Coesite from the Lake Wanapitei crater,Ontario |
| |
Authors: | MR Dence PB Robertson RL Wirthlin |
| |
Institution: | 1. Earth Physics Branch, Department of Energy, Mines and Resources, Ottawa, Ont. Canada |
| |
Abstract: | Glacial float from Lake Wanapitei, Ontario (latitude 46° 44.7′N, longitude 80° 44.6′W), which has an approximately circular central basin 8.6 km in diameter, includes breccias and glassy rocks containing abundant evidence of shock metamorphism. One glass-rich boulder, a strongly shocked feldspathic quartzite, contains coesite in clasts of diaplectic silica glass (refractive index 1.4605±0.0005) held in a matrix of mixed vesicular glasses including alkali feldspar glass. This association is indicative of shock pressure of 425–500 kbar, and is additional strong evidence supporting a hypervelocity impact origin for the basin. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|