Palaeontologists and others have been repeatedly amazed by reports of spectacularly well-preserved fossils from China, and one of the key sources has been. Request PDF on ResearchGate | The Jehol Fossils | No other single volume reference to the Jehol site and its fossils exists and nowhere is there such a. Jehol Biota: feathered dinosaur: Discoveries in the Liaoning deposits: are part of the larger Jehol Biota, a vast assemblage of Cretaceous fossils from.
|Published (Last):||17 June 2018|
|PDF File Size:||18.52 Mb|
|ePub File Size:||14.11 Mb|
|Price:||Free* [*Free Regsitration Required]|
In these, ever-more amazing fossils were announced from the Jehol beds in NE China: The specimens came from a time interval, the Early Cretaceous, whose faunas and floras were relatively poorly known from other locations and yet these specimens tended to be complete and they were often remarkably well preserved.
So far, the Jehol Group has yielded some 60 species of plants, nearly species of invertebrates, and species of vertebrates fishes and tetrapods. The tetrapods are listed in more detail here. This page reviews the history, geology, and fossils of the Jehol Group of China, and further detail may be found in reviews by Zhou et al.
History The Jehol beds are so extensive and so rich in fossils that it seems amazing that the remarkable birdsdinosaursand other fossils were not reported earlier. The first report in the s announced a small teleost fish that was later assigned to Lycoptera by Arthur Smith Woodward at the Natural History Museum in London.
The first broad overview of the faunas was made by the German-American palaeontologist, Amadeus William Grabau in the s.
He began his career in North America, and then became Professor of Geology at Peking University inone of a small number of Americans and Europeans who were brought in at that time to develop and Westernize the leading universities in China. He wrote numerous papers, and seven books, about the geology of China. Among his many studies, Grabau gave the first description of what he called the ‘Jehol fauna’, consisting of abundant examples of the conchostracan Eosestheriathe mayfly Ephemeropsis and the teleost fish Lycoptera Fig.
These three dominant fossils gave rise to an alternative name, the ‘EEL’ fauna. Grabau dated the Jehol fauna as Jurassic and Cretaceous, although predominantly Cretaceous, based on comparison of the fossils with those from elsewhere. The classic triumvirate of fossils that define the Jehol Biota: Photographs courtesy of IVPP. Through the s and s, additional isolated fossils were reported, including new invertebrates, fishes, plants and occasional vertebrates.
The next substantial work on the Jehol fossils was by the Chinese geologist and palaeontologist Gu Zhi-wei born Because the Jehol fauna included plants, Gu renamed it the Jehol Biota. Work continued at a modest level until, in the late s and early s, a series of papers on fossil birds Sereno et al. Comparable deposits of similar age occur across northern China and adjacent areas of eastern and central Asia, including Kazakhstan, Mongolia, Siberia, Japan and Korea, and many of these have yielded fossils very like those of the Jehol Biota Zhou et al.
The Yixian and Jiufotang formations are a nearly conformable sequence of weakly laminated to finely bedded siliciclastic sediments, mainly low-energy sandstones and shales that are interpreted as having been deposited in ancient lakes. There is no evidence of other kinds of continental deposits, such as channel infills, palaeosols or aeolian dune beds.
The lake sediments preserve fantastic numbers of fossils, many of them showing soft tissues. These finely bedded sediments are interrupted by volcanic beds, largely conformable tuffs and basalts, as well as occasional cross-cutting dykes and sills Zhou et al. The Jehol beds were deposited on the Eurasian landmass Fig. The volcanic beds throughout the Jehol Group resulted from igneous activity around the then Pacific rim, and it was largely contemporaneous, as indicated by the fact that most volcanic beds are conformable with the sediments.
Volcanic activity peaked at the time of deposition of the Yixian Formation and dwindled through the time of deposition of the Jiufotang Formation. The filled square marks the position of the major vertebrate-bearing sites in Liaoning Province. The arrow indicates the Jehol Group, at palaeolatitude o N. Courtsey of Zhou Zhonghe. Stratigraphy The Jehol Group Fig. A further unit, the Dabeigou Formation in Fengning, northern Hebei Province, has been added as the lowest part of the Jehol Group below the Yixian Formation, although it has also been considered as equivalent to the lower part of the Yixian Formation in Liaoning Province.
There was a problem providing the content you requested
A stratigraphic column of the Jehol Group showing the five main fossil-bearing beds I-V. The lithological key is: Courtesy of Xu Xing. Age In many earlier papers e. This added to the apparent significance of the fossils and would have suggested that several major groups, including angiosperms, various clades of birds, and placental mammals had had much fosdils origins than otherwise understood.
Subsequent work has shown that the early claims for a Late Jurassic age, based mainly on comparisons of faunas, but also on some radiometric dates, were flawed Zhou et al. When this is corrected to the current boundary date Mathese Yixian dates become Cretaceous, although still rather old.
The dating has now become clearer as a result of further comparisons of the fossils, but particularly because there are now high-quality radiometric dates throughout the Dabeigou and Yixian formations and, to a lesser extent, the Jiufotang Formation. As a result of sporadic eruptions throughout the time of deposition of the Jehol Group, tuffs are commonly interbedded with the shales or mudstones, even distal lacustrine sediments may contain tuffaceous horizons.
Published dates for the Yixian Formation range from Ma to The top of the overlying Jiufotang Formation was dated at older than The Dabeigou Formation may date to Ma.
The Yixian Formation lasted c. A tentative timescale for the Jehol Group is: Many of these fossils are exceptionally preserved. Archaefructus liaoningensis Sun et al. Image from Wikimedia Commons. The forests around the lakes were dominated by conifers, including members of the podocarp Podocarpitespine, araucaria Araucarites and cypress families. There were also ginkgos, czekanowskialeans, bennettitaleans, gnetaleans EphedritesGurvanellahorsetails Equisetitesferns and mosses Zhou et al.
The leaves and needles of the trees show adaptations to a dry season, and these were presumably derived from plants living on higher land, while the ferns and mosses normally grow in wet habitats, presumably around the waters’ edge.
Revision of the age of the deposits see above means that Archaefructus is certainly an early angiosperm, but by no means the oldest. More details of Archaefructuswith photographs of specimens and reconstructions, are here.
Pompeii-style volcano gave China its dinosaur trove
Many authors, including Amadeus Grabau and Gu Zhi-wei, have described invertebrate fossils from the Jehol Group, and Chen showed there were three phases of evolutionary radiation, corresponding fossols the Dabeigou, Yixian and Jiufotang formations.
The majority of the fossils come from the lower Yixian Formation and the Jiufotang Formation. Methods of collection and study have changed over the years.
The Dabeigou Formation assemblage includes the Nestoria-Keratestheria conchostrachan assemblage, the Luanpingella-Eoparacypris-Darwinula ostracod assemblage, the Arguniella bivalve assemblage, the Lymnaea websteri jeho assemblage, and the Peipiaosteus fengningensis-Yanosteus longidorsalis acipenseriform fish assemblage. The oldest confuciusornithid bird, Eoconfuciusornis zhengi Zhang et al.
Ulwellia muriculata-Djungarica camarata and Cypridea C.
These invertebrate assemblages represent the most abundant and diverse fossils of the Jehol Biota. Most are from the lower Yixian Formation Jianshangou Bedwhich has also been the source of a diverse vertebrate assemblage, including many well-known dinosaurs, birds Fig. The Jehol flora was also most diverse at this time, including nearly all the typical Mesozoic plant groups, as well as some early angiosperms.
The Jiufotang Formationand equivalent units from northern China, dated at Ma or slightly younger, shows the third radiation in the Jehol Group. The invertebrate assemblages are characterized by the appearance of the Yanjiestheria conchostrachan assemblage, the Mengyinaia-Nakamurania-Sphaerium bivalve assemblage and the Cypridea Cypridea veridica veridical-C.
Yumenia acutiuscula and C. Yumenia casta-Limnocypridea abscondida-Dijungarica ostracod assemblages. The birds and pterosaurs from the Jiufotang Formation are distinct from those recorded in the Yixian Formation, and some of the taxa are more cosmopolitan Zhou et al.
The dinosaur Microraptor gui Fig. One of the most spectacular fossils of all time from the Yixian Formation, two specimens, a presumed male with long tail plumes and female of Confuciusornis sanctusa species now known from more than specimens. The type specimen of Microraptor gui Xu et al. Literature cited Benton, M. The remarkable fossils from the Early Cretaceous Jehol Biota of China jrhol how they have changed our knowledge of Mesozoic life.
Proceedings of the Geologists’ Association Palaeogeography, Palaeoclimatology, Palaeoecology Distribution and migration of the Jehol fauna with reference to non-marine Jurassic-Cretaceous boundary in China. Acta Palaeontologica Sinica 27, [in Chinese, abstract in English]. An exceptionally well-preserved theropod dinosaur from the Yixian Formation fossila China.
Archaefructus jeehol angiosperm precursor or specialized early angiosperm? Trends in Plant Science 8, Cretaceous Mollusca from north China.
Bulletin of the Geological Survey of China 5, Jurassic and Cretaceous of China. Geophysical Research Letters 31, L A late Mesozoic bird from Inner Mongolia.
Vertebrata PalAsiatica 32, [in Chinese with English summary]. A new fossil bird from Lower Cretaceous of Gansu and early evolution of birds. A new fossil bird from the Lower Cretaceous of Liaoning. Vertebrata PalAsiatica 31, [in Chinese with English summary]. A beaked bird from iehol Jurassic of China.
A new symmetrodont mammal from China and its implications for mammalian evolution. Two feathered dinosaurs from northeastern China. On discovery of the earliest bird fossil in China and the origin of birds.
Chinese Geology 10, [in Chinese]. Biostratigraphy of new pterosaurs from China. Early evolution of avian flight and perching: Ceratopsiaa new psittacosaur from the Lower Cretaceous of northeastern China. Journal of Vertebrate Paleontology 8, In search of the first flower: