Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F18%3A10369787" target="_blank" >RIV/00216208:11310/18:10369787 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985831:_____/18:00486216

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Gv.NiJjAa0" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Gv.NiJjAa0</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.geomorph.2017.11.013" target="_blank" >10.1016/j.geomorph.2017.11.013</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

Popis výsledku v původním jazyce

Cavernous weathering (cavernous rock decay) is a global phenomenon, which occurs in porous rocks around the world. Although honeycombs and tafoni are considered to be the most common products of this complex process, their origin and evolution are as yet not fully understood. The two commonly assumed formation hypotheses - hydraulic and case hardening - were tested to elucidate the origin of honeycombs on sandstone outcrops in a humid climate. Mechanical and hydraulic properties of the lips (walls between adjacent pits) and backwalls (bottoms of pits) of the honeycombs were determined via a set of established and novel approaches. While the case hardening hypothesis was not supported by the determinations of either tensile strength, drilling resistance or porosity, the hydraulic hypothesis was clearly supported by fieldmeasurements and laboratory tests. Fluorescein dye visualization of capillary zone, vapor zone, and evaporation front upon their contact, demonstrated that the evaporation front reaches the honeycomb backwalls under low water flow rate, while the honeycomb lips remain dry. During occasional excessive water flow events, however, the evaporation front may shift to the lips, while the backwalls become moist as a part of the capillary zone. As the zone of evaporation corresponds to the zone of potential salt weathering, it is the spatial distribution of the capillary and vapor zones which dictates whether honeycombs are created or the rock surface is smoothed. A hierarchical model of factors related to the hydraulic field was introduced to obtain better insights into the process of cavernous weathering.

Název v anglickém jazyce

Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

Popis výsledku anglicky

Cavernous weathering (cavernous rock decay) is a global phenomenon, which occurs in porous rocks around the world. Although honeycombs and tafoni are considered to be the most common products of this complex process, their origin and evolution are as yet not fully understood. The two commonly assumed formation hypotheses - hydraulic and case hardening - were tested to elucidate the origin of honeycombs on sandstone outcrops in a humid climate. Mechanical and hydraulic properties of the lips (walls between adjacent pits) and backwalls (bottoms of pits) of the honeycombs were determined via a set of established and novel approaches. While the case hardening hypothesis was not supported by the determinations of either tensile strength, drilling resistance or porosity, the hydraulic hypothesis was clearly supported by fieldmeasurements and laboratory tests. Fluorescein dye visualization of capillary zone, vapor zone, and evaporation front upon their contact, demonstrated that the evaporation front reaches the honeycomb backwalls under low water flow rate, while the honeycomb lips remain dry. During occasional excessive water flow events, however, the evaporation front may shift to the lips, while the backwalls become moist as a part of the capillary zone. As the zone of evaporation corresponds to the zone of potential salt weathering, it is the spatial distribution of the capillary and vapor zones which dictates whether honeycombs are created or the rock surface is smoothed. A hierarchical model of factors related to the hydraulic field was introduced to obtain better insights into the process of cavernous weathering.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA16-19459S" target="_blank" >GA16-19459S: Vliv napětí daného gravitací na erozi pískovce: fyzikální a numerické modelování</a><br>

Návaznosti

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

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Geomorphology

ISSN

0169-555X

e-ISSN

1872-695X

Svazek periodika

303

Číslo periodika v rámci svazku

February

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

16

Strana od-do

68-83

Kód UT WoS článku

000426330400006

EID výsledku v databázi Scopus

2-s2.0-85035363468