Deep marine trace fossil assemblages from the Lower Carboniferous of Menorca,Balearic Islands,western Mediterranean

Sediments of Lower Carboniferous age in eastern Menorca, Balearic Islands contain a diverse and exceptionally well preserved ichnofauna, including Neonereites biserialis, Nereites isp., Arthrophycus isp., Dictyodora liebeana, two ichnospecies of Chondrites, several ichnospecies of Lophoctenium, two ichnospecies of Phycosiphon, Syncoprulus pharmaceus, annulated burrows and a vertical burrow. The host lithologies are conglomerates, sandstones, siltstones and mudstones; most are the product of debris flows, and of high concentration [Ta(bc) intervals] to relatively dilute (Tcd/Tde intervals) turbidity currents. The rocks are interpreted as deposits of an inner- to mid-fan palaeoenvironment. Channelized deposits, sequences of overbank deposition and interchannel deposits interspersed with the deposits of unconfined debris flows and high concentration turbidity currents are present. The ichnofauna is most frequently, and best, preserved within the Td interval of turbidities, which are interpreted as interchannel deposits, produced by low concentration turbidity flows. The distribution of the ichnofauna is partly controlled by the lithologies in which they are preserved. The rarity and poor preservation of trace fossils in the coarser grained facies contrasts with the detailed preservation of very delicate traces in the finer grained lithologies. However, the ichnofauna is also partitioned between different subenvironments of the mid-fan to produce a series of palaeoichnocoenoses. Thin intervals of interchannel deposits, separated by deposits of high concentration turbidity currents, repeatedly contain only Phycosiphon incertum and small (?juvenile)Dictyodora liebeana. These traces are interpreted as the products of opportunistic colonization of near-channel environments during episodes of quiescent deposition. Thicker intervals of interchannel deposits contain diverse assemblages of trace fossils characteristic of more stable environments, in which widespread colonization occurred. Overbank deposits at Cabo de Favaritz are medium- to thick-bedded, fine-grained beds. In these, the ichnofauna occurs in a simple, two-tier profile. The upper tier is dominated by Nereites isp.; this is underlain by a partially bioturbated layer characterized by large Dictyodora liebeana and Arthrophycus isp.     

Two rare taxa from the type area of the Devonian,south-west England

The rarity of certain taxa in the type Devonian, south-west England, may be real, but it is probably, in part, an artefact of preservation. In part this is a product of Variscan deformation, but disarticulation of multi-element skeletons into minute plates must also be a contributory factor. Echinoids are rare from these deposits and were hitherto limited to the Upper Devonian. A single radiole (=spine) from the Middle Devonian (Givetian) Lummaton Shell Beds, Torquay Limestone Formation, is referred to echinoid sp. indet. Although stromatoporoids are common in these same beds, true sponges were hitherto unknown. In the same rock specimen, a moderately well preserved siliceous spicule is referred to octactinellid sp. indet.     

New Species of Enantiornithes (Aves: Ornithothoraces) from the Qiaotou Formation in Northern Hebei,China

<正>We report on a new species of enantiornithine bird from the Lower Cretaceous Qiaotou Formation of northern Hebei,China.The new taxon,Shenqiornis mengi gen.et sp.nov.,possesses several enantiornithine synapomorphies but is unique from other known species.The specimen has a well-preserved skull that reveals new information about enantiornithine cranial morphology.The new taxon possesses a large postorbital with a long tapering jugal process indicating that some enantiornithines may have had a fully diapsid skull,as in Confuciusornis.The tooth morphology of the specimen is unique and likely represents a previously unknown trophic specialization within Enantiornithes.     

记甘肃华池的一件空棘鱼类化石

本文记述了一件产自甘肃华池晚三叠世的空棘鱼类化石,并讨论了陕甘宁盆地中生代早,中期一些含鱼沉积的海相成因及可能与油气生成的关系。     

Upright crinoids of the Thornton Reef,Wenlock (Silurian) of Illinois,USA

The rare preservation of columns perpendicular to bedding may provide convincing evidence that ancient crinoids adopted an upright attitude during life. However, taphonomic and sedimentological analyses are important in determining whether such occurrences are truly in situ or represent unusual allochthonous accumulations. The Crinoid Biosome of the Thornton Reef Complex, Silurian of Illinois, USA, includes pluricolumnals preserved perpendicular to bedding, in association with more common specimens parallel or angled to bedding. Upright pluricolumnals are relatively shorter (<150 mm) than the longest non-upright specimens; they sometimes occur as imbricate accumulations and lack attachment structures (although these are preserved separately). Brachiopod valves and colonial corals may also be preserved perpendicular to bedding. These features suggest that the Thornton beds were formed as viscous mass flow deposits and that the upright crinoid columns are allochthonous or, at best, parautochthonous. © 1996 John Wiley & Sons, Ltd.     

Area,length and thickness conservation: Dogma or reality?

The basic assumption of quantitative structural geology is the preservation of material during deformation. However the hypothesis of volume conservation alone does not help to predict past or future geometries and so this assumption is usually translated into bed length in 2D (or area in 3D) and thickness conservation. When subsurface data are missing, geologists may extrapolate surface data to depth using the kink-band approach. These extrapolations, preserving both thicknesses and dips, lead to geometries which are restorable but often erroneous, due to both disharmonic deformation and internal deformation of layers. First, the Bolivian Sub-Andean Zone case is presented to highlight the evolution of the concepts on which balancing is based, and the important role played by a decoupling level in enhancing disharmony. Second, analogue models are analyzed to test the validity of the balancing techniques. Chamberlin's excess area approach is shown to be on average valid. However, neither the length nor the thicknesses are preserved. We propose that in real cases, the length preservation hypothesis during shortening could also be a wrong assumption. If the data are good enough to image the decollement level, the Chamberlin excess area method could be used to compute the bed length changes.     

Enantiornithine Bird with Diapsidian Skull and Its Dental Development in the Early Cretaceous in Liaoning, China

A Iarge number of enantiornithine birds are discovered from the Early Cretaceous Jiufutang Formation in western Liaoning, China. They are all small-sized birds with a few small teeth. The enantiornithine bird from the Jiufutang Formation in the Shangheshou area, Chaoyang, Liaoning Province reported in this paper is the largest individual known in all enantiornithine birds of the Early Cretaceous. However, its teeth possess a feature of pseudoheterodont. Some different development stages of the new teeth substitute the earlier stages and the stages of development are preserved in this specimen. This development pattern is similar to that of Archaeopteryx and alligator but not dinosaur. A well-developed postorbital was also preserved in the skull, which was a diapsidian skull like that of Confuciusornis. Additionally, the distinctive preservation of its prefrontal distinguishes it from other enantiornithine birds of the Early Cretaceous.     

Diminutive trace fossils in the Chengjiang Lagerstätte

Diminutive trace fossils described here have been well preserved in connection with certain pliable carapaces or skeletons of the Chengjiang animals. Taphonomic evidence suggests that these traces were formed in situ. The peculiar preservation indicates that some bilaterians of uncertain affinities seem to have been active at the burial site, constituting an important group of the hidden majority of Cambrian marine community. This may be an essential feature closely associated with the palaeoecology and exceptional preservation of the Cambrian fossil Lagerstätten. The rare preservation of such millimetre‐sized trace fossils raises further doubts about the timing of the initial benthic bilaterians by applying trace fossil evidence.     

云南昆明下寒武统筇竹寺组洒普山虫(三叶虫)的一个新种

洒普山虫是关杨虫(Kuanyangia)的一个亚属,乃1966年张文堂教授建立的,过去只有两个种:一个种名瘤点洒普山虫Kuanyangia(Sapushania)granulosa Chang,产于云南武定洒普山及狮子山,下寒武统筇竹寺组;另一个种名陕西洒普山虫Kuanyangia(Sapushania)shaanxiensis Zhang et Lin,产于陕西宁强坑家洞,下寒武统郭家坝组。本新种Kuanyangia(Sapushania)bella Chen(sp.nov.),产于云南昆明筇竹寺,下寒武统筇竹寺组。虽然只有一块标本,但标本保存的十分精美完好,与之共生的还有云南云南头虫Yunnanocephalus yunnanensis(Mansuy),产出层位系筇竹寺组的中上部。     

Tobler's oyster and the age of the Tabir Formation,Jambi Province,central Sumatra

For over 85 years, the stratigraphic determination of the Tabir Formation of Sumatra has been confused by a single fossil identification. Professor Fritz Frech recognized a specimen collected at the Batoe Kidjing locality by August Tobler to be an indeterminate, diminutive, ribbed oyster. Subsequently, this formation has been considered Upper Jurassic, perhaps Kimmeridgian, by several authors on the basis of this scant and inconclusive evidence; indeed, at least one author referred this sample to the genus Ostrea. However, these specimens are neither ribbed nor can they be demonstrated to be oysters; rather, this rock fragment contains a number of indeterminate mouldic fragments of fossils, too poorly preserved for confident identification. Modern determinations of the Tabir Formation as of Late Permian age are not contested by the evidence of this specimen. Copyright © 2008 John Wiley & Sons, Ltd.     

Quartz–garnet isotope thermometry in the southern Adirondack Highlands (Grenville Province, New York)

Quartz–garnet oxygen isotope thermometry of quartz‐rich metasedimentary rocks from the southern Adirondack Highlands (Grenville Province, New York) yields metamorphic temperatures of 700–800 °C, consistent with granulite facies mineral assemblages. Samples from the Irving Pond quartzite record Δ¹⁸O(Qtz–Grt) = 2.68 ± 0.21‰ (1 s.d. , n = 15), corresponding to peak metamorphic conditions of 734 ± 38 °C. This agrees well with the estimates from garnet–biotite exchange thermometry. Similar temperature estimates are obtained from Swede Pond (682 ± 47 °C, n = 3) and King's Station (c. 700 °C). The Whitehall area records higher temperatures (798 ± 25 °C, n = 3). All of these temperatures are higher than previous regional temperature estimates. The c. 800 °C temperatures near Whitehall are consistent with preservation of pre‐granulite contact temperatures adjacent to anorthosite. The preservation of peak metamorphic temperatures in garnet of all sizes is consistent with slow oxygen diffusion in garnet, and closure temperatures of at least 730 °C. Peak metamorphic fractionations are preserved in rocks with varying quartz:feldspar ratios, indicating that the modal percentage of feldspar does not affect retrograde oxygen exchange in these rocks. The lack of this correlation suggests slow rates of oxygen diffusion in quartz and feldspar, consistent with the results of anhydrous oxygen diffusion experiments.     

First report of gastroliths in the Early Cretaceous basal bird Jeholornis

Seeds preserved in association with the holotype of Jeholornis prima provided the first direct evidence of granivory in any Mesozoic bird. Although this long boney-tailed bird also displays several morphological indicators correlated with herbivory such as reduced dentition and a deep mandible, Jeholornis has not been previously reported to possess a gastric mill. However, this feature is commonly linked to herbivory in theropod dinosaurs and present in at least one sympatric ornithuromorph and the basal pygostylian Sapeornis, which also preserve direct evidence of granivory. Here we describe gastrolith masses preserved in five specimens of Jeholornis. The cluster of gizzard stones is nearly identical in each specimen, consisting of a tightly associated mass of proportionately small stones. Three previously undescribed specimens preserving seeds are also identified. Unlike in Sapeornis and a previously described ornithuromorph, no specimen of Jeholornis preserves both seeds and gastroliths. This may be due to the fact that, unlike in other Early Cretaceous birds, the seeds preserved in specimens of Jeholornis are found in the abdomen, suggesting that Jeholornis may have resembled extant ratites in lacking an esophageal crop. Consistent differences in the preservation and morphology of the gastrolith mass between Jeholornis and other early birds hint at subtle variations in alimentary function among basal lineages. Differences in ingested seed morphology among taxa in turn suggest these functional variations may be at least partially related to differences in diet.     

准噶尔盆地车排子地区下白垩统沉积体系分布及油气成藏模式

准噶尔盆地车排子地区自排2井区发现春光油田后,未能取得更大的勘探突破,该区存在斜坡带薄层砂体识别困难以及油气成藏主控因素及成藏模式不清等问题。通过高精度层序地层学、地震沉积学和石油地质的综合研究,明确了研究区白垩系的沉积相类型,包括扇三角洲前缘水下分流河道和水下分流河道间微相以及滨浅湖坝砂、滩砂和湖泥微相。有利的储集砂体、阶梯式输导体系和保存封堵条件是车排子地区下白垩统油气藏的主控因素。由于保存条件的不同,工区不同层位、不同位置发育的油气藏,其油品具有显著的差异。进而建立了斜坡带下部、中部和上部3种不同的成藏模式,最终指出斜坡带下部的SQq _1-SQq_2是油气勘探的有利区带和有利层位。研究结果为下一步勘探指明了方向。     

山东诸城地区早白垩世一新龟类足迹

1923年Nopcsa命名的Emydichnium是龟类足迹最早的报道,后来其他一些中生代的足迹也被陆续报道描述。但是大多数化石只显示出或多或少的明显爪印或者划痕,无法反映造迹者足部较为全面的生物学特征。山东诸城皇龙沟足迹点保存了早白垩世大量形态多样的龟类足迹,本文对其中一保存较好,能够反映足部生物学特征的龟类足迹进行了详细描述,并依据数据统计与莱阳足迹Liayangpus进行对比,显示两者存在明显不同。诸城的龟类足迹区别于以往发现的龟类足迹,因此根据其形态建立新种：完整诸城足迹Zhuchengichnites perfectus。本文亦对中国发现的龟类足迹化石点的层位、保存类型等进行了总结。     

中国东北地区早白垩世无尾两栖类化石一新属

描述了发现于中国东北地区中生代地层中的蛙类化石一新属、新种,即莫旗蒙蟾(新属、新种)Mengbatrachus moqi gen. et sp. nov.。化石产于内蒙古自治区最东部与黑龙江省相邻的莫旗。该类化石的的主要特征如下:头宽大于头长,上颌骨和前颌骨具有密集排列的牙齿;两鼻骨在中线相接;副蝶骨长条状;翼骨较大,鳞骨、上肩胛骨发育,乌喙骨近端膨大显著;荐前椎8个,脊椎横突发育;第Ⅱ—Ⅳ荐前椎具有短粗肋骨;肋骨单头,近端膨大;荐椎横突呈近似棒状,远端仅稍加宽;尾杆骨上有一对椎后横突;胫跗骨和腓跗骨仅在近端和远端愈合。这是除辽蟾外,在中国发现的另一新的中生代无尾两栖类化石。     

山东诸城地区早白垩世一新龟类足迹

1923年Nopcsa命名的Emydichnium是龟类足迹最早的报道,后来其他一些中生代的足迹也被陆续报道描述。但是大多数化石只显示出或多或少的明显爪印或者划痕,无法反映造迹者足部较为全面的生物学特征。山东诸城皇龙沟足迹点保存了早白垩世大量形态多样的龟类足迹,本文对其中一保存较好,能够反映足部生物学特征的龟类足迹进行了详细描述,并依据数据统计与莱阳足迹Liayangpus进行对比,显示两者存在明显不同。诸城的龟类足迹区别于以往发现的龟类足迹,因此根据其形态建立新种：完整诸城足迹Zhuchengichnites perfectus。本文亦对中国发现的龟类足迹化石点的层位、保存类型等进行了总结。     

A Middle Ordovician crinoid from the beach gravels of Ristna Cape,Hiiumaa Island,Estonia

Reworked fossils may be exotic, but more typically are locally derived. Echinoderms have only rarely been identified from beach clasts; most commonly, these are Upper Cretaceous echinoids from the Chalk. A pebble collected from a beach in Estonia has yielded a moderately well preserved specimen of the crinoid stem, Baltocrinus (col.) antiquus (Eichwald). This species is typical of the Baltic region, only being known from the Middle Ordovician (Darriwilian) of Estonia, but is exotic because the local outcrop is Upper Ordovician to Silurian.     

A Fresh Look at Dickinsonia： Removing It from Vendobionta

The Ediacaran Dickinsonia is well-known for being the only fossil to be assigned to many phyla, ranging from lichens, Cnidaria, Piatyheiminthes, Annelida, and a phylum of its own to a nonmetazoan kingdom. A new specimen from the Ediacaran fine-grained sandstone on the Winter Coast of the White Sea in northern Russia, which has an age of -555 million years ago, preserved convincing internal anatomies of definite animals, comparable with meridionai canals of extant ctenophores （comb jellies）. Additionally, we reconsidered Dickinsonia as a biradiaily symmetrical animal rather than a bilateral one as previously thought. The animal nature of Dickinsonia is, thus, well established and its affinities are most probably allied to ctenophores. This research is not only removing Dickinsonia from Vendobionta, but also bringing the fossil record of ctenophores forward to 20 million years before the Cambrian ＂explosion＂.