The Neugrund meteorite crater on the seafloor of the Gulf of Finland, Estonia

The Neugrund marine impact structure is located on the southern coast of the entrance to the Gulf of Finland (59 degrees 20' N, 23 degrees 31' E), straight eastward of the Osmussaar Island (Odensholm, Swed.: Odin's Grave, Engl.). The structure is very well preserved and the only One with morphological units, visible and easily accessible for the researchers and skin divers. The Neugrund is a complex meteorite crater about 20 km in diameter. In the centre of the structure emerges the inner crater with a two ridged rim wall having approximately 7 km rim to rim diameter: an inner ridge of about 6 km and an outer ridge of about 8 km. The presence of a central peak (uplift) of about 5.5 km diameter in the deep part of the crater is not proven. A 4-5 km wide terrace or zone of dislocations surrounds the inner crater. The Neugrund impact structure formed in the Early Cambrian (ca. 535 Ma ago) as the result of impact of an asteroid about 1 km in diameter.