Effects of Rock Surface Temperature on Exfoliation, Rock Varnish, and Lichens on a Boulder in the Hunza Valley, Karakoram Mountains, Pakistan

1998 ◽  
Vol 30 (2) ◽  
pp. 184 ◽  
Author(s):  
Tetsuya Waragai
Keyword(s):  
Surface Temperature ◽  
Rock Surface ◽  
Rock Varnish ◽  
Karakoram Mountains

scholarly journals Rock Emissivity Measurement for Infrared Thermography Engineering Geological Applications

2021 ◽  
Vol 11 (9) ◽  
pp. 3773
Author(s):  
Simone Mineo ◽  
Giovanna Pappalardo
Keyword(s):  
Surface Temperature ◽  
Infrared Thermography ◽  
High Sensitivity ◽  
Point Of View ◽  
Rock Surface ◽  
Rock Types ◽  
Ornamental Stones ◽  
Emissivity Measurement ◽  
Laboratory Tool ◽  
Non Destructive

Infrared thermography is a growing technology in the engineering geological field both for the remote survey of rock masses and as a laboratory tool for the non-destructive characterization of intact rock. In this latter case, its utility can be found either from a qualitative point of view, highlighting thermal contrasts on the rock surface, or from a quantitative point of view, involving the study of the surface temperature variations. Since the surface temperature of an object is proportional to its emissivity, the knowledge of this last value is crucial for the correct calibration of the instrument and for the achievement of reliable thermal outcomes. Although rock emissivity can be measured according to specific procedures, there is not always the time or possibility to carry out such measurements. Therefore, referring to reliable literature values is useful. In this frame, this paper aims at providing reference emissivity values belonging to 15 rock types among sedimentary, igneous and metamorphic categories, which underwent laboratory emissivity estimation by employing a high-sensitivity thermal camera. The results show that rocks can be defined as “emitters”, with emissivity generally ranging from 0.89 to 0.99. Such variability arises from both their intrinsic properties, such as the presence of pores and the different thermal behavior of minerals, and the surface conditions, such as polishing treatments for ornamental stones. The resulting emissivity values are reported and commented on herein for each different studied lithology, thus providing not only a reference dataset for practical use, but also laying the foundation for further scientific studies, also aimed at widening the rock aspects to investigate through IRT.

scholarly journals Rock varnish on petroglyphs from the Hima region, southwestern Saudi Arabia: Chemical composition, growth rates, and tentative ages

The Holocene ◽  
2019 ◽  
Vol 29 (8) ◽  
pp. 1377-1395 ◽  
Author(s):  
Dorothea S Macholdt ◽  
Klaus Peter Jochum ◽  
Abdullah Al-Amri ◽  
Meinrat O Andreae
Keyword(s):  
Saudi Arabia ◽  
Inductively Coupled Plasma ◽  
Rock Art ◽  
Femtosecond Laser Ablation ◽  
Areal Density ◽  
Rock Surface ◽  
Inductively Coupled ◽  
Rock Varnish ◽  
Plasma Mass Spectrometry ◽  
The Individual

We investigated rock varnish formed on sandstone and petroglyphs in the Hima area, southwestern Saudi Arabia. To characterize the rock varnish, we made in-situ measurements by portable x-ray fluorescence (pXRF) and analyzed samples by femtosecond laser-ablation inductively coupled–plasma mass spectrometry (fs LA-ICP-MS). Detailed chemical analysis of the rock varnish samples and adjacent soil or aeolian dust yielded information about the varnish’s geochemical context and formation mechanism. Untypically low positive Ce anomalies in the rock varnish samples correlated with negative Ce anomalies in the dust, supporting the hypothesis that the dust is the source of the varnish material. To study the varnish development, we made use of the fact that engraving the petroglyphs exposes a fresh bare sandstone surface without varnish, on which varnish regrows subsequently. We determined by pXRF the areal density of manganese (Mn) and iron (Fe) that had been deposited as rock varnish since the creation of the rock art. The rates of Mn deposition in the newly formed varnish were then estimated by correlating the areal density of Mn in Ancient Arabian and Old Arabic inscriptions with their known age ranges. The observed deposition rates showed substantial variability resulting from differences in exposure conditions of the rock surface, but were in a range comparable with that of our previous measurements in northwestern Arabia. This variability could be reduced significantly by referencing the measurements to the intact varnish adjacent to the individual petroglyphs. This normalization provided a much clearer relationship between varnish deposition and age, and enabled tentative ages to be assigned to rock art motifs without previously known ages. These tentative ages spanned most of the Holocene period and were consistent with the culturally or ecologically derived ages of the animal and human figures depicted in the rock art and the styles of scripts used in different periods.

scholarly journals Surface temperatures and their influence on the permafrost thermal regime in high-Arctic rock walls on Svalbard

2021 ◽  
Vol 15 (5) ◽  
pp. 2491-2509
Author(s):  
Juditha Undine Schmidt ◽  
Bernd Etzelmüller ◽  
Thomas Vikhamar Schuler ◽  
Florence Magnin ◽  
Julia Boike ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Temperature ◽  
Surface Energy Balance ◽  
High Arctic ◽  
Heat Fluxes ◽  
Rock Surface ◽  
Permafrost Degradation ◽  
Rock Wall ◽  
Surface Temperatures

Abstract. Permafrost degradation in steep rock walls and associated slope destabilization have been studied increasingly in recent years. While most studies focus on mountainous and sub-Arctic regions, the occurring thermo-mechanical processes also play an important role in the high Arctic. A more precise understanding is required to assess the risk of natural hazards enhanced by permafrost warming in high-Arctic rock walls. This study presents one of the first comprehensive datasets of rock surface temperature measurements of steep rock walls in the high Arctic, comparing coastal and near-coastal settings. We applied the surface energy balance model CryoGrid 3 for evaluation, including adjusted radiative forcing to account for vertical rock walls. Our measurements comprise 4 years of rock surface temperature data from summer 2016 to summer 2020. Mean annual rock surface temperatures ranged from −0.6 in a coastal rock wall in 2017/18 to −4.3 ∘C in a near-coastal rock wall in 2019/20. Our measurements and model results indicate that rock surface temperatures at coastal cliffs are up to 1.5 ∘C higher than at near-coastal rock walls when the fjord is ice-free in winter, resulting from additional energy input due to higher air temperatures at the coast and radiative warming by relatively warm seawater. An ice layer on the fjord counteracts this effect, leading to similar rock surface temperatures to those in near-coastal settings. Our results include a simulated surface energy balance with shortwave radiation as the dominant energy source during spring and summer with net average seasonal values of up to 100 W m−2 and longwave radiation being the main energy loss with net seasonal averages between 16 and 39 W m−2. While sensible heat fluxes can both warm and cool the surface, latent heat fluxes are mostly insignificant. Simulations for future climate conditions result in a warming of rock surface temperatures and a deepening of active layer thickness for both coastal and near-coastal rock walls. Our field data present a unique dataset of rock surface temperatures in steep high-Arctic rock walls, while our model can contribute towards the understanding of factors influencing coastal and near-coastal settings and the associated surface energy balance.

scholarly journals Testing A Methodology to Assess Fluctuations of Coastal Rocks Surface Temperature

2019 ◽  
Vol 7 (9) ◽  
pp. 315 ◽  
Author(s):  
Marta Pappalardo ◽  
Martina D’Olivo
Keyword(s):  
Surface Temperature ◽  
Temperature Fluctuations ◽  
Daily Temperature ◽  
Contactless Measurement ◽  
Rock Surface ◽  
Short Term ◽  
Infrared Thermometer ◽  
Measuring Point ◽  
Wind Gusts ◽  
Order Of Magnitude

The aim of this work is testing a cheap and user-friendly methodology suitable for studying temperature fluctuations of coastal rocks’ surfaces. An infrared thermometer was used, that permits a contactless measurement of the average surface temperature of a patch around a measuring point. Temperature was measured in an array of selected plots every 45 min from dawn to sunset in a 20 m2 study area along the rocky coast of Calafuria (NW Italy). During the experiment daily temperature in all plots was minimum at dawn and quickly reached its peak value shortly after sun culmination; subsequently, it underwent a small-gradient decrease until sunset. In connection with temporary sun-shading and wind gusts relevant short-term rock surface temperature fluctuations were recorded. Considering mean daily temperature in each plot, it proved to be positively correlated with distance from the shoreline. As regards daily temperature range, its amplitude progressively increased moving farther from the shoreline. The measuring points located where the rock is extensively covered by barnacles experience a temperature magnification effect, possibly due to a micro-greenhouse effect triggered by the production of carbon dioxide by this biota. The entity of measured daily temperature fluctuations is ca. one order of magnitude greater than air temperature fluctuations measured at the same elevation in the closest meteorological station. The results of this work highlight that the infrared thermometer is an effective tool to measure rock surface temperature along rocky coasts, capable of detecting temperature fluctuations more effectively than traditionally employed data loggers. Moreover, this work emphasizes the relevance of temporary sun-shading and wind gusts in triggering short-term rock surface temperature fluctuations, potentially capable of enhancing thermal fatigue and foster surface rock breakdown.

scholarly journals Cave Rock Surface Temperature Evaluation Using Non-Contact Measurement Methods

2014 ◽  
Vol 43 (2-3) ◽  
Author(s):  
Hana Středová ◽  
Tomáš Středa ◽  
Miroslav Vysoudil
Keyword(s):  
Surface Temperature ◽  
Measurement Methods ◽  
Rock Surface ◽  
Contact Measurement

Taxonomic and functional insights into rock varnish microbiome using shotgun metagenomics

2019 ◽  
Vol 95 (12) ◽  
Author(s):  
Alfonso Esposito ◽  
Luigimaria Borruso ◽  
Jayne E Rattray ◽  
Lorenzo Brusetti ◽  
Engy Ahmed
Keyword(s):  
Microbial Communities ◽  
Ecosystem Dynamics ◽  
Survival Strategies ◽  
Rock Surface ◽  
Shotgun Metagenomics ◽  
Complete Genomes ◽  
Rock Varnish ◽  
Functional Features ◽  
Microbial Habitat ◽  
Mn Oxides

ABSTRACT Rock varnish is a microbial habitat, characterised by thin (5–500 μm) and shiny coatings of iron (Fe) and manganese (Mn) oxides associated with clay minerals. This structure is well studied by geologists, and recently there have been reports about the taxonomical composition of its microbiome. In this study, we investigated the rock varnish microbiome using shotgun metagenomics together with analyses of elemental composition, lipid and small molecule biomarkers, and rock surface analyses to explore the biogeography of microbial communities and their functional features. We report taxa and encoded functions represented in metagenomes retrieved from varnish or non-varnish samples, additionally, eight nearly complete genomes have been reconstructed spanning four phyla (Acidobacteria, Actinobacteria, Chloroflexi and TM7). The functional and taxonomic analyses presented in this study provide new insights into the ecosystem dynamics and survival strategies of microbial communities inhabiting varnish and non-varnish rock surfaces.

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