Arandas (crater) km in diameter) they usually have a central peak. The peak is caused by a rebound of the crater floor following the impact. Sometimes craters expose layers that were buried. Rocks from deep underground are tossed onto the surface. Hence, craters can show us what lies deep under the surface. Arandas (crater) Arandas Crater is a crater in the Mare Acidalium quadrangle of Mars, located 42.77° North and 15.17° West. It is 24.76 km in diameter and is named after the town of Arandas in Mexico. South is the scalloped terrain of Cydonia Labyrinthus and further south is Cydonia Colles,
Chesapeake Bay impact crater from oil exploration revealed the extent of the crater. The continual slumping of the rubble within the crater has affected the flow of the rivers and shaped the Chesapeake Bay. The impact crater created a long-lasting topographic depression which helped predetermine the course of local rivers and the eventual location of Chesapeake Bay. Most important for present-day inhabitants of the area, the impact disrupted aquifers. The present freshwater aquifers lie above a deep salty brine, remnants of 100–145 million year old Early Cretaceous North Atlantic seawater, making the entire lower Chesapeake Bay area susceptible to groundwater contamination. The crater is