Facies and diagenesis of some upper proterozoic dolomites of South China

Summary The Dengying Formation exposed at Sansha, Human Province, central South China, comprises unfossiliferous dolomitized platform carbonates and a solution-collapse breccia sequence. Microfacies analysis indicates a cyclic, increasingly restricted lagoonal to oolithic platform marginal facies. Sedimentation was repeatedly interrupted by periods of subaerial exposure as suggested by features of meteoric diagenesis and karstification. During a final regressive phase selective karst-dissolution of strata, interpreted as dolomite-evaporite interbeds, created a solution-residual/collapse breccia sequence. The Dengying Fm. is disconformably overlain by Lower Cambrian transgressive phosphatic conglomerates and fossiliferous black shales. These local facies data add another piece to the puzzle of Proterozoic/Cambrian Yangtze platform sedimentational history and demonstrate the applicability of microfacies analysis to uppermost Proterozoic strata.     

The genus Kepplerites Neumary et Uhlig (Kosmoceratidae,Ammonoidea) in the Bathonian-Callovian beds (Middle Jurassic) of the Russian Platform

The succession of early species of the genus Kepplerites is established in the Upper Bathonian-Lower Callovian beds of Central Russia and compared with the ammonoid succession of East Greenland and Western Europe. Late Bathonian members of the genus Kepplerites from the Middle Volga Region are generally similar, though not identical to those from Greenland, whereas the Early Callovian Kepplerites species and their immediate Bathonian ancestors are represented by species common to all three regions. The analysis of the ammonoid distribution suggests a connection between the East Greenland and Central Russian marine basins in the Early and Middle Bathonian and in the Early Callovian, and their short-term isolation in the Late Bathonian. A new species, Kepplerites (Kepplerites) aigii sp. nov., is described from the Upper Bathonian (keuppi Zone) of the Alatyr River basin (Middle Volga Region).     

Lipophilic Extracts from Needles and Defoliated Twigs of Pinus pumila from Two Different Populations

Hexane extracts of needles and defoliated twigs of Pinus pumila (Pall. ) Regel from two distant populations, located in the southwest and the east (i.e., Lake Baikal region and Sakhalin Island) of the species distribution range were studied by GC/MS analysis. Composition and retention indices of major components were determined. A drastic composition divergence for the extracts of P. pumila needles and defoliated twigs, depending on growth location, was established. Needle extracts from the eastern population sample contained mainly labdane‐type acids (anticopalic acid derivatives), whereas the predominant components of needle extracts from the other population sample were abietane‐type acids (abietic, neoabietic acids) and isopimarane‐type diterpenoids (sandaracopimaric acid, sandaracopimaradien‐3β‐ol). The main components of defoliated twig extracts from Sakhalin Island population sample were abietane‐type acids and cembrane‐type diterpenoids, while content of these compounds in the extracts of the southwestern marginal population sample was remarkably lower.     

A nearshore–offshore trend in acritarch distribution from the Early–Middle Ordovician of the Yangtze Platform, South China

The stratigraphical interval of the late Early Ordovician Didymograptus deflexus and the early Middle Ordovician Azygograptus suecicus graptolite Biozones was investigated from seven sections from the upper Yangtze Platform, southern China. These are located on different parts of the platform, between the nearshore environments of the Kunming area, Yunnan Province, and the offshore carbonate shelf of the Yichang area, Hubei Province. The assemblages recovered from the different parts of the platform vary both in terms of diversity and composition. The nearshore environments show low diversity assemblages with about 10 acritarch species, whereas the offshore shelf environments reflect higher diversities with about 40 species. The composition of the assemblages also changes from simple morphologies (micrhystrids, leiosphaerids, fusiform acritarchs) in nearshore environments to specimens with longer and more complexly branched processes on the shelf. The polygonomorph acritarchs are common over all the upper Yantze Platform, while the acanthomorph genera Baltisphaeridium and Peteinosphaeridium are the most abundant taxa on the offshore carbonate shelf area. Phylogenetic or sea-level changes are probably not responsible for the compositional and diversity changes that occurred during the investigated interval. This study confirms previous interpretations that poorly diversified Palaeozoic acritarch assemblages occur in neritic environments and more complex, highly diversified assemblages are found on the shelf.     

Tide-dominated Middle Devonian sequence from the northern part of the Holy Cross Mountains (Central Poland)

Summary The dolomitic Wojciechowice Formation distinctly differs from the remaining, mainly shaly Middle Devonian succession in northern part of the Holy Cross Mountains (Central Poland). The upper Member of the Formation (Crystalline Dolostone Mb.), in greater part dolomitized but also containing limestone beds, is composed of shallowing-upward cyclothems well exposed in Skaly quarry in the Bodzentyn syncline. The lower parts of the cyclothems, interpreted as subtidal facies, contain fossils characteristic for restricted environments. They are grouped into two assemblages. The first, with brachiopods (largeBornhardtina andEmanuella), massive stromatoporoids, and subordinate gastropods and amphiporoids is related to a deeper subtidal environment, while the second (mainly amphiporoids, gastropods, ostracodes and calcareous algae) is shallower subtidal. Towards the top of succession the fossil content radically decreases. The upper parts of cyclothems are composed mainly of different types of laminites. In these parts of the section, interpreted as intertidal/supratidal units, stromatolites, desiccation polygons, intraformational breccias, and common bioturbations are present. The whole succession was deposited in a low-energy environment, only intermittently affected by high-energy events. For their most spectacular example of this, aBornhardtina-coquinite, a tempestitic origin is proposed. The interval with cyclic sedimentation studied correlates with the dolomitized lower “Unit I” of the Stromatoporoid-Coral Kowala Formation from the southern part of the Holy Cross Mountains, which exhibits sabkha-type cyclicity. The differences in development of cyclothems in both regions resemble outer and inner part of an extensive platform, and correspond well with basic trends of the Lower-Middle Devonian transgression in the Holy Cross Mountains. The general succession of formations deposited during this process coincides with transgressive events on Johnson's eustatic curve for the Devonian.     

A Maeotian (Late Miocene) freshwater fish-fauna from Romania

Isolated pharyngeal teeth, pectoral, dorsal and suborbital fish spines were unearthed in a new outcrop located on the right bank of the Prut River, at F?lciu, Romania. They document Late Miocene aquatic ecosystems of the Dacian basin. Seven taxa were identified and described, six of them belonging to the order Cypriniformes and one to Siluriformes. The Cobitidae is here firstly reported in the fossil record of Romania. All the fish teeth and skeletal remains are from representatives marking shallow water. The fossils were probably buried into sediments accumulated near the mouth of a rather fast-flowing river that drained into a brackish body of water, part of the Dacian basin. The composition of the fauna is similar to the coeval ones from the North (Ukraine and Republic of Moldova) and from the South (Turkey) of the Black Sea basin.     

Genomes of Pleistocene Siberian Wolves Uncover Multiple Extinct Wolf Lineages

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