Biologically-initiated rock crust on sandstone: Mechanical and hydraulic properties and resistance to erosion

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F17%3A00475873" target="_blank" >RIV/67985831:_____/17:00475873 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985891:_____/17:00475873 RIV/00216208:11310/17:10363676

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.geomorph.2016.09.040" target="_blank" >http://dx.doi.org/10.1016/j.geomorph.2016.09.040</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.geomorph.2016.09.040" target="_blank" >10.1016/j.geomorph.2016.09.040</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Biologically-initiated rock crust on sandstone: Mechanical and hydraulic properties and resistance to erosion

Popis výsledku v původním jazyce

Biocolonization on sandstone surfaces is known to play an important role in rock disintegration, yet it sometimes also aids in the protection of the underlying materials from rapid erosion. There have been few studies comparing the mechanical and/or hydraulic properties of the BIRC (Biologically-Initiated Rock Crust) with its subsurface. As a result, the overall effects of the BIRC are not yet well understood. The objective of the present study was to briefly characterize the BIRC, and especially to quantify the effect of the BIRC upon the mechanical and hydraulic properties of friable sandstone. The mineralogical investigation of a well-developed BIRC showed that its surface is enriched in kaolinite and clay-to silt-sized quartz particles. Total organic carbon increases with the age of the BIRC. The BIRC is formed by various fungi, including components of lichens and green algae. Using the method of drilling resistance, by measuring tensile strength, and based on water jet testing, it was determined that a BIRC is up to 12 times less erodible and has 3-35 times higher tensile strength than the subsurface friable sandstone. Saturated hydraulic conductivity of the studied BIRC is 15-300 times lower than the subsurface, and was measured to also decrease in capillary water absorption (2-33 times). The BIRC thus forms a hardened surface which protects the underlying material from rain and flowing water erosion, and considerably modifies the sandstone's hydraulic properties. It was shown that a major contribution to the surface hardening is provided by organic matter. In firmer sandstones, the BIRC may still considerably decrease the rate of weathering, as it is capable of providing cohesion to strongly weathered sandstone surfaces. However, only a near-surface zone of the sandstone is stabilized by the BIRC, and additional sources of stabilization contribute to the resistance of the subsurface zone of sandstone exposures.

Název v anglickém jazyce

Biologically-initiated rock crust on sandstone: Mechanical and hydraulic properties and resistance to erosion

Popis výsledku anglicky

Biocolonization on sandstone surfaces is known to play an important role in rock disintegration, yet it sometimes also aids in the protection of the underlying materials from rapid erosion. There have been few studies comparing the mechanical and/or hydraulic properties of the BIRC (Biologically-Initiated Rock Crust) with its subsurface. As a result, the overall effects of the BIRC are not yet well understood. The objective of the present study was to briefly characterize the BIRC, and especially to quantify the effect of the BIRC upon the mechanical and hydraulic properties of friable sandstone. The mineralogical investigation of a well-developed BIRC showed that its surface is enriched in kaolinite and clay-to silt-sized quartz particles. Total organic carbon increases with the age of the BIRC. The BIRC is formed by various fungi, including components of lichens and green algae. Using the method of drilling resistance, by measuring tensile strength, and based on water jet testing, it was determined that a BIRC is up to 12 times less erodible and has 3-35 times higher tensile strength than the subsurface friable sandstone. Saturated hydraulic conductivity of the studied BIRC is 15-300 times lower than the subsurface, and was measured to also decrease in capillary water absorption (2-33 times). The BIRC thus forms a hardened surface which protects the underlying material from rain and flowing water erosion, and considerably modifies the sandstone's hydraulic properties. It was shown that a major contribution to the surface hardening is provided by organic matter. In firmer sandstones, the BIRC may still considerably decrease the rate of weathering, as it is capable of providing cohesion to strongly weathered sandstone surfaces. However, only a near-surface zone of the sandstone is stabilized by the BIRC, and additional sources of stabilization contribute to the resistance of the subsurface zone of sandstone exposures.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Geomorphology

ISSN

0169-555X

e-ISSN

—

Svazek periodika

278

Číslo periodika v rámci svazku

FEB 1

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

16

Strana od-do

298-313

Kód UT WoS článku

000392555000022

EID výsledku v databázi Scopus

2-s2.0-85002637762