The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata .
6-495: The Beclabito Formation is a late Jurassic sedimentary geologic formation , found in northwestern New Mexico and northeastern Arizona . The formation is composed mostly of thinly bedded sandstone , siltstone , and mudstone which is reddish-orange to reddish-brown in color. The sandstone is very fine to medium grained and displays ripple crossbedding , trough crossbedding, and horizontal laminations . The siltstones are reddish-brown and show wavy laminations. The formation
12-698: Is 108 feet (33 m) thick. The formation conformably overlies the Todilto Formation and conformably underlies the Bluff Formation . The formation is interpreted as having been deposited in a marginal marine or coastal sabkha environment. The formation was first named by S.M. Condon and H.C. Huffman, Jr., as the Beclabito Member of the Wanakah Formation . The beds making up the formation were previously assigned to
18-837: The Summerville Formation on the basis of similar lithology and stratigraphic position, and on the similarity of the Curtis Formation that underlies the Summerville Formation to the Todilto Formation that underlies the Beclabito beds, but the correlation is questionable. Steven M. Cather concurred with reassigning the beds from the Summerville to the Beclabito, which he also proposed raising to formation rank. Cather pointed out that
24-511: The Curtis appears to be younger than the Todilto, calling into question the correlation between the overlying Summerville and Beclabito beds, and that there are significant lithological differences between the Summerville and the Beclabito. Late Jurassic In European lithostratigraphy , the name " Malm " indicates rocks of Late Jurassic age. In the past, Malm was also used to indicate
30-596: The south. The result of this break-up was the spawning of the Atlantic Ocean . However, at this time, the Atlantic Ocean was relatively narrow. This epoch is well known for many famous types of dinosaurs , such as the sauropods , the theropods , the thyreophorans , and the ornithopods . Other animals, such as some crocodylomorphs and the first birds , appeared in the Jurassic. Listed here are only
36-479: The unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units. The Late Jurassic is divided into three ages, which correspond with the three (faunal) stages of Upper Jurassic rock: During the Late Jurassic Epoch, Pangaea broke up into two supercontinents , Laurasia to the north, and Gondwana to
#527472