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2013-11-27

How old is Earth Science?

Many geoscientists think of their field as not much older than Lyell or Hutton; as a science that bloomed sometime during the eighteenth century.

The term geology was in fact first used by Ulisse Aldrovandi in 1603 (Vai and Cavazza, 2003) and introduced as a regular term by Horace de Saussure in 1779. Short after, the danish scholar Nicolas Steno (1638-1686) set the bases of stratigraphy: the law of superposition and the principle of original horizontality. But the roots of the scientific interest for the history of the Earth are even deeper than that.

Ortelius' world map, inspiring his own anticipation of
continental drift
In 1596, a Dutch geographer working for the Spanish crown named Abraham Ortelius wrote: "America (...) was (...) torn away from Europe and Africa, by earthquakes and flood" "the vestiges of the rupture reveal themselves: if someone brings forward a map of the world and considers carefully the coasts of the three aforementioned parts of the earth, where they face each other". This quotation extraordinarily anticipated by more than three centuries the theory of continental drift, but it remained forgotten and was rediscovered only in 1994.
Ortelius' idea was in turn a direct result of the vast exploration discoveries that took place in the previous decades. In the words of Alvarez & Leitao (2012, Geology): "The Iberian Voyages of Discovery of the fifteenth and sixteenth centuries marked a major advance in the understanding of the Earth—the greatest advance since antiquity, and comparable in scope and importance with the Geological Revolution, the Darwinian Revolution, and the Plate Tectonic Revolution, and we encourage geologists and other Earth scientists to embrace the Voyages as part of our geological scientific heritage."
This Edmund Halley’s map of geomagnetic declination (~1700 
AD) came about two centuries later than similar studies by 
Portuguese explorers, who used these magnetic anomalies for the 
long-lived challenge of determining longitude during navigation.

An example of the practical drive behind those first geoscientific questions: In the 16th century, "the Portuguese began to make systematic surveys of magnetic declination by comparing the direction of a compass needle with the line of shadow of the Sun at local noon". Magnetic declination could in this way be used to estimate the geographical longitude, a fundamental navigation problem at the time which final solution had to wait for the eighteenth century, when accurate chronometers were first developed.
In 1736, a franco-spanish expedition is set to south America to determine the size and shape of the globe, whether it is flattened or elongated at its poles, a long standing scientific question at the time. The expedition included Charles de La Condamine, Jussieu, Pierre Bouguer, Jorge Juan & Antonio de Ulloa. Several books were published out of these expeditions that had great novelty and impact at the time. Juan & Ulloa's (Relacion historica del viage a la America Meridional hecho de orden de S. Mag. para medir algunos grados de meridiano terrestre y venir por ellos en conocimiento de la verdadera figura y magnitud de la tierra, con otras observaciones astronomicas y phisicas), was published 3 years after La Condamine's but showed far more detail, maps and illustrations.
Juan & Ulloa's cover, 1748


In summary, the systematic study of the Earth has a history behind as long as in any other scientific field. Quoting again A&L: geoscientists can "trace their intellectual ancestry back to the Copernican Revolution of the 16th and 17th centuries, just as astronomers and physicists do"

References:
  • Alvarez & Leitao, 2010, Geology, 38, 231–234, doi: 10.1130/G30602.1
  • Romm, James, Nature 367, 407-408, 1994, A new forerunner for continental drift. doi:10.1038/367407a0
  • G. B. Vai et W. Cavazza, ed, Four centuries of the word 'Geology', Ulisse Aldrovandi 1603 in Bologna, Minerva Edizioni, Bologna, 2003