Franz Ottner

This experimental study analyses the extent of chemo-mineralogical changes that occur when a building stone encounters a cycling isothermal treatment at 600 °C. Four carbonate and two silicate European building stones were analysed in their fresh quarried and thermally treated conditions by means of colour measurements, in situ X-ray diffraction (XRD), and optical microscopy. Furthermore, powdered samples were characterised by Fourier-transform infrared spectroscopy, simultaneous thermal analysis, and cycling thermogravimetry (TG). The in situ XRD spectra revealed a surface-limited phase transformation of solid calcite and dolomite under isothermal conditions during the first 10 min at 600 °C and 500 °C, respectively. The onset of thermal decomposition and extent of phase transformation were governed by the microstructure of the solid samples. Inter- and intragranular microcracks are induced to varying degrees, and their incidence depended on the stone’s microstructure. Discolouration indicated a transformation of minor elements across the entire analysed sample volumes. Kaolinite was preserved even after three hours of thermal treatment at its dehydroxylation temperature due to its sheltering in confined pore spaces. Mass loss was more pronounced when cyclic treatment was employed compared to a non-periodic treatment, as determined by a TG analysis performed at same time intervals. Examining the chemo-mineralogical and microstructural changes caused by heat treatment allows us to study how and if regaining mechanical strength and restoring physical properties are possible for purposes of heritage restoration after fire damage.

This experimental study analyses the extent of chemo-mineralogical changes that occur when a building stone encounters a cycling isothermal treatment at 600 °C. Therefore, four carbonate and two silicate European building stones have been analysed in their fresh quarried and thermally treated conditions by means of colour measurements, in-situ X-ray diffraction (XRD) and optical microscopy. Furthermore, powdered samples have been characterised by Fourier-transform infra-red spectroscopy, simultaneous thermal analysis and cycling thermogravimetry (TG). In-situ XRD spectra reveal a surface limited phase transformation of solid calcite and dolomite at isothermal conditions during the first 10 min at 600 °C and 500 °C, respectively. The onset of thermal de-composition and extend of phase transformation is governed by the microstructure of the solid samples. Inter- and intragranular micro cracks are induced in varying degrees and their incidence depends likewise on the stone’s microstructure. Discolouration indicates a transformation of minor elements across the entire analysed sample volumes. Kaolinite is preserved even after three hours of thermal treatment at its dehydroxylation temperature due to its sheltering in confined pore spaces. Mass loss is more pronounced when cyclic treatment is employed as compared to a nonperiodic treatment, as determined by TG analysis performed at same time intervals.

Authigenic Mg‐calcite and dolomite are frequently observed in restricted, evaporative environments, such as lagoon or lake systems, but their formation is difficult to capture due to slow growth rates. Lake Neusiedl, an alkaline and subhaline lake with a mean water depth of 0.7 m in Austria, offers a natural system to study the precipitation of Ca‐Mg‐carbonate phases, which occur as fine‐grained, unconsolidated and largely homogenized mud. To elucidate the timing and formation mechanisms of these authigenic carbonate phases, the mineralogical and isotopic composition and radiocarbon age of different sediment grain‐size fractions from 3.0 μm were analysed. X‐ray diffraction analyses show two broad peaks of Mg‐calcite and protodolomite (lacking ordering peaks), suggesting that the carbonates are authigenic rather than detrital in origin. Calibrated carbon‐14 ages range between 200 cal yr bp and 3700 cal yr bp. The linear correlation of age and grain size suggests a very slow growth rate of single crystals of 0.23 to 0.60 μm/ka. These rates suggest an extremely slow sedimentation rate in a shallow lake that existed during most of the Holocene. The higher abundance of protodolomite in older grain fractions, in contrast to the presence of high‐Mg calcite in the youngest fractions, suggests a growth succession where high‐Mg calcite develops first and subsequently transforms into protodolomite. Much higher ages of 6 cal ka bp to 15 cal ka bp are measured in carbonates of lake deposits exposed on land, in a section north‐west of the recent lake, suggesting a growth rate of those carbonate minerals of 0.13 μm/ka. These time constraints further suggest that some carbonate grains could already have nucleated from lake water before or during the last glacial maximum, although under slightly different hydrochemical conditions.

The Banjarnegara–Jemblung Landslide was triggered on 12 December 2014 near the village of Jemblung in Central Java (Indonesia). The disaster occurred on the northern slope of Gunung Telagalele and caused more than 100 fatalities, making it the most disastrous landslide to have occurred in Indonesia in the past few decades. The event was characterized by multiple slope failures forming two landslide events A and B, with two connected scarps but two separated runout paths. According to eyewitnesses, landslide A was mobilized only a few minutes after the initial failure of B. Initially, both landslides began as earth slides that developed subsequently into very to extremely rapid earth flows. Although the failure volume was moderate, both slide flows reached very high velocities of several metres per second and travelled long distances, leading to remarkably low travel angles of 14° and 15°. Field investigations confirmed that slope failure was exacerbated by its geological predisposition based on a slope-parallel layering of volcaniclastic sediments of different origin and age, as well as intensive tropical weathering that generated clay-rich soils. Temporal relationships, as well as stability analysis, indicate that antecedent rainfall over 2 months and heavy rainfall the day before triggered the slope failure. Thematic collection: This article is part of the Leading to Innovative Engineering Geology Practices collection available at: https://www.lyellcollection.org/topic/collections/leading-to-innovative-engineering-geology-practices

The vernacular architecture in many regions in Eastern Austria was characterized by the use of unfired clay, at least until the 19th century, and in some areas until the 20th century. Farmhouses and associated farm buildings, such as storage buildings or press houses for the production of wine and cider, were erected using different earth construction techniques. The study area stretches from the Weinviertel, a region located in the province of Lower Austria in the north-east of Austria, to the Burgenland, a region located in the south-east of Austria, which belonged to Western Hungary until 1921. From a geological point of view, in the east of Austria—in the Vienna Basin and the Molasse Zone—huge areas of Tertiary clay are covered with loess deposits, which is the best-known basic material used in local earth-building traditions. A core question in the research on vernacular earthen heritage focuses on the impact of the geological conditions in Eastern Austria on the local earth-building techniques. The mineralogical composition of the different clays had an impact on the local building techniques. From a material-culture point of view, research on the relationship between the mineralogical properties of clay resources and local building techniques sheds light on the factors which influenced the evolution of certain vernacular building features. Tertiary clays and loess from the Pleistocene favoured the making of earth lumps, cob walls and adobe bricks over the whole Eastern Austrian region. Contrarily, regions in Burgenland with a high amount of gravel preferred, by tradition, to make walls by ramming. The clay mineral smectite acts as a binding agent in earth-building techniques over the whole investigated region—Weinviertel, Burgenland and Western Hungary.

Icelandic soils develop in a dynamic environment affected by both natural processes and anthropogenic impacts. We present an extensive investigation of soil mineralogy and pedogenesis in a disturbed (i.e., by solifluction) pedon under such conditions. The study focuses on two distinct tephra layers, a rhyolitic tephra from the Öræfajökull eruption in 1362 CE (Ö1362) and a basaltic Veiðivötn tephra from 1477 CE (V1477). Both tephra layers form an important parent material in the study area south of Vatnajökull, Iceland. The Andosol developed from tephra and aeolian material, rich in volcanic glass. The pH (H ₂ O) values were between 5.5 and 6.6 and clay mineralogy displayed a predominance of allophanic material in both soil and tephra. The pedon can be seen in its early stage of chemical weathering and soil development. Despite the overall predominance of non‐ and poorly‐crystalline short‐range order secondary materials and Fe (hydr)oxides in the clay‐size fraction, we found indication of smectite. High exchangeable Ca ²⁺ and Mg ²⁺ concentrations reflect enhanced aeolian input of volcanic material, while elevated exchangeable‐Na ⁺ concentrations are most likely caused by the oceanic composition of precipitation. The impact of erosion and aeolian processes on pedogenesis seemed to be higher between the deposition of Ö1362 and V1477, than in the soils above. Both, soil and tephra layers appeared disturbed by erosion–deposition processes over time. Characterised by a significantly coarser particle size composition, low soil organic carbon (SOC) content, and a more diverse mineralogy, a distinct fluvial sediment layer at 10–30 cm depth appeared sharply contrasting to the other soil layers in the profile. This possibly reflects the diverse composition of glaciofluvial material from a landslide originating from a Kvíárjökull moraine in the north. Changed weathering patterns and properties in the soils above the Ö1362 tephra indicated soil degradation following the deposition of the rhyolitic tephra.

The Galápagos archipelago is a well‐suited model ecosystem for investigating soil evolution. Here, we study mineral transformations and pedogenesis of the volcanic soils of Galápagos in response to weathering duration (1,500–1,070,000 yr) and climate (humid vs. dry). Our results show that soil pH, electrical conductivity, organic C content, cation exchange capacity (CEC), and water retention decreased whereas clay content and bulk density increased with soil age under humid climate. Andic properties were expressed in soils ≤4,300 yr old, but disappeared relatively early in pedogenesis and were absent in soils ≥26,000 yr old. The clay fraction of the young andic soils (≤4,300 yr old) was dominated by allophane and ferrihydrite. After 26,000 yr of pedogenesis, illitic–vermiculitic phases were predominant, and in the older soils (≥166,000 yr old), kaolinite, hematite, and gibbsite prevailed. The sequence of soil orders from the youngest to the second oldest site was Histosol–Andisol–Alfisol (vermiculitic)–Alfisol (parasesquic)–Ultisol. The oldest soil of the humid chronosequence (1,070,000 yr old) met all diagnostic criteria for an Oxisol except for the required low CEC. The soils at two dry comparison sites were less developed with low clay contents and vitric materials at 26,000 yr of age (Entisol), and dominantly smectitic clay mineralogy and pronounced shrink–swell features at 813,000 yr of age (Vertisol). Our results highlight a rapid transition through the Andisol stage during early pedogenesis as well as strongly divergent pedogenic development in humid vs. dry zones of the Galápagos Islands, both of which have important bearings on soil functioning and ecosystem evolution on this unique archipelago.

Sintering is a process of agglomeration of fine particles into porous sinters for blast furnaces. During the sintering process, high volumes of sinter plant gas containing high loads of dust, SO₂ and NO_X and toxic pollutants, such as heavy metals (e.g., Hg, Pb, Cr and Cd) and PCDD/F, are emitted. The objective of this study was to characterize dusts of different plants as the basis for suggestions of reutilization and treatment options. Dusts, eluates and residues were produced and DOC, T-N, ions and heavy metals were analyzed. The results show that dusts from different plants are very similar in terms of DOC, T-N, Mg, Ca and many heavy metals and only differ in criteria such as suspended solids and ions such as K, Na, Cl and SO₄. Based on the high levels of alkalis and low levels of iron, direct recycling into the sinter or furnace process is not recommended. The dissolution of the soluble substances in water reduces the MEROS dust by 90% of the weight and extracts the alkalis. The remaining wastewater needs to be treated to reduce DOC, T-N and some heavy metals. The solid residues can be recycled into the sinter to reduce potential PCDD/F, which are attached to the activated carbon.