The subject of December’s #geolegends was thinking about geomorphology, paleoclimatology and the Earth’s age over 900 years ago, centuries before modern geology kicked off in the west. He also was one of the first to separate true north from magnetic north and invented the magnetic needle compass. Cool eh?
Shen Kuo Bust, By Hans A. Rosbach - Own work, CC BY-SA 3.0
https://commons.wikimedia.org/w/index.php?curid=89508454
Shen Kuo (1031-1095 AD) was born in Hangzhou, the capital city of Zhejian Province in eastern China during the Song Dynasty. Shen had many interests in science, engineering, inventing and rose to power in as a government military advisor. As a military strategist, Shen helped the Empire fortify its armies against invaders. When a rival advisor was given favor and tragically botched a battle billed as a “guaranteed” victory, the blame fell on Shen Kuo. Shen was demoted, put on house arrest for the next 6 years, and ultimately retired thereafter.
During his retirement, he assembled a collection of his thoughts in a book called Dream Pool Essays. In it, Shen hypothesized about his geologic observations among other subjects. He had observed marine bivalve shells in a mountain outcrop, miles from the ocean. His hypothesis was that the continent must have formed over an enormous span of time, and that the outcrop was formed in an ancient sea that had retreated east over time. When a canal bank collapsed near Yanzhou, Shen wrote about an exposure of petrified bamboo that didn’t quite make sense. In 1038, bamboo did not grow in Yanzhou, thus Shen deduced that “in very ancient times the climate was different so that the place was low, damp, gloomy and suitable for bamboos”.
Dream Pool Essays is full of observations on astronomy, math, physics, mapping, and inventions. Shen Kuo experimented with magnetic compasses and referred to the concept of magnetic north, writing that the needle is “always displaced slightly east rather than pointing due south”, thus advancing navigation and greatly aiding the Empire’s navigation of the seas.
Shen Kuo observed and asked why, a common trait among #geolegends, and for that we salute you.
Check out these pages for more detail on Shen Kuo’s life and work: