Quarry Wall Research Articles

Geoconservation History of a Basalt Quarry – The Case of Mt. Wilkołak, Land of Extinct Volcanoes Geopark, SW Poland

Mt. Wilkołak is one among many hills built of mid-Cenozoic basalts in SW Poland, within the Land of Extinct Volcanoes UNESCO Global Geopark. Appreciated as a recreational ground since the first half of the 19th century, it began to be quarried at the beginning of the 20th century. The quarry located on the western slope was soon abandoned, leaving impressive exposures of variously oriented basaltic columns due to thermal jointing and volcanic breccia. Briefly re-used after World War II, the quarry was definitely closed in 1956 and a small geological reserve was established in 1959. In the meantime, basalt exploitation developed at a much larger scale within the eastern slope, leading to the major conflict between conservation and industry, with frequent voices to delist the reserve and continue quarrying towards complete exhaustion of resources and removal of the entire hilltop. In addition, as a result of poor management of the reserve and uncontrolled vegetation growth its values significantly diminished. In the 21st century various actions initiated by the local community, supported by scientists, concurrent with incoming termination of quarrying, opened the debate about the future of Mt. Wilkołak and its quarries. Stone extraction ended in 2019, after a catastrophic collapse of one quarry wall, and rehabilitation works were executed in 2021–2023, aimed at the conversion of the locality into a place focused on geo-education and recreation. Opened in May 2023, it has various interpretation facilities and offers unprecedented insights into the internal structure of a volcanic plug. However, challenges related to site management, enhancement of educational content, and the future of the nature reserve remain.

Mathematical modeling the quarry wall stability under conditions of heavily jointed rocks

Purpose. To develop techniques for estimating the pit wall stability in terms of occurring of a zone of heavily jointed rock mass during ore mining at the Akzhal deposit (Kazakhstan), to work out measures to strengthen the rock opening and to verify the effectiveness of the developed measures. Methodology. The finite element analysis of the rock stress-strain state is implemented on the basis of the elastic-plastic model and the generalized Hoek-Brown failure criterion. The rock mass quality was assessed using the RMR and GSI rating classifications. This made it possible to simulate a zone of intense fracturing by changing the characteristics of the jointed surface. The shear strength reduction procedure was used to determine the safety factor for the quarry wall. Findings. The strain distributions in the rock mass forming the quarry wall have been obtained in terms of the Akzhal polymetallic ore deposit (Kazakhstan). The case of creating a zone of heavily jointed rocks in the area of a tectonic fault was considered. The safety factor of the quarry wall was determined under conditions of increased rock fracturing, as well as after carrying out measures to strengthen the rocks with a hardening solution. Originality. The effect of intense jointness on the pit wall stability is demonstrated. A method for the consistent evaluation of the quarry wall stability is proposed considering the change in the rock properties due to natural factors and artificial reinforcement. It is shown that a change in the joint surface quality due to the hardening injection reduces the shear strains in the sliding zone. Practical value. The pit wall stability was predicted considering the formation of a zone of intense fracturing under mining and geological conditions of the Akzhal deposit. The possibility of testing the effectiveness of rock strengthening measures based on mathematical modeling was shown.

Environmental forcings and micro-seismic monitoring in a rock wall prone to fall during the 2018 Buran winter storm

This study reports a comparative analysis of the environmental conditions and micro-seismicity recorded on a rock wall resulting from an intense meteorological event. The findings are focused on a quarry wall located in the Acuto Field Laboratory (Central Italy), where multi-parametric environmental monitoring is operating and an Artificial intelligence Camera Prototype has been placed to detect rock falls reaching a railway target. Six accelerometers were installed to detect micro-seismic events caused by the expected strong thermal transient caused by the Buran storm on February 2018. Within a few hours, a steep decrease in the average air and rock mass temperature down to 8 °C was recorded, and −4 °C and −8 °C were reached for the rock and air temperatures, respectively. A total of 103 micro-seismic events were analysed with respect to both rainfall and thermal forcing: while no correlation with rainfall was reported, the steep thermal transient was responsible for the strain effect that occurred during the heating phase of the rock mass following the Buran storm. An elastic deformation event with a maximum daily amplitude of 165 μ strain was recorded by the strain gages installed on the mm-joints due to the rock heating and cooling caused by the variation in temperature. The collected evidences show the relevance of short thermal transients in modifying stress conditions within rock masses and their relationship to a peculiar micro-seismic response. The main outcomes established the key role played by integrated monitoring systems to better understand the relationship between vibrational behaviour and environmental forcings in terms of understanding the precursors to rock failure.

Modelling of thermo-mechanical effects in a rock quarry wall induced by near-surface temperature fluctuations

Mechanical response of rock masses to the periodical fluctuation of surface temperatures is a relevant topic to be focused on for the comprehension of short- to long-term stability of rock slopes continuously stressed by slight yet periodical actions. To better understand how preparatory factors can lead rock masses toward failure, thermal and strain monitoring activities are ongoing in a selected quarry wall, where an experimental test-site was implemented on a jointed rock block. The role of pervasive joints in perturbing the heating-cooling process of the rock mass and their related effects was already output by direct and remote monitoring. For these purposes, FDM numerical modelling was focused on the comprehension and simulation of induced mechanical effects due to cyclical thermal forcings over a simplified 2D half-space. Therefore, the role of rock mass joints on both heat propagation and resulting thermo-mechanical effects was analysed, basing on monitoring data, field experiments and numerical modelling. Numerical results output the role of periodic daily, annual and compound thermal input in inducing irreversible deformation along joints under different rock mass jointing configuration, as a function of the intrinsic period of thermal input and joint attitude. Temperature distribution across joints was also analysed as a possible constraining effect for time and space distribution of yielding. A sensitivity analysis of heat propagation conditions was performed in order to infer the role of joint sets on induced thermo-mechanical strains at the rock block scale. A non-negligible influence on surficial as well as deeper portions of the rock mass was observed, highlighting how near-surface temperature fluctuations can drive the long-term evolution of rock block conditions towards failure.

Electrical resistivity tomography (ERT) and sedimentological analysis applied to investigation of Upper Jurassic limestones from the Krzeszowice Graben (Kraków Upland, southern Poland)

This paper highlights the application of shallow non-invasive geophysics (electrical resistivity tomography) supported by sedimentological analysis applied to the investigation, description and interpretation of Upper Jurassic limestones exposed in the abandoned quarry near the village of Tomaszowice (Krakow Upland, southern Poland). Within this site, on the northern margin of the Krzeszowice Graben, a facies diversity of Upper Jurassic limestones can be observed. Field exposures were analysed to broadly characterize these Upper Jurassic limestones in terms of facies and microfacies development. Three facies types, including pelitic limestones, bedded limestones and carbonate gravity-flow deposits, composed of numerous microfacies, have been distinguished. ERT study using a dipole-dipole array has been carried out, along 5 parallel 110 m long profiles and along a perpendicular 110 m long profile, north of the Tomaszowice Quarry wall. The use of ERT in combination with the geological data allowed characterization and description of the geology at the research site as well as the determination of the lithological composition and internal architecture of the subsurface. Furthermore, the ERT interpretation results indicated the presence of a series of a secondary faults closely linked with the Krzeszowice Graben. The distribution of the gravity-flow deposits reflects the fault zone pattern of the graben and Late Jurassic fault activity.

Ground-based hyperspectral imaging as a tool to identify different carbonate phases in natural cliffs

ABSTRACTRecent research has shown hyperspectral imaging to be a powerful tool to distinguish carbonate phases with slight compositional differences on quarry cliff faces. The traditional remote sensing set-up uses an optimal short distance between the hyperspectral camera mounted on a tripod and a quarry wall characterized by a planar, mostly unweathered surface. Here we present results of a modified workflow geared to the application of ground-based hyperspectral imaging of rough and weathered cliff faces in order to map large scale dolomite bodies from a distance of up to several kilometres. The goal of the study was to determine unique spectral properties of fracture-controlled dolomite bodies in order to be able to distinguish them from a dolomitic host rock. In addition, the impact of weathering on carbonate phases and thus, the modification of the spectral signature between altered and unaltered carbonates is assessed. The spectral analysis is complemented by ICP-AES (inductively coupled plasma atomic emission spectroscopy) measurements of the spectrally measured powders. Furthermore, we examined the detection limits and characterisation potential of dolomite bodies from hyperspectral images captured at varying distances from cliff faces in the study area. Hyperspectral images of 10 natural cliffs distributed across the Central Oman Mountains were obtained with a Push broom scanner system. The high resolution of 5.45 nm (288 bands in total) enabled the visualization of small-scale changes in the near infrared continuous spectrum of all present lithofacies types. The determination of dolomite bodies of varying sizes (metre to hundreds of metres) on natural cliffs was achieved with the hyperspectral mapping approach and mapping results have been tested with the position of visually defined dolomite bodies on field panoramas. Spectra of natural cliffs contain a strong absorption peak indicative for iron which is absent in spectra of unweathered sample powders. However, ICP-AES analysis of powders revealed relatively low contents of iron of 12,392 ppm. The strong peaks in field images are interpreted as linked to intensive weathering associated with the precepitation of goethite, hematite, specularite and manganese as well as intensive dedolomitization. Dedolomitization is indicated by calcitic spectra derived from the dolomite bodies. The spectral difference of laboratory and field spectra interferes significantly the application of laboratory spectra of powdered samples for the identification of dolomite bodies in the field. Furthermore, the process of late dedolomitization puts an additional challenge on the determination of dolomite bodies. Due to these strong spectral variations between laboratory and field spectra, we recommend that the mapping approaches should not solely rely on spectral algorithms but also consider normal light field panoramas and representative outcrop analysis. We also note that the quality of resolution is too low for the determination of small-scale variations of diagenetic phases at distances larger than 4 km. However, when the limitations mentioned are taken into account, hyperspectral imaging proves to be a powerful tool that helps in the determination of the distribution of diagenetic phases, even in challenging conditions.

MIDDLE PALEOLITHIC SITE RUBAN’ IN TRANSCARPATHIA: STRATIGRAPHY, CHRONOLOGY, INDUSTRY

The Ruban’ Paleolithic site was discovered in 2005 by the Transcarpathian Paleolithic expedition of the Archaeological Museum of the IA NASU. The site is located on the territory of the former Zatysnansky chemical plant (Fig. 1b) at a distance of 800 m north of the eastern outskirts of the village of Gorbky, Vynohradiv district, in the Transcarpathian region, in the Ruban’ tract, and about 2 km to the southeast of the Korolevo site.
 At the time when the site Ruban’ was discovered, the upper part the quarry wall where the site is located, has been ruined by the quarrying that made it impossible to determine a stratigraphic position of the archaeological layer and to establish the age of the culture. In order to solve these problems, 15 geological profiles of the Quaternary deposits have been set along the less disturbed quarry wall in 2016—2017. The stratigraphic subdivision of the sections, according to the Quaternary stratigraphic framework of Ukraine, and their correlation with the profile of the archaeological site have been carried out that enables to determine the geological age of the cultural layer.
 The geological site Ruban’ is located along the paleoslope and, thus, there are erosional brakes in its sedimentary record. The lowermost stratigrpahical unit is represented by reddish-brown soil of Martonosha unit overlain by gleyed loam of Sula unit and strongly dissected by wedges of the Sula cryogenesis. The other Lower and Middle Pleistocene units have been truncated and now they are represented by pedosediments (with exception of the yellowish-brown soil of Upper Zavadivka unit).
 Kaydaky unit (the brown forest soil of a warm interglacial climate) is separated from Zavadivka soil by the level of wedges of the Dnieper cryogensis.
 Pryluky unit is represented by two soils (pl1 and pl3), separated by cryogenic fissures and, in places, by a thin loess layer (pl2). The dark-brown soil pl1 is characterized by both manganese concretions and thick managanese films in its upper part, whereas the brown forest soil pl3 is overlain by a thin layer of dense iron-manganese concretions (pl3c). This layer reflects unstable hydrothermal regime during the transition from the warm interstadial to the cold stadial climate of the Uday time. Uday unit is represented, in places, by a thin loess layer, which is overlain by brown forest soil of Vytachiv unit. The latter is dissected by cryogenic fissures, filled with the non-soil material of Bug unit. The Holocene unit is truncated in many places but the Holocene pedogenic processes (translocation) overprint the underlying units.
 The stratigraphic correlation of the studied sections with the archaeological site (excavation 1) demonstrates that the archaeological layer is located in the transitional bed of iron-manganese concretions (pl3c). According to the accepted comparison of the Ukrainian stratigraphy with marine isotopic-oxygen scale, the chronostratigraphic position of the archaeological layer corresponds to the transition from the end of the MIS 5 (5a) i. e. 74—64 ka BP.
 In the industry of Ruban’ site are prevailing the non-Levallois reduction methods of exploataion of Kombewa, centripetal, crossed and sub-crossed cores with a flat working surface. The parrallel reduction system is not typical and random. Blades are practically absent.
 In the collection of tool-kit dominated side scrapers, among which there is a series of natural backed side scrapers with a thick working edge, created by 2—3 rows of a stepped scaled retouch (Quina retouch type). Such samples can be attributed to a specific type of side scrapers, such as Quina or Semi-Quina (Fig. 7).
 In general, the main technological and typological features of the Ruban’ site industry are closely related to the cultural layer II of the Korolevo I site. These collections can be attributed to the local variant of the so-called Charantienne Techno-Complex.

Insights into the radial water jet drilling technology – Application in a quarry

In this context, we applied the radial water jet drilling (RJD) technology to drill five horizontal holes into a quarry wall of the Gildehaus quarry close to Bad Bentheim, Germany. For testing the state-of-the-art jetting technology, a jetting experiment was performed to investigate the influence of geological heterogeneity on the jetting performance and the hole geometry, the influence of nozzle geometry and jetting pressure on the rate of penetration, and the possibility of localising the jetting nozzle utilizing acoustic activity. It is observed that the jetted holes can intersect fractures under varying angles, and the jetted holes do not follow a straight path when jetting at ambient surface condition. Cuttings from the jetting process retrieved from the holes can be used to estimate the reservoir rock permeability. Within the quarry, we did not observe a change in the rate of penetration due to jetting pressure variations. Acoustic monitoring was partially successful in estimating the nozzle location. Although the experiments were performed at ambient surface conditions, the results can give recommendations for a downhole application in deep wells.

Titanosaur trackways from the Late Cretaceous El Molino Formation of Bolivia (Cal Orck’o, Sucre)

The Cal Orck’o tracksite is exposed in a quarry wall, approximately 4.4 km NW of Sucre (Department Chuquisaca, Bolivia) in the Altiplano/Cordillera Oriental, in the El Molino Formation (Middle Maastrichtian). Fossiliferous oolitic limestones, associated with large, freshwater stromatolites and nine levels of dinosaur tracks in the El Molino Formation document an open lacustrine environment. The main track-bearing level is almost vertical with a surface area of ~ 65,000 m 2 . The high-resolution mapping of the site from 1998 to 2015 revealed a total of 12,092 individual dinosaur tracks in 465 trackways. Nine different morphotypes of dinosaur tracks have been documented. Amongst them are several trackways of theropods, ornithopods, ankylosaurs and sauropods, with the latter group accounting for 26% of the trackways. Two different types of sauropod trackways are present. One exhibits speech-bubble-shaped manus impressions that are rotated outwardly and located more outwards than pes prints, and oval to rounded pes imprints with few details, but with a characteristic oval track shape. The second morphotype has more rounded and axially compressed pes imprints and horseshoe-like manus impressions. The manus shows clear impressions of digits I and V. The first morphotype with the more rounded manus can be attributed to a derived titanosaur. The second is assigned to the new ichnogenus Calorckosauripus and was probably made by a basal titanosaur. Both sauropod morphotypes exhibit a narrow-gauge and a wide-gauge stance along the same trackway, and therefore the authors suggest that trackway width may not be correlated, or may not be correlated completely with the osteological characters of the trackmaker’s skeleton.

ARE SHOAL RESERVOIRS DISCRETE BODIES? A COQUINA SHOAL OUTCROP ANALOGUE FROM THE MID TRIASSIC UPPER MUSCHELKALK, SW GERMANY

Carbonate ramp reservoirs may show a much higher degree of complexity than the schematic and often layer‐cake type depositional models which are widely used in exploration and reservoir characterisation, especially in three dimensions. This complexity was investigated in an outcrop study of the Ladinian (Middle Triassic) Quaderkalk Formation (Upper Muschelkalk) from SW Germany. The formation was deposited on an epicontinental, gently inclined carbonate ramp in the regressive part of a third‐order depositional sequence and represents a sub‐seismic‐scale coquina‐dominated shoal reservoir analogue. In the study area, coquina carbonates make up a complex system of four stratigraphically separated shoal complexes. The present paper investigates the 1‐D to 3‐D facies distribution, reservoir architecture and sequence stratigraphic evolution of the largest shoal complex of the Quaderkalk Formation, the Oberer Hauptquader. The object of this outcrop analogue study was to improve the understanding of internal reservoir heterogeneities (such as connectivity and continuity) in similar carbonate shoal complexes in the subsurface. To that end, detailed analyses of 71 quarry outcrop and core samples were carried out, together with the study of more than 400 thin sections, the 2‐D analysis of three quarry wall panels and regional‐scale 2‐D correlations, and facies mapping.This investigation documents significant sedimentological heterogeneities at different scales within the studied shoal reservoir analogue. Instead of a continuous facies belt, a number of separate potential reservoirs form a shoal complex “mosaic”. Shoal development is controlled by sequence stratigraphic architecture, mainly by cycles which were responsible for shoal expansion during times of regression (forming potential reservoir‐volume) and shoal drowning during times of transgression (forming seals and potential stratigraphic traps). Within the individual shoal complexes, thickness and lithofacies types show gradational lateral changes. Correspondingly, lithofacies associations within the studied shoal analogue are not defined by sharp boundaries. Thus the present “shoals” do not in fact represent discrete “bodies”, as often depicted in reservoir models and as commonly used in reservoir simulation. In addition, shoal‐internal sedimentological heterogeneities (potential flow baffles in the subsurface) are strongly influenced by a combination of small‐scale cyclicity and event‐type deposition. This study therefore demonstrates the need for sedimentological studies of reservoir heterogeneities at various scales in order to decrease uncertainties and risks in exploration and production.

New active faults on Eurasian-Arabian collision zone: Tectonic activity of Özyurt and Gülsünler faults (Eastern Anatolian Plateau, Van-Turkey).

The Eastern Anatolian Plateau emerges from the continental collision between Arabian and Eurasian plates where intense seismicity related to the ongoing convergence characterizes the southern part of the plateau. Active deformation in this zone is shared by mainly thrust and strike-slip faults. The Ozyurt thrust fault and the Gulsunler sinistral strike-slip fault are newly determined fault zones, located to the north of Van city centre. Different types of faults such as thrust, normal and strike-slip faults are observed on the quarry wall excavated in Quaternary lacustrine deposits at the intersection zone of these two faults. Kinematic analysis of fault-slip data has revealed coeval activities of transtensional and compressional structures for the Lake Van Basin. Seismological and geomorphological characteristics of these faults demonstrate the capability of devastating earthquakes for the area.

Engineering geological and geotechnical analysis of a rock slide in the quarry Frauenmühle near Metten (Lower Bavaria)

AbstractIn spring 2008 a rock slide detached from one of the walls in the quarry ”Frauenmühle“ locally used as climbing park, mobilizing a volume of 50 m3. The binary granite is relative fresh on the bottom of the walls, but the weathering increases significantly to the natural surface. The bedrock shows an orthogonal joint system enabling the so‐called ”Wollsackverwitterung“. Mapping of the joints followed by a kinematic analysis of the quarry wall by DIPS (Rocscience) indicates the slope failure to be of a planar sliding type on a medium‐steep dipping plane. As the contributing factor for the slide, weathering along the plane has to be considered. Thereby the destruction of rock bridges downgrades the overall shear strength. A stability analysis based on the reconstructed block geometry and the determined shear parameters verifies the instability of the block. For today's situation, the kinematic analysis detects some critical intersections of joints being able to generate slide wedges.

Cézanne in Baltimore

Cézanne in Baltimore Joseph Harrison (bio) Mont Sainte-Victoire Seen from the Bibémus Quarry He painted it, then painted it again For twenty years or more, week after week Layering slope, ridge, double limestone peak Till rhomboid, trapezoid, block and plane, Green pines, deep orange cliffs, mauve-tinted sky Composed an art that’s somehow both abstract And representational: when we react With five steps back to realign the eye Space opens in a rush of vertigo Between the near trees and the quarry wall, Perspective drops this room, which seemed so small, Echoing into cavernous effects. Mont Sainte-Victoire still towers over Aix Both on and off the canvas. Scene from below. [End Page 335] Joseph Harrison JOSEPH HARRISON is the author of five books of poetry, most recently Shakespeare’s Horse (Waywiser, 2015). His poems have appeared in numerous journals and anthologies. His honors include an Academy Award in Literature from the American Academy of Arts and Letters and a Guggenheim fellowship. Copyright © 2017 Joseph Harrison

Size-dependent shell growth and survival in natural populations of the rock-dwelling land snail Chondrina clienta

Rock-dwelling land snails, feeding on algae and lichens that grow on stone surfaces, may influence the structure and function of these ecosystems. Yet, little is known about the life history of rock-dwelling snails. We performed a 30-month mark–release–resight study in four populations of Chondrina clienta (Westerlund, 1883) inhabiting vertical walls of abandoned limestone quarries on the Baltic island of Öland, Sweden, to assess growth rate and survival of juvenile snails and determine age at maturity. We marked 800 individuals ranging in shell height from 1.4 to 4.9 mm, released them in their original habitat, and remeasured their shell height at intervals of 6 months. Shell growth of juvenile C. clienta was affected by the site (quarry wall) and the size of the individual, being highest in medium-sized snails. Shell growth occurred during both summer and winter. Annual apparent survival rates of C. clienta were size-dependent and ranged from 58.6% to 96.3%. Sexual maturity was reached at an age of 5 years, which is later than in most large snail species. Our study extends current knowledge on life history of land snails to a rarely studied group dwelling on rock surfaces.

Quarry Wall Stability Assessment Using TLS Method

The aim of this paper is to test the possibility of terrestrial laser scanning use to analyze the stability of quarry walls. In recent years the laser scanners started being tested and used for the documentation of geological structures and various phenomena such as landslides, rock collapses and observation of their morphological changes. The subject of our research was a quarry wall in the open-pit mine Brestov, with a significant bench or block disintegration of the andesite massif and therefore, there is a risk of rock blocks crashing. Selected quarry wall was repeatedly measured in the autumn and spring season by a terrestrial laser scanner and movements of rock blocks were evaluated. The observation results show that on the selected quarry wall there were no major movements or block collapse detected and the wall is stable after the winter shutdown.

Complex Geodetic and Photogrammetric Monitoring of the Kral’ovany Rock Slide

ABSTRACT Purpose The complex monitoring of rock slides with the size of 16 ha in order to predict the development of other slides and prevent possible human and material losses. Methods Precise geodetic point measurement, terrestrial laser and image scanning and aerial photogrammetry were used to obtain detailed knowledge about the geometry and behaviour of the rock slide. Except for terrestrial images, the images were taken using an SLR camera (set on a motor paraglide) and a compact camera (set on a remotely piloted system). The state and condition of the locality before the rock slide was taken from archive images taken by a digital large format camera. Results Vectors and velocities of the displacements of discrete points were determined with high precision; the changes in quarry wall surfaces were determined by laser and photogrammetry scanning. Finally, high resolution orthophotomosaics of the site were generated using aerial photogrammetry at each observation point. Practical implications The termination of mining and the design of the remediation works were determined according to the results of the measurements. Also, monitoring was carried out in order to observe any changes due to the implementation of a highway project based in the localisation. Originality/value Complex geodetic and photogrammetric monitoring of rock slides offers detailed information about slide surfaces and has previously been used in Slovakia on a significant scale.

Discovery of New Gem Tourmaline Pockets in the Sosedka Pegmatite, Malkhan, Russia

10.1080/00357529.2013.796748-F0001 Figure 1. Sosedka pegmatite quarry wall with the blocky zone in the center surrounded by a graphic zone. Excavated cavity in the lower center contained only cryst...

Rockfall Hazard in an Old Abandoned Aggregate Quarry in the City of Tétouan, Morocco

Quarries are places of high instability due to blastings, if left without rehabilitation they become sites of great risk of rockfall, which are the case of the Carian quarry, a small abandoned aggregate quarry, which turned into a slum neighborhood in the north western part of the city of Tétouan, and that has a long history of rockfall incidents since it was shut down in the 60’s. Using rockmass characterization techniques, kinematic study and stability analysis, it was confirmed that many instability mechanisms are found on the walls of the quarry and cause a high risk of rockfall during the rain season, especially that the study area is inhabited. Rockfall trajectory modelling techniques allow the calculation of vertical distribution of rocks falling from the quarry’s walls along different profiles in the area and therefore the determination of a safety perimeter from the quarry wall.

Tectonics of the Chęciny Anticline (Holy Cross Mts., central Poland) in the light of new cartographic data and calcite vein analysis (reply)

The Variscan orogeny of NE–SW compression has folded the Paleozoic core of the Holy Cross Mountains (Central Poland). The Checiny Anticline, formed during this tectonic event, is located in the southwestern part of the Kielce Unit. This paper presents structural data from two newly found outcrops of Cambrian rocks that modify the geometric reconstruction of the Checiny Anticline, especially within its southern limb that is subdivided into two second-order structures: the Rzepka Syncline and the Wrzosy Anticline. The eastern part of the Checiny Anticline has been reconstructed, pinpointing its fragmentation into a series of blocks (horsts and grabens) separated by faults semi-perpendicular to the anticline axis. New mapping data reveals deep, pre-Triassic erosion of folded Variscan basement, uncovering Cambrian rocks outcropping in the hinge of the Wrzosy Anticline. In the Checiny Anticline, folding-related shortening has been accompanied by along-strike extension and the formation of syn-tectonic calcite veins, which filled fractures oriented perpendicular to the fold axis. The magnitude of extension has been estimated along a 215 m long main quarry wall of Rzepka Hill, approximately parallel to the Variscan structures and located within the southern limb of the Checiny Anticline. The total thicknesses of veins filling extension fractures and spaces between clasts in tectonic breccia were summed and indicate 8.4% of strike-parallel extension (~120o) in the Checiny area. This value was compared to ca. 30% of folding-induced shortening, related to NE–SW late Variscan compression. We hence obtain a strain ratio of 30:8.4 = 3.5. This high value of strain ratio indicates that longitudinal extension was a significant component contributing to the late Variscan deformation in the Kielce Unit.

Integrated geophysical and geological investigation of a heterogeneous fluvial aquifer in Columbus Mississippi

A heterogeneous fluvial aquifer system exposed in a sand and gravel quarry outcrop in northeastern Mississippi was examined to quantify the relationship between geophysical attributes and lithostratigraphic properties. Two dimensional seismic reflection, ground penetrating radar, and DC resistivity profiles collected along the top of the quarry wall were compared with outcrop descriptions, photographs, and laboratory resistivity measurements and grain-size analysis conducted on a core collected near the center of the geophysical profiles. The aquifer is composed of an upper laterally continuous sandy-clay meandering fluvial system and a lower cross-bedded gravelly-sand braided fluvial system separated by a terrace. Seismic reflection data image the terrace, but depositional structures within the aquifer are below seismic resolution. These structures, including meter-scale channels and decimeter-scale channel-fill facies are imaged with ground penetrating radar , which correlates well with the outcrop and with the DC resistivity profile. The meandering fluvial facies is characterized by relatively low resistivity values (500–1250 Ω-m) and laterally continuous high-amplitude radar reflections. Lateral reflection terminations in the radar data indicate onlap at channel boundaries, which are filled with silty clay and clayey silt with very low resistivity values (50–400 Ω-m). The braided fluvial facies is characterized by higher resistivity values (1600–2600 Ω-m) and low-amplitude short bidirectional dipping radar reflections. Laboratory measurements of resistivity from a core collected along the quarry wall show a linear correlation to clay + silt content in all units within the meandering facies that have greater than 2% clay fraction, allowing surface DC resistivity data to be used as a predictor of clay + silt content in this facies. This is confirmed by comparison of predictions of clay + silt fraction based on the resistivity data to outcrop lithology. The combination of all three geophysical datasets is essential to fully characterize compartmentalization within this heterogeneous aquifer system.