杨氏天镇龙性双形现象的初步研究

通过对河北地质大学地球科学博物馆和山西大同博物馆收藏的4具杨氏天镇龙（甲龙类）骨架化石的研究,主要根据其头颅和尾锤的形态特征,认为杨氏天镇龙存在明显的性双形现象。雄性个体的鳞骨角粗大,向后上方两侧突伸;尾锤呈亚圆形,大而扁平。雌性个体的鳞骨角细小、低矮,向后侧方向突伸;尾锤呈亚圆形,小而扁平,表面具核桃纹纹饰。对甲龙类性双形现象的探讨为恐龙的研究提出了一种新的思路,可避免分类时出现同物异名的现象。     

Evidence for the Carnian Pluvial Episode in Gondwana: New multiproxy climate records and their bearing on early dinosaur diversification

The Triassic hothouse world experienced dynamic changes in climate and ecosystems that set the Earth's climate and biotic states for much of the Mesozoic Era. A critical time interval was the Carnian Stage (~237–227 Ma), which not only saw the first appearance of dinosaurs in the fossil record but witnessed a large igneous province eruption (Wrangellia LIP) and a sudden climate shift, the Carnian Pluvial Episode (CPE). Compelling hypotheses suggest that the Wrangellia eruptions caused the CPE, which in turn set the stage for the origin and initial diversification of dinosaurs. Unfortunately, testing these hypotheses is difficult because most relevant Carnian sedimentary archives possess few if any absolute age constraints, and there are little detailed paleoclimatic data for the CPE outside of the Tethys region. There is little existing evidence for the CPE in Gondwana, even though this region contains by far the best fossil record of early dinosaurs and their close relatives. We present new high-resolution geochronologic and paleoclimatic data from Carnian-aged strata in the Ischigualasto-Villa Unión Basin of northwest Argentina, which also preserves fossils of the earliest-known dinosaurs. New CA-TIMS UPb zircon age of 234.47 ± 0.44 Ma from the lower Los Rastros Formation demonstrates that most of the overlying lacustrine strata within this basin was deposited during or after the CPE, including large dinosauriform footprints. Multiproxy paleoenvironmental data (sedimentology, clay mineralogy, C and O stable isotopes, and fossils) from the same strata are the first detailed paleoclimate data for the CPE in Gondwana, and provide evidence that the CPE interval in western Gondwana was indeed warmer and more humid than before or after. These data are consistent with the interpretation of the CPE as a global event, but direct linkages in Gondwana and the Tethys with the origin and initial diversification of dinosaurs are less clear.     

自贡大山铺恐龙动物群埋藏环境及集中埋藏原因分析

四川自贡大山铺以其集中埋藏数量众多的恐龙化石而闻名于世,恐龙化石集中埋藏的原因一直是人们关注的焦点问题之一.笔者在对自贡恐龙博物馆内及其附近地层剖面调查的基础上,根据对该处埋藏恐龙化石地层的岩相、沉积构造、砂体形态特征以及沉积背景的分析,认为恐龙化石的埋藏环境为湖泊三角洲,恐龙由于某种原因死亡后,经过河流搬运埋藏于湖泊三角洲前缘的河口砂坝之中,而非由于中毒异常死亡原地埋藏.     

Deformation of host rocks and stratiform mineralization in the Hilton Mine area,Mt Isa

The Hilton deposit is a deformed and metamorphosed Proterozoic stratiform Pb‐Zn‐Ag‐Cu deposit hosted by dolomitic and carbonaceous sediments of the Urquhart Shale of the Mt Isa Group. Rocks in the Hilton area show a history of folding and faulting which spans the time range recognized elsewhere in the Western Succession of the Mt Isa Inlier, though the effects of relatively late and brittle deformation are more pronounced in the Hilton area. The Hilton area shows intense faulting relative to similar rocks to the south in the Mt Isa‐Hilton belt. Faulting in the Hilton area has generally resulted in east‐west shortening and extension in both north‐south and vertical directions. This relatively intense late strain is attributed to the geometry of the Paroo Fault Zone, a major north‐trending zone that bounds the Hilton area to the west, and the Sybella Batholith, which formed a relatively rigid indenter during late deformation in the Hilton area. The structural history of the Hilton area is broadly consistent with ongoing east‐west shortening during progressive uplift from mainly ductile to more brittle conditions. Based on these observations, thinning of the Mt Isa Group which was previously attributed to synsedimentary faulting, can now be shown to be related to heterogeneous strain during late faulting. Sulphide layers show a history of folding which is similar to that of the surrounding rocks. Pyrite which is paragenetically associated with mineralization is overprinted by a bedding‐parallel foliation which predates all other structures in the area. This suggests that stratiform sulphide mineralization in the Hilton area predates deformation. Deformation has affected the Hilton orebodies at all scales. Changes in thickness and ‘fault windows’ in the orebody interval occur on the scale of the entire deposit. Mesoscopic ore thickness changes are often clearly related to extensional and contractional structures within sulphide layers. These macroscopic and mesoscopic ore‐thickness variations are spatially associated with cross‐cutting brittle faults, suggesting that strain incompatibility between brittle host rocks and more ductile ore layers played a major role in the present geometry and thickness of sulphide ores at Hilton.     

山东青岛莱西地区首次发现恐龙蛋化石及其沉积环境分析

本文报道了首次在山东青岛莱西地区晚白垩世红土崖组发现的恐龙蛋化石,蛋化石呈圆形,其直径为11 cm,蛋壳的显微构造研究表明,它属于树枝蛋类,可能为镰刀龙类恐龙所产。沉积环境和岩石地球化学分析显示,该时期研究区主要为河道—河漫滩沉积环境,适宜的古气候条件是恐龙蛋孵化的理想地区;同时镰刀龙类蛋的发现,预示着将来在该地区很有可能发现镰刀类恐龙骨骼化石。     

Conflicting rights to the city in New York's community gardens

In the mid-1990s, New York City initiated what would prove to be a long, highly visible struggle involving rights claims related to property, housing, and public space in the form of community gardens. The competing discourses of rights were part of a struggle over the kind of city that New York was to become, and more specifically, whether it would be one in which difference is accepted and in which access to the city and the public realm would be guaranteed. Using interviews with participants in the conflict over community gardens, we evaluate how the resolution to the gardens crisis, which in part occurred through the privatization of what are often taken to be public or community rights to land, transform not only the legal status of the gardens but also, potentially, their role as places where different `publics' can both exercise their right to the city and solidify that right in the landscape.     

The strange case of the Dudley Bug

Or, how the 'Dudley Bug' escapes from a town Museum in the English Midlands and tries to find its way back on to Dudley's Coat of Arms…     

A new Isochirotherium trackway from the Triassic of Vieux Emosson, SW Switzerland: stratigraphic implications

The footprint assemblage of Vieux Emosson, located at 2400 m altitude in the Swiss Alps, was first described in 1982. The assemblage was regarded as Late Ladinian or Carnian in age, but the dating was questioned because the taxa show few affinities with other Triassic assemblages. Here we describe a short trackway with shallow but well-preserved tracks referred to the ichnogenus Isochirotherium, showing affinities with Isochirotherium soergeli and Isochirotherium lomasi. The trackway is present on a piece of slab ex situ lying on a mass of fallen rocks, but the slab can be attributed with confidence to the same level as the main one previously mapped. Preliminary observations in situ and of the footprint casts made in 1979 and deposited in the Natural History Museum of Geneva suggest that none of these are attributable to dinosaurs and that the Vieux Emosson footprints are mainly “track preservation variations” of chirotherian tracks. The occurrence of the ichnogenus Isochirotherium favours an older age, probably Early or Middle Triassic, than previously suggested for the Vieux Emosson tracksite.     

义县组底部层位发现恐龙化石

义县组是一套中生代火山-沉积地层,含有丰富的以热河生物群为代表的生物化石.20世纪80年代以来,在义县组沉积夹层中陆续发现珍稀鸟类、小型兽脚类恐龙中华龙鸟,以及原始被子植物辽宁古果等珍稀化石,但是有关珍稀化石沉积层的空间分布、上下层位关系、沉积环境和时代归属等问题,一直悬而未决,中国地质调查局东北地区地调中心从1999年10月开始,对辽宁省北票市-义县之间的义县组进行了1：5万区域地质调查填图,不仅确定了珍稀化石沉积层在地层层序中的确切位置,而且在珍稀化石沉积层以下,即义县组底部发现了大量恐龙化石.     

鸟类是插上翅膀的恐龙吗?

近年，越来越多的化石证据表明：过去长期被认为只有鸟类才有的，并作为鸟类区别于其他脊椎动物的一些重要特征，如羽毛、叉骨、胸骨、尾综骨、前肢可折叠于体侧、眼眶与下颞孔相连的头骨及耻骨向侧后伸展的骨盆等，却也在1亿多年前的不少小型兽足类恐龙身上或多或少地存在。于是，越来越多的人们相信鸟类是从小型兽足类恐龙起源。但迄今发现的所有具鸟类特征的恐龙，在时间上却晚于或至多也只是接近目前公认的最早鸟类——晚侏罗世的始祖鸟，而原始鸟类双弓型头骨似乎在暗示：鸟类可能起源于比恐龙更古老的初龙类。这些都对鸟类起源于恐龙的假说提出了质疑。就目前的化石记录而言，鸟类和兽足类恐龙系统演化关系密切是毋庸质疑的。但由于至今未找到在时间上足以演化出鸟类的更古老近裔恐龙，因此还不能说恐龙就是鸟类的祖先。它们可能只是与原始鸟类平行独立发展的姊妹群，二者也许出自一个共同祖先。     

A blast from the past: the lost world of dinosaurs at Tendaguru,East Africa

The superbly preserved dinosaurs and associated organisms from the Late Jurassic fossil Lagerstätte Tendaguru in southern Tanzania mark an exceptional success story in palaeontology. The new permanent exhibits of the Museum für Naturkunde in Berlin, highlighting the spectacular dinosaurs ( Fig. 1 ), are telling evidence. In more than 100 years of research, geoscientists produced a considerable amount of knowledge about the composition and diversity of the ancient fauna and flora at Tendaguru, their unique palaeobiological characteristics, and the continental to marginal marine ecosystems in which they lived. Several questions are still open to debate. These include the detailed genesis of the Lagerstätte, aspects of dinosaur palaeobiology, and their biogeographical affinities to contemporaneous assemblages from the Northern Hemisphere.

Figure 1 Open in figure viewer PowerPoint The discovery of Brachiosaurus was the crowning achievement of the German Tendaguru expedition of 1909–1913. The skeleton is about 13 metres tall and 23 metres long. It is on display in the dinosaur hall of the Museum für Naturkunde (MfN) in Berlin along with Dicraeosaurus, Kentrosaurus, Dysalotosaurus and Elaphrosaurus. They constitute the most significant dinosaur discoveries ever made in Africa. Photo: Antje Dittmann, MfN.     

The pedigree and influence of fossil collections from the Falkland Islands: From Charles Darwin to continental drift

The Falkland Islands are typical of remote territories in that their early geological exploration was piecemeal and opportunistic. Whilst the resulting fossil collections (dominantly a Devonian fauna of the Malvinokaffric realm) remain the basis for modern interpretations, published accounts misrepresent their extent and provenance. Charles Darwin first discovered fossils during his 1833 visit aboard HMS Beagle, with subsequent British collections acquired in 1842 and 1876, respectively, by the Erebus and Terror and Challenger expeditions and in 1903 by the Scotia expedition. Darwin's collection, and much of the other material, is now held by The Natural History Museum, London (NHM) but some Darwin specimens were assimilated into other collections whilst at least one NHM ‘Darwin’ specimen was not collected by him. There may also be some uncertainty as to the origin of the Scotia collection, now held in Edinburgh by National Museums Scotland, in relation to a contemporary Swedish collection now held in Stockholm. The NHM holdings were supplemented by a number of enigmatic donations from private individuals and then by fossils collected during the first ‘official’ geological survey of the islands in 1920–1922. Meanwhile a large collection was built up in New York through collaboration in 1909 with a local collector – the Governor's wife! The regional associations of the fossils established the African heritage of Falklands geology, and thereby contributed to an understanding of continental drift as the mechanism for the fragmentation of the Gondwana supercontinent. The Falkland Islands are now regarded as a rotated microplate created during the break-up.     

Overabundance of piscivorous dinosaurs (Theropoda: Spinosauridae) in the mid-Cretaceous of North Africa: The Algerian dilemma

The informally called ‘Continental intercalaire’ is a series of continental and brackish deposits that outcrops in several regions of North Africa. The age of the series is not well-constrained, but its upper part, visible in the ‘Kem Kem beds’ in Morocco and in Bahariya in Egypt, is regarded as early Cenomanian in age. Spinosaurid remains are an important component of this series, but records of this dinosaur are surprisingly rare in Algerian localities of the ‘Continental intercalaire’. Here, we describe a vertebrate assemblage from two localities, Kénadsa and Menaguir, situated in the Guir basin, Western Algeria. The assemblage comprises hybodont sharks, sarcopterygian fishes, ray-finned fishes, turtles, crocodiles and dinosaurs. Among the latter, only teeth of theropods have been recovered and 94% belong to Spinosaurus. The assemblage is taxonomically very similar to the Moroccan and Egyptian assemblages mentioned above. This study: 1) suggests a likely early Cenomanian age for the Guir basin deposits containing the assemblage; 2) provides a new evidence of the homogeneity of the early Cenomanian vertebrate fauna throughout North Africa; and 3) confirms the overabundance of theropod dinosaurs, especially spinosaurs, in the assemblage showing a possible shortcut in the vertebrate food chain. The northern most locality, Menaguir, shows sedimentological and ichnological evidence of marine influences indicating that the palaeoenvironment shows spatial heterogeneities.     

Sources and reservoirs of anthropogenic iodine-129 in western New York

Large quantities of iodine-129 have been released during nuclear weapons testing, and from nuclear power and fuel reprocessing plants. The distribution of this isotope was investigated in 110 surface water and soil samples from western New York (where several potential point sources are located) and other areas of North America, to evaluate its sources, transport pathways, and reservoirs. Elevated ¹²⁹I concentrations associated with a former reprocessing facility at West Valley, NY, can be tracked to Lakes Erie and Ontario via site drainage, and for over 200 km via atmospheric transport, while only a negligible signal is associated with active power plants in the area. The results point to local reprocessing as the major source of ¹²⁹I in western New York, while bomb fallout constitutes less than 0.5% of the signal. Surface soil is the dominant reservoir for anthropogenic ¹²⁹I in this region. Across North America, ¹²⁹I concentrations are lower than in western New York, although still significantly higher than expected weapons fallout. Reprocessing releases are currently seen to be the major source for elevated ¹²⁹I concentrations on a global scale, in contrast to previous suggestions that most anthropogenic ¹²⁹I was still derived from weapons fallout. Concentrations of ¹²⁹I and iodine in surface reservoirs are generally found to be uncorrelated, implying that natural iodine and anthropogenic ¹²⁹I are not yet in equilibrium. The results suggest that anthropogenic ¹²⁹I is cycled between the atmosphere-soil-vegetation systems more rapidly than natural, pre-anthropogenic iodine.     

Exceptional stegosaur integument impressions from the Upper Jurassic Morrison Formation of Wyoming

Dinosaur skin impressions are rare in the Upper Jurassic Morrison Formation, but different sites on the Howe Ranch in Wyoming (USA), comprising specimens from diplodocid, camarasaurid, allosaurid and stegosaurian dinosaurs, have proven to be a treasure-trove for these soft-tissue remains. Here we describe stegosaurian skin impressions from North America for the first time, as well as the first case of preservation of an impression of the integument that covered the dorsal plates of stegosaurian dinosaurs in life. Both have been found closely associated with bones of a specimen of the stegosaurian Hesperosaurus mjosi Carpenter, Miles and Cloward 2001. The scales of the skin impression of H. mjosi are very similar in shape and arrangement to those of Gigantspinosaurus sichuanensis Ouyang 1992, the only other stegosaurian dinosaur from which skin impressions have been described. Both taxa show a ground pattern of small polygonal scales, which in some places is interrupted by larger oval tubercles surrounded by the small scales, resulting in rosette-like structures. The respective phylogenetic positions of G. sichuanensis as a basal stegosaurian and H. mjosi as a derived form suggest that most stegosaurians had very similar skin structures, which also match the most common textures known in dinosaurs. The integumentary impression from the dorsal plate brings new data to the long-lasting debate concerning the function of dorsal plates in stegosaurian dinosaurs. Unlike usual dinosaur skin impressions, the integument covering the dorsal plates does not show any scale-like texture. It is smooth with long and parallel, shallow grooves, a structure that is interpreted as representing a keratinous covering of the plates. The presence of such a keratinous covering has affects on all the existing theories concerning the function of stegosaurian plates, including defense, thermoregulation, and display, but does not permit to rule out any of them.     

Assessing future risk: quantifying the effects of sea level rise on storm surge risk for the southern shores of Long Island, New York

Sea level rise threatens to increase the impacts of future storms and hurricanes on coastal communities. However, many coastal hazard mitigation plans do not consider sea level rise when assessing storm surge risk. Here we apply a GIS-based approach to quantify potential changes in storm surge risk due to sea level rise on Long Island, New York. We demonstrate a method for combining hazard exposure and community vulnerability to spatially characterize risk for both present and future sea level conditions using commonly available national data sets. Our results show that sea level rise will likely increase risk in many coastal areas and will potentially create risk where it was not before. We find that even modest and probable sea level rise (.5 m by 2080) vastly increases the numbers of people (47% increase) and property loss (73% increase) impacted by storm surge. In addition, the resulting maps of hazard exposure and community vulnerability provide a clear and useful example of the visual representation of the spatial distribution of the components of risk that can be helpful for developing targeted hazard mitigation and climate change adaptation strategies. Our results suggest that coastal agencies tasked with managing storm surge risk must consider the effects of sea level rise if they are to ensure safe and sustainable coastal communities in the future.     

Dinosaur remains from the type Maastrichtian: an update

Isolated cranial and post-cranial remains of hadrosaurid dinosaurs have been collected from various outcrops in the type area of the Maastrichtian stage during the last few years. In the present contribution, dentary and maxillary teeth are recorded from the area for the first time. Post-cranial elements comprise a newly collected, fragmentary, large right metatarsal III and a broken ?right humerus, recently recognised in the collections of Teylers Museum (Haarlem). Unfortunately, none of these remains can be identified to species level. The available material suggests, however, that more than one taxon of non-lambeosaurine hadrosaurid and a possible euhadrosaurian are represented. Most of the new finds are stratigraphically well documented, which means that they may be linked to the recently published sequence-stratigraphic interpretation of the type Maastrichtian. Dinosaur remains recorded previously from the Maastrichtian type area are tabulated.

     

Titanoceratops ouranos, a giant horned dinosaur from the late Campanian of New Mexico

At the end of the Cretaceous, 65.5 million years ago, the giant ceratopsids Triceratops and Torosaurus dominated North America’s dinosaur fauna. The origins of these giant ceratopsids, the Triceratopsini, are poorly understood. This paper describes Titanoceratops ouranos, a giant ceratopsid from the late Campanian (73-74 Ma) of New Mexico, and the earliest known triceratopsin. The holotype was previously interpreted as an aberrant and exceptionally large specimen of Pentaceratops sternbergi, but the animal does not show the diagnostic features of Pentaceratops. Instead, cladistic analysis shows that Titanoceratops is the sister taxon of a clade formed by Eotriceratops, Triceratops, and Torosaurus. With an estimated mass of 6.5 tons, Titanoceratops is among the largest dinosaurs known from the Campanian of North America, and rivaled Triceratops in size. The recognition of Titanoceratops suggests that giant chasmosaurines evolved once, among the Triceratopsini, and that the group evolved large size five million years earlier than previously thought. The giant horned dinosaurs probably originated in the southern part of the North American continent during the Campanian but only became widespread during the Maastrichtian.     

Time and space in stratigraphy: The ‘3-m gap’ story

Even for earth scientists it appears difficult to keep in mind that a sedimentary succession does not form due to accumulation at a constant rate, but that long periods of slow accumulation may alternate with short phases of event sedimentation and/or shorter or longer time-spans of non-deposition or even erosion. An example of this incorrect way of thinking is a recently published article in which it is postulated that the find of a ceratopsian brow horn only 13 cm below the K/T boundary in the Hell Creek Formation (Montana, USA) proves that dinosaurs did not become extinct before the K/T impact. It is argued why the postulated consequence (closure of the so-called 3-m gap: a zone of some metres thick underneath the K/T boundary in which, thus far, no dinosaur remnants had been found in the USA) is based on incorrect presumptions, particularly the relationship between time and space.