There is no doubt that the Siljan Ring is an impact crater. The mere existence of an almost circular ring syncline with down-faulted cover rocks not anymore occurring in the surroundings of the structure is a strong argument. The finds of shock metamorphic minerals finally decided the issue after a long period of silence from the geo-science establishment. The large amount of data collected in connection with the Deep Gas Project has not yet been fully evaluated with regard to its potential to better describe the Siljan structure. Several issues are still unclear. The crater size and the depth of erosion are not well constrained. Substantial amounts of melt that would be expected for a large complex crater have so far not been found.
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