharp, were three boatmen.
sharp was very much the junior
geologist of the group, and he later described his role as
that of “the gun bearer, so to speak.”
the specific geologic studies to be carried out by senior
members of the group had been parceled out rigidly, and
sharp found himself searching for an activity that did not
“step on toes.”
early on, as they approached the inner
gorge of the Grand
canyon he became intrigued by the
two profound geologic discontinuities separating the three
major rock groups of the canyon.
the oldest rocks in the
deepest part of the gorge (now known to be some 2 billion
years old) were made up of crystalline units typified by the
Vishnu schist.
these had been uplifted and then truncated
by regional erosion prior to deposition of overlying sedi
-
mentary rocks of
algonkian age (about 1 billion years)—
a regional discontinuity termed by geologists a “unconfor
-
mity.”
it represented a period of elapsed time between the
erosion of the older deformed rocks and deposition of the
younger overlying rocks, in this case about a billion years.
both of these older rock units had still later been tilted,
uplifted, and then once again eroded in a second regional
unconformity, prior to the laying down of the great layer-
cake series of near horizontal, varicolored sedimentary rocks
that are the most striking feature of the upper two-thirds of
the Grand
canyon that is seen by visitors today.
8
b i o
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a P h i c a l
m e m o i
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the winding path of the
colorado River and its many
tributaries made for superb three-dimensional exposures
of these two profound semihorizontal unconformities, and
whenever the group paused,
sharp took to observing and
documenting them by ascending the tributary canyons of
the gorge, where possible.
one of the senior geologists
commented that
bob climbed “so fiercely” that he wore out
the soles of his boots.
he often found himself a thousand feet
or more above the river when the group was ready to shove
off again, but he appreciated the patience of
ian
campbell
and the others in putting up with his ventures.
his objec
-
tive was to understand better the fundamental erosional
and depositional processes, as revealed by the truly unique
exposures of the ancient eroded surfaces and the younger
overlapping sediments.
bob’s subsequent publication on the
ep-
archaen and ep-
algonkian erosion surfaces of the Grand
canyon is another true geologic classic.
most geologists
today would probably agree that it is by all odds the most
significant geologic contribution to come from the entire
expedition, albeit by the very junior “gun bearer” member
of the group.
shortly before
bob left
harvard, and through the auspices
of a former
caltech classmate Richard Jahns, he met Jean
todd, who was pursuing graduate work in geology at Radcliffe
college.
bob and Jean hit it off, and they were married in
19
8.
Jobs were scarce when
sharp obtained his doctorate, and
he felt lucky to land an academic position at the University of
illinois (at $1,800 per annum), where he served until called
into the army in 194
. Probably because of recommenda
-
tions by his former
harvard professors, he was recruited in
1941 to participate in an expedition along the
alaska-
yukon
border by Walter Wood, director of field exploration for the
american Geographical
society.
sharp was the only geolo
-
9
R o b e
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gist of the group, which was oriented primarily toward map
making and mountain climbing, but he managed to gather
data for several papers on the glacial history and soil devel
-
opment in the remote region on the
canadian side of the
st. elias Range.
With
sharp’s extensive wilderness experience it is hardly
surprising that World War
ii found him in the
arctic-
desert-
tropic
information
center of the U.
s. army
air
corps
researching and writing survival manuals for downed fliers
in the
north Pacific-
alaska region.
in carrying out these
assignments he had some unique experiences.
in order
to test survival techniques he was at one point put ashore
alone—with nothing but a rudimentary survival kit and not
even a tent—on uninhabited agattu island in the westernmost
aleutian chain.
captain
sharp not only managed to survive
well (mainly by primitive fishing and by gathering shellfish),
but when the “rescue” boat arrived some time later, he also
had with him his field notes on the geology of the island,
which were published the following year as the first scientific
description of extensive uplifted sedimentary rocks in the
aleutians—previously thought to be almost solely volcanic
in makeup.
in another survival episode that was to help shape
sharp’s later career, he and
bradford Washburn, a noted
alaska mountaineer, were put down on the north slope of
mt. mcKinley in midwinter, together with a hapless young
air
corps pilot who had never before even camped out.
sharp and Washburn’s assignment was to observe how the
flier reacted to the very harsh environment and to advise the
air corps on what survival equipment and knowledge should
be made available to fliers who might be downed under
such circumstances.
during the several weeks of snowshoe
traverses that it took for the trio to reach the
alaska Railroad,
in constantly subzero temperatures, it very quickly became
10
b i o
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a P h i c a l
m e m o i
R s
clear that the only practical answer for a neophyte under
such circumstances was to not travel at all.
as a young World
War
ii air
corps flier myself,
i can testify that servicemen
were subsequently instructed that if downed in inhospitable
terrain, they should almost always stay put awaiting rescue
and not try to walk out.
as a sidelight of this venture
sharp
became fascinated with the nature and mechanics of glacier
flow, to which he devoted much of his subsequent profes
-
sional career.
at one point
sharp’s army unit had been stationed briefly
at the University of
minnesota, and he had come to know
a number of the eminent geologists there.
subsequently,
and while he was still in the army, he was asked to join the
University of
minnesota faculty, which he did upon discharge.
by this time
sharp was building up a very notable publica
-
tion record in a wide variety of geologic endeavors, and
after only a couple of enjoyable years at
minnesota, he was
avidly recruited by both
stanford and
caltech.
sharp had
looked forward to eventually returning to the West, and after
prolonged consideration elected to return in 1947 to
caltech,
where he spent the remainder of his academic career.
in 1947 the
division of Geological
sciences at
caltech
was a good but not a distinguished department.
its notable
strengths were in seismology (with
beno Gutenberg,
charles
Richter, and
hugo
benioff) and in vertebrate paleontology
(with
chester
stock, division chair).
three years following
sharp’s arrival
stock died unexpectedly, and the search was
on for a new leader.
it remains unknown what travails took
place during the search, but in 1952
sharp emerged at age
41 as the new chair, an appointment that was welcomed
by the students, of whom
i was one, and seemingly by the
division faculty, many of whom were senior to
sharp.
thus
was to begin a new era of vigorous growth and delving into
new areas of earth sciences.
that’s another story in its own,
11
R o b e
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to which we shall return after summarizing
sharp’s own
personal research career.
taking over as division chair undoubtedly had some
dampening effect on
bob’s research efforts, but it certainly
wasn’t obvious.
he continued to get some research support
from Walter Wood, and in 1951 he embarked on a major
drilling program on the
malaspina Glacier in southeastern
alaska, in an attempt to better understand the physics of
glacier flow. Up until that time there had been only limited
success in determining the velocity gradient with depth in
a flowing glacier—with its implication for the flow law of ice.
mechanical drilling is very difficult in a temperate glacier
(which is at the pressure-melting point almost throughout),
and
sharp designed and built a thermal “hot-point” system
that succeeded—with innumerable travails—in implanting
a hollow aluminum pipe to a depth of
05 meters into the
glacier, which was about half of the total ice thickness at that
point, which
i determined with seismic charges.
the subse
-
quent incremental deformation of the pipe was measured with
a photographic inclinometer on four subsequent occasions,
over a period of several years.
these revisits were significant
backpacking ventures in themselves.
Partly because of the logistical difficulties of carrying out
a complicated drilling program on the
malaspina Glacier—
hundreds of miles from the nearest hardware store—
sharp
chose in 1957 to initiate a somewhat similar but expanded
effort on the
blue Glacier on the slopes of
mt.
olympus
in Washington state.
here supplies could be flown in from
nearby Port
angeles by a short ski-plane hop.
he assembled
a crew of colleagues and students who worked for a number
of subsequent years on a variety of glaciological efforts aimed
at better understanding the mechanism of glacier flow, such
as the intriguing question of what proportion of the observed
surface flow results from internal ice deformation as opposed
12
b i o
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to basal sliding.
among the participants (the
blue Glacier
gang), many of whom went on to careers in glaciology and
related fields, were
carl
benson,
noel
hinners,
barclay Kamb,
mark
meier, James
savage, Ronald
shreve, myself, and, of
course,
bob
sharp.
in a move that turned out to have dramatic scientific
payoff
sharp convinced
samuel
epstein, one of
caltech’s
recently arrived geochemists from the University of
chicago,
to participate in the glacier studies.
epstein had been devel
-
oping laboratory techniques for using the ratio of stable
isotopes
18
o and
1
o
in understanding geological processes,
and the hope was that similar studies might reveal something
about the history of the old ice within a glacier, such as
the temperature and atmospheric conditions under which
the original snow had been deposited in the icefield.
the
sampling and laboratory techniques developed by
epstein and
sharp were tested successfully on the
blue Glacier, as well
as on the
malaspina Glacier in
alaska and the
saskatchewan
Glacier in
alberta.
but most importantly, this led directly to
their later pioneering studies in
antarctica, where a vastly
longer time column of ice layers could be obtained from
deep cores.
such studies today, based in part on
epstein and
sharp’s pioneering work, are a primary window into climatic
changes over the past hundreds of thousands of years and are
immediately relevant to the problem of global warming.
one of the other surface geological processes that
sharp
puzzled over was the importance of wind.
is it a significant
geological agent, and how could its role be understood and
quantified?
to throw light on these problems
sharp designed
and set up novel observation and sampling stations at several
sites in sand dune areas of
california’s
coachella and
imperial
valleys, as well as in the Kelso dunes of the eastern
mojave
desert.
these studies served to shed considerable light on
1
R o b e
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the way sand moves and how sand ripples are formed and
change.
of all the wind-related enigmas that fascinated
sharp
none was more frustrating and long-lived as that of the origin
of the sliding stones of Racetrack Playa, near
death Valley.
here scattered boulders resting on the playa surface—derived
from the adjacent steep mountain slopes and weighing up
to
5 kg—had clearly skidded across the playa surface on
seemingly chaotic paths and had left distinct grooves as
trails on the clay surface.
high winds in association with
icy winter conditions on the high-altitude playa had long
been suspected of being a key factor, but no one had ever
demonstrated this.
sharp visited the remote locality 1
times
during a seven-year investigative period, carefully mapping the
tracks of
0 individual boulders.
during this period, all but
two of the boulders moved several meters in three discrete
sliding episodes.
neither
sharp nor anyone else to this day
has recorded ever seeing the skidding in actual action, but
he reasoned, mainly from the geometry of the trails and the
nature of the skid marks, that very high winds together with
a thoroughly wetted playa surface were necessary conditions.
Physicists recruited by
sharp confirmed that high-wind stresses
within the thin boundary layer might indeed be adequate
to start the stones to move, and once the static friction was
broken, they would essentially “sail.”
although some of
the tracks suggested that individual stones may have been
locked together within large wind-driven ice sheets,
sharp
demonstrated that the presence of ice was not a necessary
prerequisite.
he readily admitted that the phenomenon
“was hardly a matter of great scientific import,” but it was
certainly an intriguing and provocative one—and one that
garnered a fair amount of public interest.
in about 19
1 another important chapter in
sharp’s
scientific career began with attempts to understand geologic
14
b i o
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surface processes on planet
mars.
caltech physicist Robert
leighton had been asked by
nasa
’s Jet Propulsion
labo
-
ratory, operated by
caltech, to submit a proposal for
tV
imaging on
mars.
leighton was designing the imaging
instruments themselves but turned to
bob
sharp to lead
in the image interpretation.
bob in turn recruited
bruce
murray, his colleague in the division, and the trio made up
the
tV investigative team.
the first fly-by mission,
Mariner
4
, revealed much about the cratering history of the planet,
but later missions, particularly the
Mariner 9
orbiter, clearly
portrayed the spectacular canyons of the
martian surface,
which came to be the subject of much debate.
sharp and
his colleagues were, of course, not the first to suggest that
fluid action—probably by water—must have played the major
role in developing many of these channel-like features.
however, the trio together with
murray’s student
michael
malin systematically garnered and put forth the evidence
in a series of landmark papers that depended heavily on
comparisons with planet
earth.
for example, significant
terrestrial analogs—very familiar to
sharp—were the gigantic
geomorphic features in central and eastern Washington state
carved by and deposited by the massive Pleistocene “
spokane
floods,” which were in turn caused by rupturing of ice dams
in the upper columbia River. the team argued that the origin
of the water on
mars had been primarily lithospheric and
not atmospheric, particularly as indicated by the evidence
for groundwater sapping associated with headward growth
of many of the canyons.
these interpretations have been
largely verified by subsequent
mars missions.
sharp participated in the
mars program at JP
l for more
than 10 years.
he later stated that no activity of his career
involved a more demanding and exhausting effort, and anyone
associated with the
mars program will testify to
sharp’s very
major leadership role in it during this period.
15
R o b e
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now let us return to
bob
sharp’s other major area of
contribution—that of leading
caltech’s
division of Geolog
-
ical
sciences upon becoming chair in 1952.
the immediate
question, in light of
chester
stock’s death, was what to do
about the vertebrate paleontology program, and the exten
-
sive vertebrate fossil collection.
over a period of seven
years the division grappled with this issue, but it gradually
became clear that other emerging areas of earth sciences
simply appeared more exciting and, especially, were more
appropriate for
caltech.
for example, the geologists then
had very good rapport with the
caltech chemists and physi
-
cists, but only very limited mutual interests with the biolo
-
gists, who might otherwise have been logical cosponsors in
a continuing vertebrate paleontology program.
in the end it
was decided instead to put a major effort into the emerging
area of geochemistry, and in fact the proceeds from sale of
the valuable vertebrate fossil collection went to building one
of the first geochemistry laboratories.
the new emphasis on geochemistry was a major shift
in the division’s direction, and although clearly led by
bob
sharp, it was a divisionwide decision that the great bulk of
the faculty supported.
it was not, however, looked upon so
favorably by many classical geological colleagues around the
country (including a number of division alumni), who literally
accused
caltech of “selling out” geology to the geochemists.
sharp pleaded for patience, however, and in retrospect most
members of the earth scientist community today agree that
the somewhat gut-wrenching decision was an innovative,
forward-looking, and daring move on
caltech’s part.
in setting up the new geochemistry program
sharp turned
for advice to
caltech chemist
linus Pauling, who suggested
that we recruit
harrison
brown from
chicago to spearhead
the effort.
this was successful, and
brown then convinced
samuel
epstein and
claire Patterson, both also then at
1
b i o
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m e m o i
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chicago, to join him in Pasadena.
sharp later commented
that
harrison
brown “had a half-life of only about 5 years”
on any given endeavor, which turned out to be true, but
brown nevertheless was a major factor in getting the new
program successfully underway, and
sharp was grateful.
soon
thereafter Gerry Wasserburg, again from
chicago, was also
added to the new group.
sharp’s hope, and that of the division, was that the new
geochemists would interact with the more classical geologists
in attacking earth science problems with new and imaginative
tools, and this turned out to be exactly what happened.
as
described above,
bob himself teamed up with
sam
epstein
to carry out pioneering geochemical studies relevant to
paleoclimates.
several of the classically trained geologists
of the faculty turned much of their attention to problems
where geochemistry might provide new insights.
notable
among these were
heinz
lowenstam,
hugh
taylor, and
leon
silver.
With the maturation of the geochemistry program the
division again looked for promising areas into which to move,
and
frank Press, who was then director of the division’s
eminent
seismological
laboratory, urged that ocean-floor
geophysics be the next target.
everyone agreed that this was
indeed an exciting field, particularly with the plate tectonics
revolution then underway.
but the division decided that
a small, inland school like
caltech was simply not the appro
-
priate place to start a major new oceanography effort.
sharp
argued that “owning a ship is like marrying a harem; you’ve
got problems.”
again under
sharp’s leadership and after prolonged
discussion the division instead embarked on a new program
in the field of planetary science.
the presence in Pasadena
of the Jet Propulsion
laboratory was a strong argument in
favor of this move, and
sharp even received the blessing
17
R o b e
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of the
caltech astronomers, who were deeply engrossed in
far-out space and were quite willing to give away the solar
system to the geologists.
like the geochemistry development,
this turned out to be a forward-looking move and had an
invigorating effect on the rest of the faculty.
bruce
murray,
for example, although trained as a classical geologist, turned
his attention to planetary science endeavors and subsequently
spent six years as the JP
l director.
once again
bob
sharp
was among those who took advantage of the new horizons
to delve into the origin of the surface features of
mars.
and
a surprisingly high proportion of the current scientific leaders
in the nation’s space exploration program are graduates of
what is now termed the
division of Geological and Planetary
sciences.
although
sharp sought and received the faculty’s support
in all of his major moves, he can take the great bulk of the
credit for leading the division to its current distinguished
status—through his truly remarkable vision, unselfishness,
and leadership skills.
throughout his 1
-year tenure as
chair of the division
sharp maintained a full graduate and
undergraduate teaching load—even into “retirement.”
in
addition, his teaching was legendary, particularly his intro
-
ductory geology course for first- and second-year students.
Upon nomination by a group of undergraduates, he was
named in 1950 by
Life
magazine as one of the top 10 U.
s.
college teachers of the year.
sharp was particularly concerned about the young faculty
of the division. his files reveal that virtually every year—almost
as a ritual—he wrote to
caltech’s president complaining that
the salary increase awarded to him should have instead gone
to the young faculty.
typical is his letter of
march
, 1974,
to
harold
brown, president at the time. “
here is my annual
letter of protest regarding your note of
feb. 28th reporting
a salary increase...
caltech can and should use its meager
18
b i o
G R
a P h i c a l
m e m o i
R s
resources for salary adjustments on younger people.
they
are the future, not us old codgers.”
if there was one activity that
sharp enjoyed above all, it
was the planning and leading of geological field trips for
students, alumni, and others.
bob had a knack for planning
such trips so that they ran like clockwork and yet were rela
-
tively informal and relaxed.
his ability to enthrall partici
-
pants with his vivid explanations is renowned. Perhaps most
notable among these trips, albeit somewhat unique, were
three Grand
canyon boat trips organized by the division as
part of a major fund-raising effort—eventually culminating
(much to
bob’s embarrassment) in the establishment of
the endowed Robert P.
sharp Professorship at
caltech.
a number of eminent
caltech trustees and their families
participated in these trips, which were roughly patterned
after
bob’s pioneering trip down the Grand
canyon in 19
7,
and other
caltech leaders included professors with special
interests in the canyon—
barclay Kamb, Gene
shoemaker,
and
leon
silver.
it was indeed a remarkable bargain to be
escorted down the river by these leading scientists, although
the “fee”—in reality a donation to
caltech—was $50,000 per
individual or $75,000 per couple.
another related tradition founded by
sharp was the
annual Project Pahoehoe field trip to
hawaii for division
students nearing graduation, graduate or undergraduate.
bob went to considerable effort to solicit private funding
to endow support for these yearly trips, which are vividly
remembered by former students, and they continue today
under younger professors.
in addition, for many years
sharp
led a yearly field trip to the
owens Valley and elsewhere for
the division’s nonacademic staff members and their families,
which are likewise recalled with warmth and nostalgia.
his
repeated alumni trips to
alaska,
yellowstone, and
iceland are
particularly well remembered.
as part of his regular teaching
19
R o b e
R t P h i l l i
P s h a
R P
program
sharp ran innumerable field trips—all camping-out
affairs—and many students who had little or no background
in geology (particularly graduate students in seismology and
planetary sciences) signed up for these courses solely for
the joy of participating in these field trips, which were often
among their most fondly remembered—as well as profoundly
educational—experiences at
caltech.
as a natural outgrowth of
bob’s love of field trips, in his
later years he took to writing geologic field guides for nonsci
-
entists.
together with coauthors he researched and published
some five volumes on different areas of the
american West,
some in several editions, and he was in the midst of writing
a roadside guide to
idaho at the time of his death.
these
beautifully illustrated guides had remarkable public as well
as scientific reception and have served to make his name
known to a wide spectrum of admirers.
throughout his professional career
sharp tended to shun
service on national committees and advisory boards, for which
his experience and wisdom were often sought.
he declined
more than once the presidency of at least one major profes
-
sional society, and he participated only modestly in activities
of the
national
academy of
sciences (elected to member
-
ship in 197
).
not only did his severe dietary restrictions
and rigid habits make out-of-town hotel living unpleasant
for him he also strongly felt that he owed his primary obli
-
gations to the educational institution he served; he did not
want to become unduly distracted—as he felt a number of
his colleagues had been.
and insofar as
i am aware, he only
served on one commercial board, that of the family citrus
enterprise started by his grandfather, on which he served
for many years until his death.
on the other hand,
sharp was certainly not overtly anti
-
social.
in fact, he thoroughly enjoyed leading field trips and
participating in team research activities, such as those on the
20
b i o
G R
a P h i c a l
m e m o i
R s
malaspina and
blue glaciers.
and he had an immensely wide
circle of lasting friends, including many eminent
caltech
trustees as well as a host of nonacademic employees.
he
wrote more postcards to personal friends in a single day
than most of us do in 10 years.
despite a career devoted largely to rigorous outdoor
activities—many under very trying circumstances—
sharp
was plagued with numerous health problems throughout
his life.
he described himself as being somewhat sickly in
his grammar- and high-school days, and he had continuing
periodic bronchial problems.
a knee injury sustained while
playing football as an undergraduate at
caltech came to haunt
him in later years.
a severe lifelong stomach problem—akin
to an ulcer—seemingly led to his exceedingly rigid eating
schedule:
dinner was on the table (or off the campfire)
exactly
at
:00 p.m. even if the hatch was on and the trout were just
beginning to rise.
his student field trips were renowned for
departing on the dot of the hour, even leaving would-be
participants standing on the steps.
for many of us it was not
clear whether the stomach problems were the cause of the
extreme self-discipline or vice versa.
in any event
bob was
never one to complain, and he was very seldom in a dour
mood.
it was always both a pleasure and a privilege to be in
his company.
numerous national honors were bestowed on
bob
sharp
during his career.
the two that he prided above all were the
Penrose
medal of the Geological
society of
america—its
highest honor—in 1977, and the
national
medal of
science,
presented to
sharp by President
bush senior in 1989.
in
his response to the presentation of the Penrose
medal he
commented, “
few scientists in other professional fields
seem to enjoy and savor their work as fully as do the earth
scientists.”
21
R o b e
R t P h i l l i
P s h a
R P
sharp died from injuries that resulted from a fall in his
santa
barbara home, where he was still actively working on
a number of writing projects.
he is survived by two children,
Kristin and
bruce, and by his caregiver,
silvia
cockrun.
his
wife Jean preceded him in death in 2000.
it is an intriguing enigma that
bob
sharp, with his
profoundly rigid self-discipline and his basically conserva
-
tive ways, would nevertheless leave a lasting legacy of truly
forward-looking innovation in both his scientific and academic
ventures, and be remembered so fondly as an immensely
warm and generous individual by a multitude of friends
from all walks of life.
22
b i o
G R
a P h i c a l
m e m o i
R s
s e l e c t e d
b i b l i o
G R
a P h y
19
8
Pleistocene glaciation in the Ruby-
east
humboldt Range, northeastern
nevada.
J. Geomorph.
1(4):29
-2.
19
9
basin-range structure of the Ruby-
east
humboldt Range, northeastern
nevada.
Geol. Soc. Am. Bull.
50(
):881-919.
1940
ep- archean and ep-
algonkian erosion surfaces, Grand
canyon,
arizona.
Geol. Soc. Am. Bull.
51(8):12
5-1270.
a cambrian slide breccia, Grand
canyon,
arizona.
Am. J. Sci.
28(9):
8- 72.
1942
soil structures in the
st. elias Range,
yukon
territory.
J. Geomorph.
5(4):274-
01.
194
Geology of the Wolf
creek area,
st. elias Range,
yukon
territory,
canada.
Geol. Soc. Am. Bull.
54(5):
25-
49.
194
note on the geology of
agattu, an
aleutian island.
J. Geol.
54(
):19
-
199.
1951
thermal regimen of firn on upper
seward Glacier,
yukon
territory,
canada.
J. Glaciol.
1(9):47
-487.
1958
malaspina Glacier,
alaska.
Geol. Soc. Am. Bull.
9( ): 17-
4.
1959
With
s. epstein.
oxygen-isotope variations in the
malaspina and
saskatchewan glaciers.
J. Geol.
7(1):88-102.