A new U–Pb LA-ICP-MS age of the Rumburk granite (Lausitz Block,Saxo-Thuringian Zone): constraints for a magmatic event in the Upper Cambrian     

Zieger  J.  Linnemann  U.  Hofmann  M.  Gärtner  A.  Marko  L.  Gerdes  A. 《International Journal of Earth Sciences》2018,107(3):933-953

International Journal of Earth Sciences - The basement of the Saxo-Thuringian Zone consists of Upper Neoproterozoic (c. 650-570 Ma) Cadomian arc sediments (Lusatian greywackes) and...  相似文献   

A new U–Pb zircon age and a volcanogenic model for the early Permian Chemnitz Fossil Forest     

Luthardt  Ludwig  Hofmann  Mandy  Linnemann  Ulf  Gerdes  Axel  Marko  Linda  Rößler  Ronny 《International Journal of Earth Sciences》2018,107(7):2465-2489

International Journal of Earth Sciences - The Chemnitz Fossil Forest depicts one of the most completely preserved forest ecosystems in late Paleozoic Northern Hemisphere of tropical Pangaea. Fossil...  相似文献   

Low permeability Neogene lithofacies in Northern Croatia as potential unconventional hydrocarbon reservoirs     

Tomislav Malvić  Antonija Sučić  Marko Cvetković  Filip Resanović  Josipa Velić 《Central European Journal of Geosciences》2014,6(2):182-194

We present two examples of describing low permeability Neogene clastic lithofacies to outline unconventional hydrocarbon lithofacies. Both examples were selected from the Drava Depression, the largest macrostructure of the Pannonian Basin System located in Croatia. The first example is the Beni?anci Field, the largest Croatian hydrocarbon reservoir discovered in Badenian coarse-grained clastics that consists mostly of breccia. The definition of low permeability lithofacies is related to the margins of the existing reservoir, where the reservoir lithology changed into a transitional one, which is mainly depicted by the marlitic sandstones. However, calculation of the POS (probability of success of new hydrocarbons) shows critical geological categories where probabilities are lower than those in the viable reservoir with proven reserves. Potential new hydrocarbon volumes are located in the structural margins, along the oil-water contact, with a POS of 9.375%. These potential reserves in those areas can be classified as probable. A second example was the Cremu?ina Structure, where a hydrocarbon reservoir was not proven, but where the entire structure has been transferred onto regional migration pathways. The Lower Pontian lithology is described from well logs as fine-grained sandstones with large sections of silty or marly clastics. As a result, the average porosity is low for conventional reservoir classification (10.57%). However, it is still an interesting case for consideration as a potentially unconventional reservoir, such as the ”tight” sandstones.  相似文献   

Slope stability and landslides in proglacial varved clays of western Estonia     

Marko Kohv  Peeter Talviste  Tiit Hang  Volli Kalm  Alar Rosentau 《Geomorphology》2009,106(3-4):315-323

During the last decade the frequency of landslides at river valley slopes eroding into the glaciolacustrine plain in western Estonia has grown considerably. We studied in detail nine recent landslides out of 25 known and recorded sliding events in the area. All landslides occurred at the river banks in otherwise almost entirely flat areas of proglacial deposits capped with marine sands. Glaciolacustrine varved clay is the weakest soil type in the area and holds the largest landslides. Slope stability modelling shows that critical slope gradient for the clay is ≥ 10° and for the marine sand ≥ 20°. Fluvial erosion is the main process in decreasing slope stability at the outer bends of the river meanders. An extra shear stress generated by groundwater flow following the high stand of the groundwater level or rapid water level drawdown in the river channels are responsible for triggering the landslides. Consecutive occurrence of small-scale slides has a direct effect in triggering the large, retrogressive complexes of slides in the glaciolacustrine clay. A landslide hazard zonation map was composed based on digital elevation model and the data on spatial distribution of glaciolacustrine clays and marine sands, and on existing and critical slope angles of these deposits.  相似文献   

Envelope‐based pushover analysis procedure for the approximate seismic response analysis of buildings          下载免费PDF全文

Marko Brozovič  Matjaž Dolšek 《地震工程与结构动力学》2014,43(1):77-96

An envelope‐based pushover analysis procedure is presented that assumes that the seismic demand for each response parameter is controlled by a predominant system failure mode that may vary according to the ground motion. To be able to simulate the most important system failure modes, several pushover analyses need to be performed, as in a modal pushover analysis procedure, whereas the total seismic demand is determined by enveloping the results associated with each pushover analysis. The demand for the most common system failure mode resulting from the ‘first‐mode’ pushover analysis is obtained by response history analysis for the equivalent ‘modal‐based’ SDOF model, whereas demand for other failure modes is based on the ‘failure‐based’ SDOF models. This makes the envelope‐based pushover analysis procedure equivalent to the N2 method provided that it involves only ‘first‐mode’ pushover analysis and response history analysis of the corresponding ‘modal‐based’ SDOF model. It is shown that the accuracy of the approximate 16th, 50th and 84th percentile response expressed in terms of IDA curves does not decrease with the height of the building or with the intensity of ground motion. This is because the estimates of the roof displacement and the maximum storey drift due to individual ground motions were predicted with a sufficient degree of accuracy for almost all the ground motions from the analysed sets. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Deep reflection seismic imaging of iron-oxide deposits in the Ludvika mining area of central Sweden     

Magdalena Markovic  Georgiana Maries  Alireza Malehmir  Julius von Ketelhodt  Emma Bäckström  Monica Schön  Paul Marsden 《Geophysical Prospecting》2020,68(1):7-23

Reflection seismic data were acquired within two field campaigns in the Blötberget, Ludvika mining area of central Sweden, for deep imaging of iron-oxide mineralization that were known to extend down to 800–850 m depth. The two surveys conducted in years 2015 and 2016, one employing a seismic landstreamer and geophones connected to wireless recorders, and another one using cabled geophones and wireless recorders, aimed to delineate the geometry and depth extent of the iron-oxide mineralization for when mining commences in the area. Even with minimal and conventional processing approaches, the merged datasets provide encouraging information about the depth continuation of the mineralized horizons and the geological setting of the study area. Multiple sets of strong reflections represent a possible continuation of the known deposits that extend approximately 300 m further down-dip than the known 850 m depth obtained from historical drilling. They show excellent correlation in shape and strength with those of the Blötberget deposits. Furthermore, several reflections in the footwall of the known mineralization can potentially be additional resources underlying the known ones. The results from these seismic surveys are encouraging for mineral exploration purposes given the good quality of the final section and fast seismic surveys employing a simple cost-effective and easily available impact-type seismic source.  相似文献   

Results from the first ballast water sampling study in the Mediterranean Sea - the Port of Koper study     

David M  Gollasch S  Cabrini M  Perkovic M  Bosnjak D  Virgilio D 《Marine pollution bulletin》2007,54(1):53-65

The ongoing transfer of harmful organisms by shipping, especially via ballast water transport, may result in a change of biodiversity, alteration of ecosystems, negative impacts on human health and economic loss. Species introductions which cause irreversible consequences to receiving environments and economies call for particular attention. One critical issue is a need to evaluate the quantities and processes of species introductions. Consequently ballast water was sampled on 15 ships calling at the Port of Koper, Slovenia. This was the first ballast water sampling study in the Mediterranean Sea. This paper summarises the sampling results. Samples were analysed for all types of aquatic organisms including bacteria. The results may be considered as background information for an initial risk assessment of future species introductions - an important tool for the implementation of ballast water management measures.  相似文献   

Charles Lyell from 1832 to 1835: marriage, Principles, 2 trips to Heidelberg, snails and loess     

Ian Smalley  Slobodan Markovic  Ken O’Hara-Dhand 《Central European Journal of Geosciences》2010,2(1):15-18

Charles Lyell, on his way to becoming a famous geologist, married Mary Horner in Bonn in July 1832; volume 3 of his ‘Principles of Geology’ was published by John Murray in London in May 1833. Between these two dates Lyell encountered the loess of the Rhine valley. The loess impressed Lyell and he included mentions of it in the Principles, first in 1833 and then, with some revised ideas, in volume 4 of the 4th edition published in 1835. Twelve editions of the Principles were published between 1830 and 1875 and it became one of the most important works in the development of geology, and made a major contribution to the worldwide spread of loess awareness. It is possible that Lyell was drawn to the loess because of its high molluscan content, he was particularly attracted to the study of shells.  相似文献   

The INQUA Loess Commission as a Central European Enterprise     

Ian J. Smalley  Slobodan B. Markovic  Ken O’Hara-Dhand 《Central European Journal of Geosciences》2010,2(1):3-8

The International Union of Quaternary Research (INQUA) organized the study and consideration of the Quaternary Period (the last 2.6 million years in Earth’s history) via a set of commissions, sub-commissions, working groups, projects and programmes. One of the most successful and best records was the Loess Commission (LC) which functioned assub-commission and then commission from 1961 to 2003, resulting in 40 years of useful activity. The history of the LC can be divided into three phases: 1, from 1961–1977 when the President was Julius Fink; 2, from 1977–1991, with President Marton Pecsi; 3, from 1991–2003 with Presidents An Zhi-Sheng and Ian Smalley. Fink, from Vienna, and Pecsi, from Budapest, gave the LC a distinctly Central European aspect. The nature of loess in Central Europe influenced the nature of the LC but the settings for phases 1 and 2 were quite distinct. Phase 1 was a small scale academic operation, carried out in German. As phase 2 began in 1977 the scope expanded and Central Europe became a base for worldwide loess studies. where the LC language changed to English. Phase 2 was run from a National Geographical Institute and demonstrated a different approach to loess research, although the basic programmes of continent-wide mapping and stratigraphy remained the same. The Commission benefited from this change of style and emphasis. In phase 3 the administration moved away from Central Europe but the Finkian ethos remained solid.  相似文献   

Climatic and environmental changes recorded in loess     

Ian J. Smalley  Slobodan B. Markovic  Ludwig Zöller  János Kovács 《Central European Journal of Geosciences》2010,2(1):1-2

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