Expand (73kb, 800 x 378) Credit Darren Garrison (kudos to him for making available the pictures)
Partly melted and/or decarbonised limestone fragments in a dense and extremely hard matrix showing flow texture. The basal breccia is considered an equivalent to suevite impactites in other impact structures
The 35 - 40 km-diameter Azuara impact structure is located in northeast Spain roughly 50 km south of Zaragoza. From stratigraphic considerations, its age is estimated to be Upper Eocene or Oligocene. Except for very small magmatic intrusions, the target was purely sedimentary, which is a rare case with very large impact structures. The target was composed of the Paleozoic core of the Iberian chain and the Mesozoic cover overlain by Tertiary molasse sediments of probably 1000 - 2000 m thickness. See more
The 35-40-km diameter Azuara impact structure is located in northeast Spain roughly 50 km south of Zaragoza. Its age is estimated to be Upper Eocene or Oligocene, though ages of 130 and 40 Million years have been offered. It is possible that Azuara and the close by Rubiela de la Cérida impact craters formed during the same event.