关键词: 太湖；震裂锥；冲击坑；冲击角砾岩；熔融&mdash, 气化作用

Abstract: The shatter cones have been recognized as a sign of meteorite impact on the earth's surface. Research and statistical data
show that shatter cones are related to medium-or larger-scale impact craters. The shatter cones found in Xishan, Suzhou provides a
diagnostic evidence for the existence of impact crater happened in Taihu Lake. The shatter cones are characterized by the conical shapes
and coved with conical striations radiating downward from the top of the cones. The striation has been shown as the feature of
bifurcation. The evidences are consistent with the international definition and standard for the shatter cone. In addition, special
characteristics are also found in shatter cones in Xishan: remarkable cataclasis and the obvious melt-gasification phenomenon. On
surface of cones, there are mesh—structure and the ripples-like, honeycomb-like gas imprint developed. Results of petrographic study
show that shatter cones and cone-contained target rocks have visible impact metamorphism. Planar Deformation Features [PDFs], Planar
Features [PFs] and target rock melting indicate the impact metamorphism happened. All of these show that shatter cones in Xishan are
distinctly different from cone-sharp karst limestone formed by the surface water dissolution or ventifacts formed by eolian erosive action.
The discovery of Xishan shatter cones and the breccias“Taihu stone” occurring at the bottom of the Taihu Lake has provided the new
diagnostic evidence for the Taihu impact crater. There are also existed impact ejecta identified in earlier studies which fallen back into
the silt layers under the Taihu Lake. Numerous evidences show a beautiful prospect for the determination of “Taihu impact crater” or
“Taihu impact event”. However, there is still much work to be done to determine the detailed locations, size and structural model of the
impact crater in Taihu Lake.

Key words: Taihu Lake, shatter cone, impact crater, impact breccias, melt-gasification