25 ene 1842 año - W.B. & Henry D.
Rogers - The
Laws of Structure
of the more
Disturbed Zones
of the Earth's Crust
// " wave theory " of
mountain chains
Descripción:
In this important work, he dealt also with the structure of the great coal fields, the method of formation of the strata, and the changes in the character of the coal from the bituminous type to anthracite.
https://archive.org/stream/pioneersscience01youmgoog/pioneersscience01youmgoog_djvu.txt
From his examinations of the Virginia coal deposits he dis-
covered that the condition of any coalbed stands in a close
genetic relation to the amount of disturbance to which the
4 I2 PIONEERS OF SCIENCE IN AMERICA.
enclosing strata have been submitted, the coal becoming harder
and containing less volatile matter as the evidence of disturb-
ance increases.
But the most notable contribution that Prof. Rogers made
to the advance of geologic science was the " wave theory " of
mountain chains. This was the joint work of William B. and
Henry D. Rogers, being founded on their researches in the
Appalachian chain, and was presented by them to the Associa-
tion of Geologists in 1842 in the form of an oral statement,
with the title, The Laws of Structure of the more Disturbed
Zones of the Earth's Crust. The theory represented the ele-
vation of mountain chains as the result of movements of the
earth's surface similar to the movements which raise up waves
upon a body of water. The grandeur of the conception, the
immense amount of evidence piled up in support of it, and the
eloquence with which the whole was presented made a pro-
found impression at the meeting.
The " wave theory " was further supported by the discover-
ies of Prof. Rogers in regard to the distribution of those rup-
tures of the strata called faults. He showed in another paper
that they do not occur on gentle waves, but on the sharpest
flexures of mountain chains, which have given way at the
summit where the strain was greatest. Furthermore, the
plane of the fault was usually parallel to, if not coincident
with, the plane of the ridge. The evidence for this statement
was afforded by the observed positions of more than fifty ther-
mal springs in the Appalachian belt, occurring in an area of
about fifteen thousand square miles, which were shown to
issue from anticlinal axes and faults, or from points very near
such lines.
Añadido al timeline:
Bartram Barton
fecha:
