rss_2.0Geologos FeedSciendo RSS Feed for Geologos 's Cover as a record of regional tectonics and palaeoslope changes in the Satpura Basin, central India<abstract> <title style='display:none'>Abstract</title> <p>Soft-sediment deformation structures play an important role in interpreting regional tectonics and basin evolution during slumping events. The Satpura Basin is interpreted as pull-apart with a monoclinal northerly palaeoslope throughout its evolution. The basin formed as a result of sinistral strike-slip faulting, induced by the ENE–WSW-trending Son-Narmada South fault in the north and the Tapti North fault in the south. We have analysed the slump folds within the basalmost Talchir Formation and related these to regional tectonics and palaeoslope changes in the Satpura Basin. The glaciofluvial strata of the Talchir Formation, exposed in the southern part of the Satpura Basin, record intricacies of folds created during slumping. Several fold styles can be distinguished, within alternations of competent sandstone and incompetent shale layers, some of which indicate buckling. Upright folds, resulting from pure shear, underwent rotation of their axial planes and fold axes during simple shear-dominated progressive deformation when the slump moved downslope. The soft-sediment deformation structures that we have studied show refolding patterns that closely resemble comparable folds known from lithified rocks. These layers with refolded structures are overlain by unde-formed sediments, which proves that they are the product of a single ongoing slumping process, rather than of successive deformation events. Our analysis of their fold axes and axial planes, together with fold vergences and thrust directions within the slumps, suggests a mean slumping direction towards the southwest. Analyses of slump folds and their relationship with regional tectonics have allowed us to reinterpret basin evolution history. The southwesterly trending palaeoslope of the basin suggest that the slope of the basin was not uniform throughout its evolution. At the opening, the oblique slip fault, which trended NE–SW, generated due to movement along the ENE–WSW basin bounding faults, was more active and triggered slumping event within the Talchir deposits in the basin. With progressive overlapping of the basin-bounding faults, the Satpura Basin gradually tilted towards the north.</p> </abstract>ARTICLE2021-09-17T00:00:00.000+00:00Caves as geoheritage resource in remote desert areas: a preliminary evaluation of Djara Cave in the Western Desert of Egypt<abstract> <title style='display:none'>Abstract</title> <p>Caves are rare in northeast Africa and, thus, deserve attention as potential geoheritage objects (geosites). Assessment of Djara Cave and its vicinity (Western Desert, Egypt) has permitted to document unique features, such as the cave itself as a peculiar subsurface landform, speleothems providing data for palaeoenvironmental reconstructions, rock art demonstrating elements of past landscapes, siliceous nodules weathered from Eocene limestones and a network of dry drainage channels indicative of wetter palaeoenvironments. These features are assigned to geomorphological, sedimentological and palaeogeographical types of geoheritage. Djara Cave and its vicinity are proposed as a geosite of national rank; it is vulnerable to anthropogenic stress and needs geoconservation measures and instalment of interpretative signs. This geosite is already popular among tourists, and can be used for further tourism development. More generally, the presence of caves in Egyptian desert areas makes possible the recognition of national speleological heritage that requires special country-level strategies of management.</p> </abstract>ARTICLE2021-09-17T00:00:00.000+00:00Book Review: Handbook of geotourism, by Ross Dowling and David Newsome (Eds.), 2018. Edward Elgar Publishing Limited, Cheltenham, UK. 520 pages. Hardback: price £190, ISBN: 9781785368851. foraminifera of the northwest High Zagros Thrust Belt, southwest Iran<abstract> <title style='display:none'>Abstract</title> <p>The foraminiferal contents of the lower–middle Miocene succession exposed in three sections in north Nur Abad on the northwestern side of the High Zagros Thrust Belt were studied. Assemblages of larger foraminifera from these sections can be referred to Zone SBZ 25 (and the <italic>Miogypsina globulus</italic> and <italic>Miogypsina intermedia</italic> subzones), which correlates with the Burdigalian Stage. For the first time, planktonic foraminifera documented from the Nur Abad area document Lang-hian deposits in the High Zagros, the upper 20 metres of the upper Sayl Cheshmeh section being characterised by the occurrence of planktonic foraminifera such as <italic>Globigerina concinna</italic> (Reuss), <italic>Globigerina diplostoma</italic> (Reuss), <italic>Globigerinoides obliquus</italic> (Bolli), <italic>Orbulina bilobata</italic> (d’Orbigny) and <italic>O.universa</italic> (d’Orbigny). This association characterises the <italic>Orbulina suturalis</italic> Interval Zone.</p> </abstract>ARTICLE2021-09-17T00:00:00.000+00:00Methods of management of bottom sediments from selected water reservoirs – a literature review<abstract> <title style='display:none'>Abstract</title> <p>Sediment accumulation is a process that is typical of all types of water reservoirs. The rate and pattern of such accumulation are related to processes taking place in catchments that produce the sediments and to those within reservoirs that determine the percentage of the inflowing load that is trapped and where it is deposited. To keep reservoirs in working order requires desilting and managing of such bottom sediments once they are removed. The choice of strategy for sediment management depends on chemical and physical properties which result from both natural and anthropogenic processes. To varying degrees, these sediments may be contaminated with chemical compounds, especially trace metals. Therefore, research is needed in order to assess the quality of sediments, which will allow to opt for the proper management strategy. Based on an analysis of the available literature, the possibility of using sediments from reservoirs has been determined, using quality criteria and in accordance with applicable law and regulations.</p> </abstract>ARTICLE2021-09-17T00:00:00.000+00:00Book Review: , by J. Zalasiewicz, C.N. Waters, M. Williams & C.P. Summerhayes, 2019. Cambridge University Press, Cambridge, UK. 361 pages. Hardback: price £44.99, ISBN 9781108475235. evidence suggests that the Palaeoproterozoic Gowganda Formation in Canada is non-glacial in origin<abstract> <title style='display:none'>Abstract</title> <p>During more than a century since its original identification, the Gowganda Formation in Ontario (Canada) has gradually been reinterpreted from representing mainly subglacial tillites to secondary gravity flow and glaciomarine deposits. The main pieces of geological evidence advanced in favour of glaciation in recent articles are outsized clasts that have been interpreted as dropstones and patches of diamictites in a single small-sized area at Cobalt which is still interpreted as displaying subglacial basal tillites. The present research considers field evidence in the Gowganda Formation in the light of more recent work on gravity flows linked to tectonics. Detailed studies have demonstrated that the clasts which are interpreted to be dropstones rarely penetrate laminae and are commonly draped by sediments the appearance of which is similar to lonestones in gravity flows. The “subglacial area” at Cobalt displays evidence of tectonics and gravity flows, which can be traced from the underlying bedrock, and then further in the overlying sequence of diamictites and rhythmites. The sum of geological features displays appearances at odds with a primary glaciogenic origin, and there is no unequivocal evidence present of glaciation. The data indicate deposition by non-glaciogenic gravity flows, including cohesive debris flows for the more compact units, probably triggered by tectonic displacements.</p> </abstract>ARTICLE2021-09-17T00:00:00.000+00:00Book Review: , by Abhijit Mukherjee, Bridget Scanlon, Alice Aureli, Simon Langan, Huaming Guo and Andrew McKenzie (Eds.), 2020. Elsevier, Amsterdam. 676 pages. Paperback: price $150.00, ISBN 9780128181720; e-Book: price $105.00, ISBN 9780128181737. environment of the Bagh-e-Vang Formation – the only occurrence of upper Lower Permian in Iran<abstract> <title style='display:none'>Abstract</title> <p>A transgression of the Tethys Ocean occurred in east central Iran, like in other areas of the Tethys Ocean, around the Yakhtashian/Bolorian (regional chronostratigraphical units corresponding with the Artinskian/Kungurian of the Early Permian) transition. This led to the development of a carbonate platform that is represented in the Shirgesht area on the northern part of the Tabas Block by the Bagh-e-Vang Formation, which constitutes the only known sedimentary unit from the late Early Permian in Iran. Field data and thin-section analysis indicate deposition on a carbonate ramp with barriers separating a lagoonal area with intertidal mud flats from the open-marine environment. The overall transgressive development is indicated by the presence of open-marine sediments on top of the barrier and lagoonal sediments.</p> </abstract>ARTICLE2021-05-12T00:00:00.000+00:00Assessment of river water infiltration conditions based on both chloride mass-balance and hydrogeological setting: the Krajkowo riverbank filtration site (Poland)<abstract> <title style='display:none'>Abstract</title> <p>In the present work measurements of chloride concentrations were used to assess the variability of infiltration conditions and contributions of surface water and local groundwater to the discharge of wells at Krajkowo riverbank filtration site (western Poland). Tests were performed on samples from 26 wells located in a well gallery close to the River Warta. Due to higher chloride concentrations in river water in comparison with local groundwater, significant differences in concentrations in samples from individual wells were noted. In particular, lower chloride concentrations in 11 wells were recorded, which can be linked to the local occurrence of low-permeability deposits in the superficial zone; a locally higher degree of riverbed sediment clogging in the highly convex meandering zone, where strong erosion of the riverbed occurred, which in turn led to increased clogging; the occurrence of a more intensive groundwater inflow into the river valley due to water infiltration from a smaller river entering the River Warta valley, as well as unfavourable conditions for the infiltration of surface water to the lower part of the aquifer with a greater thickness. Differences in chloride concentrations observed were also used to quantify approximately river water contribution to the well production. The average contribution of the River Warta to the recharge of the entire well gallery was estimated at 59.8%.</p> </abstract>ARTICLE2021-05-12T00:00:00.000+00:00Lacustrine deltas and subaqueous fans: almost the same, but different – a review<abstract> <title style='display:none'>Abstract</title> <p>Although deltas and subaqueous fans are both formed in the same near-shore zones of basins, the hydraulic conditions for their formation, development and sedimentary records are different. The present review discusses the results of previously published studies of fan deltas (Gilbert-type deltas) and subaqueous fans of lacustrine and glaciolacustrine environments. The depositional mechanisms of deltas and subaqueous fans, textural and structural features of the lithofacies associations and their typical lithofacies are presented. The characteristics of subaqueous fans, which are still relatively poorly understood and are often overlooked in sedimentological interpretations of lacustrine sedimentary successions, receive particular attention. The palaeoenvironmental and lithological differences between deltas and sub-aqueous fans are highlighted.</p> </abstract>ARTICLE2021-05-12T00:00:00.000+00:00Book reviews: Forecasting and planning for volcanic hazards, risks, and disasters, by Paolo Papale (Ed.), 2020. Elsevier, London, 708 pages. Paperback: price $150.00, ISBN 9780128180822. dominated Miocene deltaic deposits and pipe rocks in the Tebessa Basin, eastern Algeria: sedimentological and ichnological characteristics<abstract> <title style='display:none'>Abstract</title> <p>Analyses of sedimentology, ichnology and depositional environments of Langhian–Tortonian siliciclastic deposits in the southern Tebessa Basin (eastern Algeria) have revealed a tidally dominated deltaic setting with a high concentration of vertical burrows. From south to north, two depositional environments are here distinguished in the Tebessa Basin: a subaerial lower delta plain in the Oum Ali region with the trace fossils <italic>Ophiomorpha</italic> and <italic>Skolithos linearis</italic>, and a proximal delta front with numerous <italic>Skolithos</italic>, situated in the Hjer Essefra area. The occurrence of <italic>Skolithos</italic> pipe rock in this Miocene subtidal domain is unusual. Pipe rocks have been commonly reported from shallow and well-oxygenated environments, especially from Cambrian strata; their number decreased significantly during the Ordovician, coupled with an increase in biodiversity. Here different deltaic subenvironments and tidal signals that are exceptionally well preserved in outcrops are analysed and interpreted. Different ichnotaxa are briefly described, and the uncommon density and size of <italic>Skolithos</italic> pipe-rock in these Miocene strata are discussed.</p> </abstract>ARTICLE2021-05-12T00:00:00.000+00:00Book reviews: , by M. Engel, J. Pilarczyk, S.M. May, D. Brill & E. Garrett (Eds.), 2020. Elsevier Inc., Amsterdam. 848 pages. Paperback: price €156,19, ISBN 9780128156865; e-Book: price €156,19, ISBN 9780128156872 power of colour in geoheritage studies and marketing: some tentative reflections<abstract> <title style='display:none'>Abstract</title> <p>Colour is a common physical property in exposures of unique geological objects, but is only marginally addressed in geoheritage literature. We here present our point of view on how this feature can be treated in geoheritage studies, with the general aim at setting up a broad discussion. Three functions of colour in geoheritage are outlined, namely geological interpretation (e.g., compositional and genetic peculiarities of sedimentary rocks), higher visibility due to colour contrast and aesthetic attractiveness to geotourists. Assessment of colour at geosites is challenging, especially because of uncertain colour nomenclatures. We propose to focus on colour identification, calculation of the number of colours, qualitative evaluation of colour contrast and comparison of colours of a given geological object to its landscape context. Geoheritage colours may have different meanings to geosite visitors, and colour-emotion associations revealed by national and international studies are important to trace these meanings.</p> </abstract>ARTICLE2021-05-12T00:00:00.000+00:00Book reviews: Earth materials. Introduction to mineralogy and petrology (Second edition), by Cornelis Klein and Anthony R. Philpotts, 2017. Cambridge University Press, Cambridge, UK. 616 pages. Paperback: price £44.99 ISBN: 9781316608852. induced by ice-sheet advances in NE Poland<abstract xml:lang="en"><title style='display:none'>Neotectonics induced by ice-sheet advances in NE Poland</title><p>Differences in the geological structure of the hard-rock substratum of the Warmia and Mazury regions (NE Poland) resulted during the Pleistocene in different reactions on the load exerted by the land-ice masses. In the (western) Warmia province, vertical glacio-isostatic movements caused cyclic erosional events affecting the relatively thick sedimentary cover, which became more compacted. In contrast, the thinner sedimentary cover of the rigid crystalline basement favoured quiet sedimentation in the (eastern) Mazury province. The zone in between these two areas runs NNE-SSW for some 80 km. It is several kilometres wide and is composed of landforms that owe their origin to the sedimentary infilling of crevasses. This intermediate zone formed an interlobe are between the two huge ice lobes that covered the Warmia and Mazury areas during the last ice age. The basement of the zone coincides with the crystalline craton slope, which is accompanied to the west by a parallel marginal trough.</p><p>Cyclic advances and retreats of the Pleistocene ice sheet induced neotectonic mobility. Glacio-isostatic processes resulted in the intermediate zone in block movements (uplift and subsidence) that affected the whole Cenozoic succession, creating mainly vertical discontinuity zones. Glacio-isostasy also induced vertical tectonic movements within the older deposits, reaching down to the crystalline basement. A tectonic graben thus developed. It is bounded by flexures accompanied on both sides by positive structures that may indicate transpressional movements with a strike-slip stress component.</p></abstract>ARTICLE2009-12-24T00:00:00.000+00:00Easily-accessible digital palaeontological databases-a new perspective for the storage of palaeontological information<abstract xml:lang="en"><title style='display:none'>Easily-accessible digital palaeontological databases-a new perspective for the storage of palaeontological information</title><p>Techniques that allow to render diverse types of palaeontological data as publicly available internet resources are described. In order to develop an easily accessible digital palaeontological database, three steps should be followed: (1) digitization of the studied specimens, (2) acquisition of morphometric data, and (3) contribution of the data to open and searchable geoinformatic (palaeontological) databases. Digital data should be submitted to internet databases that allow a user to fetch various types of information from dispersed sources (semantic web services).</p></abstract>ARTICLE2009-12-24T00:00:00.000+00:00Large-scale land-suitability mapping in the GIS environment for the construction site of the University Olympic Village in Izmir (Turkey)<abstract xml:lang="en"><title style='display:none'>Large-scale land-suitability mapping in the GIS environment for the construction site of the University Olympic Village in Izmir (Turkey)</title><p>Participants of the 23<sup>rd</sup> University Olympic Games held in Izmir (Turkey) were hosted in a Universiade Olympic Village that had to be newly constructed. A risk analysis has been performed to assess potential engineering problems at the envisaged construction site. The risk analysis was largely based on a new, large-scale land-suitability map that was prepared in the GIS environment with much detail for this type of construction work. Information was collected from several maps, in combination with mapping in the field, drilling and seismic data. Geological, geotechnical, geophysical and morphological data were then superimposed on these analyses. This sequence of overlay analyses was performed with the help of GIS software (MapInfo Professional 7.5); this resulted in five hazard maps. Risk points (1-11) were then attributed to the different zones in the five digital hazard maps.</p><p>A land-suitability map indicating the suitability for envisaged constructional activities was subsequently obtained in the form of an overlay of the five hazard maps, thus allowing to calculate a total risk for each zone on this map. The land-suitability map that was thus obtained, has been prepared for a 1:1,000 scale development plan; such a large scale is uncommon in this context.</p></abstract>ARTICLE2009-12-24T00:00:00.000+00:00Differences in the regional stratigraphy of NE Poland caused by vertical movements due to glacioisostasy<abstract xml:lang="en"><title style='display:none'>Differences in the regional stratigraphy of NE Poland caused by vertical movements due to glacioisostasy</title><p>Geological mapping in combination with geophysical investigations and borehole analyses show differences of the Pleistocene between the Warmia and Mazury palaeogeographic provinces in NE Poland. The (more western) Warmia province has a crystalline basement that is covered by a folded sedimentary succession of 2-4 km thick. The (more eastern) Mazury province (eastern) has a basement that forms part of the rigid East European crystalline craton, which is covered by a sedimentary cover of only 1-1.5 km thick.</p><p>Cyclic loading by the Pleistocene ice sheets in this area induced glacioisostatic processes of different intensities, resulting in changing palaeogeographic conditions. The changes were increased by intense neotectonic activity that was induced by the ice sheets in the intermediate zone between the two provinces, stretching along the western slope of the crystalline craton. Significant part of intermediate zone forms a belt of crevasse-infill landforms deposited between the Warmia and Mazury lobes of the last glaciation. Studied deposits reveal a cyclic reactivation of the interlobe zone during the successive Pleistocene glaciations. Considerable variations of the relief of the top-Neogene, vertical discontinuities cutting the Pleistocene and Neogene, stratigraphic gaps within the Pleistocene succession, and thick glaciolacustrine successions result from the vertical neotectonic movements in the intermediate area between the two provinces.</p></abstract>ARTICLE2009-12-24T00:00:00.000+00:00en-us-1