Late Mesozoic stratigraphy and vertebrates of the Gobi Basin
TL;DR: The Gobi Basin is a complex mosaic of grabens and semigrabens which were infilled with vertebrate-bearing strata of late Mesozoic age as mentioned in this paper.
About: This article is published in Cretaceous Research.The article was published on 1991-08-01. It has received 247 citations till now. The article focuses on the topics: Cretaceous & Chronostratigraphy.
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TL;DR: The Triassic land-vertebrate faunachrons provide a framework for the correlation of Triassic nonmarine deposits with a temporal resolution comparable to the seven Triassic Stage/Ages of the standard global chronostratigraphic scale.
396 citations
TL;DR: The phylogenetic history of ornithischian and saurischian dinosaurs reveals evolutionary trends such as increasing body size and Adaptations to herbivory in dinosaurs were not tightly correlated with marked floral replacements.
Abstract: ▪ Abstract Phylogenetic studies and new fossil evidence have yielded fundamental insights into the pattern and timing of dinosaur evolution and the emergence of functionally modern birds. The dinosaurian radiation began in the Middle Triassic, significantly predating the global dominance of dinosaurs by the end of the period. The phylogenetic history of ornithischian and saurischian dinosaurs reveals evolutionary trends such as increasing body size. Adaptations to herbivory in dinosaurs were not tightly correlated with marked floral replacements. Dinosaurian biogeography during the era of continental breakup principally involved dispersal and regional extinction.
362 citations
TL;DR: This article used the palaeodistribution of fossil crocodilians to examine the spatial distribution of palaeoclimate during the transition from the hot-house world of the Cretaceous (a time interval without significant polar icesheets) to the "ice-house" world in which we now live.
309 citations
TL;DR: An embryonic skeleton of a nonavian theropod dinosaur was found preserved in an egg from Upper Cretaceous rocks in the Gobi Desert of Mongolia, and cranial features identify the embryo as a member of Oviraptoridae.
Abstract: An embryonic skeleton of a nonavian theropod dinosaur was found preserved in an egg from Upper Cretaceous rocks in the Gobi Desert of Mongolia. Cranial features identify the embryo as a member of Oviraptoridae. Two embryo-sized skulls of dromaeosaurids, similar to that of Velociraptor, were also recovered in the nest. The eggshell microstructure is similar to that of ratite birds and is of a type common in the Djadokhta Formation at the Flaming Cliffs (Bayn Dzak). Discovery of a nest of such eggs at the Flaming Cliffs in 1923, beneath the Oviraptor philoceratops holotype, suggests that this dinosaur may have been a brooding adult.
306 citations
TL;DR: The East Gobi basin of Mongolia is a poorly described Late Jurassic-Early Cretaceous extensional province that holds great importance for reconstructions of Mesozoic tectonics and paleogeography of eastern Asia as mentioned in this paper.
Abstract: The East Gobi basin of Mongolia is a poorly described Late Jurassic–Early Cretaceous extensional province that holds great importance for reconstructions of Mesozoic tectonics and paleogeography of eastern Asia. Extension is especially well recorded in the structure and stratigraphy of the Unegt and Zuunbayan subbasins southwest of Saynshand, Mongolia, where outcrop and subsurface relationships permit recognition of prerift, synrift, and postrift Mesozoic stratigraphic megasequences. Within the synrift megasequence, three sequences developed in response to climatic and rift-related structural controls on sedimentation. Where best exposed along the northern margin of the Unegt subbasin, each of the synrift sequences is bounded by unconformities and generally fines upward from basal alluvial and fluvial conglomerate to fluvial and lacustrine sandstone and mudstone. Resedimented ashes and basalt flows punctuate the synrift megasequence. Rifting began in the Unegt subbasin prior to 155 Ma with coarse alluvial filling of local fault depressions. Subsidence generally outstripped sediment supply, and fresh to saline lacustrine environments, expanding southward with time, dominated the Unegt- Zuunbayan landscape for much of latest Jurassic–Early Cretaceous time. Episodic faulting and volcanism characterized the basin system for the balance of the Early Cretaceous. A brief period of compressional and/or transpressional basin inversion occurred at the end of the Early Cretaceous, prior to deposition of a widespread Upper Cretaceous overlap sequence. The driver(s) of Late Jurassic–Early Cretaceous extension remain uncertain because southeast Mongolia occupied an intraplate position by the beginning of the Cretaceous. Extension in the East Gobi basin was coeval with collapse and extension of early Mesozoic contractional orogenic belts along the northern and southern borders of Mongolia and probably was a linked phenomenon. Strike-slip faulting associated with collisions on the southern Asian and Mongol- Okhotsk margins likely also played a role in late Mesozoic deformation of the East Gobi region, perhaps partitioning the Gobi from apparently coeval large-magnitude contractional deformation in the Yinshan- Yanshan orogenic belt south of the study area in Inner Mongolia.
272 citations
Cites background from "Late Mesozoic stratigraphy and vert..."
...Jerzykiewicz and Russell (1991), in the most extensive and bestdocumented discussion of Mesozoic stratigraphy of Mongolia in the English-language literature, employed a dual rock-stratigraphic and biostratigraphic nomenclature (Fig....
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...Taken together, this family of depressions in Mongolia is termed the Gobi basin, and it appears to be the continuation of the Erlian basin of China (Jerzykiewicz and Russell, 1991; Traynor and Sladen, 1995), although the two are separated by the large Toto Shan basement block (also called Hutag Uul) (Fig....
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...5, Jerzykiewicz and Russell, 1991)....
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...Thus, the northern-basin synrift section is equivalent to the Sharilyn and Tsagantsav Formations of Jerzykiewicz and Russell (1991) and Badamgarav et al. (1995) (Fig....
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...5; Jerzykiewicz and Russell, 1991) and the faunas found at Har Hotol previously discussed....
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References
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TL;DR: An effort has been made to develop a realistic and accurate time scale and widely applicablechronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework.
Abstract: Advances in sequence stratigraphy and the development of depositional models have helped explain the origin of genetically related sedimentary packages during sea level cycles. These concepts have provided the basis for the recognition of sea level events in subsurface data and in outcrops of marine sediments around the world. Knowledge of these events has led to a new generation of Mesozoic and Cenozoic global cycle charts that chronicle the history of sea level fluctuations during the past 250 million years in greater detail than was possible from seismic-stratigraphic data alone. An effort has been made to develop a realistic and accurate time scale and widely applicable chronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework. A description of this approach and an account of the results, illustrated by sea level cycle charts of the Cenozoic, Cretaceous, Jurassic, and Triassic intervals, are presented.
6,928 citations
Book•
01 Jan 1973
TL;DR: The persistence of facies the fleeting fossil more gaps than record catastrophic stratigraphy catastrophic uniformitarianism the process of sedimentation Marxist stratigraphys and the golden spike the nature of the control as mentioned in this paper.
Abstract: The persistence of facies the fleeting fossil more gaps than record catastrophic stratigraphy catastrophic uniformitarianism the process of sedimentation Marxist stratigraphy and the golden spike the nature of the control.
244 citations
Journal Article•
TL;DR: Webb et al. as mentioned in this paper focused on land mammals, which are the most thoroughly studied of the participants in the Great American Interchange, and analyzed their migration patterns and extinction rates through time.
Abstract: Xhe continents of South America, Africa, Antarctica, Australia, and India were once joined in a large land mass in the southern hemisphere called Gondwana. About 100 million years ago (mya) South America began to separate from Africa, moving in a primarily westward direction. There is no convincing geological evidence to indicate that South America had a continuous land connection with any other continent _ until about 3 mya, when the Bolivar Trough marine barrier disappeared and the Americas were united by the emergence of the Panamanian land bridge. The long-isolated continental biotas of North and South America were brought into contact, resulting in an intermingling that has come to be known as the Great American Interchange (Webb 1976; Fig. 1). The site of the former Bolivar Trough is thus the gateway for this event, de noting the historical boundary be tween two biotic provinces (Fig. 2). Although many different groups of plants and animals took part in the interchange, I will focus on land mammals, which are the most thoroughly studied of the participants. The Great American Interchange was first recog nized by Wallace (1876), but it has taken another hun dred years of intense paleontological study by Amegh ino, Matthew, Scott, Patterson, Simpson, Webb, and others to clarify patterns of dispersal (see, for example, Marshall 1981, 1985; Webb 1985; Webb and Marshall The emergence of the Panamanian land bridge three million years ago permitted the mingling of the long-separated faunas of North and South America 1982). It is only during the last decade, moreover, that greater precision in dating the sediments containing interchange taxa has provided a firm time frame for various aspects of the event. It is now possible to assess the interchange in detail, and to analyze the tempo and mode of dispersal and the rates of extinction and origina tion in successive faunas through time. As a result, the _ Great American Interchange repre sents the best-documented example in the fossil record of the intermin
178 citations