Jurassique

Restoration of Analong chuanjieensis, a sauropod dinosaur from the Middle Jurassic of China

Dinosaur National Monument is a United States National Monument located on the southeast flank of the Uinta Mountains on the border between Colorado and Utah at the confluence of the Green and Yampa Rivers. Although most of the monument area is in Moffat County, Colorado, the Dinosaur Quarry is located in Utah just to the north of the town of Jensen, Utah. The nearest communities are Jensen, Utah, and Dinosaur, Colorado. The park contains over 800 paleontological sites and has fossils of dinosaurs including Allosaurus, Deinonychus, Abydosaurus (a nearly complete skull, lower jaws and first four neck vertebrae of the specimen DINO 16488 found here at the base of the Mussentuchit Member of the Cedar Mountain Formation is the holotype for the description) and various long-neck, long-tail sauropods. It was declared a National Monument on October 4, 1915. The rock layer enclosing the fossils is a sandstone and conglomerate bed of alluvial or river bed origin known as the Morrison Formation from the Jurassic Period some 150 million years old. The dinosaurs and other ancient animals were carried by the river system which eventually entombed their remains in Utah. The pile of sediments were later buried and lithified into solid rock. The layers of rock were later uplifted and tilted to their present angle by the mountain building forces that formed the Uintas during the Laramide orogeny. The relentless forces of erosion exposed the layers at the surface to be found by paleontologists. The dinosaur fossil beds (bone beds) were discovered in 1909 by Earl Douglass, a paleontologist working and collecting for the Carnegie Museum of Natural History. He and his crews excavated thousands of fossils and shipped them back to the museum in Pittsburgh, Pennsylvania for study and display. President Woodrow Wilson proclaimed the dinosaur beds as Dinosaur National Monument in 1915. The monument boundaries were expanded in 1938 from the original 80-acre (320,000 m2) tract surrounding the dinosaur quarry in Utah, to its present extent of over 200,000 acres (800 km²) in Utah and Colorado, encompassing the spectacular river canyons of the Green and Yampa. Though lesser-known than the fossil beds, the petroglyphs in Dinosaur National Monument are another treasure the monument holds. Due to problems with vandals, many of the sites are not listed on area maps. The "Wall of Bones" located within the Dinosaur Quarry building in the park consists of a steeply tilted (67° from horizontal) rock layer which contains hundreds of dinosaur fossils. The enclosing rock has been chipped away to reveal the fossil bones intact for public viewing. In July 2006, the Quarry Visitor Center was closed due to structural problems that since 1957 had plagued the building because it was built on unstable clay. The decision was made to build a new facility elsewhere in the monument to house the visitor center and administrative functions, making it easier to resolve the structural problems of the quarry building while still retaining a portion of the historic Mission 66 era exhibit hall. It was announced in April 2009 that Dinosaur National Monument would receive $13.1 million to refurbish and reopen the gallery as part of the Obama administration's $750 billion stimulus plan. The Park Service successfully rebuilt the Quarry Exhibit Hall, supporting its weight on 70-foot steel micropile columns that extend to the bedrock below the unstable clay. The Dinosaur Quarry was reopened in Fall 2011. en.wikipedia.org/wiki/Dinosaur_National_Monument en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_...

Life restoration of the Triassic ichthyosaur Callawayia neoscapularis. Three specimens of this ichthyosaur are known, the holotype, ROM 41993, and two referred specimens, TMP 94.380.11 and 94.382.2. The skull is primarily based on ROM 41993, cross-checked against TMP 94.380.11 and TMP 94.382.2. The vertebral column is based primarily on TMP 94.382.2 as it is the most complete of these specimens, while the ribs were based on ROM 41993. The forelimbs were mainly based on those of ROM 41993, with TMP 94.380.11 used to determine their breadth. The hindlimbs were based on TMP 94.380.11, especially the more complete right hindlimb. ROM 41993 was cross-scaled with TMP 94.380.11 by the dimensions of the forelimb epipodials, which produced similar vertebral dimensions. The two TMP specimens were cross-scaled based on femoral length, also producing similar vertebral dimensions. Nicholls & Manabe (2001) stated that no wedge-shaped caudal centra supporting a tailbend were found and that there was no evidence of a bend being present, though considered that they might have existed in the gap in the preserved caudals. Since various other Triassic ichthyosaurs have since been found to have tail bends, one was illustrated here. A modest downturn of roughly 15° was illustrated, comparable to that in Guanlingsaurus, and the location of the bend within the gap in the preserved vertebrae matches well with the location of the bend in Guizhouichthyosaurus. References McGowan, C. (1994). "A new species of Shastasaurus (Reptilia: Ichthyosauria) from the Triassic of British Columbia: The most complete exemplar of the genus". Journal of Vertebrate Paleontology 14 (2): 168–179. DOI:10.1080/02724634.1994.10011550. Nicholls, E. L.; Manabe, M. (2001). "A new genus of ichthyosaur from the Late Triassic Pardonet Formation of British Columbia: Bridging the Triassic-Jurassic gap". Canadian Journal of Earth Sciences 38 (6): 983–1002. Ji, C.; Jiang, D.Y.; Hao, W.; Sun, Y. (2011). "True tailbend occurred in the Late Triassic: Evidence from ichthyosaur skeletons of South China". Acta Scientiarum Naturalium Universitatis Pekinensis 47 (2): 309–314. Shang, Q. H.; Li, C. (2009). "On the occurrence of the ichthyosaur Shastasaurus in the Guanling biota (Late Triassic), Guizhou, China". Vertebrata PalAsiatica 47 (3): 178–193.

Ichthyosaurus communis, Early Jurassic of England. Digital.

Permineralized Jurassic fern rhizome from Korsaröd (Sweden) of Osmundastrum pulchellum. It has preserved Nuclei and Chromosomes, a fine subcellular detail has rarely been documented in fossils. It´s Rooted in DNA content was used to extrapolate relative genome, finding relationships with extant Osmundastrum cinnamomeum, and confirmed a monophyletic Osmunda. Osmundastrum pulchellum is one of the earliest fossil Osmundastrum rhizomes known so far, and the first of its kind from the Mesozoic of Europe. Its impressive preservation has lead to know even the biotic interactions with the Plant. It also has recovered the only know case know to preserve the ongoing mitosis processes in plant cells via calcification from volcanic hydrothermal brine.

Early Jurassic (Lias γ, Pliensbachian) ferruginous limestone (the bed below the hammer) and marl (the bed ‘behind’ the hammer) in the cap rocks of the oolithic iron ore deposit at the village of Rottorf am Klei, Lower Saxony, Germany, largely obscured by weathered material of the same rocks.

Upper Jurassic (Oxfordian) sedimentary rock layers at the base of a cliff at low tide at Filey Brigg in North Yorkshire, England.

Passage Beds (Jurassic) at Filey Brigg, North Yorkshire.

Cliff at Filey Brigg in North Yorkshire, England (at low tide). Soft Quaternary deposits lie on top of horizontal layers of Upper Jurassic (Oxfordian) sedimentary rocks.

Jurassic Forest, Cathedral of Ferns - Blue Mountains, New South Wales.

A life reconstruction of the middle Jurassic sauropod, Spinophorosaurus nigerensis, from the nigerian Irhazer Shale.

Osgodby Formation (Middle Jurassic) exposed on the shore of Cayton Bay, North Yorkshire.

Matmor Formation (Jurassic, Callovian) exposed in Makhtesh Gadol, Israel. (Electricity pylon for scale).

A lampshell of the genus Acanthothiris, Class Rhynchonellata, Order Rhynchonellida, Family Acanthothirididae, 20mm along the axis, view of the pedunculate valve, from Woodeaton, Oxfordshire, UK, middle Middle Jurassic (Bathonian)

A lampshell of the genus Acanthothiris, Class Rhynchonellata, Order Rhynchonellida, Family Acanthothirididae, 20mm along the axis, view of the opening, from Woodeaton, Oxfordshire, UK, middle Middle Jurassic (Bathonian)

A lampshell of the genus Acanthothiris, Class Rhynchonellata, Order Rhynchonellida, Family Acanthothirididae, 20mm along the axis, lateral view, from Woodeaton, Oxfordshire, UK, middle Middle Jurassic (Bathonian)