My experiments with volcanoesJaggar, Thomas Augustus
Science
My experiments with volcanoes
Jaggar, Thomas Augustus
Geologists -- Biography; Volcanoes
All my experience of volcanoes and of deep oceans militated against a
thin crust, a shallow underlayer of basalt to feed volcanoes, and a
nickel iron core. The core is heavy, and sixty-two elements are heavier
than iron. All reason seemed against the notion that the vast volcanic
sea bottoms are a thin crust wrinkling under contraction. Reason found
every evidence on both earth and moon for a thick peridotite or olivine
crust, broken into ancient blocks, bounded by long lines of fracture,
the blocks variously settling and scraping against each other from
time immemorial, actuated by volcanic forces from the core. The whole
of volcanology points toward sinking and down-faulted ocean basins,
alongside the remnant upstanding continents which are the minor feature
of the primitive earth surface. Water condensed and filled hollows.
The processes of the core that made all this were volcanism--mother of
air, ocean, seabottom, land, and life. The crust was thick enough to
make cracks 2,000 miles long on a globe 8,000 miles in diameter. If
there was a balancing of weights as in “isostasy,” it was between high
silica in continental lava and low silica basalt that spread under the
oceans. This is not static, but is a continuing process of a kinetic,
or changing, earth.
This excursion into theory is intentional, so that in the middle
of this book the geologically trained reader will understand that
experience of volcanoes in Hawaii, the Caribbean, New Zealand, Alaska,
Italy, and Japan had made me a rebel against conventional geology. The
reason is that the great submerged mountain range of the long Hawaiian
Archipelago is different from the mountain ranges of Europe and Asia
and must be accounted for in global history. How would the three
decades 1921 to 1950 confirm expectation that the deep ocean bottom is
the most important and volcanic thing in geology, just as it is the
biggest thing?
Routine observation and photography at Halemaumau pit reached a climax
of recording brilliant fiery events in March 1921, and it changed
to the recording of explosive steam in May 1924. The first of these
fireworks, after lava flows from a rift in the Kau Desert, draining the
pit and fluctuating with the ups and downs of the pit lava, occurred in
1919–1920. This was a return to Halemaumau of effervescence in frothy
volumes, so that the pit was overflowing on five sides. On March 20,
1921, occurred the most intense display of brilliancy, culminating the
gradual rising of the lava column to outflow following 1918.
Public-domain text, read in full here on John Shaqi.
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