On the binder of some ancient mortars     

M. Franzini  L. Leoni  M. Lezzerini  F. Sartori 《Mineralogy and Petrology》1999,67(1-2):59-69

Summary About 90 samples of mortars from historical buildings in Pisa have been analysed and compared with some samples of ancient mortars characterized by pozzolanic aggregates. Chemical (XRF), mineralogical (XRD) and petrographical (optical microscopy) data have been collected on bulk samples. An X-ray energy-dispersive system (EDS) attached to a SEM was used to determine the chemical compositions of binder, clots and pozzolanic grains (whenever present). The binder components which could not be directly assessed (CO₂, H₂O+) have been indirectly derived through a computation method.Data collected suggest that the main stock of analysed samples (i.e., mortars from Pisa monuments) contains two principal types of binder: the first type corresponds to a common carbonated lime; the second type is a hydraulic lime, where the carbonate component is associated with an important silicate fraction, which constitutes 13 to 89 wt% of the total binder (on average 47%). This hydraulic type had a widespread application in the construction of ancient monuments in Pisa; for example, it was constantly employed in the building of the famous Leaning Tower. This study shows that the silicate fraction of such hydraulic mortar, which is amorphous to X-ray diffraction, is made up by a hydrated calcium alumino-silicate having a very low Al₂O₃/SiO₂ ratio (on average 0.125). On the basis of chemical and optical characteristics of hydraulic mortar binders from Pisa and the results of laboratory tests, as well as through comparison with the characteristics of ancient hydraulic mortars having pozzolanic aggregates, it is concluded that such mortars were prepared most likely by mixing slaked lime with a reactive, highly siliceous material such as a diatomaceous earth.

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Über Bindemittel in antiken Mörteln

Zusammenfassung Etwa 90 Mörtelproben von historischen Gebäuden in Pisa wurden analysiert und mit Proben von antiken Mörteln, die durch pozzolanische Aggregate charakterisert sind, verglichen. Chemische (XRF), mineralogische (XRD) und petrographische (optische Mikroskopie) Daten wurden an den Gesamtproben ermittelt. Ein an ein SEM angeschlossenes energiedispersives System (EDS) wurde für die Bestimmung der chemischen Zusammensetzung des Bindemittels, der Mörtelklümpchen und der pozzolanischen Körner (sofern vorhanden) verwendet. Die Komponenten des Bindemittels, die nicht direkt gemessen werden konnten (CO₂, H₂O⁺) wurden indirekt durch ein Berechnungsverfahren ermittelt.Die gesammelten Daten belegen, dass die meisten untersuchten Proben (i.e. Mörtel von Monumenten aus Pisa) zwei Typen von Bindemittel enthalten: Der erste Typ entspricht einem gewöhnlichen karbonatisierten Kalk. Der zweite Typ ist ein hydraulischer Kalk, in dem die Karbonatkomponente mit einer mengenmäßig bedeutenden Silikatfraktion assoziiert ist, die 13–89 Gew.% des gesamten Bindemittels ausmachen kann (durchschnittlich 47%). Dieser zweite Typ wurde häufig beim Bau alter Monumente in Pisa verwendet, z.B. wurde er ständig beim Bau des Schiefen Turms herangezogen. Diese Studie zeigt, dass die Silikatfraktion dieses hydraulischen Mörtels, die röntgenamorph ist, aus einem hydratisierten Aluminosilikat mit einem niedrigen Al₂O₃/SiO₂ Verhältnis (im Durchschnitt 0.125) besteht.Auf Basis der chemischen und optischen Charakteristika des hydraulischen Mörtel, die pozzolanische Aggregate führen, schließen wir, dass diese Mörtel höchstwahrschein lich durch Mischung von Löschkalk mit sehr reaktivem, silikatischen Material, wie etwa Diatomeenerde hergestellt wurden.

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Heavy metal and arsenic distributions in sediments of the Elba-Argentario basin, southern Tuscany, Italy   总被引：2，自引：0，他引：2  

Leonardo Leoni  F. Sartori 《Environmental Geology》1997,32(2):83-92

 Arsenic, chromium, cobalt, copper, lead, nickel, vanadium and zinc distributions in surficial and core sediments of the Elba-Argentario marine basin (southern Tuscany, central-western Italy) are reported. Analysis of such distributions compared with grain size and mineralogical data allowed the identification of areas showing trace element enrichments with respect to natural background. These enrichments are moderate and essentially restricted to Pb and Zn; only As shows a widespread, though not high, positive anomaly. This general pattern is in good agreement with the minor industrialization affecting the basin's watershed. An unexpected anomaly, concerning Co, Pb, and As, as well as Fe and Ti, has been pointed out close to Montecristo Island. This has been ascribed to illegal local dumping of chemical waste. Received: 12 January 1996 / Accepted: 9 September 1996  相似文献   

The impact of heat waves on surface urban heat island and local economy in Cluj-Napoca city,Romania     

Ioana?Herbel  Adina-Eliza?CroitoruEmail author  Adina?Viorica?Rus  Cristina?Florina?Ro?ca  Gabriela?Victoria?Harpa  Antoniu-Flavius?Ciupertea  Ionu??Rus 《Theoretical and Applied Climatology》2018,133(3-4):681-695

The association between heat waves and the urban heat island effect can increase the impact on environment and society inducing biophysical hazards. Heat stress and their associated public health problems are among the most frequent. This paper explores the heat waves impact on surface urban heat island and on the local economy loss during three heat periods in Cluj-Napoca city in the summer of 2015. The heat wave events were identified based on daily maximum temperature, and they were divided into three classes considering the intensity threshold: moderate heat waves (daily maximum temperature exceeding the 90th percentile), severe heat waves (daily maximum temperature over the 95th percentile), and extremely severe heat waves (daily maximum temperature exceeding the 98th percentile). The minimum length of an event was of minimum three consecutive days. The surface urban heat island was detected based on land surface temperature derived from Landsat 8 thermal infrared data, while the economic impact was estimated based on data on work force structure and work productivity in Cluj-Napoca derived from the data released by Eurostat, National Bank of Romania, and National Institute of Statistics. The results indicate that the intensity and spatial extension of surface urban heat island could be governed by the magnitude of the heat wave event, but due to the low number of satellite images available, we should consider this information only as preliminary results. Thermal infrared remote sensing has proven to be a very efficient method to study surface urban heat island, due to the fact that the synoptic conditions associated with heat wave events usually favor cloud free image. The resolution of the OLI_TIRS sensor provided good results for a mid-extension city, but the low revisiting time is still a drawback. The potential economic loss was calculated for the working days during heat waves and the estimated loss reached more than 2.5 mil. EUR for each heat wave day at city scale, cumulating more than 38 mil. EUR for the three cases considered.  相似文献   

Impacts of river impoundment on dissolved heavy metals in floodplain soils of the Lahn River (Germany)     

Jens Hahn  Christian Opp  Nina Zitzer  Gabriela Laufenberg 《Environmental Earth Sciences》2016,75(15):1141

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The geology of the Oceanographer Transform: The transform domain     

P. J. Fox  R. H. Moody  J. A. Karson  E. Bonatti  W. S. F. Kidd  K. Crane  D. G. Gallo  J. B. Stroup  D. J. Fornari  D. Elthon  P. Hamlyn  J. F. Casey  D. Needham  R. Sartori 《Marine Geophysical Researches》1985,7(3):329-358

Three dives in submersible ALVIN and four deep-towed camera lowerings have been made along the transform valley of the Oceanographer Transform. These data constrain our understanding of the processes that create and shape the distinctive morphology that is characteristic of slowly slipping ridge-transform-ridge (RTR) plate boundaries. Our data suggest that the locus of strike-slip tectonism, called the transform fault zone (TFZ), is confined to a narrow swath (<4 km) that is centered along the axis of maximum depth. The TFZ is flanked by the inward facing slopes of the transform valley. The lower portions of the valley walls are characterized by broad sloping exposures of undisrupted sediment but at higher elevations the walls are made up of inward facing scarps and terraces of variable dimensions. Although the scarps have been badly degraded by mass wasting, there is no evidence to suggest that these scarps have accommodated significant amounts of strike-slip motion. Plutonic and ultramafic rocks are exposed on these scarps and the occurrence of this diverse assemblage on small-throw faults indicates that the crust is thin and/or discontinuous in this environment. We suggest that this complex igneous assemblage is the product of anomalous accretionary processes that are characteristic of slowly-slipping RTR plate boundaries.  相似文献   

A seismic reflection study of the External Calabrian Arc in the northern Ionian Sea (eastern Mediterranean)     

Sergio Rossi  Renzo Sartori 《Marine Geophysical Researches》1981,4(4):403-426

The External Calabrian Arc is located off the convex side of the Calabro-Peloritanian Arc in the northern Ionian Sea. A systematic reflection seismic survey indicates that it is made of different structural elements whose characters seem consistent with an active accretionary margin. The main structures are the Crotone-Spartivento slope (comparable to an inner trench slope) and the intermediate depressions (comparable to a trench area). Internal to these elements, the Crotone-Spartivento basin may represent a fore-arc basin. This partly outcrops in Calabria and its structure suggests that the accretionary margin developed at least since middle-upper Miocene.Subduction processes do not affect a true oceanic crust, because of the great thickness of sediments covering the whole eastern Mediterranean. Hence some peculiar features occur in the system. as the cobblestone topography, or are lacking, as a typical and continuous trench zone.In the areas with cobblestone topography we distinguish a Calabrian Ridge sensu stricto from a Calabrian Ridge sensu lato. The former is a N-S trending swell, external to the supposed trench zone, interpreted as a sedimentary outer-arc ridge produced by rather surficial tectonic accumulation of sediments further chaoticized by gravitative mechanisms. The Ridge s.l. is a very wide area with low relief and little or no seismic penetration. Tectonization seems gentler than in the Ridge s.s. and structural axes seem to possess different orientations. These areas are interpreted as due to a widespread surficial chaoticization above presumed decollement layers occurring within the sedimentary column of the Ionian bathyal plain.The pattern of deformations of the Calabrian Ridge seems consistent with the Calabro-Peloritanian Arc actively overriding the eastern Mediterranean, with a resultant direction of movement essentially towards the East.  相似文献   

Sedimentary facies,depositional processes and climatic controls in a Triassic Lake,Tanzhuang Formation,western Henan Province,China     

María Gabriela Mángano  Luis Alberto Buatois  Xiantao Wu  Junmin Sun  Guocheng Zhang 《Journal of Paleolimnology》1994,11(1):41-65

The Middle to Upper Triassic Tanzhuang Formation represents part of the infill of the early Mesozoic Jiyuan-Yima Basin. The upper part of this stratigraphic unit records deposition within prevailing shallow lake conditions. Well-developed sequences crop out near Jiyuan, western Henan Province, central China. Six sedimentary facies clustered into two facies assemblages were recognized in the lacustrine section. Facies assemblage 1 consists of stacked coarsening-upward sequences composed, from base to top, of organic-rich shales (facies E, type I), laminated siltstones (facies A) and current-rippled laminated sandstones (facies B). Units of assemblage 1 record progradation of small mouth-bar deltas within a perennial open lacustrine system under temperate and humid conditions. Facies assemblage 2 lacks a clear vertical pattern and consists of interbedded fine-grained carbonates and siltstones (facies C); deformed and wave-reworked sandstones (facies D); organic-rich shales (facies E, type II) and clayey mudstones (facies F). The assemblage also represents a perennial, hydrologically-open, shallow lacustrine system, but characterized by strong seasonal climatic control. Water stratification probably occurred in several periods of the lake history. Pangaean megamonsoonal influence is envisaged to explain the strong seasonality imprint evidenced toward the upper part of the Tanzhuang lacustrine column.This is the fourth paper in a series of papers published in this issue on Climatic and Tectonic Rhythms in Lake Deposits.  相似文献   

Fluid–Rock Interactions in Geothermal Reservoirs,Germany: Thermal Autoclave Experiments Using Sandstones and Natural Hydrothermal Brines     

Schäffer  Rafael  Götz  Emilia  Schlatter  Nils  Schubert  Gabriela  Weinert  Sebastian  Schmidt  Stefanie  Kolb  Ute  Sass  Ingo 《Aquatic Geochemistry》2022,28(2):63-110

As renewable energy, geothermal can contribute substantially to the energy transition. To generate electricity or to harvest heat, high-saline fluids are tapped by wells of a few kilometres and extracted from hydrothermal reservoirs. After the heat exchanger units have been passed by, these fluids are reinjected into the reservoir. Due to the pressure and temperature differences between the subsurface and the surface, as well as the cooling of the fluids in the power plant, unwanted chemical reactions can occur within the reservoir, in the borehole, and within the power plant itself. This can reduce the permeability of the reservoir as well as the output of the geothermal power plant. This study aims to simulate real subsurface reactions using batch and leaching experiments with sandstone or sandstone powder as solid phase, and deionised water or natural brine as liquid phase. It is demonstrated that fluid composition changes after only a few days. In particular, calcite, aragonite, clay minerals, and zinc phases precipitate from the natural brine. In contrast, in particular minerals containing potassium, arsenic, barium, and silica are dissolved. Due to the experimental set-up, these mineral reactions mainly took place on the surface of the samples, which is why no substantial changes in petrophysical properties could be observed. However, it is assumed that the observed reactions on the reservoir scale have a relevant influence on parameters such as permeability.

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Hydrogeochemical and nitrate isotopic evolution of a semiarid mountainous basin aquifer of glacial-fluvial and paleolacustrine origin (Lake Titicaca,Bolivia): the effects of natural processes and anthropogenic activities     

Flores Avil&#;s  Gabriela Patricia  Spadini  Lorenzo  Sacchi  Elisa  Rossier  Yvan  Savarino  Joel  Ramos  Oswaldo Eduardo  Duwig  C&#;line 《Hydrogeology Journal》2022,30(1):181-201

Hydrogeology Journal - A hydrogeochemical and stable isotopic ( $${\updelta }^{15}{\mathrm{N}}_{{\mathrm{NO}}_{3}}$$ and $${\updelta }^{18}{\mathrm{O}}_{{\mathrm{NO}}_{3}}$$ ) multitracer approach...  相似文献   

Analytic hierarchy process applied to landslide susceptibility mapping of the North Branch of Argentino Lake,Argentina     

Moragues  Silvana  Lenzano  María Gabriela  Lanfri  Mario  Moreiras  Stella  Lannutti  Esteban  Lenzano  Luis 《Natural Hazards》2021,105(1):915-941

Natural Hazards - In the present study, we achieved the susceptibility mapping to slope instability processes by the implementation of Analytic Hierarchy Process and Weighted Linear Combination...  相似文献