Geoscience Reference
In-Depth Information
attend night school at George Washington University. Even with such
a rigorous schedule, he somehow finished in four years, after which he
entered Yale University as a graduate student. Once Cloud completed
his PhD, he taught a year at the Missouri School of Mines but was sum-
moned in 1941 to the wartime strategic minerals program run by the
United States Geological Survey (USGS). After the war, he accepted a
position as Assistant Professor at Harvard University, but left after two
years to rejoin the USGS as chief paleontologist; he stayed in that posi-
tion for 10 years. Cloud then moved to the University of Minnesota, and
here his interest in early Earth problems was sparked. his made sense
given the close proximity of the university to banded iron formations
and other early Earth rocks. In 1965 he left Minnesota for the Univer-
sity of California Los Angles (UCLA), and three years later made his
final move to the University of California Santa Barbara (UCSB), where
I met him near the end of his life.
Preston Cloud's convoluted career path, and all his varied appoint-
ments, responsibilities, and experiences, no doubt provided him the
breadth and depth of understanding needed for some truly BIG think-
ing. And think big he did, on the scale of Vernadsky, in my opinion.
Indeed, in many ways, both Vernadsky and Cloud shared similar visions.
The interface between biology and geology was central to both of them.
However, Vernadsky's prime concern was to understand how life worked
as a geological force, his interest in Earth history was secondary. For
Cloud, Earth history was primary, and he was especially interested in
unraveling the relationship between the evolution of life and the chemi-
cal evolution of Earth's surface environment. In 1968 he published his
first “Big Think” paper with the rather academic title “Atmospheric and
hydrospheric evolution on the primitive Earth.” He developed his
thoughts further with a 1972 paper owning one of the best titles ever in
earth sciences: “A working model of the primitive Earth.” With a title like
that, the paper better be good, and this one was no disappointment.
Cloud's thesis was that the histories of Earth's biological and chemi-
cal evolution are intertwined. There wasn't much evidence back then to
support this idea, but as a great scientist, Cloud was able to see patterns
and make connections with the limited information he had. We will not
just now journey through all of Earth history, as Cloud did. Rather, we
will concentrate on a particular part of this history.
