Discovery of Shatter Cones at Jueshan Island, Taihu Lake

【摘要】 <正> Shatter cones are conical fragments of rock characterized by striations that radiate from the apex. In 1905, they were first observed at Steinheim Basin in Germany. In the United States, the well-known occurrence site of shatter cones is Kentland, Indiana. In 1938, when the existence of terrestrial impact crater was still a hypothesis, J. D. Boon had suggested that the structures similar to the Kentland were the products of meteoritic crater. In 1947, when making frequent investigations on Kentland quarry, R. S. Dietz pointed out that the axes of these cones were oriented normal to the bedding, with the apexes pointing toward the top of the bed. Thus, they were formed by giant forces which came from above rather than below. Because except the impact of meteorite, there is not any giant force from space, shatter cones should be "root" of crater. This argument was proved because of the discovery of更多还原