Upper Maastrichtian depositional environments and sea-level history of the Kopet-Dagh Intracontinental Basin, Kalat Formation, NE Iran

The Kopet-Dagh Basin is located in northeastern Iran and southern Turkmenistan. The Late Maastrichtian Kalat Formation caps the Cretaceous interval in this Basin. Based on eight measured stratigraphic sections, the depositional environments and the sea-level history of the Kalat Formation have been interpreted. Petrographic and field observations led to identification of four major carbonates (A–D) and two siliciclastic lithofacies types. Carbonate rocks were deposited on a ramp setting within three zones including restricted and semi-restricted lagoons, bars, and open marine environments, while the siliciclastics were deposited at the shoreline. Sequence stratigraphic analysis identified two depositional sequences in the western and eastern parts and three depositional sequences in the central parts of the study area. Comparing the sea-level curve of Late Maastrichtian time in the Kopet-Dagh Basin with the global sea-level curve for the same time interval, there are some geometrical similarities and differences. The variations in the Basin are related to regional tectonic settings and sediment loading of the study area. Reconstructions of depositional environment during eight time slices of the Late Maastrichtian are presented. These results could be used for comparison with other localities worldwide and provide additional data for Late Cretaceous paleogeographic reconstructions.     

Relationships between foraminiferal assemblages and depositional sequences in Jahrum Formation,Ardal area (Zagros Basin,SW Iran)

The Jahrum Formation was deposited in the foreland basin in southwest Iran (Zagros Basin). The Zagros mountain belt of Iran, a part of the Alpine–Himalayan system, extends from the NW Iranian border through to SW Iran, up to the strait of Hormuz. The various facies of the Jahrum Formation were deposited in four main genetically related depositional environments, including: tidal flat, lagoon, shoal and open marine. These are represented by 14 microfacies. The Jahrum Formation represents sedimentation on a carbonate ramp. Tidal flat facies are represented by fenestral fabric, stromatolitic boundstone and thin-bedded planes. Carbonate deposition in a shallow marine lagoon was characterised by wacke–packstone, dominated by various taxa of imperforate foraminifer. The shoals are made up of medium- to coarse-grained skeletal and peloidal grainstone. This facies was deposited predominantly in an active high energy wave and current regime, and grades basinward into middle ramps facies are represented by wackestones–packstones with a diverse assemblage of echinoderm and large benthic foraminifers with perforate wall. Outer ramp facies consist of alternating marl and limestones rich in pelagic foraminifera. There is no evidence for resedimentation processes in this facies belt. The sequence stratigraphy study has led to recognition of three third-order depositional sequences.     

黑龙江绥滨地区晚侏罗世Buchia带

绥滨地区晚侏罗世东荣组的双壳类Buchia,划分为4个带:(1)晚牛津至早启莫利期的B.concentrica带;(2)晚启莫利期的B.tenuistriata带;(3)早-中伏尔加期的B.mosquensis-B.rugosa带;及(4)晚伏尔加期的B.fischeriana带。文内共描述3属9种。     

A New Pterosaur Tracksite from the Jurassic Summerville Formation,Near Ferron,Utah

Pterosaur tracks (cf. Pteraichnus) from the Summerville Formation of the Ferron area of central Utah add to the growing record of Pteraichnus tracksites in the Late Jurassic Summerville Formation and time-equivalent, or near time-equivalent, deposits. The site is typical in revealing high pterosaur track densities, but low ichnodiversity suggesting congregations or “flocks” of many individuals. Footprint length varies from 2.0 to 7.0 cms. The ratio of well-preserved pes:manus tracks is about 1:3.4. This reflects a bias in favor of preservation of manus tracks due to the greater weight-bearing role of the front limbs, as noted in other pterosaur track assemblages. The sample also reveals a number of well-preserved trackways including one suggestive of pes-only progression that might be associated with take off or landing, and another that shows pronounced lengthening of stride indicating acceleration.

One well-preserved medium-sized theropod trackway (Therangospodus) and other larger theropod track casts (cf. Megalosauripus) are associated with what otherwise appears to be a nearly monospecific pterosaur track assemblage. However, traces of a fifth pes digit suggest some tracks are of rhamphorynchoid rather than pterodactyloid origin, as usually inferred for Pteraichnus. The tracks occur at several horizons in a thin stratigraphic interval of ripple marked sandstones and siltstones. Overall the assemblage is similar to others found in the same time interval in the Western Interior from central and eastern Utah through central and southern Wyoming, Colorado, northeastern Arizona, and western Oklahoma. This vast “Pteraichnus ichnofacies,” with associated saurischian tracks, remains the only ichnological evidence of pre-Cretaceous pterosaurs in North America and sheds important light on the vertebrate ecology of the Summerville Formation and contiguous deposits.     

吐鲁番盆地连木沁剖面齐古组轮藻化石

吐鲁番盆地连木沁剖面侏罗系齐古组的轮藻化石在早年资料中未见提及。后期曾有不同单位多人次对此剖面进行观察实测,除偶有提起见到轮藻外,亦均未见描述报道,本文首次正式报道了齐古组的轮藻化石,为吐鲁番盆地齐古组与广布于新疆各地区的齐古组进行横向对比提供了这类化石依据。     

关于董氏狼鳍鱼(Lycoptera tungi)的种上归类

本文重新研究了董氏狼鳍鱼 (Lycoptera tungi Liu et al 1963).将产自宁夏隆德石窑寺的董氏狼鳍鱼 V2323 号标本从狼鳍鱼属 (Lycoptera) 中分出来,归入华夏鱼属 (Huashia), 修定为董氏华夏鱼 (Huashia tungi (Liu et al.)).同时对华夏鱼科 (Huashiidae) 的系统位置作了初步讨论.     

吐鲁番盆地鄯善地区中、晚侏罗世介形类

报道吐鲁番盆地连木沁剖面七克以组及齐古组的介形类化石３属１０种,其中２新种１未定种;Ｔｈｅｒｉｏｓｙｎｏｅｃｕｍ？ｑｉｋｔｉｍｅｎｓｉｓ ｓｐ．ｎｏ。,Ｔｈ．ｈｕｏｙａｎｓｈａｎｅｎｉｓ ｓｐ．ｎｏｖ．,Ｄａｒｗｉｎｕｌａ ｓｐ．,根据化石组合面貌,自上而下可建立两个组合,即Ｄａｒｗｉｎｕｌａ－Ｍｅｔａｃｙｐｒｉｓ组合和Ｔｈｅｒｉｏｓｙｎｏｅｃｕｍ？－Ｄａｒｗｉｎｕｌａ组合,其时代分别为晚侏罗世和     

苏北盆地高邮凹陷D1井白垩纪-古近纪微体古生物地层及沉积环境

高邮凹陷D1井富含介形虫、轮藻和孢粉等化石。通过系统的微体古生物分析,首次对该地区白垩纪一古近纪微体古生物地层进行了精确划分,从下到上共建立11个化石组合：其中介形虫4个,轮藻4个,孢粉3个。文中还简要探讨了沉积环境演变,为该地区油气勘探提供有力的生物地层依据。     

A model for the paleoenvironmental distribution of larger foraminifera of Oligocene–Miocene carbonate rocks at Khaviz Anticline,Zagros Basin,SW Iran

Platform carbonate sediments of Oligocene–Miocene age (Asmari Formation) in the Zagros Basin (SW Iran) have been investigated in order to determine their paleoecology and depositional environment. The Zagros Basin is the result of the opening and closure of the Neo-Tethys Ocean along the northeastern border of the Arabian Plate. The thick sedimentary sequences of the Zagros Basin contain rocks ranging in age from Cambrian to recent. The geological evidence suggests that the region was part of a passive continental margin, which subsequently underwent rifting in the Permo-Trias and collision in the Late Tertiary. The Asmari carbonate system was dominated by foraminifera and corallinacean assemblage. Based on the distribution of the larger foraminifera, four assemblage zones have been recognised. Facies analysis allowed the recognition of nine microfacies types that are grouped into three depositional environments that correspond to the inner, middle and outer shelf. The biota assemblage of the Asmari Formation suggests that carbonate sedimentation took place in tropical waters and oligotrophic to slightly mesotrophic conditions. Our detailed analysis of microfacies and paleoecology shows that the Asmari Formation deposited on a carbonate open shelf dominated by heterozoan and, subordinately, photozoan skeletal assemblage.     

辽西中上侏罗统土城子组植物化石的新发现

报道产自辽宁北票三宝营土城子组２种木化石及１０种植物化石（包括５新种）。它们反映了干旱气候条件下沙漠绿洲型的植被特征,时代属时代属中晚侏罗世。     

Late Jurassic sea-level fluctuations in NW Switzerland (Late Oxfordian to Late Kimmeridgian): closing the gap between the Boreal and Tethyan realm in Western Europe

In Late Jurassic times, the Swiss Jura carbonate platform occupied the transition between the Paris Basin and the Tethys and thus connects the Boreal and Tethyan realm. Up to now, the lack of index fossils in the Reuchenette Formation prevented a reliable correlation between both areas (its sediments are characterised by a prominent sparseness of index fossils). Now, seven recently in situ collected species of ammonites helped to establish a new sequence-stratigraphical frame for the platform sediments of the Reuchenette Formation in NW Switzerland. Based on biostratigraphical data, five third-order sedimentary sequences were assigned to the Late Oxfordian to Late Kimmeridgian. The upper three third-order sequences correspond to the Boreal sequences Kim3–5 of Hardenbol et al. (1998). The deduced large-scale sea-level fluctuations match those from other European regions (Spain, Russia). This biostratigraphically based sequence-stratigraphical frame is a prerequisite to refine correlations within a wider area covering the Swiss Jura and parts of adjacent France and Germany. Electronic Supplementary Material Supplementary material is available for this article at     

新疆准噶尔盆地侏罗纪石树沟组上部一大型兽脚类跖骨

准噶尔盆地中侏罗世晚期到晚侏罗世早期沉积的石树沟组产出过包括多种兽脚类恐龙在内的大量脊椎动物化石。描述了一件新的采自准噶尔盆地东北缘五彩湾地区石树沟组上部的兽脚类恐龙左第四跖骨标本(IVPPV18060)。通过与其他兽脚类恐龙第四跖骨对比,该标本可归入异特龙超科(Allosauroidea)。它与其他异特龙超科第四跖骨的相似性包括:近端关节面三角形并有一向后方延伸的舌状突出,向外侧轻微弯曲的骨干,位于骨干后方靠近外侧边的半月形肌肉凹陷,三角形骨干横截面。在异特龙超科当中,V18060与准噶尔盆地将军庙地区石树沟组中发现的董氏中华盗龙(Sinraptordongi)最为相似(除了以上相似性,V18060和董氏中华盗龙的相似性还包括远端关节轮廓呈近梯形,骨干后部肌肉凹陷与周围边界呈半开放状态)。但是,V18060和董氏中华盗龙也存在着一些明显的区别:V18060明显比董氏中华盗龙的第四跖骨粗壮,远端内外两髁大小差异相反。这些形态差异可能是由于个体发育或者性双形造成的,也可能代表分类学差异。对比研究和基于第四跖骨形态信息进行的分支系统学分析结果更偏向后一种解释:V18060代表一个不同于董氏中华盗龙但与后者亲缘关系很近的新的兽脚类恐龙。新材料的发现增加了中晚侏罗世石树沟动物群兽脚类恐龙的分异度。在五彩湾和将军庙地区发现不同的中华盗龙类恐龙指示了晚侏罗世早期准噶尔盆地中相邻地区可能存在着一定的生态分异性或者地理隔离。     

Sequence stratigraphic significance of sedimentary cycles and shell concentrations in the Upper Jurassic-Lower Cretaceous of Kachchh, western India

Upper Jurassic and Lower Cretaceous siliciclastic shallow water sediments of the Kachchh Basin, western India, form strongly asymmetric coarsening-upward cycles, which are interpreted as recording changes in relative sea level (deepening-shallowing cycles). These cycles correspond to depositional sequences, in which deposits of the lowstand systems tract are not present, the sequence boundary coinciding with the transgressive surface. Shell concentrations are found in the transgressive lags at the base of the transgressive systems tract (TST), in the maximum flooding zone (MFZ), and at or close to the top of the highstand systems tract. They belong to six assemblages, five of them dominated by large bivalves such as Seebachia, Herzogina, Gryphaea, Gervillella, Megacucullaea, Pisotrigonia and Indotrigonia, the sixth by the coral Amphiastraea. Three types of shell concentrations can be distinguished that differ from each other in a number of ecological and taphonomic features, such as species diversity, preservation quality, orientation in cross-section, percentage of disarticulation, and degree of biogenic alteration. Characteristic features of concentrations at the base of the TSTs are moderate time-averaging, sorting, a preferred convex-up orientation, and nearly total disarticulation of shells. They are suggestive of an environment in which reworking and local transport were frequent events. Similar features are shown by concentrations near the tops of the HSTs, except that there shells were largely concentrated in lenses and in pavements rather than in beds as in the transgressive lags. Associated sedimentary structures indicate deposition above fair weather wave base in a high-energy environment. Concentrations occurring in the MFZ, in contrast, are autochthonous and highly time-averaged, having accumulated during times of low rates of sedimentation below storm wave base. This is supported by their high preservation quality (comparatively high percentage of articulated shells, shells of infaunal organisms commonly preserved in life position), biogenic alteration being the most important taphonomic agent. The dominant elements of these shell concentrations, i.e. Seebachia, Megacuccullaea, and Indotrigonia in the Upper Jurassic, and Pisotrigonia in the Lower Cretaceous, are endemic to the Ethiopean faunal province and belong to lineages that rapidly evolved during this time period.     

湖北秭归盆地中侏罗世泄滩组孢粉组合

本文记录了鄂西秭归盆地东缘泄滩组上部21个属36个种的孢粉植物群,其中包括3个新种,讨论了主要属种组合特征和地层延限,根据中侏罗世孢粉植物群组合在国内外的对比,提出泄滩组上部Cyathidites minor-Classopollis-Callialasporites组合的时代属于中侏罗世,这个组合以桫椤科,掌鳞杉科植物的繁盛,和出现大量Cal-lialasporites母体植物为特点,暗示泄滩组上部形成于炎热而干旱的气候环境。