Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

Bruthans, Jiří; Filippi, Michal; Slavík, Martin; Svobodová, Eliška

doi:10.1016/j.geomorph.2017.11.013

Cited by 56 publications

(41 citation statements)

References 47 publications

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“…In the past few decades, a range of microtopographic data collection methods have been used in rock breakdown and soil erosion studies. These include (1) laser scanning techniques (Fardin et al, 2001(Fardin et al, , 2004Bourke et al, 2007;Bourke et al, 2008;Aguilar et al, 2009;Sturzenegger and Stead, 2009;MŁynarczuk, 2010;Medapati et al, 2013;Chen et al, 2014;Ge et al, 2014;Lai et al, 2014), (2) stereophotogrammetry (Rieke-Zapp and Nearing, 2005;Taconet and Ciarletti, 2007;Aguilar et al, 2009;Bui et al, 2009;Sturzenegger and Stead, 2009;Kim et al, 2015), and (3) micro-roughness meters (MRMs) (McCarroll, 1992;Mc-Carroll and Nesje, 1996;White et al, 1998). However, there are significant logistical, technical, and, for some, financial constraints that have hindered the adoption of these methods, particularly in physically challenging terrains such as remote, difficult to access, and steep terrains.…”

Section: Introductionmentioning

confidence: 99%

A method based on structure-from-motion photogrammetry to generate sub-millimetre-resolution digital elevation models for investigating rock breakdown features

Verma

Bourke

2019

Earth Surf. Dynam.

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Abstract. We have generated sub-millimetre-resolution DEMs of weathered rock surfaces using SfM photogrammetry techniques. We apply a close-range method based on structure-from-motion (SfM) photogrammetry in the field and use it to generate high-resolution topographic data for weathered boulders and bedrock. The method was pilot tested on extensively weathered Triassic Moenkopi sandstone outcrops near Meteor Crater in Arizona. Images were taken in the field using a consumer-grade DSLR camera and were processed in commercially available software to build dense point clouds. The point clouds were registered to a local 3-D coordinate system (x, y, z), which was developed using a specially designed triangle-coded control target and then exported as digital elevation models (DEMs). The accuracy of the DEMs was validated under controlled experimental conditions. A number of checkpoints were used to calculate errors. We also evaluated the effects of image and camera parameters on the accuracy of our DEMs. We report a horizontal error of 0.5 mm and vertical error of 0.3 mm in our experiments. Our approach provides a low-cost method for obtaining very high-resolution topographic data on weathered rock surfaces (area < 10 m2). The results from our case study confirm the efficacy of the method at this scale and show that the data acquisition equipment is sufficiently robust and portable. This is particularly important for field conditions in remote locations or steep terrain where portable and efficient methods are required.

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Section: Introductionmentioning

confidence: 99%

A method based on structure-from-motion photogrammetry to generate sub-millimetre-resolution digital elevation models for investigating rock breakdown features

Verma

Bourke

2019

Earth Surf. Dynam.

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“…Recently, Bruthans et al (2018) conclusively demonstrated that moisture flux followed by salt crystallization at the boundary layer govern the case hardening model in temperate climates. In addition, biological mechanisms have been proposed to promote rock weathering through mechanisms such as flaking via colony growth (Viles, 2012), acidification by bacterial extractions (Garcia-Pichel, 2006;Warscheid and Braams, 2000), or alkalization during photosynthesis by cyanobacteria (Büdel et al, 2004). In contrast, it has been proposed that micro-and macro-organism colonization can mitigate weathering in temperate, coastal regions (McIlroy de la Rosa et al, 2014;Mustoe, 2010) via encrustation or protection from direct rain impact.…”

Section: Introductionmentioning

confidence: 99%

The origin and role of biological rock crusts in rocky desert weathering

et al. 2019

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Abstract. In drylands, microbes that colonize rock surfaces have been linked to erosion because water scarcity excludes traditional weathering mechanisms. We studied the origin and role of rock biofilms in geomorphic processes of hard lime and dolomitic rocks that feature comparable weathering morphologies, although these two rock types originate from arid and hyperarid environments, respectively. We hypothesized that weathering patterns are fashioned by salt erosion and mediated by the rock biofilms that originate from the adjacent soil and dust. We used a combination of microbial and geological techniques to characterize rock morphologies and the origin and diversity of their biofilms. Amplicon sequencing of the SSU rRNA gene suggested that bacterial diversity is low and dominated by Proteobacteria and Actinobacteria. These phyla only formed laminar biofilms on rock surfaces that were exposed to the atmosphere and burrowed up to 6 mm beneath the surface, protected by sedimentary deposits. Unexpectedly, the microbial composition of the biofilms differed between the two rock types and was also distinct from the communities identified in the adjacent soil and settled dust, showing a habitat-specific filtering effect. Moreover, the rock bacterial communities were shown to secrete extracellular polymeric substances (EPSs) that form an evaporation barrier, reducing water loss rates by 65 %–75 %. The reduced water transport rates through the rock also limit salt transport and its crystallization in surface pores, which is thought to be the main force for weathering. Concomitantly, the biofilm layer stabilizes the rock surface via coating and protects the weathered front. Our hypothesis contradicts common models, which typically consider biofilms to be agents that promote weathering. In contrast, we propose that the microbial colonization of mineral surfaces acts to mitigate geomorphic processes in hot, arid environments.

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“…In addition, our approach will ease the cumbersome task of collecting morphometric data on individual weathering features in the field (e.g. Norwick 10 and Dexter, 2002;Bruthans et al, 2018).…”

Section: Importance Of Microtopographic Data In Rock Breakdownmentioning

confidence: 99%

A Structure from Motion photogrammetry-based method to generate sub-millimetre resolution Digital Elevation Models for investigating rock breakdown features

Verma

Bourke

2018

Preprint

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Abstract. We have generated sub-millimetre resolution DEMs of weathered rock surfaces using SfM photogrammetry techniques. We apply a close-range Structure from Motion (SfM) photogrammetry-based method in the field and use it to generate high-resolution topographic data for weathered boulders and bedrock. The method was pilot tested on extensively weathered Triassic Moenkopi Sandstone outcrops near Meteor Crater in Arizona. Images were taken in the field using a consumer grade DSLR camera and were processed in commercially available software Agisoft Photoscan to build dense point cloud. Dense point clouds were registered to a local 3D coordinate system (x, y, z) which was developed using a specially designed triangle coded control target and then exported as Digital Elevation Models (DEMs). The accuracy of the DEMs was validated under controlled experimental conditions. A number of checkpoints were used to calculate errors. We also evaluated the effects of image and camera parameters on the accuracy of our DEMs. We report a horizontal error of 0.5 mm and vertical error of 0.3 mm in our experiments. Our approach provides a low-cost method, for obtaining very high-resolution topographic data on weathered rock surfaces (area

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Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

Cited by 56 publications

References 47 publications

A method based on structure-from-motion photogrammetry to generate sub-millimetre-resolution digital elevation models for investigating rock breakdown features

A method based on structure-from-motion photogrammetry to generate sub-millimetre-resolution digital elevation models for investigating rock breakdown features

The origin and role of biological rock crusts in rocky desert weathering

A Structure from Motion photogrammetry-based method to generate sub-millimetre resolution Digital Elevation Models for investigating rock breakdown features

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