Edward C. T. Chao

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 researchers who examined particularly the consequences of meteorite impacts on the Earth's crust. He is best known for the discovery of two natural high-pressure modifications of quartz, coesite and stishovite.

Life

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

Theses

Throughout his scientific career, Chao worked on a variety of topics. In 1960, he found in a sandstone sample from near the Meteor Crater in Arizona, an unusual mineral with high refractive index. He was able to isolate a high-pressure modifications of quartz. Chao named the new mineral coesite in honor of the scientist Loring Coes, Jr., who had the same modification, seven years earlier, synthesized in the laboratory. Some years later, Chao took a second high-pressure modifications of quartz in these rocks. Also these had previously been synthesized in the laboratory studies, but an occurrence in nature was unknown. He named this mineral stishovite in honor of Russian physicist Sergei Stishov who had synthesized the first. Coesite and stishovite was known as indicator for the effects of impact events. These are the only natural processes that produce such high pressures that of ordinary quartz these two dense minerals can mainly arise. Chao and Eugene Shoemaker, they also found in rocks of the Ries and thus provided evidence for the formation of the Ries by an impact.

Chao has made many ground-breaking insights into the origin of tektites. He discovered evidence of a passage of tektites by the Earth's atmosphere.

Chao was also concerned with the analysis of moon rocks Apollo missions.

Publications

• Book: " outcrops in the Ries meteorite crater " description, photo documentation and interpretation of Edward CT Chao, Rudolf Huettner, Schmidt- Kaler Hemann
• Comparative water- quality assessment of the Hai He River basin in the People 's Republic of China and three similar basins in the United States U.S. Geological Survey Professional Paper no. 1647 (2001)
• Comparison of the Cretaceous - Tertiary boundary impact events and the 0.77 - Ma Australasian tektite event; relevance to mass extinction U.S. Geological Survey Bulletin no. 2050 (1993)
• Allocation of subsamples of Apollo 17 lunar rocks from the boulder at station 7, for study by the International Consortium U.S. Geological Survey Open - File Report no. 78-511 (1978)
• Merumite; a complex assemblage of chromium minerals from Guyana U.S. Geological Survey Professional Paper no. 887 (1976)

Honors

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 Chaoit that originated from carbon and was discovered in the Ries Crater, is also named after him.