<abstract xmlns="http://www.w3.org/1999/xhtml">An oolite in the Furongian (Late Cambrian) Chaomidian Formation in Shandong Province, China, which was deposited on the North China Platform in an epeiric sea, contains several limestone breccia lenses of various dimensions (centimetres to decimetres thick and decimetres to more than 10 metres in length) in an E-trending section. The oolite, which is approximately 40 cm thick, was originally thicker, as indicated by a planar truncation surface that formed by wave abrasion. The breccia lenses in this oolite are generally mound-shaped with a flat base and a convex top. The western margin of the lenses is commonly rounded whereas the eastern margin commonly has a tail (consisting of a rapidly eastwards thinning breccia horizon that gradually ends in a horizon of isolated clasts). Some of the breccia lenses are underlain by a shear zone.The formation of the breccia lenses cannot be easily explained by normal depositional or deformational processes. It is concluded that the lenses represent fragments of a partly consolidated layer, consisting of both rounded and angular platy clasts, which slid down over a very gently inclined sedimentary surface which acted – possibly together with a water film – as a lubricant layer. During transport, the layer broke up into several discrete bodies that formed small ‘highs’ at the sedimentary surface of the shallow epeiric sea. Subsequently, waves partially eroded the lenses, mostly at their margins, producing their mound-shaped form.Sliding of blocks is known from a wide variety of environments in the sedimentary record; however, this is the first description of the sliding of blocks in an epeiric sea. This indicates that such a low-relief submarine carbonate setting is, like its siliciclastic counterparts, susceptible to this process.</abstract>

Geological Institute, Adam Mickiewicz University, Maków Polnych 16, 61-606 Poznan, Poland

College of Geological Science and Engineering, Shandong University of Science and Technology, Qingdao 266510, China

School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China

Slide origin of breccia lenses in the Cambrian of the North China Platform: new insight into mass transport in an epeiric sea

<abstract xmlns="http://www.w3.org/1999/xhtml">Two sections of sediment from small oxbow-lake infillings located in different river valleys in central Poland were studied by cladoceran analysis in order to examine the response of aquatic ecosystems to the Younger Dryas. Lithological and geochemical records, as well as chydorid (Chydoridae) ephippia analysis were also used to reconstruct Younger Dryas climate trends. A high concentration of cladocerans, as well as the presence of Cladocera taxa preferring warmer water, was found. It is likely that local processes in the oxbow lakes were important, because the presence of warm-preferring taxa was also related to their habitats and their development. Yet local environmental forces, such as the influence of the rivers, habitat modification, macrophyte abundance, and eutrophication, were not only major factors to affect the Cladocera diversity in the Younger Dryas. The observation of changes in the composition and concentration of Cladocera in oxbow-lake infillings indicates that most of the changes occurred in response to climate changes.</abstract>

Younger Dryas Cladocera assemblages from two valley mires in central Poland and their potential significance for climate reconstructions

<abstract xmlns="http://www.w3.org/1999/xhtml">Sediment samples have been collected from the Schirmacher Oasis and adjoining area in East Antarctica; these areas consist of polar ice, ice-free area, lakes and the coastal shelf area. The 37 samples have been analysed for their grain-size parameters and statistical relationships. The oasis is characterised by ongoing glacial processes, including deposition and erosion of the sediments by ice, meltwater and winds, thus influencing the sediments in various ways. Basic statistical grain-size parameters like graphic mean, standard deviation, skewness and kurtosis have been calculated for the four units. The sediments of all areas are almost all poorly to very poorly sorted, fine-skewed to near-symmetrical and platykurtic to leptokurtic in nature. Bivariate plots between the grain-size parameters have been interpreted. They do, apart from a few exceptions, not show any trend suggesting relationships between the sediments of the four landscape types. Both t- and F-tests have been applied on the samples, and the phi values and grain-size parameters have been analysed; these show that the group variances of the samples are not significant, but that the phi-values are significant.</abstract>

Department of Geology, SGB Amravati University, Amravati 444 602, India

Department of Statistics, SSC College, Amravati – 444 602, India

Ministry of Earth Sciences, Lodhi Road, New Delhi – 110003, India

Grain-size characteristics of deposits derived from different glacigenic environments of the Schirmacher Oasis, East Antarctica

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Geologos

GEOLOGOS is an international, peer-reviewed journal publishing research results and review articles covering all earth-science disciplines, with a focus on the geology of central and eastern Europe. Studies on areas of poorly known geology (e.g. Asia and Africa) are also published. Articles from non-European areas should be universal and problem-related, while purely regional issues are avoided.  Over the last years, Geologos has published studies on many topics, including:    mineralogy and geochemistry  sedimentology (siliciclastics and carbonates, sedimentary structures, facies analysis)  palaeontology (invertebrate palaeontology, trace fossils, micropalaeontology)  stratigraphy and petroleum geology (sequence stratigraphy)  glacial geology (Pleistocene palaeogeography and stratigraphy, lithology of glaciogenic deposits)  hydrogeology (groundwater circulation, groundwater flow models, drainage systems, deep aquifers)  meteorites (Morasko meteorite fall).    GEOLOGOS has been issued since 1995 as the journal of the Institute of Geology, Adam Mickiewicz University (AMU) in Poznań, Poland.  GEOLOGOS is an open access journal; all content is freely available without charge.  Three issues of GEOLOGOS are published each year. Electronic versions of all papers are published on the Sciendo platform.  Why subscribe and read    Journal on geology of Central and Eastern Europe as well as other areas of poorly known geology   Why submit    Quick publication, colour pages free of chargé. To publish in GEOLOGOS, authors are not required to pay an Article Processing Charge.   Reviewing    Each manuscript, as a rule, is reviewed by two referees, commonly one Polish and one foreign. Reviews are double-blind.   Rejection Rate    About 40%    Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 

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Volume 18 (2012): Issue 4 (December 2012)

Slide origin of breccia lenses in the Cambrian of the North China Platform: new insight into mass transport in an epeiric sea

Younger Dryas Cladocera assemblages from two valley mires in central Poland and their potential significance for climate reconstructions

Grain-size characteristics of deposits derived from different glacigenic environments of the Schirmacher Oasis, East Antarctica

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