Edward CT Chao

from Wikipedia, the free encyclopedia

Edward Ching-Te Chao (born November 30, 1919 in Suzhou , China , † February 3, 2008 in Fairfax , Virginia , USA ), was an American-Chinese petrologist and impact researcher who studied the consequences of meteorite impacts on the earth's crust. He is known for the discovery of two natural high pressure modifications of quartz, coesite and stishovite .


Born in China, Chao came to the United States in 1945 where he taught Chinese to American troops. He then attended the University of Chicago and received a doctorate in geology in 1948. From 1949 until his retirement in 1994, he worked for the United States Geological Survey (USGS).

Scientific work

Over the course of his academic career, Chao has worked on a wide variety of topics. In 1960, he found an unusual mineral with a high refractive index in a sandstone sample near the Meteor Crater in Arizona. He was able to isolate a high pressure modification of quartz. Chao named the new mineral Coesite in honor of the scientist Loring Coes Jr. , who had synthesized the same modification in the laboratory seven years earlier. A few years later, Chao found a second high pressure modification of quartz in these rocks. This, too, had previously been synthesized in laboratory studies, but it was not known to occur in nature. He named this mineral stishovite in honor of the Russian physicist Sergei Michailowitsch Stischow , who was the first to synthesize it. Coesite and stishovite became known as hallmarks of the effects of impact events. These are essentially the only natural processes that generate pressures so high that ordinary quartz can produce these two dense minerals. Chao and Eugene Shoemaker also found them in the rocks of the Nördlinger Ries and thus provided evidence that the Ries was formed by an impact .

Chao has made a lot of groundbreaking discoveries about the origin of tektite . He discovered evidence of the passage of tektites through the earth's atmosphere.

Chao was also busy with analyzes on the moon rocks of the Apollo missions .



Chao received the Wetherill Medal of the Franklin Institute and in 1992, the Barringer Medal of the Meteoritical Society for his work on the effects of Impakten to geology. An asteroid, (3906) Chao , is named after him. The mineral chaoite , which arose from carbon and was discovered in the Ries crater, is also named after him.

Web links