<abstract xmlns="http://www.w3.org/1999/xhtml"> Fining-upwards cyclothems found in five boreholes in the Carboniferous (Lower Bashkirian) of the Lublin Basin were analysed sedimentologically. It was established that the cyclothems represent fluvial deposits, and the lithofacies were grouped into lithofacies associations. Most lithofacies associations represent three types of sand-bed braided rivers: (1) high-energy, (2) deep and (3) distal sheetflood-affected. Other associations represent hyperconcentrated flows. Both coarse-grained (type I) and fine-grained (types IIa and IIb) occur among the fining-upward cyclothems. The formation of most thick cyclothems was related mainly to allocyclic factors, i.e. a decrease in the river’s gradient. The thickest fining-upward cyclothems are characteristic of hyperconcentrated flows and braided-river channels. The aggradation ratios were commonly high.During the early Namurian C and early Westphalian A (Early Bashkirian), the eastern part of the Lublin Basin was located close to the source area. The sedimentary succession developed due to a transition from high-energy braidedrivers and hyperconcentrated flows to lower-energy braided rivers, controlled by a rise of the regional base level.</abstract>

Braided-river and hyperconcentrated-flow deposits from the Carboniferous of the Lublin Basin (SE Poland) – a sedimentological study of core data

<abstract xmlns="http://www.w3.org/1999/xhtml">Hydrocarbon exploration in The Netherlands has a chequered history from serendipitous oil shows via chance oil/ gas discoveries to finding the largest continental European oil field in 1943, followed by finding the largest gas field in the world in 1959. The present contribution traces the development of moderate to good porosity/permeability trends in depositional facies of Zechstein Stassfurt carbonates in a ‘gas play’ intermediate in significance between the above two plays but all in the northern part of The Netherlands. Various depositional facies in the Stassfurt carbonates were turned into ‘carbonate fabric units’ by diagenetic processes creating or occluding the porosity/permeability. This formed moderate to good gas reservoirs in barrier-shoal, open-marine shelf and proximal-slope carbonates in the subsurface of the province of Drenthe in the NE Netherlands. The diagenetic models forming these carbonate fabric units are linked to the variety of facies in a depositional model which shows explain and predicts the reservoir trends. Such depositional/diagenetic facies are ‘translated’ into characteristic petrophysical values recognisable on wire line logs in uncored wells, and in characteristic seismic expressions that show these trends in undrilled areas. This approach has been proven to be effective in delineating porosity trends, visualised by 3-D seismic in the Collendoornerveen field, and thus provides a new exploration ‘tool’ in hydrocarbon exploration .</abstract>

Sedimentology and diagenesis as ‘hydrocarbon exploration tools’ in the Late Permian Zechstein-2 Carbonate Member (NE Netherlands)

<abstract xmlns="http://www.w3.org/1999/xhtml">Several important earthquake source models that have been extensively used in seismological research and earthquake prediction are presented and discussed. A new fault source model is used to explain the earthquake focal mechanism solution and tectonic stress field, which play a crucial role in earthquake initiation and preparation. The elastodynamic-dislocation theory is demonstrated which provides the theoretical background of most earthquake source models. Important earthquake source models reviewed here include the double-force-couple point-source model, the circular-shear dislocation model, the finite moving-source model, the Brune model, and the spherical explosive source model.</abstract>

Shanghai Earthquake Administration, Shanghai 200062, China

Department of Mechanical Engineering, University of Louisiana, Lafayette, LA 70504, USA

Commonly used earthquake source models

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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. 

Geologos

Volume 18 (2012): Issue 3 (November 2012)

Braided-river and hyperconcentrated-flow deposits from the Carboniferous of the Lublin Basin (SE Poland) – a sedimentological study of core data

Sedimentology and diagenesis as ‘hydrocarbon exploration tools’ in the Late Permian Zechstein-2 Carbonate Member (NE Netherlands)

Commonly used earthquake source models

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