Darwin the geologist in southern South America

Abstract

Charles Darwin was a reputable geologist before he achieved biological fame. Most of his geological research was accomplished in southern South America during the voyage of H.M.S. Beagle (1831–1836). Afterward he published four books and several articles about geology and coral atolls and became active in the Geological Society of London. We have followed Darwin's footsteps during our own researches and have been very impressed with his keen observations and inferences. He made some mistakes, however, such as appealing to iceberg rafting to explain erratic boulders and to inundations of the sea to carve valleys. Darwin prepared an important hand-colored geological map of southern South America, which for unknown reasons he did not publish. The distributions of seven map units are shown. These were described in his books wherein he also documented multiple elevated marine terraces on both coasts of South America. While exploring the Andean Cordillera in central Chile and Argentina, he discovered two fossil forests. Darwin developed a tectonic theory involving vertical uplift of the entire continent, which was greatest in the Andes where magma leaked up from a hypothetical subterranean sea of magma to form volcanoes and earthquakes. The theory had little impact and was soon eclipsed by theories involving lateral compression of strata. His and other contemporary theories suffered from a lack of knowledge about the earth's interior. Finally with modern plate tectonic theory involving intense lateral compression across the Andean Cordillera we can explain satisfactorily the geology so carefully documented by Darwin.

Exposed Areas Above Sea Level on Earth >3.5 Gyr Ago: Implications for Prebiotic and Primitive Biotic Chemistry

“…If chemical evolution proceeded to the point of producing complex molecules with the capacity for imperfect self-replication, there could have been a range of differing primitive biochemistries that emerged. As Darwin so eloquently noted “ Daily it is forced home on the mind of the geologist, that nothing, not even the wind that blows, is so unstable as the level of the crust of this earth.” [56]. Volcanic islands would have eventually eroded and their diverse inventory and possible primitive biochemistries been released into the oceans, where competition for increasingly more effective biochemistries could have taken place.…”

South Georgia microcontinent: Displaced fragment of the southernmost Andes

“…The first geologist to work in this area was Charles Darwin, who visited on board HMS Beagle in 1832 and 1834. Among many other geologic observations in the area, he recognized that the flysch was Mesozoic; he also made the first geological map of the region; sadly, this was never published (Dott and Dalziel, 2016). From Darwin's visit until the mid-20 th Century, scientific visits were few and far between.…”