Marly Clay Research Articles

Mineralogical and geochemical studies of Ypresian marly clays and silica rocks of phosphatic series, Gafsa-Metlaoui basin, southwestern Tunisia: implication for depositional environment

Thick Ypresian marly clays and silica rich rocks constitute the so-called interbedded facies of phosphatic series, in the Gafsa-Metlaoui basin, southwestern Tunisia. Mineralogical and geochemical investigations are carried out on selected samples from Kef Eddour section. The data obtained by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Energy Dispersive X-ray microanalysis (EDX) and chemical analysis and IR of clay fractions indicate that the bulk rock samples are composed of cristobalite-tridymite and dolomite. Observation by SEM showed the occurrence of dolomite as a well-crystallized and a weathered shape. Whereas, cristobalite-tridymite observed in the cherty bed appears as a spheres, filling the pore spaces. However, samples which contain moderately a significant amount of feldspars, clinoptilolite and pyrite occur in the upper part of Kef Eddour section. Clay minerals consist mainly of smectite, palygorskite, and sepiolite. In this clay assemblages, the N-alkane (m/z = 57) distributions, revealed that organic matter has phytoplankton and bacterial origin. The Pristane/Phytane ratio indicated that the organic matter is deposited in a reduced environment. In this latter, sulfate-reducing bacteria generate hydrogen sulfur, which is incorporated on the organic biomolecules that occurred at the lower part of Kef Eddour section. However, the high Fe activity on the depositional environment favored the occurrence of pyrite in the upper part.

Origin and Depositional Environment of Palygorskite and Sepiolite from the Ypresian Phosphatic Series, Southwestern Tunisia

AbstractThe Ypresian phosphatic series of the Gafsa-Metlaoui basin, southwestern Tunisia, is represented by an alternation of phosphatic levels and interbedded facies, which are composed of marly clay and silica-rich rocks. The present work aimed to clarify the genesis of palygorskite and sepiolite of the interbedded facies and to understand the depositional environment of the phosphatic series. The interbedded facies of the Stah and Jellabia mines were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Energy Dispersive X-ray microanalysis (EDX) of individual constituents and their aggregates. The data obtained indicate that samples are made up of francolite, calcite, dolomite, quartz, feldspars, and clay minerals; the latter consist of palygorskite-sepiolite minerals associated with smectite. Observations by SEM revealed the occurrence of palygorskite and sepiolite as fine and filamentous fibers with thread-like facies and coating dolomite, calcite, and a marly matrix. Such features can be considered as textural evidence of authigenic palygorskite-sepiolite. At the bottom of the Stah section, SEM observations revealed that the fine fibers are more abundant within silica-rich rocks. Silica is commonly available due to bacterial activity saturating its environment with the silicic acid required for the formation of palygorskite-sepiolite. In the interbedded facies of the Jellabia section, the moderate fibrous clay content and the presence of well crystallized dolomite revealed that the shallow-marine water was characterized by high-Mg and low-Si activities.

Nuovi dati litostratigrafici e biostratigrafici sulla Scaglia Toscana nella Toscana meridionale (area di Rapolano Terme)

Nuovi dati litostratigrafici e biostratigrafici sulla Scaglia Toscana nella Toscana meridionale (area di Rapolano Terme)

Petrological, organic geochemical and geochemical characteristics of coal from the Soko mine, Serbia

A petrological, organic geochemical and geochemical study was performed on coal samples from the Soko Mine, Soko Banja basin, Serbia. Ten coal and two carbonaceous clay samples were collected from fresh, working faces in the underground brown coal mine from different parts of the main coal seam. The Lower Miocene, low-rank coal of the Soko Mine is a typical humic coal with huminite concentrations of up to 76.2 vol.%, liptinite less than 14 vol.% and inertinite less than 11 vol.%. Ulminite is the most abundant maceral with variable amounts of densinite and clay minerals. Sporinite and resinite are the most common macerals of the liptinite group. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral-bituminous groundmass identified in some coal samples, and carbonaceous marly clay, indicate sub-aquatic origin and strong bacterial decomposition. The mean random huminite reflectance (ulminite B) for the main coal seam is 0.40 ± 0.05% Rr, which is typical for an immature to early mature stage of organic matter. The extract yields from the coal of the Soko Banja basin ranges from 9413 to 14,096 ppm, in which alkanes constituted 1.0–20.1%, aromatics 1.3–14.7%, asphaltenes 28.1–76.2% and resins 20.2–43.5%. The saturated hydrocarbon fractions included n-C15 to n-C32, with an odd carbon number that predominate in almost all the samples. The contents of n-C27 and n-C29 alkanes are extremely high in some samples, as a contribution of epicuticular waxes from higher plants. Acyclic isoprenoid hydrocarbons are minor constituents in the aliphatic fraction, and the pristane/phytane (Pr/Ph) ratio varies between 0.56 and 3.13, which implies anaerobic to oxic conditions during sedimentation. The most abundant diterpanes were abietane, dehydroabietane and 16α(H)-phyllocladane. In samples from the upper part of the coal seam, diterpanes are the dominant constituents of the alkane fraction. Polycyclic alkanes of the triterpane type are important constituents of alkane fractions. The occurrence of ββ- and αβ-type hopanes from C27 to C31, but without C28, is typical for the Soko Banja coals. The major and trace elements in the coal were analysed using X-ray fluorescence (XRF), and inductively coupled plasma-mass spectrometry (ICP-MS). In comparison with world lignites, using the geometric mean value, the coal from the Soko Banja Basin has a high content of strontium (306.953 mg/kg). Higher values than the world lignites were obtained for Mo (3.614 mg/kg), Ni (8.119 mg/kg), Se (0.884 mg/kg), U (2.642 mg/kg) and W (0.148 mg/kg). Correlation analysis shows inorganic affinity for almost all the major and trace elements, except for S, which has an organic affinity.

Palynologic and Lithostratigraphic Research of Lacustrine, Marsh and Fluvial Quaternary Deposits in Rašica Dolina and Mišja Dolina, and on Radensko Polje

Palynologic and Lithostratigraphic Research of Lacustrine, Marsh and Fluvial Quaternary Deposits in Rašica Dolina and Mišja Dolina, and on Radensko Polje The article deals with the results of palynological and stratigraphical research of lacustrine, marsh and fluvial Quaternary deposits in the Rašica dolina and Mišja dolina, and on Radensko polje. Correlation with equivalent Quaternary deposits and their palynoflora from the Grosuplje polje area was also performed. In the study area, Mesozoic, predominantly carbonate rocks are transgressively covered by Quaternary deposits which are in general composed of five lithostratigraphic units (from bottom to top): 1. gravel, 2. grey lacustrine clay, 3. reddish brown loam, 4. light grey marly clay and 5. alluvial marsh deposits. On the basis of pollen analysis the Quaternary sediments of the study area are chronostratigraphically classified to the Late or Middle Pleistocene and Holocene.

GIS analysis to assess landslide susceptibility in a fluvial basin of NW Sicily (Italy)

Landslide hazard assessment, effected by means of geostatistical methods, is based on the analysis of the relationships between landslides and the spatial distributions of some instability factors. Frequently such analyses are based on landslide inventories in which each record represents the entire unstable area and is managed as a single instability landform. In this research, landslide susceptibility is evaluated through the study of a variety of instability landforms: landslides, scarps and areas uphill from crown . The instability factors selected were: bedrock lithology, steepness, topographic wetness index and stream power index. The instability landform densities computed for all the factors, which were arranged in Unique Condition Unit, allowed us to derive a total of three prediction images for each landslide typology. The role of the instability factors and the effects generated by the use of different landforms were analyzed by means of: a) bivariate analysis of the relationships between factors and landslide density; b) predictive power validations of the prediction images, based on a random partition strategy. The test area was the Iato River Basin (North-Western Sicily), whose slopes are moderately involved in flow and rotational slide landslides (219 and 28, respectively). The area is mainly made up of the following complexes: Numidian Flysch clays (19%, 1%), Terravecchia sandy clays (5%, 1%), Terravecchia clayey sands (3%, 0.3%) and San Cipirello marly clays (9%, 0%). The steepness parameter shows the highest landslide density in the [11–19°] class for both the typologies (8%, 1%), even if the density distributions for rotational slides are right-asymmetric and right-shifted. We obtained significant differences in shape when we used different instability landforms. Unlike scarps and areas uphill from crowns, landslide areas produce left-asymmetric and left-shifted density distributions for both the typologies. As far as the topographic wetness index is concerned, much more pronounced differences were detected among the instability landforms of rotational slides. In contrast, the flow landslides produce normal-like density distributions. The latter and the rotational slide landslide areas produce the highest density values in the class [5.5–6.7], despite an abrupt decreasing trend starting from the first class [3.2–4.4], which is generated by the density values of the rotational slide scarps and areas uphill from crowns. The stream power index at the foot of the slopes, which was automatically derived using a GIS-procedure, shows a positive correlation with the landslide densities marked by the maximum classes: [4.8–6.0] for flows, and [6.0–7.2] for rotational slides. The validation procedure results confirmed that the choice of instability landform influences the results of the susceptibility analysis. Furthermore, the validation procedure indicates that: a) the predictive models are generally satisfactory; b) scarps and zones uphill from crown areas are the most diagnostically unstable landforms, for flow and rotational slide landslides respectively.

Stratigraphy and Detrital Modes of Upper Messinian Post-evaporitic Sandstones of the Southern Apennines, Italy: Evidence of Foreland-Basin Evolution during the Messinian Mediterranean Salinity Crisis

During the Messinian, the southern Apennines thrust belt experienced a period of strong tectonic rearrangement and accretion, activation of overthrusts, and consequent migration of depocenters. The upper Miocene successions cropping out in the northern segment of the southern Apennine thrust belt have good potential for improving our understanding of the interplay between Messinian salinity-crisis events and foreland-basin evolution. The local Messinian stratigraphy includes: (1) pre-evaporitic thin-bedded euxinic marly clay, interbedded with diatomaceous marls; (2) evaporitic limestone, crystalline gypsum, and reworked gypsum; (3) post-evaporitic deposits subdivided into two main units: the Torrente Fiumarella unit and the Anzano Molasse Formation that grade upward into ostracod-rich deposits (Lago-Mare facies). The evaporitic and post-evaporitic sequences are separated by an angular unconformity. This paper deals with the stratigraphic and petrographic study of the post-evaporitic deposits. The Torrente Fiumarella unit includes lacustrine and alluvial conglomerates, quartzolithic sandstones containing abundant carbonate detritus, shale, and reworked clastic gypsum. The Anzano Molasse Formation includes thick-bedded deltaic to turbiditic conglomerates and sandstones passing upward to thin-bedded turbidite sandstones and marlyclayey siltstones. Sandstones are quartzofeldspathic with variable proportions of sedimentary (both carbonate and siliciclastic) and plutonic detritus. In particular, two populations are present, plutonic-rich and mixed plutonic-sedimentary. Volcaniclastic layers, composed of dominantly vitric particles (shards and pumice), are also interbedded within Anzano Molasse sandstones. The Anzano succession includes rare freshwater ostracods that increase in abundance in the uppermost Lago-Mare facies. The Lago-Mare facies deposits are represented by silty-marly clay with abundant Ostracoda shells (Ilyocypris gibba, Cyprideis torosa and Candona sp.) and intrarenite having abundant intrabasinal carbonate particles (ooids, peloids, and bioclasts) and subordinate extrabasinal noncarbonate and carbonate particles. The post-evaporitic sequences represent an infilled foredeep basin, with a lacustrine environment progressively deepening and experiencing gravity resedimentation. Detrital modes document complex provenance relations from upper Messinian accreted terranes of the southern Apennines thrust belt. Post-evaporitic sandstones in the Irpinia-Daunia sector of the southern Apennines foreland-basin system record both the effects of the foreland tectonic evolution and the Messinian Mediterranean salinity crisis. They may represent alternative models for foreland-basin evolution during a restricted time in late Messinian, which can be applicable also in other portions of the circum-Mediterranean orogen.

Settlements control in driving a shallow tunnel

This paper will introduce an experience of tunnelling through a difficult ground, under low overburden and in the presence of some buildings located less than ten meters above the tunnel crown. The tunnel portion is in very weak clayey marl and marly clay. A clayey and sandy weathered surface affected the crown increasingly as the overburden decreased. The design provided a full section excavation with the RPUM. In this case RPUM (Reinforced Protective Umbrella Method) is a steel pipe roof protection of the opening boundary, a fiberglass tube face consolidation, a first phase lining consisting of shot concrete and steel ribs, invert casting close to the face and crown lining completion at the least possible distance from the face. All these devices had to be performed in subsequent advancement fields of reduced length. With the aim of safeguarding the buildings and their inhabitants, a measuring system, to monitor both superficial and deep ground movements, had been installed. This system allowed us to set up the design working phases and the suitable expedients to progressively reduce the settlement basin extension and the settlements entity despite the constant reduction of the overburden as the tunnel progressed. Particularly, for every main working phase, the ground deformation results were verified. Cavity boundary and surface movement were also checked, with the purpose of fixing the operative choices which have allowed the successful completion of the job. For more details you can visit the website www.sinc.it. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

Foraminiferal biostratigraphy and paleoenvironmental reconstruction at the Yaxcopoil‐1 drill hole, Chicxulub crater, Yucatán Peninsula

Abstract The Yaxcopoil‐1 (Yax‐1) drill hole comprises Cretaceous limestones and calcarenites, the K/P boundary cocktail unit (including impact breccia), and a Danian marly clay layer overlain by calcareous marls. The biostratigraphy, paleobathymetry, and environmental turnover across the K/P interval were inferred after analyzing the planktic and benthic foraminiferal assemblages. The Cretaceous samples only contain a few poorly preserved planktic foraminifera of a middle Campanian to Maastrichtian age, while low‐diversity benthic foraminiferal assemblages suggest a sufficient nutrient supply to the sea floor and a shallow neritic, occasionally stressed environment. The impact breccia and the redeposited suevite are overlain by a 46 cm‐thick dolomitic calcareous sandstone unit that contains scarce, reworked planktic foraminiferal specimens. This unit probably represents the uppermost part of the initial infill of the crater. The uppermost centimeters of this unit are bioturbated, and its top represents a hiatus that spans at least the G. cretacea, Pv. eugubina, and part of the P. pseudobulloides biozones. This unit is overlain by a 3–4 cm‐thick marly clay layer that represents a condensed layer. Benthic foraminiferal assemblages suggest a low food supply to the sea floor and environmental instability during the deposition of the marly clay layer. The increase in diversity of the assemblages indicates that the environmental conditions improved and stabilized from the G. compressa biozone toward the A. uncinata (P2) biozone. The Danian planktic and benthic foraminiferal assemblages indicate a deeper, probably bathyal environment.

Heaven and Earth – ‘Madonne col Bambino’ and ‘Rustiques figulines’

Analyses of the productions of della Robbia and Palissy, two masters of Renaissance ceramics in France and in Italy, have enlightened their contributions to the improvement of the glazed terracotta technique. Della Robbia used very homogeneous materials: marly clay for the bodies, and tin-opacified coloured glazes. The technique is here very robust and very mastered. Palissy used different types of clay with different colours and physical properties, associated with specific productions. So far, we have identified seven pastes. Concerning the glazes, he played with transparency and opacity, with lead glazes and with tin-opacified lead glazes. He added traditional colouring oxides as well as specific pigments (lead–tin yellow, haematite, etc.). The mixed-earth technique is specific to his palette. So, the materials used by both artists are completely different and illustrate their different philosophical approaches. To perform the different analyses, new methodologies have been developed: ICP/AES-MS, petrography and X-ray diffractometry for the bodies, PIXE and micro-PIXE, SEM coupled with EDS and Raman spectrometry for the glazes.

Macroseismic Survey of the 2002 Molise, Italy, Earthquake and Historical Seismicity of San Giuliano di Puglia

The eastern Molise earthquake had an epicentral intensity of Io=7–8 MCS (Mercalli-Cancani-Sieberg scale) and a maximum intensity of Imax=8–9 in the village of San Giuliano di Puglia. The historical portion of this village, built on a marly limestone hill, had intensities of 6–7 MCS, whereas the most recently developed area, on a crest of marly clays, had a local intensity of I=9–10 MCS, and was almost totally destroyed. Neighboring villages were generally struck with an intensity of 6–7 MCS. In several places, the damage was due to gravity-driven phenomena affecting both the rocky and clayey substratum of the villages. The epicentral area is characterized by the lack of historical earthquakes comparable to the 2002 sequence, having suffered only the effects of distant, strong (M>6.5) events, coming either from the Apennine seismogenic belt or from the Gargano area.

Palaeoclimatic interpretation based on Middle Miocene planktonic Foraminifera: the Silesia Basin (Paratethys) and Monferrato (Tethys) records

A comparative study of the distribution and palaeoclimatic interpretation of temperature-related taxa of Middle Miocene planktonic foraminifera from the Paratethys Silesia Basin (southern Poland) and Tethys Monferrato area (northwestern Italy) is presented. The time span considered (Badenian–Langhian/Serravallian) is the last period of significant connection between the Paratethys and Mediterranean Tethys, even though the depositional conditions, water circulation and connection with the oceanic realm were not always favourable to the life and preservation of significant planktonic foraminiferal taxa. The Silesia Basin, located in the western segment of the Karpathian Foredeep, is filled by an autochthonous, non-folded cover of Miocene deposits. Four stratigraphic sections were studied in this area, characterised by Carpathian sandy deposits of the Kłodnica Formation, Lower Badenian unbedded marly clays, marls and strongly bedded Lithothamnium marls (Skawina Formation), Middle Badenian anhydrite and laminated clay shales (Krzyźanowice Formation), Upper Badenian unbedded marly clays, followed by fine-grained sands, sandy limestone layers, and bioclastic levels rich in molluscs and calcareous algae (Gliwice Formation). The Monferrato area corresponds to the northwestern termination of the Apennines thrust belt and consists of an Eocene–Miocene mainly terrigenous succession, resting unconformably on Upper Cretaceous and Eocene Ligurian flysch. Three stratigraphic sections are studied in the eastern area, characterised by Late Oligocene to Early Burdigalian deepwater terrigenous sediments (Marne di Antognola Formation), followed unconformably by Early to Middle Miocene carbonate sediments, originating in a foramol platform depositional environment (Pietra da Cantoni Group), and by grey–whitish glauconitic marls of the Marne di Mincengo Formation (Late Langhian–Serravallian). Twenty-three species of Tethys and Paratethys planktonic foraminifera were grouped in cold ( Globigerina bulloides, Globigerina quinqueloba, Globigerina praebulloides gr., Globorotaloides spp., Catapsydrax spp.), cold–temperate ( Zeaglobigerina woodi, Z. brazieri Globorotalia scitula gr., Globorotalia bykovae), warm ( Globigerinoides spp., orbuliniforms, including Praeorbulina spp. and Orbulina spp., Globigerina ciperoensis, Dentoglobigerina altispira gr., Velapertina indigena, Globorotalia praemenardii), and warm–temperate indices ( Paragloborotalia siakensis gr., Dentoglobigerina baroemoenensis gr., Globoquadrina praedehiscens and G. dehiscens, Tenuitellinata angustiumbilicata, Globigerinella obesa, Globigerina venezuelana). Their relative abundance was used to reconstruct palaeoclimatic curves. Comparison of the palaeoclimatic curves makes it possible to recognise a climatic change from warmer conditions in the Langhian towards relatively colder conditions in the Serravallian. The fall in warm-related taxa was much more pronounced in the Silesia Basin than in the Monferrato area. This palaeoclimatic evidence may be interpreted as the beginning of a series of oscillations pointing to a period of cooling, corresponding to one of the major global changes in the palaeoclimatic/palaeoceanographic history of the Cenozoic, i.e. the ‘Mid-Miocene event’, Mi3 [Miller et al. (1991) Paleoceanography 6, 33–52].

Seabed morphology and hydrocarbon seepage in the Gulf of Cádiz mud volcano area: Acoustic imagery, multibeam and ultra-high resolution seismic data

Extensive mud volcanism, mud diapirism and carbonate chimneys related to hydrocarbon-rich fluid venting are observed throughout the Spanish–Portuguese margin of the Gulf of Cádiz. All the mud volcanoes and diapirs addressed in this paper lie in the region of olistostrome/accretionary complex units which were emplaced in the Late Miocene in response to NW-directed convergence between the African and Eurasian plates. The study area was investigated by multibeam echo-sounder, high and ultra-high resolution seismic profiling, dredging and coring. The structures observed on multibeam bathymetry, at water depths between 500 and 1300 m, are dominated by elongate mud ridges, mud cones, mud volcanoes and crater-like collapse structures ranging in relief from 50 to 300 m and size from 0.8 to 2 km in diameter. The main morphotectonic features, named the Guadalquivir Diapiric Ridge (GDR) and the Cádiz Diapiric Ridge (CDR), are longitudinally shaped diapirs which trend NE–SW and consist of lower–middle Miocene plastic marly clays. The GDR field and the TASYO field, which consist of mud volcanoes and extensive fluid venting related to diapiric ridge development, are described in this paper. The GDR field is characterised by numerous, single, sub-circular mud volcanoes and mud cones. The single mud volcanoes are cone-shaped features with relatively gentle slopes of 3°–6°, consisting of several generations of mud breccia deposition with indications of gas-saturation, degassing structures and the presence of H 2S. The mud cones have asymmetric profiles with steep slopes of up to 25° and contain large surficial deposits of hydrocarbon-derived carbonate chimneys and slabs. The TASYO field is characterised by an extensive concentration of small, sub-circular depressions, oval and multi-cone mud volcanoes and large sediment slides. Mud volcanoes in this area are characterised by moderate slopes (8°–12°), have bathymetric relief ranging from 100 to 190 m and consist of sulphide-rich mud breccia, calcite chimneys, carbonate crusts and chemosynthetic fauna (Pogonophora tube worms). We propose that all these hydrocarbon seepage structures are related to lateral compressional stress generated at the front of the olistostromic/accretionary wedge. This stress results in the uplifting and squeezing plastic marly clay deposits. Additionally, the compressional stress at the toe of the olistostrome forms overpressurised compartments which provide avenues for hydrocarbon-enriched fluids to migrate.

The Effects on the Lignite Ash Quality Characteristics by the Coexcavated Thin Intercalations in Ptolemais Mines, Northern Greece

The lignite deposit of the Southern Field Mine in the Ptolemais Basin is characterized by the multiple interchanges between lignite and thin intercalated sterile layers of marly limestones, marls, clays, and sands. This form of deposit imposes selective excavation where, unavoidably, thin intercalated sterile layers are coexcavated with lignite ones, thus increasing the quantity of ash. Apart from quantity, the quality of ash is of great importance since it affects the overall power plant performance. In this study the role of the thin intercalated sterile layers coexcavated with lignite is investigated, producing laboratory mixtures of lignite-marly limestone, lignite-carbonaceous marl, and lignite-clay (in proportions of 10 and 20% by weight in sterile layer). These mixtures were analyzed and their ash quality parameters were compared with the pure lignite and the run-off mine lignite. The addition of carbonates increases the CaO and CaO (free) content and reduces the SiO 2 and Al 2 O 3 content of ash, respectively. On the other hand, the addition of clays increases the SiO 2 and Al 2 O 3 and reduces the CaO content.

Textural evidence of peperites inside pillow lavas at Acicastello Castle Rock (Mt. Etna, Sicily)

Globular and microglobular peperites, with mingled sediment in millimetric to decimetric domains, are described from inside pillow lavas at Acicastello Castle Rock, Mt. Etna, Sicily for the first time. The peperites now comprise basalt and minor remnants of fine-grained detrital material, with smectite and zeolite crystallised during late hydrothermal activity. We propose that peperites formed when the magma, ascending towards the surface, intruded and intermixed with the unconsolidated wet Pleistocene bluish marly clays of the substrate. Subsequently they were transported by the uprising magma from the source region towards the surface, where they are preserved in pillow lavas.

Plio-Pleistocene sedimentary facies and their evolution in centre-south-eastern Sicily: a working hypothesis

This paper examines the distribution and evo- lution of the Plio-Pleistocene sedimentary facies in centre- south-eastern Sicily, especially around Enna, Licata and Caltagirone. Sectors occur in this region (Caltanissetta- Enna-Centuripe, Pietraperzia-Barrafranca-Piazza Armerina- Butera, S. Michele di Ganzaria-Caltagirone-Niscemi, Licata- Gela) where, in relation to the late Zanclean-Piacenzian / Selinuntian period, the sedimentary succession has different lithostratigraphic characteristics. The area studied belongs to the Caltanissetta Basin, which is a paleogeographical-sedimentary unit. From the Late Mio- cene to the Quaternary period it consisted of a dynamic fore- deep basin between the Hyblean Foreland and the Apennine- Maghrebian Trust front. Between the Early Pliocene and Early Pleistocene periods this front advanced about 50 km southwards and south-eastwards. The Plio-Quaternary lithostratigraphic sequence is mainly represented by 11 units: Zanclean Trubi Fm, Pliocene Argille Brecciate Fm. (Pliocene Brecciated Clays-AB IV, V), Enna Marls of the late Zanclean-Piacenzian, Centuripe Sandstones and Capodarso Calcarenites of the late Zanclean-Piacenzian, Geracello Clayey Marls of the Piacenzian-Selinuntian, Pi- azza Armerina Sands of the Piacenzian-Selinuntian, Mt. S. Giorgio Marly Clays of the Selinuntian, Caltagirone-Niscemi Sands of the Selinuntian, Terraced sediments of the Middle- Late Pleistocene, Present day sediments. There are three clear unconformities in the sequence, ex- cluding the one at the base of the quaternary terraced de- posits. The first, of late Zanclean age, is located above the Trubi Fm., and developed immediately after the beginning of the Enna Marls sedimentation; it has a synsedimentary char- acter and developed in a marine environment without emer- gence. The second, of late Piacenzian age, lies at the base of the Geracello Clayey Marls, while the third (Selinuntian), is located at the base of the Mt. S. Giorgio Marly Clays. Mi- nor unconformities, probably of glacio-eustatic origin, are locally present.

Mineralogy of the Upper Albian sediments from the Kirchrode I borehole with special emphasis on the clay mineralogy

The mineralogy of a 245 m thick section of Upper Albian marly clay stones to clayey marlstones from the Kirchrode I borehole (Lower Saxony basin of NW Germany) has been studied by X-ray diffractometry, infrared spectrometry, chemical analysis and microscopy. The investigations were carried out on bulk samples and grain-size fractions. The mineralogy of the sediments is characterised by biogenous carbonates, mainly calcite, by terrigenous-detrital components and diagenetic minerals, often enriched in concretions. The calcite content fluctuates considerably (between 20 and 50%), most probably because of changes in the marine palaeoenvironment. Illite, montmorillonite, and kaolinite are the predominant clay minerals, but in changing portions. Chlorite and alkali feldspars were detected only in traces. Mixed-layer minerals such as illite/smectites (I/S) are also present, in higher amounts in the lower part and less in the upper part of the core. Reworked Upper Carboniferous mudstones and siltstones are interpreted to have delivered part of the well crystallised illite, kaolinite, chlorite and quartz. Montmorillonites and mixed-layer minerals together with kaolinite and illite may be inherited from weakly consolidated Jurassic sediments, Aptian and Albian claystones and marlstones, and from palaeosols. The increase in the proportion of montmorillonite among the clay minerals in the upper part of the Upper Albian may be due to redistribution of volcanic sediments after either terrestrial or submarine alteration of volcanic ash. Volcanic activity is known in this area (e.g. the Middle to Upper Albian Flammenmergel at the southern margin of the Lower Saxony basin) and around the North Atlantic throughout Aptian–Albian time. But in the Kirchrode I core, ash fall was identified as a source for montmorillonite in only one layer, namely at 87.25 m, where high Zr and Nb concentrations were also found. The mineralogical composition of the concretionary material is generally a mixture of biogenous calcite, siliciclastic debris (quartz and clay minerals), and microcrystalline, diagenetically formed Fe–Mn carbonates (rhodochrosite, siderite) and carbonate–fluorapatite (francolite). Rhodochrosite is more abundant in the lower part, Mn-siderite in the upper part of the core. Concretions with fluorapatite (francolite) occur sporadically.

Influence of inheritance and pedogenesis on heavy metal distribution in soils of Sicily, Italy

The recognition of the potential health hazards associated with heavy metals has focused attention on the levels and behaviours of these elements both in natural and contaminated environments. Various soil types developed from different parent materials in Sicily, Italy, have been analysed in order to compare heavy metal distribution under different geopedological conditions. Total metal concentrations, metal partitioning and distribution profiles are discussed in relation to the inheritance factor and pedogenic processes. Parent material composition largely influences the contents of heavy metals in most of the analysed soils, mainly differentiating pedons for their metal concentration on the basis of sedimentary and volcanic parent materials. However, an exception is represented by the carbonate-free Alfisols and Mollisols, which are markedly enriched in heavy metals with respect to the underlying limestones and calcarenites. On the basis of chemical and mineralogical results, supported by data from sequential extraction (SEP), heavy metal enrichment in these soils is associated with the formation of common to abundant Fe–Mn oxides and clay accumulation. For Mollisols there is evidence for a major role of organic matter in heavy metal retention in surface horizons. In the other pedons, pedogenic processes appear to mainly influence the redistribution of heavy metals throughout the soil horizons rather than affecting the total content. Argillopedoturbation seems to be responsible for a uniform distribution of heavy metals in Vertisol profiles on marly clays. Accumulation of heavy metals in the topsoil of Inceptisols on clays with gypsum and Entisols on gypsarenites and diatomites is caused partially by adsorption on organic matter and mainly by dissolution of primary gypsum and opal-A. A pedogenic influence is less evident in young Andisols whose heavy metal composition greatly reflects that of hawaiitic pyroclastic deposits interbedded within the profiles. However, a certain redistribution of Cu accumulated as metal–organic matter complexes is evidenced in the surface horizon by SEP.

98/00913 Geological and industrial evaluation of coal deposits: Vereda, V. S. Ugol' Ukr., 1996, (8), 47. (in Russian)

A petrological, organic geochemical and geochemical study was performed on coal samples from the Soko Mine, Soko Banja basin, Serbia. Ten coal and two carbonaceous clay samples were collected from fresh, working faces in the underground brown coal mine from different parts of the main coal seam. The Lower Miocene, low-rank coal of the Soko Mine is a typical humic coal with huminite concentrations of up to 76.2 vol.%, liptinite less than 14 vol.% and inertinite less than 11 vol.%. Ulminite is the most abundant maceral with variable amounts of densinite and clay minerals. Sporinite and resinite are the most common macerals of the liptinite group. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral-bituminous groundmass identified in some coal samples, and carbonaceous marly clay, indicate sub-aquatic origin and strong bacterial decomposition. The mean random huminite reflectance (ulminite B) for the main coal seam is 0.40 ± 0.05% Rr, which is typical for an immature to early mature stage of organic matter.The extract yields from the coal of the Soko Banja basin ranges from 9413 to 14,096 ppm, in which alkanes constituted 1.0–20.1%, aromatics 1.3–14.7%, asphaltenes 28.1–76.2% and resins 20.2–43.5%. The saturated hydrocarbon fractions included n-C15 to n-C32, with an odd carbon number that predominate in almost all the samples. The contents of n-C27 and n-C29 alkanes are extremely high in some samples, as a contribution of epicuticular waxes from higher plants. Acyclic isoprenoid hydrocarbons are minor constituents in the aliphatic fraction, and the pristane/phytane (Pr/Ph) ratio varies between 0.56 and 3.13, which implies anaerobic to oxic conditions during sedimentation. The most abundant diterpanes were abietane, dehydroabietane and 16α(H)-phyllocladane. In samples from the upper part of the coal seam, diterpanes are the dominant constituents of the alkane fraction. Polycyclic alkanes of the triterpane type are important constituents of alkane fractions. The occurrence of ββ- and αβ-type hopanes from C27 to C31, but without C28, is typical for the Soko Banja coals.The major and trace elements in the coal were analysed using X-ray fluorescence (XRF), and inductively coupled plasma-mass spectrometry (ICP-MS). In comparison with world lignites, using the geometric mean value, the coal from the Soko Banja Basin has a high content of strontium (306.953 mg/kg). Higher values than the world lignites were obtained for Mo (3.614 mg/kg), Ni (8.119 mg/kg), Se (0.884 mg/kg), U (2.642 mg/kg) and W (0.148 mg/kg). Correlation analysis shows inorganic affinity for almost all the major and trace elements, except for S, which has an organic affinity.

Sedimentary facies in an extensional and deep-lacustrine depositional system: the Pliocene Tiberino Basin, Central Italy

The Tiberino Basin was formed during Plio-Pleistocene extensional tectonic activity in Central Italy. The Pliocene sediments that fill this structure consist predominately of fine-grained clastic lithofacies deposited in a lacustrine system; four facies associations have been distinguished. Facies association A was deposited in a deep-offshore lacustrine environment and consists of massive, laminated, bluish-gray marly clays that lack benthonic fauna but have preserved organic matter (leaves, wood). This facies association is the main lacustrine deposit, whereas the other three represent marginal facies. Facies association B is interpreted as a delta system deposit; it has Gilbert-type sandy gravel bodies with foresets up to 50 m high and prodelta bodies consisting of laminated to massive marly clays that alternate with sandy and gravelly mud strata. Association C corresponds to a coastal environment, where two sub-environments are recognized: (1) a wave-dominated coastline characterized by interbedded muddy and sandy strata with sedimentary structures attributed to hummocky cross-stratification; and (2) clayey silts and lignites interpreted as a coastal wetland; a spectacular fossil forest is preserved in situ within this unit. Association D, formed on the distal part of a muddy alluvial fan, consists of sheet-flood clayey sandy silts, that alternate with incipient paleosols; rare, ribbon-channel fills are also present. Paleoenvironmental reconstruction indicates that the Tiberino Basin was occupied by a narrow, deep meromictic lake during the Pliocene. The size, shape, depth and sub-environment distribution of this lake were controlled by tectonic phenomena, such as the high subsidence rate, which caused the lake to be large and deep. Only in the few coastal areas that had high sedimentary input were wetland or alluvial fan deposits formed.