Gravity study of great impact

The residual Bouguer gravity field associated with the 65‐km‐diameter Manicouagan circular structure in eastern Quebec consists of a peripheral −4‐ to −10‐mGal ring that grades gently upward to a central high of 0 mGal. This pattern of gravity anomalies is consistent with the distribution of upper crustal density contrasts predicted by a hypervelocity meteorite impact origin for the structure. Excavation of a transient cavity produced by meteorite impact is limited to crustal depths between 2 and 8 km and is most likely between 3 and 5 km at Manicouagan on the basis of gravity model calculations of the vertical component of cavity infilling.