ArticlePDF Available

Abstract and Figures

Cavernous rock decay processes represent a global phenomenon, ubiquitous to all environments, with the viewable-in-landscape form usually being the final descriptor (e.g. “alveoli”), sometimes alluding to the specific decay process (e.g. “pitting”), other times not (e.g. “honeycombing”). Yet, definitive terminology remains inconsistent, usually owing to variability in dimension, morphometry, distribution, and/or academic lineage. This lack of an established lexicon limits scientific collaboration and can generate scientific bias. With no official consensus on appropriate distinctions, researchers and scientists must either be familiar with all the possible terminology, or know the apparent distinction between “forms”—which can seem arbitrary and, even more frustrating, often differs from researcher to researcher, scientist to scientist. This article reviews the historical and contemporary progression of scientific inquiry into this decay—and, arguably, erosional—feature to identify lexical inconsistencies and promote a singular unifying term for future scholars. Ultimately, the authors support using “tafoni” (singular: “tafone”) as the non-scalar universal term—the form created by numerous processes involved in cavernous decay features—and strongly suggest researchers adopt the same vernacular in order to promote collaboration.
Content may be subject to copyright.
Article
Defining tafoni: Re-examining
terminological ambiguity for
cavernous rock decay phenomena
Kaelin M. Groom
University of Arkansas, USA
Casey D. Allen
University of Colorado Denver, USA
Lisa Mol
Cardiff University, UK; Oxford University, UK
Thomas R. Paradise
University of Arkansas, USA
Kevin Hall
University of Pretoria, South Africa
Abstract
Cavernous rock decay processes represent a global phenomenon, ubiquitous to all environments, with the
viewable-in-landscape form usually being the final descriptor (e.g. ‘‘alveoli’’), sometimes alluding to the specific
decay process (e.g. ‘‘pitting’’), other times not (e.g. ‘‘honeycombing’’). Yet, definitive terminology remains
inconsistent, usually owing to variability in dimension, morphometry, distribution, and/or academic lineage.
This lack of an established lexicon limits scientific collaboration and can generate scientific bias. With no
official consensus on appropriate distinctions, researchers and scientists must either be familiar with all the
possible terminology, or know the apparent distinction between ‘‘forms’’—which can seem arbitrary and,
even more frustrating, often differs from researcher to researcher, scientist to scientist. This article reviews
the historical and contemporary progression of scientific inquiry into this decay—and, arguably, erosional—
feature to identify lexical inconsistencies and promote a singular unifying term for future scholars. Ultimately,
the authors support using ‘‘tafoni’’ (singular: ‘‘tafone’’) as the non-scalar universal term—the form created by
numerous processes involved in cavernous decay features—and strongly suggest researchers adopt the same
vernacular in order to promote collaboration.
Keywords
Cavernous weathering, honeycombing, tafoni, terminology, rock decay
I Introduction
Characterized as cavities or hollows of various
sizes in stone surfaces, cavernous rock decay
is a globally occurring phenomenon that has
Corresponding author:
Kaelin M. Groom, University of Arkansas, Department of
Geosciences and the King Fahd Center for Middle East
Studies, 216 Ozark Hall, Fayetteville, AR 72701, USA.
Email: kmgroom@uark.edu
Progress in Physical Geography
1–19
ªThe Author(s) 2015
Reprints and permission:
sagepub.co.uk/journalsPermissions.nav
DOI: 10.1177/0309133315605037
ppg.sagepub.com
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
been under scientific exploration for centuries
and yet definitive terminology remains incon-
sistent. Publications on the enigmatic rock
decay features vary considerably from qualita-
tive interpretations (e.g. Bryan, 1928; Tschang,
1974) and temporal modeling of cell growth
(e.g. Norwick and Dexter, 2002; Sunamura,
1996), to meticulous laboratory analyses (e.g.
McBride and Picard, 2004; Rodriguez-Navarro
et al., 1999) and complex multidisciplinary field
studies (e.g. Brandmeier et al., 2010; Martini,
1978). However, variability in dimension, mor-
phometry, and distribution of these decay fea-
tures has resulted in the adoption of assorted
terms such as alveoli, stone lace, honeycomb-
ing, caverns, pitting, and so forth. All of these
refer to cavernous decay features with a gener-
ally accepted assumption that each term is
somehow scale dependent (e.g. alveoli refer to
smaller cells). However, no apparent consensus
exists on the appropriate distinctions between
terms. At what point is alveoli confidently
alveoli and not honeycombing? Or, what is the
definable difference between tafoni and stone
lace? Some argument has been made that the
distinction between such terms could depend
on cell depth vs. width vs. clarity of separating
ridges (e.g. Tschang, 1974), but even then what
are the defining thresholds of these values? For
example, when is a cell deep enough to be con-
sidered honeycombing instead of pitting? This
lack of established lexicon restricts scientific
collaboration and future research through termi-
nology disconnects or misunderstandings, as
evidenced throughout the history of cavernous
decay research.
Despite, or perhaps spurred-on by, fluctuating
scientific interest in cavernous decay research,
different distinctions and terminology for decay
features emerged seemingly autonomous from
each other (Smith, 1982). Martini (1978) defined
tafoni as ‘‘a landform and refers to weathering
conditions and processes that lead to formation
and maintenance of the morphological form’
(Martini, 1978: 46), but this definition is
ambiguous and open to multiple interpreta-
tions. Scientific confusion is continually perpe-
tuated as researchers use different terminology
to describe analogous decay phenomena. The
significance of this situation is not lost on
the rock decay research community, who have
recently struggled with a similar conundrum
advocating ‘‘rock decay’’ as a more accurate
and encompassing replacement terminology
for the widely used ‘‘weathering’’ to define
stone deterioration (e.g. Dorn et al., 2013;
Hall et al., 2012). Likewise with Bracken and
Wainwright’s (2006) contention of ambiguity
over the term ‘‘equilibrium,’’ especially in
geomorphology, and Berthling’s (2011: 98)
argument that process (the usual ‘‘morphologi-
cal definition’’) should not necessarily be the
primary consideration when defining geomor-
phological features (in this case specifically
rock glaciers). Related to tafoni specifically,
in his 1982 Nature article, ‘‘Why Honeycomb
Weathering?,’’ Smith (1982: 121) aptly describes
the situation: ‘‘With so many independent obser-
vations of so many examples in so many different
places, it is perhaps not surprising that it has
come to have a variety of names.’’
There have been previous attempts to stan-
dardize the nomenclature, but few such pleas
have been successful and terminological incon-
sistency remains. In The Geomorphology of
Rock Coasts, Trenhaile (1992) writes ‘‘the lack
of a precise definition of honeycombs, tafoni,
and other related forms makes it difficult ...
to determine the meaning of the terminology
as it is used by different workers’’ (Trenhaile,
1992: 31). At some point during the late
1900s, researchers began designating large,
meter-sized cavities as tafoni and smaller, simi-
larly shaped, millimeter- to decimeter-scale
cavities as honeycomb, honeycomb weathering,
alveoli, alveolar weathering, and small tafoni,
but with no official clarification of scale-
dependence (e.g. Kelletat, 1980; McBride
and Picard, 2000; Smith, 1982; Turkington
and Paradise, 2005; Figure 1). Despite this
2Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
pseudo-collaboration, established distinctions
between the myriad of terms, whether based
on size, shape, or cavity frequency per rock
surface, are still absent and many studies con-
tinue to use varied terminologies (e.g. Andre
and Hall, 2005; Young and Young 1992). How-
ever, this begs even more complex questions:
are they the same feature, just at different
scales, and, thus, require a universal term,
or are all the various distinctions warranted?
Are honeycombing, tafoni, and other caver-
nous decay features’ geomorphology synon-
ymous despite historically observational and
lexical differences? What are the scientific
implications inherent to inconsistent terminology
and how might moving towards a single, common
terminology benefit future research? With such
questions left unaddressed, it has become difficult
to establish basic processes such as the influence
of salts, micro-climate, air circulation, mineral-
ogy, and case hardening, to name a few, if
scholars cannot even agree on the form being
studied. As the eventual aim of cavernous decay
research is to establish overarching processes
causing similar features in different lithologies
and environments, then adopting common termi-
nology allows significantly more efficient com-
parison within the literature.
To address these key issues, this article out-
lines a number of instances where this consensus
is not reached and fluid terminologies are used
despite researching very similar forms. This is
accomplished through a temporal and thematic
approach in discussing pertinent questions to
gain a better evolutionary understanding of
nomenclature ambiguity in cavernous decay
research. Significant eras of tafoni literature are
outlined in detail, chronologically from oldest
to most recent. The first research period spans
the late 1800s to the early 1900s, when systema-
tic tafoni research and terminology were first
beginning to emerge. The second era focuses
on cavernous decay investigations following
geography’s so-called ‘‘Quantitative Revolu-
tion’’ (*1960s to 1970s, cf. Barnes, 2009;
Burton 1963; Livingstone, 1992: chapter 9).
Finally, the most recent cavernous decay studies
from the 1980s into the 21st century are exam-
ined for terminology, definitions, and other sig-
nificant findings. The purpose of this review is
to outline the progression of tafoni and caver-
nous decay research and, by doing so, identify
terminological inconsistencies that may be
hindering future scientific discoveries and
research. By offering an alternative through a
structured terminology framework, we can
move forward, perhaps finding overarching
processes within tafoni development rather
than creating disconnected literature ‘‘islands’
of case studies.
Figure 1. Tafoni of various sizes with scale bars for reference. Locations from left to right: Bean Hollow State
Beach, CA; Bean Hollow State Beach, CA; Moenkopi Formation in Wupatki NM, AZ; DISI formation in
Beidha, Petra, Jordan; and the Remarkable Rocks in Flinders Chase NP, Australia. Photographs by T.R.
Paradise.
Groom et al. 3
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
II The scientific beginning
of cavernous decay features
Descriptions of tafoni and cavernous decay fea-
tures have been recorded for thousands of years,
the earliest being 3500-year-old intricate Min-
oan fresco paintings (Boxerman, 2005). Early
explorers and scholars, such as Charles Darwin
(1839) and James Dana (1849), offer casual
reflections in their journal, but hardly more than
curious observation. Much of the earlier studies
on cavernous features come from the Mediterra-
nean region by scholars such as Casiano de
Prado (1797–1866), who first described tafoni
in the Sierra de Guadarrama, Central Spain
(De Prado, 1864). In fact, the earliest printed
uses of the term ‘‘tafoni’’ (singular: tafone)—
stemming from the verb tafonare meaning ‘‘to
perforate’’—referring to cavernous decay fea-
tures were by Hans Henrik Reusch in 1882 and
later by Albrecht Penck in 1894, both of whom
researched tafoni cells in Corsica.
Cavernous decay was not given any serious
scientific attention in the Americas until the
early 1900s. During this era of exploratory sci-
ence, two of the founding reports on tafoni not
only present different formation hypotheses, but
also, unfortunately, initiated the habit of arbi-
trary terminology and categorization for the
decay phenomena. These authors were Kirk
Bryan (1888–1950) and Eliot Blackwelder
(1880–1969). Bryan and Blackwelder’s succes-
sive articles on tafoni and cavernous decay in
the southwestern United States laid the ground-
work for future research, though they contained
throughout them numerous arbitrary terms.
Pioneering empirical tafoni research, Bryan’s
1928 article ‘‘Niches and Other Cavities in
Sandstone at Chaco Canyon, New Mexico’’
introduced various terms and designations for
cavernous decay features. Suggesting larger
than average tafoni cells, Bryan defined many
of the cavities at his site as ‘‘desert niches’’
(though he also mentioned a contemporary
scholar who would have defined these larger
voids as ‘‘caves’’) and the smaller cells ‘‘nests’’
(Bryan, 1928). Additionally, Bryan labeled
intricate bands of smaller cells as ‘‘stone lace’
or ‘‘stone lattice.’’ Despite his variety of cate-
gories, Bryan acknowledged a fundamental
resemblance in forms and processes: ‘‘The holes
of stone lace have, therefore, the same origin as
the small niches which they closely resemble in
form’’ (Bryan, 1928: 137). While the main pur-
pose of Bryan’s article was to support differen-
tial physical processes producing tafoni, he also
recognized the complexity of cavernous decay
and the potential for polygeneity: ‘‘There are
many kinds of holes and cavities and many valid
means by which they may have been formed’
(Bryan, 1928: 125). Although Bryan founded
many of the underlying theories in tafoni forma-
tion, he admittedly adopted dissimilar terms to
define features of similar forms.
Conversely, Blackwelder (1929) supported a
chemical approach to cavernous decay and
added his own terminology into the mix. While
he acknowledged Bryan’s designation of ‘‘des-
ert niches,’’ Blackwelder primarily used more
general and utilitarian terminology such as
‘cavities,’’ ‘‘pockets,’’ or simply ‘‘cavernous
decay.’’ Blackwelder disagreed with Bryan’s
conclusions that the primary formation pro-
cesses behind cavernous decay were physical
and this disparity might explain his reluctance
to adopt his terminology. In fact, despite being
two of the earliest and most influential scientific
explorations of cavernous decay, neither used
any of the same designations or nomenclature.
Additionally, both Blackwelder and Bryan’s
blatant rejections of other scholars’ designa-
tions for similar forms without proposing the
establishment of a singular, universal definition
for cavernous decay features denotes a poor lack
of foresight for future studies. This inconsis-
tency resulted in an unfortunate acceptance of
personalized terminology from researcher to
researcher that is still perpetuated today.
Besides Bryan and Blackwelder, cavernous
decay research and continuity within tafoni
4Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
terminology remained scarce until the Quantita-
tive Revolution in the 1960s. The term ‘‘desert
niches’’ never really caught on and by the 1930s
designations ranged from ‘‘honeycomb weather-
ing’’ (Bartrum, 1936) to ‘‘decay pits’’ (Palmer and
Powers, 1935; Figure 2; Appendix 1). It was not
until later in the century when Penck’s and
Reusch’s term ‘‘tafoni’’ began to gain popularity
outside of Corsica.
III The quantitative revolution
and cavernous rock decay research
During the 1960s the world’s technological and
intellectual advancements opened new opportu-
nities for studying the universe’s mechanisms and
science thrived, includingrock decay science and
tafoni research. By end of 1980s, tafoni research
had been conducted across the globe in sites as
varied as Antarctica (e.g. Calkin and Cailleux,
1962; Prebble, 1967), Hong Kong (Tschang,
1974), Southern Australia (e.g. Dragovich,
1967; Winkler, 1979), Northwest Sahara (Smith,
1978), and Italy (Martini, 1978). By its own nature,
the Quantitative Revolution also prompted more
empirically based approaches to tafoni formation
hypotheses. During this era, tafoni researchers
gained a greater understanding of the roles of salt
crystallization (Bradley et al., 1978; Winkler,
1979), biochemical decay (Mustoe, 1971), and
flaking (Dragovich, 1967) connected to environ-
mental influences on rock decay rates. Contradict-
ing the historic chemical or physical standpoint as
posed by Bryan and Blackwelder, respectively,
some authors during this era suggested a more
polygenetic approach where multiple processes
could have been the source of the same landforms
(e.g. Martini, 1978).
With this surge in cavernous decay research
came an array of divergent terminology (Figure
3; Appendix 2). Part of the inconsistency that
arose during this time was due to continued dis-
agreement on what tafoni were and how they
should be defined. Jennings (1968: 1103) defined
tafoni as ‘‘forms of cavernous weathering,
chiefly found in medium and course grained, acid
to intermediate crystalline rocks, but also occur-
ring in other rocks such as sandstone, limestone,
and schist.’’ This definition was less ambiguous
than earlier suggestions, but, as tafoni research
increased, exceptions to these parameters were
discovered. Martini (1978) added another com-
ponent into the equation by trying to define both
form and process: ‘‘Tafone is a term that has
Figure 2. Diagram of prominent tafoni terminology for both form and process published from the late-1880s
through the 1930s. For brevity ‘‘Wx’’ represents ‘‘Weathering.’’ K.M. Groom.
Groom et al. 5
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
been used both to describe a landform, and to
refer to weathering conditions and processes that
lead to formation and maintenance of the mor-
phological form’’ (Martini, 1978: 46). As tafoni
literature expanded, these decay conditions and
processes became as varied as the terms used
to describe them, so attempting to define tafoni
by the host rock’s geology and decay processes
were inadequate.
This era also marked the beginning of concep-
tualizing size as a contributing factor in caver-
nous decay terminology. Larger voids were
known as ‘‘caverns’’ (Dragovich, 1967) or
‘caves’’ (Grantz, 1976), even though the decay
processes and research questions for these studies
are arguably synonymous to contemporary tafoni
research (Turkington and Paradise, 2005). Simi-
larly, the names for smaller cells ranged from
‘hollows’’ (Cailleux and Calkin, 1963) to ‘‘hon-
eycombing’’ (Mustoe, 1971). There are also sev-
eral publications that use the terms ‘‘cavernous
weathering’’ and ‘‘tafoni’’ exclusively, despite
scale, such as Bradley et al. (1978) and Wilhelmy
(1964). Although the understanding that caver-
nous decay terminology is scale dependent has
remained relatively acceptable, the thresholds at
which terms become more or less appropriate
than others are poorly defined.
The Quantitative Revolution did witness a push
for common nomenclature (e.g. Jennings, 1968;
Tschang, 1974), but to no avail. The range of sizes,
locations, and types of cells prompted scholars to
create more ambiguous adjectives or classifica-
tion systems, yet very few seemed to catch on for
any significant amount of time. For example,
Tschang (1974) attempted to create different
classes and subclasses of tafoni based on their
shape and location on the stone surface. His main
classes included miniature tafoni, side tafoni,
basal tafoni, horn tafoni, and pseudotafoni. These
classes were then divided into sub-categories by
formation directions and processes: horizontal
extension type, curved extension type, vertical
extension type, oblique extension type, lotus petal
type, mixed type, ruined type, and a miscellaneous
type for cells that did not fit into any of the other
subclasses (Tschang, 1974). Representing an
acknowledged need for an overarching terminol-
ogy, Tschang’s distinctions appear to be relatively
arbitrary and unnecessarily complicated.
IV Modern scientific discoveries
and tafoni terminology
With even more advances in technology and sci-
entific exploration, tafoni research continued
Figure 3. Diagram of prominent tafoni terminology for both form and process published from the 1960s
through the 1970s. For brevity ‘‘Wx’’ represents ‘‘Weathering.’’ K.M. Groom.
6Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
expanding from the 1980s to the present, both
geographically and evolutionarily. By the end
of the 20th century, cavernous decay studies
had extended regionally to include Japan (e.g.
Matsurkura et al., 1989; Suzuki and Hachinohe,
1995), the United Kingdom (Pye and Motters-
head, 1995), Spain (e.g. Mellor et al. 1997;
Sancho and Benito, 1990), Scotland and South-
ern Greece (Kelletat, 1980), Northern Ireland
(McGreevy, 1985), Finland (Kejonen et al.,
1988), and even Mars (Rodriguez-Navarro,
1998). Continued research also emerged from
previously researched locales such as Antarctica
(e.g. Conca and Astor, 1987), throughout the
United States (e.g. Butler and Mount, 1986), and
Australia (e.g. Twidale and Sved, 1978). The
regional scope of cavernous decay studies con-
tinues to expand through the 21st century to
include South Africa (Mol and Viles, 2010), Jor-
dan (Paradise 2013a ; Viles and Goudie, 2004),
and Southern India (Achyuthan et al., 2010).
Formation hypotheses and foci of study are
still greatly varied during this era— though the
roles of salt and moisture have become common
themes. Previous research has shown that acceler-
ated cell growth can be tied to intensified rates of
salt crystal accumulation and movement, which,
in turn, have been associated with multiple extrin-
sic variables such as higher evaporation rates for
perpendicular surfaces to dominant wind direc-
tion (Rodriguez-Navarro et al., 1999) and crystal-
line salts and calcites deposition and migration
via precipitation (McBride and Picard, 2000). In
addition, the salts in themselves can act as decay
catalysts (Young, 1987), for example through
repeated and extended drying and wetting cycles
(Huinink et al., 2004). A general pattern emerges
from these studies: a particular climatic variable
influences the accumulation or evaporation of
moisture, which then determines the rate of salt
crystallization promoting tafoni evolution, often
intensified when combined with high porosity
and permeability (McBride and Picard, 2004).
Surface and sub-surface moisture, acknowledged
variables in mechanical rock decay, were
associated with cell development through trans-
porting salts and other dissolved minerals (e.g.
Mustoe, 1983) as well as destabilizing pressure
fluctuations through internal water movement
and expansion (e.g. Conca and Astor, 1987).
Water circulation, autonomous from salt accumu-
lation, was also directly correlated with several
hydro-geomorphological processes leading to
cavernous decay features such as ice micro frac-
tures (French and Guglielmin, 2000; Kejonen
et al., 1988) and joint-determined moisture pat-
terns (Conca and Astor, 1987). Mol and Viles
(2010) related higher internal moisture content
with reduced stone hardness and elevated rates
of decay. They later employed similar methods
to assess moisture in tafoni cells and comparable
processes seem to effect cell development (i.e.
higher moisture ¼greater cell growth, see Mol
and Viles, 2012).
Yet for all the advances, terminology and
cavernous decay labels have remained inconsis-
tent during this time (Figure 4; Appendix 3).
Popularized by Mustoe (1983), terms such as
‘honeycombing,’’ ‘‘stone lace,’’ ‘‘alveolar
weathering,’’ and ‘‘fretting’’ began to appear
interchangeably in cavernous decay research.
The distinction provided by Mustoe (1983) was
that tafoni were ‘‘large cavities [that] may reach
diameters of several meters’’ (Mustoe, 1983:
517) and the rest of these terms describe ‘‘pat-
terns consisting of many small cavities’’ (Mus-
toe, 1983: 517). This arbitrary separation has
been perpetuated through countless citations,
and many articles have adopted the term ‘‘hon-
eycombing’’ in their titles (e.g. Andre and Hall,
2005; Butler and Mount, 1986; Rodriguez-
Navarro et al., 1999). However, not all tafoni
literature accepted Mustoe’s varied terms and
definitions, as exemplified by Pestrong (1988):
‘No such distinction is made in this paper, how-
ever, for sufficient similarities in formation
mechanisms appear to exist’’ (Pestrong, 1988:
1049).
Much of the current literature admits caver-
nous decay is widely varied in geographies,
Groom et al. 7
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
geologies, and decay processes, but, unfortu-
nately, terminology has become a widely
ignored issue. In their exploratory article,
Brandmeier et al. (2010) examined the history
of tafoni and discussed new challenges and
unanswered questions for future research.
Among many pertinent statements on the condi-
tion of cavernous decay research is a comment
given in passing, but speaking volumes: ‘‘the
term is not strictly defined in the literature’’
(Brandmeier et al., 2010: 839 ). In other words,
this article tackled the history and formation
hypotheses for decay features with little concern
that they still lack a universal definition. Unfor-
tunately, this kind of treatment towards the sta-
tus of tafoni terminology is not uncommon in
modern literature. Siedel (2010), used ‘‘alveoli,’
‘pits,’’ and ‘‘honeycombs’’ interchangeably
even after recognizing the existence of ‘‘some
terminological confusion in the use of ‘alveo-
lar’ or ‘honeycomb weathering’’’ (Siedel,
2010: 12). Other abstracts and introductions
from numerous publications include state-
ments such as ‘‘a multitude of terms have been
used to describe such features’’ (McBride and
Picard, 2000: 869) or ‘‘the nomenclature for
pitted and cavernous weathering was not har-
monized throughout most of the twentieth
century’’ (Norwick and Dexter, 2002), but no
such study explicitly calls for a unified lexicon.
The latter example cited Sunamura (1996) as
the official foundation of using ‘‘tafoni’’ as a
non-scalar term, but the exact passage cited was
simply a disclaimer for that particular study:
‘These two cavernous forms are, however, col-
lectively called ‘tafoni’ in this paper, unless oth-
erwise stated’’ (Sunamura, 1996: 741). Despite
some confusion within the scientific community,
there are scholars who are actively trying to
define tafoni through further research of their for-
mation processes—such as Owen’s (2013)
research on pseudokarstic tafoni in the Baha-
mas—as a possible avenue for tafoni definition,
or through literary reviews, such as this manu-
script and Un
˜a Alvarez’s (2008) terminological
examination of granite tafoni nomenclature.
V Defining tafoni: Finding
a terminological solution
Perhaps the irregular use of terminology through-
out the history of cavernous decay research has
deeper epistemological and ontological roots.
Indeed, The Scientific Nature of Geomorphol-
ogy (Rhoads and Thorn, 1996) discusses at
length the philosophy behind geomorphology
Figure 4. Diagram of prominent tafoni terminology for both form and process published from the 1980s to
current. For brevity ‘‘Wx’’ represents ‘‘Weathering.’’ K.M. Groom.
8Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
as a discipline, yet barely touches on naming
conventions even though landform literature
remains littered with terminological ambiguity.
A few decades ago, Haines-Young and Petch
(1983) put forth a geomorphologically example-
rich study associated with the concept of equifin-
ality and its relationship to Chamberlin’s (1890)
theory of multiple working hypotheses, noting the
use of method and process for landform naming
might actually generate more vagaries. Two
decades later, Smith and Mark (2003) provoca-
tively questioned whether mountains even exist.
Their argument, bolstered by an ontological con-
text (what a mountain is), supports the notion that
the form itself (the mountain) is what gives it
meaning, not necessarily the process(es) that cre-
ated it. More recently, Brierley et al. (2011: 1981)
remind geomorphologists that, while official
bodies exist for naming places, geological time
periods, and biological species,
no formal procedures have been established for land-
scape types. In geomorphology, an inevitable outcome
of this local naming process is that overlapping or iden-
tical features are given names in different languages
(e.g. terms such as kamenitza, vasque, pia, Opferkessel
and gnamma all describe small pans in rock surfaces).
Some of these ontological and philosophical
dilemmas have translated from a wider geomor-
phological context into cavernous rock decay
research, furthering terminological disagreement
through a series of unaddressed inconsistencies:
azonality, polygenetic processes, size variance,
and lithological constraints—each of which would
benefit from collaborative terminology.
1 Azonal distribution
One major variance within tafoni development
research and, as an extension, tafoni terminol-
ogy is the diverse geographic, geologic, and
environmental contexts in which they can be
found (Figure 5). As demonstrated in this review,
cavernous decay features have been observed
worldwide in environments ranging from coasts
(e.g. Suzuki and Hachinohe, 1995) and river
basins (e.g. Sancho and Benito, 1990) to sub-
zero deserts (e.g. Selby, 1971) and other dryland
regions (e.g. Wilhelmy, 1964). The variety of
landscapes accommodating tafoni development,
both physical and climatological, discourages
assuming any single evolution hypothesis as the
primary cause for all cavernous decay (and
source of terminology), but, instead, insinuates
Figure 5. World map showing the diverse geographical settings of documented tafoni research in English,
French, German, and/or Italian languages since 1840. Icons separated by color to indicate researched
lithology. T.R. Paradise.
Groom et al. 9
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
a multifaceted connection between polygenetic
formation processes and geographic setting,
geology, and climate (Inkpen and Jackson,
2000). Paradise (2013b ) demonstrates this
variance in cavernous decay mechanisms by
emphasizing the interconnectedness of princi-
ple decay processes to lithological and envi-
ronmental settings—discouraging any kind of
terminology based on setting alone.
In addition, the spatial breadth of tafoni and
cavernous features has also hindered international
collaboration through poor dissemination and
language barriers, especially in the earlier litera-
ture. To avoid ambiguous nomenclature, scholars
may be tempted to employ simple and utilitarian
terms such as ‘‘void’’ or ‘‘hollow’’ (as seen in
Blackwelder, 1929) or even ‘‘cavernous fea-
tures,’’ but such terms would vary linguistically
and would not bridge the language barrier, leaving
the research isolated from the international scien-
tific compendium (e.g. De Prado, 1864). There-
fore, a universal term—valid in all languages,
locales, and environments – would provide the
continuity necessary for further global research.
2 Polygeneity and process
Notwithstanding substantial academic atten-
tion, scientific understanding of the principal
driving mechanisms for cavernous decay remains
yet to be discovered. Throughout the history
of tafoni research, numerous postulations have
been offered ranging from the physical (e.g.
Mottershead and Pye, 1994) versus chemical
(e.g. Campbell, 1999) process dichotomy begun
by Blackwelder and Bryan, to biological decay
influences (Andre and Hall, 2005; Mol and
Viles, 2012), to some unidentifiable mix of all
three (Martini, 1978). Pope et al. (1995: 38)
appropriately portrayed the complexity of decay
processes in the terms of ‘‘synergy’’ by saying,
‘variability in weathering [rock decay] involves
synergistic interactions of biological, chemical,
and physical factors.’’ For tafoni, the mere exis-
tence of so many different supported formation
theories supports the concept of polygeneity—
where a single form can be the result of a multi-
tude of processes (Dorn et al., 2012).
Cavernous decay research has only recently
incorporated multifaceted approaches to cell evo-
lution (Brandmeier et al., 2010; Turkington and
Phillips, 2004). In a recent textbook, Paradise
(2013b: 112 ) embraced the polygenetic com-
plexity and defined tafoni as ‘lace-like, honey-
comb, bowl, or pan-shaped cavities occurring in
a variety of rock types and locations that show a
commonly unique assemblage and morphology.’’
This definition took a different approach than pre-
vious endeavors in that it excluded exact forma-
tion processes all together. As tafoni research
expands, there is increasing recognition that
tafoni are, in fact, polygenetic and actually the
result of multiple, if not simultaneous, decay
processes varying case to case (e.g. Achyuthan
et al., 2010; Brandmeier et al., 2010; Mol and
Viles, 2012). It is, then, not difficult to under-
stand how a multifaceted and polygenetic
decay feature such as tafoni could accumulate
such a diverse assortment of names despite shar-
ing analogous characteristics. Perhaps appropri-
ate terminology can only be reflective of the
form, discarding the process, in cases when the
forms are homogeneous but the formative pro-
cesses are not? But are the forms the same? Obser-
vationally, regardless of formation processes,
location, and lithology, all cavernous features share
a universal progression: intense localized differen-
tial decay and removal of decayed material leaving
a hollowed surface (Achyuthan et al., 2010; Figure
6). It could be argued, then, that the variety in tafoni
appearances are dependent on location, lithology,
and environment—not individual processes—and
therefore an umbrella term for these features
completely disassociated from process would
provide greater inter-study communication.
3 Size
Another inconsistency impacting ambiguity
in tafoni science has been the long-standing
10 Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
assumption that cell size can be used as the qua-
lifying feature to define lexicon. While many
scholars adopted the concept of scale-dependent
terminology, the exact thresholds at which size
distinguishes one term from another are subjec-
tive and arbitrary. This has resulted in various
studies employing different designations for cells
of the same size, thus completely defeating the
purpose of threshold terminology. Exemplifying
this discourse, contemporary studies such as
Andre and Hall (2005), Paradise (2013a), and
McBride and Picard (2004) each assessed caver-
nous features 1–4 cm in diameter, but use differ-
ent terms (Figure 7). The notion that size
justifies differential terminology is not only
difficult to moderate without definitive thresh-
olds, but also cognitively separates features that
could otherwise be assessed homogeneously—
thus limiting further scientific exploration.
So why has a more rigorous threshold defini-
tion system for cavernous features not yet been
established? A primary issue with this solution
is that, in many cases, decay rates, shapes, and
sizes of tafoni are largely a function of lithology
so not all cells will follow the same formation
patterns (Hall et al., 2012), rendering a universal
size-based categorization useless. Additionally,
the concept of grouping terminology by size—
or any single characteristic—is also restrictively
simplistic. Scholars may inadvertently end up
grouping together several-millennium old sand-
stone cells in a weathering-limited desert environ-
ment with century old tropical limestone cells
simply because they appear to be the same size.
To offer a medical analogy, this would be congru-
ent with naming a similar disease by different
names depending on the height of the patient.
What information might the doctors be missing
by not collaborating with each other?
4 Lithological restraints
Lithology, the last inconsistency, accounts for
much of the variability in both size and process,
but is rarely addressed beyond identification.
The working relationship between intrinsic
(internal) and extrinsic (external) influences
on rock decay and geomorphology has been
explored for decades. GK Gilbert (1843–1918)
described landscape change as a ratio between
sheer strength and sheer stress quoting ‘‘solidity
is not absolute but relative’’ (Gilbert and
Dutton, 1880: 91). This notion can be easily
adaptable to rock decay with ‘‘sheer strength’
signifying intrinsic variables (e.g. mineralogy
or lithification) and ‘‘sheer stress’’ denoting
extrinsic variables (e.g. climate or anthropo-
genic activity). Both variables affect cavernous
decay, but have been historically researched
separately with significantly more attention
given to exogenetic (external) influences. The
irony in this is that lithology has an intense
influence on the extent and methods of decay
(Hall et al., 2012)—including the distribution
and morphometry of cavernous features (e.g.
Conca and Rossman, 1985) explaining the vari-
ety of cell shapes and appearances.
With that in mind, the variety of substrates on
which tafoni can be found is astonishing. Caver-
nous decay features have been documented on
a multitude of lithologies including volcanic
tuff (e.g. McBride and Picard, 2000), intrusive
granite and gneiss (e.g. Dragovich, 1967), vari-
ous sandstones (e.g. Grantz, 1976), limestone
(e.g. Rodriguez-Navarro et al., 1999), slightly
metamorphosed conglomerate (Martini, 1978),
and even manufactured materials such as con-
crete (Pestrong, 1988; Figure 8). The fact that
Figure 6. Cross section diagram showing a general-
ized progression of tafoni development. T.R. Paradise.
Groom et al. 11
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
so many different rock types, with all of their
inherent constraints on decay processes, can sup-
port the development of cavernous features
demonstrates a profound continuity despite vary-
ing geologic settings that have been obstructed
by ambiguous terminology. Ultimately, caver-
nous features are highly complicated with multi-
ple constraints—none of which are suitable to
singularly define terminology.
VI Discussion and conclusions
With cavernous decay features presenting
themselves in so many different locations,
lithologies, and appearances, scholars are left
with the question: do the different terms exist
for a reason? Are these features truly indepen-
dent of each other and necessitate discrete
terminology? The purpose of this article is to
challenge previously held perceptions of sepa-
rateness where it might not exist. As this paper
vigorously argues, all cavernous decay features
follow the same basic progression: localized
differential decay and subsequent removal that
leaves a hollowed surface (Achyuthan et al.,
2010). Turkington and Phillips (2004) describe
cavernous decay in terms of self-organization
and feed-back processes within the rock decay
system. This approach is applicable to all forms
of cavernous decay regardless of which terminol-
ogy is preferred. Unifying the terminology will
most likely encourage alternate ways of thinking
that can eventually lead to more process-focused
investigations between what have been histori-
cally perceived as separate forms, potentially
resulting in new and important understandings.
Figure 7. Examples of scalar discrepancies in modern tafoni literature. A: Andre and Hall (2004), B: Paradise
(2013a), C: McBride and Picard (2004).
Figure 8. Tafoni development in various lithologies. Locations from left to right: Colorado National
Monument, CO; Bean Hollow State Beach, CA: Wupatki National Monument, AZ; Bean Hollow State Beach,
CA; and Eastern Slope Yosemite National Park, CA. Photographs by T.R. Paradise.
12 Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
Obviously, appearances are not perfectly identi-
cal, but the fact that so many similarities exist
despite the incredible variations in setting, cli-
mate, and lithology warrants more cohesive
research—a unity that would be enhanced
through shared terminology.
This review demonstrates how the inconsis-
tency of tafoni terminology has limited intuitive
scientific collaboration and hindered the ability
of any scholar, novice or expert to research tafoni
and cavernous decay holistically. Researchers
interested in the formation of cavernous features
must search each term individually to gain a uni-
versal view of existing literature using any num-
ber of prevalent academic search engines, such
as Google Scholaror other online library
achieves. A query for ‘‘tafoni’’ only surfaces a
fraction of existing relevant research. An addi-
tional search for ‘‘honeycombing’’ might add
more references, but this is still an incomplete
representation of the existent literature. Exempli-
fying this disconnect, Honeyborne (1998) outlines
some major effects of ‘‘alveolar’’ decay on
masonry deterioration (an important, but under-
researched, application of tafoni science), but is
absent from any research query for either ‘‘tafoni’
or ‘honeycomb weathering.’’ In a recent cry
for common terminology, Un
˜a Alvarez (2008)
describes some issues surrounding confused
tafoni terminology: ‘‘The situation can generate
a conceptual and a categorical uncertainty in the
knowledge of the cavernous granite forms’’ (Un
˜a
Alvarez, 2008: 65). As insinuated by the quote,
Un
˜a Alvarez (2008) focused on granite fea-
tures— a, perhaps, self-defeating constraint. As
illustrated by the various inconsistencies of tafoni
research, if an established terminology is to be
appropriate, it must be devoid of any locational,
process, size, and lithological limitations.
Therefore, we support ‘‘tafoni’’ (singular:
tafone) as an overarching designation for
cavernous features. The etymological origin of
‘tafoni’’ to define cavernous features is unspeci-
fied, but is thought to have substantial Mediterra-
nean influence (Paradise, 2013b )—representing
a significant provenance in the pioneering of
cavernous decay science. One proposed origin
of the term stems from the Greek word taphos
meaning tomb or sepulcher (Battisti and Alessio
(1957) in Trenhaile, 1992). Other sources suggest
the Corsican (French) word, taffoni, meaning
windows, or tafonare meaning to perforate
(Wilhelmy, 1964). In Sicilian, tafoni means win-
dows (Goudie, 2003). Ontologically, Brierley
et al. (2011: 1981) point out that ‘‘there are some
informal precedents in which locality names have
become more widely used,’’ such as ‘‘karst’’ –
from the Kars Plateau in Slovenia where karst
research was founded (Bezlaj, 1982). So while
the ‘‘locality’’ of cavernous features is global, it
would not be without precedence to adopt a
universal term with a regional origin—i.e. the
mostly-Mediterranean term, ‘‘tafoni.’
‘Tafoni’’ is nominated not only because of
its global recognition and already popular use,
but also because it bypasses many of the termi-
nological inconsistencies found in the literature.
Geographically, tafoni is non language-specific
and, therefore, unaffected by translations so it
can remain constant in international publication
venues, further promoting more successful
global dissemination. Purely descriptive or
observational terminology such as cavernous
features, hollows, or cells would be lost in trans-
lation. In terms of polygeneity, tafoni are the
result of both decay and erosion, so any defini-
tive terms based solely on decay processes, such
as honeycomb weathering, tafone weathering,
alveolar weathering, or even cavernous weath-
ering/decay, are inadequate as they only
acknowledge half of the process necessary for
tafoni to exist. Tafoni is also a non-scalar term
that could be comfortably applied to cells
spanning a few millimeters to several meters
in diameter. This cannot be said of other
terms historically used to describe cavernous
features, such as alveoli or honeycombing, which
carry significant scalar baggage. Additionally,
tafoni is not restricted to any one lithology
or geologic context, unlike terms such as
Groom et al. 13
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
‘pitting’’—which is most commonly associated
with limestone or karst landscapes. Ultimately,
the term tafoni provides necessary terminological
continuity within cavernous decay science with-
out being limited by its own definition.
Science is a dynamic and adaptive process—
as scientists and researchers should be in our
search for knowledge. The terminology we use
reflects upon how we think (Hall et al., 2012),
for, as the Scottish philosopher Thomas Reid so
eloquently stated, ‘‘There is no greater impedi-
ment to the advancement of knowledge than the
ambiguity of words’’ (Reid, 1850: 1). In short,
then, as science delves deeper into rock decay
science, a common vernacularcan enhance colle-
gial endeavors and promote an alternative frame-
work no longer hampered by ambiguity. An
example of such a transition is the shift from
‘weathering,’’ which was often cognitively
associated to ‘‘weather’’ and environmental
factors, to ‘‘rock decay,’’ which encompasses
the myriad of internal and external influences
known to exist (Dorn et al. 2013; Hall et al.,
2012). Similarly, adopting a standard nomen-
clature provides scholars with the universal
lexicon vital to collectively promoting tafoni
research worldwide.
Once consensus can be reached on terminol-
ogy, scientists will be able to investigate incon-
sistencies in methodology, as well as address
the schools of thought that favor, variously, salt,
climate, and lithology as determining factors
in cavernous decay feature development. As it
stands, the majority of this research’s current
inconsistencies make it difficult to directly com-
pare process and form of features variously
labeled as ‘‘alveoli,’’ ‘‘tafoni,’’ and ‘‘pitting’
when, in addition to terminological diversity,
these have been investigated using differing
methods and field sites. Certainly, more research
is necessary to determine the exact constraints
and causes for the various appearances of tafoni,
but, as argued here, the collaborative benefits of
researching a singular form, tafoni, vastly out-
weighs the benefits of keeping each cognitively
separate. There is little denial that cavernous fea-
tures are complicated, which is why the push for
scientific consistency and terminological conti-
nuity is critical to ensure the effectiveness of glo-
bal research collaboration today and in the future.
Appendices
Appendix 1. Table of authors and tafoni terminology used most organized by date from
1800 to 1959
Dominant cavernous decay terminology, late-1800s to 1930s
Author(s) Year published Terms used
HH Reusch 1882 tafoni
FW Simonds 1888 nests, caves
A Penck 1894 tafoni
WF Hume 1925 choir stall weathering
K Bryan 1928 desert niches, niches, stone lace
E Blackwelder 1929 cavities, pockets, cavernous decay
HS Palmer and HA Powers 1935 pits
JB Mackie 1935 honeycomb weathering
JA Bartrum 1936 honeycomb weathering
14 Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
Appendix 2. Table of authors and tafoni terminology used most organized by date from
1960 to 1979
Appendix 3. Table of authors and tafoni terminology used most organized by date from
the1980 s to current
Dominant cavernous decay terminology, 1960s to 1970s
Author(s)
Year
published Terms used
P Calkin and A Cailleux 1962 cavernous weathering, taffonis
A Cailleux and P Calkin 1963 hollows, cavernous weathering
H Wilhelmy 1964 tafoni, hollows, cavernous rock surfaces
GT Bowra et al. 1966 honeycomb weathering
D Dragovich 1967 hollows, caverns, cavernous surfaces
JN Jennings 1968 tafoni, hollows
ED Gill 1972 honeycomb, cellular weathering
H Tschang 1974 lateral tafoni, basal tafoni, pseudo-tafoni, subordinate tafoni,
relic tafoni
PHo
¨llermann 1975 cavernous rock surfaces, tafoni
DA Robinson and RBG
Williams
1976 honeycomb hollows, honeycombing
WC Bradley et al. 1978 tafoni, basal tafoni, sidewall tafoni
IP Martini 1978 tafoni, alveoli, honeycomb weathering
Dominant cavernous decay terminology, 1980s to current
Author(s) Year published Terms used
D Kelletat 1980 honeycombs, tafoni, cavernous weathering
ED Gill 1981 tafoni, honeycomb weathering
GE Mustoe 1983 tafoni, honeycomb weathering
JP McGreevy 1985 honeycomb weathering
PR Butler and JF Mount 1986 honeycomb weathering, corrosion pits
ARM Young 1987 caverns, cavernous weathering
JL Conca and AM Astor 1987 cavernous weathering
R Pestrong 1988 tafoni
A Kejonen et al. 1988 tafoni, cavernous weathering
C Sancho and G Benito 1990 tafoni weathering, tafonis
Y Matsukura and N Matsuoka 1991 tafoni weathering, tafoni
A Mellor et al. 1997 tafoni, hollows, cavernous weathering
C Rodriguez-Navarro et al. 1999 honeycomb weathering
SW Campbell 1999 tafoni, alveolar weathering
HM French and M Guglielmin 2000 tafoni, cavernous weathering
(continued)
Groom et al. 15
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest
with respect to the research, authorship, and/or pub-
lication of this article.
Funding
The authors received no financial support for the
research, authorship, and/or publication of this article.
References
Achyuthan H, Kumar KA, Tiwari SK, et al. (2010) A
reconnaissance study of tafoni development, exfolia-
tion, and granular disintegration of natural and artificial
rock surfaces in the coastal and lowland regions of
Tamil Nadu, southern India. Zeitschrift fur Geomor-
phologie 54(4): 491–509.
Andre MF and Hall K (2005) Honeycomb development on
Alexander Island, glacial history of George VI sound
and palaeoclimatic implications (Two Step Cliffs/Mars
Oasis, W Antarctica). Geomorphology 65(1): 117–138.
Barnes T (2009) Quantitative Revolution (geography of).
In: Kitchin R and Thrifts N (eds) The International
Encyclopaedia of Human Geography. Oxford: Else-
vier, 33–38.
Bartrum JA (1936) Honeycomb weathering of rocks near
the shore-line. The New Zealand Journal of Science
and Technology 18(1): 593–600.
Berthling I (2011) Beyond confusion: Rock glaciers as
cryo-conditioned landforms. Geomorphology 131(3):
98–106.
Bezlaj France (1982) Etimoloˇ
ski slovar slovenskega jezika,
vol. 2. K–O. Ljubljana: SAZU, 82.
Blackwelder E (1929) Cavernous rock surfaces of the
desert. American Journal of Science 17(1): 393–399.
Bowra GT, Holdgate MW and Tilbrook PJ (1966)
Biological investigations in Tottanfjella and central
Heimefrontfjella. British Antarctic Survey Bulletin 9:
63–70.
Boxerman JZ (2005) The evolutionary cycle of the tafone
weathering pattern on sandstone at Bean Hollow Beach,
northern California. Geological Society of America
Sectional Meeting. Abstract. Salt Lake City, UT.
Bracken LJ and Wainwright J (2006) Geomorphologic
equilibrium: Myth and metaphor? Transactions of the
Institute of British Geographers 31(2): 167–178.
Bradley WC, Hutton JT and Twidale CR (1978) Role of
salts in development of granitic tafoni, south Australia.
Journal of Geology 86(5): 647–654.
Brandmeier M, Kuhlemann J, Krumrei I, et al. (2010) New
challenges for tafoni research: A new approach to
understand processes and weathering rates. Earth
Surface Processes and Landforms 36(6): 839–852.
Brierley G, Huang HQ, Chen A, et al. (2011) Naming
conventions in geomorphology: Contributions and
controversies in the sandstone landscape of Zhangjiajie
Geopark, China. Earth Surface Processes and Land-
forms 36(14): 1981–1984.
Bryan K (1928) Niches and other cavities in sandstone at
Chaco Canyon, New Mexico. Zeitschrift fuer Geo-
morphologie 3(1):125–140.
Appendix 3. (continued)
Dominant cavernous decay terminology, 1980s to current
Author(s) Year published Terms used
SA Norwick and LR Dexter 2002 tafoni
HP Huinink et al. 2004 tafoni, honeycomb weathering
EF McBride and MD Picard 2004 honeycomb cells, aberrant honeycombs
MF Andre and K Hall 2005 honeycombs, tafonis, alveolar weathering
AV Turkington and JD Phillips 2004 caverns, cavernous weathering
JZ Boxerman 2005 tafoni, tafone weathering
E Hejl 2005 tafoni, cavernous weathering, tafoni weathering
H Achyuthan et al. 2010 tafoni, pits
MJ Brandmeier et al. 2010 tafone weathering, tafoni
T Sunamura and H Aoki 2011 tafoni, honeycomb weathering
L Mol and HA Viles 2012 caverns, alveoli, tafoni
TR Paradise 2013a, b tafoni, honeycomb weathering
16 Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
Burton I (1963) The quantitative revolution and theore-
tical geography. The Canadian Geographer 7(4):
151–162.
Butler PR and Mount JF (1986) Corroded cobbles in
southern Death Valley: Their relationship to honeycomb
weathering and lake shorelines. Earth Surface Processes
and Landforms 11(4): 377–387.
Cailleux A and Calkin P (1963) Orientation of Hollows
in Cavernously Weathered Boulders in Antarctica:
Biuletyn Peryglacjalny, 12: 147–150.
Calkin P and Cailleux A (1962) A quantitative study of
cavernous weathering (taffonis) and its application to
glacial chronology in Victoria Valley, Antarctica.
Zeitschrift fuer Geomorphologie 6(1): 317–324.
Campbell SW (1999) Chemical weathering associate with
tafoni at Papago Park, central Arizona. Earth Surface
Processes and Landforms 24(3): 271–278.
Chamberlin TC (1890) The method of multiple working
hypotheses. Science 15(92): 281–293.
Conca JL and Astor AM (1987) Capillary moisture flow
and the origin of cavernous weathering in dolerites of
Bull Pass, Antarctica. Geology 15(2): 151–154.
Conca JL and Rossman GR (1985) Core softening in
cavernously weathered tonalite. Journal of Geology
93(1): 59–73.
Dana JD (1849) Manual of Geology. 1st ed. New York,
NY: Ivison, Blakeman, Taylor and Company.
Darwin C (1839) The Voyage of the Beagle. New York,
NY: Collier and Son Company.
De Prado C (1864) Descripcio´n fı´sica y geolo´gica de la
provincia de Madrid. Col. Ciencias, Humanidades e
Ingenierı
´
a2: 60–76.
Dorn RI, Dorn J, Harrison E, et al. (2012) Case hardening
vignettes from the western USA: Convergence of form
from a divergence of hardening processes. Association
of Pacific Coast Geographers Yearbook 74: 1–12.
Dorn RI, Gordon SJ, Allen CD, et al. (2013) The role of
fieldwork in rock-decay research: Case studies from the
fringe. Geomorphology 200: 59–74.
Dragovich D (1967) The origin of cavernous surfaces
(tafoni) in granitic rocks of southern South Australia.
Zeitschrift fuer Geomorphologie 13(2): 163–181.
French HM and Guglielmin M (2000) Cryogenic weath-
ering of granite, northern Victoria land, Antarctica.
Permafrost and Periglacial Processes 11(4): 305–314.
Gilbert GK and Dutton CE (1880) Report on the Geology of
the Henry Mountains. US Government Printing Office:
Washington, DC.
Gill ED (1972) The relationship of present shore plat-
forms to past sea levels. Boreas 1(1): 1–25.
Gill ED (1981) Rapid Honeycomb Weathering (Tafoni
Formation) in Greywacke, S.E. Australia: Earth Sur-
faces Processes and Landforms, 6: 81–83.
Goudie A (2003) Encyclopedia of Geomorphology. Lon-
don: Routledge, 1200.
Grantz A (1976) Sandstone Caves (tafoni) in the Central
Santa Cruz Mountains, San Mateo County. Sacramento,
CA: California Division of Mines and Geology, 51–54.
Haines-Young RH and Petch JR (1983) Multiple working
hypotheses: Equifinality and the study of landforms.
Transactions of the British Institute of Geographers
8(4): 458–466.
Hall K, Thorn C and Sumner P (2012) On the persistence
of ‘‘weathering’’. Geomorphology 149: 1–10.
Hejl E (2005) A pictorial study of Tafoni development
from the 2nd Millennium BC. Geomorphology 64:
87–95.
Ho¨llermann P (1975) Formen kaverno¨ ser Verwitterung
(‘‘Tafoni’’) auf Teneriffa. Catena 2: 385–409.
Honeyborne DB (1998) Weathering and decay of masonry.
Conservation of Building and Decorative Stone 1:
153–184.
Huinink HP, Pel L and Kopinga K (2004) Simulating the
growth of tafoni. Earth Surface Processes and Land-
forms 29(10): 1225–1233.
Hume WF (1925) Geology of Egypt. Egyptian Geological
Survey: Cairo. 73.
Inkpen RJ and Jackson J (2000) Contrasting weathering
rates in coastal, urban, and rural areas in southern Brit-
ain: Preliminary investigations using gravestones. Earth
Surface Processes and Landforms 25(3): 229–238.
Jennings JN (1968) TAFONI, tafone, taffoni Tafoni.
In: Fairbridge RW (ed) Geomorphology. Heidelberg:
Springer Berlin, 1103–1104.
Kejonen A, Kielosto S and Lahti SI (1988) Cavernous
weathering forms in Finland. Geografiska Annaler
70A: 315–322.
Kelletat D (1980) Studies on the age of honeycombs and
tafoni features. Catena 7(4): 317–325.
Livingstone DN (1992) Statistics don’t bleed: Quantifi-
cation and its detractors. In: Livingstone DN (ed) The
Geographical Tradition: Episodes in the history of a
contested enterprise. Oxford, UK: Blackwell, 304–346.
Mackie JB (1935) The geology of the Glenomaru survey
district, Otago, New Zealand. Transactions of the Royal
Society of New Zealand 64: 275–302.
Groom et al. 17
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
McBride EF and Picard MD (2000) Origin of development
of tafoni inTunnel Spring Tuff, Crystal Peak, Utah, USA.
Earth Surface Processes and Landforms 25: 869–879.
McBride EF and Picard MD (2004) Origin of honeycomb
and related weather forms in Oligocene Macigno
sandstone, Tuscan coast near Livorno, Italy. Earth
Surface Processes and Landforms 29: 713–735.
McGreevy JP (1985) A preliminary scanning electron
microscope study of honeycomb weathering sandstone
in a coastal environment. Earth Surfaces Processes and
Landforms 10: 509–518.
Martini IP (1978) Tafoni weathering, with examples from
Tuscany, Italy. Zeitschrift fur Geomorphologie 22(1):
44–67.
Matsukura Y and Matsouka N (1991) Rates of Tafoni
Weathering on Uplifted Shore Platforms in Nojima-
Zaki, Boso Peninsula, Japan: Earth Surfaces Processes
and Landforms, 16: 51–56.
Matsurkura Y, Matsuoka N and Yano N (1989) A pre-
liminary study on tafoni and honeycombs in Nojima-
Zaki, Boso Peninsula, Japan. Annual Report. Institute
of Geoscience, University of Tsukuba 25: 29–32.
Mellor A, Short J and Kirkby SJ (1997) Tafoni in the El
Chorro area, Andalucı´a, southern Spain. Earth Surfaces
Processes and Landforms 22: 817–833.
Mol L and Viles HA (2010) Geoelectric investigations into
sandstone moisture regimes: Implications for rock weath-
ering and the deterioration of san rock art in the Golden
Gate reserve, South Africa. Geomorphology 118: 280–287.
Mol L and Viles HA (2012) The role of rock surface hardness
and internalmoisture in tafoni development in sandstone.
Earth Surface Processes and Landforms 37: 301–314.
Mottershead DN and Pye K (1994) Tafoni on coastal
slopes, south Devon, UK. Earth Surfaces Processes
and Landforms 19: 543–563.
Mustoe GE (1971) Biochemical Origin of Coastal
Weathering Features in the Chuckanut Formation of
Northwest Washington. Washington State: Western
Washington State College, 1–85.
Mustoe GE (1983) Origin of honeycomb weathering. GSA
Bulletin 93: 108–115.
Norwick SA and Dexter LR (2002) Rates of development of
tafoni in the moekopi and kaibab formations in meteor
crater and on the Colorado plateau,northeastern Arizona.
Earth Surface Processes and Landforms 27: 11–27.
Owen AM (2013) Tafoni development in the Bahamas.
In: Lace MJ and Mylroie JE (eds) Coastal Karst
Landforms. The Netherlands: Springer, 177–205.
Palmer HS and Powers HA (1935) Pits in coastal pahoehoe
lavas controlled by gas bubbles. Journal of Geology
43(6): 639–643.
Paradise TR (2013a) Assessment of tafoni distribution and
environmental factors on a sandstone djinn block above
Petra, Jordan. Applied Geography 42: 176–185.
Paradise TR (2013b) Tafoni and other rock basins. In:
Shroder JF (ed) Treatise on Geomorphology, Vol 4. San
Diego, USA: Elsevier, 111–126.
Penck A (1894) Morphologie der Erdoberflache, trans-
lated by Englehorn John (ed). Verlag: Stuttgart,
Germany.
Pestrong R (1988) Tafoni weathering of old structures
along the northern California coast, USA. In: Marinos
PG and Koukis GC (eds) Engineering Geology of
Ancient Works, Monuments, and Historical Sites,
Balkema: Rotterdam, 1049–1053.
Pope GA, Dorn RI and Dixon JC (1995) A new conceptual
model for understanding geographical variations in
weathering. Annals of the Association of American
Geographers 85(1): 38–64.
Prebble MM (1967) Cavernous weathering in the
Taylor dry valley, Victoria land, Antarctica. Nature
216: 1194–1195.
Pye K and Mottershead DN (1995) Honeycomb weath-
ering of carboniferous sandstone in a sea wall at
Weston-Super-Mare, UK. Quarterly Journal of Engi-
neering Geology 28: 333–347.
Reid T (1850) Explanation of words. In: Walker D (ed.)
Essays on the Intellectual Powers of Man. Cambridge,
UK: Cambridge University Press, 1–9.
Reusch HH (1882) Notes sur la ge´ologie de la Corse.
Bulletin de la Socie
´te
´Ge
´ologique de France 11: 53–67.
Rhoads BL and Thorn CE (1996) The Scientific Nature of
Geomorphology. Chichester: John Wiley & Sons.
Robinson DA and Williams RBG (1976) Aspects of the
geomorphology of the sandstone cliff s of the Central
Weald. Proceedings of the Geologists Association 87:
93–100.
Rodriguez-Navarro C (1998) Evidence of honeycomb
weathering on Mars. Geophysical Research Letters
25(17): 3249–3252.
Rodriguez-Navarro C, Doehne E and Sebastian E (1999)
Origins of honeycomb weathering: the role of salts and
wind. GSA Bulletin 111(8): 1250–1255.
Sancho C and Benito G (1990) Factors controlling tafoni
weathering in the Ebro Basin (NE Spain). Zeitschrift
fur Geomorphologie 34: 165–177.
18 Progress in Physical Geography
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
Selby MJ (1971) Salt weathering of landforms and an Antarctic
example. In: Proceedings of 6th New Zealand Geography
Conference, Christchurch, New Zealand, 30–35.
Siedel H (2010) Alveolar weathering of cretaceous
building sandstones on monuments in Saxony, Ger-
many. Geological Society, London, Special Publica-
tions 333(1): 11–23.
Simonds FW (1888) The Geology of Washington County,
Arkansas. Annual Report for 1888. Arkansas Geolo-
gical Survey: Little Rock, 72–82.
Smith B and Mark DM (2003) Do mountains exist?
Towards an ontology of landforms. Environment and
Planning B: Planning and Design 30(3): 411–427.
Smith BJ (1978) The origin and geomorphic implications
of cliff foot recesses and tafoni on limestone hamadas
in the northwest Sahara. Zeitschrift fuer Geomorpho-
logie 22: 21–43.
Smith PJ (1982) Why honeycomb weathering? Nature
298: 121–122.
Sunamura T (1996) A physical model for the rate of coastal
tafoni development. The Journal of Geology 104(6):
741–748.
Sunamura T. and Aoki H. (2011) Application of an
S-shaped curve model to the temporal development
of tafoni of salt-weathering origin. Earth Surface
Processes and Landforms 36(12): 1624–1631.
Suzuki T and Hachinohe S (1995) Weathering rates in bedrock
forming marine terraces in Boso peninsula, Japan. Trans-
actions, Japanese Geomorphological Union 16: 93–113.
Trenhaile AS (1992) Chemical and salt weathering. In:
Geomorphology of Rock Coasts. Oxford, UK: Oxford
University Press, 31–58.
Tschang H (1974) Geomorphological observations on the
tafoni forms of Hong Kong. The Chung Chi Journal
13(1): 32–54.
Turkington AV and Paradise TR (2005) Sandstone
weathering: A century of research and innovation.
Geomorphology 67(1): 229–253.
Turkington AV and Phillips JD (2004) Cavernous weath-
ering, dynamical instability and self-organization.
Earth Surface Processes and Landforms 29: 665–675.
Twidale CR and Sved G (1978) Minor granite landforms
associated with the release of compressive stress.
Australian Geographical Studies 16(2): 161–174.
Un
˜aA
´lvarez E (2008) Description and nomenclature of the
tafoni features (cavernous rock forms): Tesearch
approaches in granite terrains. Cadernos do Labor-
atorio Xeolo
´xico de Laxe: Revista de xeoloxı
´
a galega e
do hercı
´
nico peninsular 33: 65–82.
Viles HA and Goudie AS (2004) Biofilms and case hard-
ening on sandstones from Al-Quwayra, Jordan. Earth
Surfaces Process and Landforms 29: 1473–1485.
Wilhelmy H (1964) Cavernous rock surfaces (tafoni) in
semiarid and arid climates Pakistan Geographical
Review 19: 8–13.
Winkler EM (1979) Role of salts in development of
granitic tafoni, South Australia. Journal of Geology 88:
119–120.
Young ARM (1987) Salt as an agent in the develop-
ment of cavernous weathering. Geology 15(10):
962–966.
Young R and Young A (1992) Sandstone Landforms,
11. Springer Series in Physical Environment. Hei-
delberg: Springer Berlin.
Groom et al. 19
at University of Colorado Denver on October 14, 2015ppg.sagepub.comDownloaded from
... Honeycombs (at times also called: alveoli, stone lace, stone lattice, fretting) are a common geomorphological phenomenon, taking the form of small cavities (typically at the centimetre scale) separated by thin walls (here called 'lips'), which usually occur in nests resembling honeycomb structure (Sunamura, 1996). Even though some authors (Groom et al., 2015) consider honeycombs to be a sub-category of tafoni, we consider tafoni as usually isolated larger caverns (tens of centimetres to metres in scale, bordered by so-called visors, along which water flows during heavy rains; Turkington & Phillips, 2004) as they might have a different genesis from honeycombs. For example, a new category of cavernous weathering formed by different processes than those for honeycombs has recently been identified and named arcadeshollows associated with fractures and bedding planes Safonov et al., 2020). ...
... Honeycombs are developed in many different environments and climates, ranging from warm or cold arid, coastal, continental (Groom et al., 2015), even the extraterrestrial on Mars (Rodriguez-Navarro, 1998). Nevertheless, the larger occurrences of honeycombs seem to be in salt-rich environments such as coastal areas affected by sea spray (Mottershead & Pye, 1994), or in deserts where potential evaporation considerably exceeds precipitation; thus leading to salt accumulation from precipitation or rock dissolution. ...
Article
Cavernous weathering (honeycombs, tafoni) is a common weathering feature of both natural and artificial exposures. Honeycombs are known from various environments but are best developed in coastal areas. There are several theories as to their origin, with salt weathering currently being the most favoured by the geomorphological community. To test if the drying pattern of salt‐laden moisture results in honeycombs (the theory of Huinink et al.), coastal honeycombs in the metasandstone of Tuscany (Italy) were studied both in the field and with a laboratory evaporation experiment. The depth of the evaporation front was measured by the "uranine‐probe" method in the honeycomb pits and lips. The evaporation intensity was calculated from the depth of the evaporation front as well as the climatic conditions at the study site. Lastly, the amounts of precipitated salts were estimated based on the evaporation intensity of seawater. In the evaporation experiment, the evaporation front retreated faster in the lips than in the pits, and the field measured evaporation front was closer to the surface in the pits (2 mm) than in the lips (7 mm). Thus, the calculated evaporation rate was higher in the pits than in the lips (16.1 and 4.6 mm/year, respectively). Similarly the amount of salts precipitated was also higher in the pits (0.7 kg/m2/year compared to 0.2 kg/m2/year in lips). Faster salt deposition in the pits as well as the evaporation front position fits well with the theory of Huinink et al. Based on surface tensile strength measurements, case hardening is not protecting the honeycomb lips.
... Their size is under debate, Migoń (2006) reported that Goudie (2004) suggests a few cubic meters in volume, but much smaller cavernous weathering was also classified as tafoni. Moreover, the cavernous rock decay process can be defined globally in all environments (Groom et al., 2015). However, there is no consensus on the terminology of these cavernous structures (Groom et al., 2015). ...
... Moreover, the cavernous rock decay process can be defined globally in all environments (Groom et al., 2015). However, there is no consensus on the terminology of these cavernous structures (Groom et al., 2015). The tafoni are singular forms, while alveoles-honeycomb weathering is the repeated forms (Migoń, 2006). ...
... Cavernous weathering: Tafoni, and alveoles or honeycomb weathering. All weathering forms developed as a result of differential weathering in the form of cavities or hollows, from a few mm to several meters in size, on rock surfaces are defined as cavernous weathering forms (Groom et al., 2015;Turkington & Phillips, 2004). Very small cavities with a dense cell-like structure, from a few cm to usually 10 cm in size, have been termed alveolar or honeycomb weathering. ...
Article
In this study, the weathering forms on the andesite of volcanic Mount Ağın (1807 m) located within the borders of Afyonkarahisar province in the Central Western Anatolia part of the Aegean Region were investigated. The climatic characteristics of the study area, chemical and mineralogical-petrographic properties of the andesites, porosity, diaclase systems, and biogenic erosion cause formation of characteristic shape generations on the andesites. In the field, andesites have been weathered by mechanical effects based on salt crystallization, freeze-thaw, shrinkage-expansion, and by the chemical effects of waterbased on hydrolysis-hydration-oxidation. The weathering product formed as a result of differential weathering has been subsequently moved by erosion, and the unweathered parts came to the surface to form distinctive forms in the topography. Weathering forms seen on the andesites have been investigated in detail for the first time in Turkey. The aim of this study is to reveal the close relationship between erosional forms of “andesite topography” and the factors playing a significant role in the formation of these weathering features. According to field observations and laboratory analyses, the original weathering forms on the mass have been explored and classified, and consequently revealed their formation mechanism and morphometric properties.
... From a geomorphological point of view, the whole area is a deeply dissected plateau/tableland (in a sense used by Duszyński et al. 2019) developed upon a horizontal, heterogeneous package of fine-to coarse-grained, trough-cross bedded sandstones (Fig. 6a), as well as conglomeratic sandstones (Fig. 6b) and minor clast-supported, poorly sorted conglomerates ( Fig. 6c; Paim et al., 2010;Borba et al., 2016a, b). This sedimentary package is cut by various sets of fractures (Fig. 7a, b, and c), mainly striking in the NE-SW and NW-SE directions, and it displays classical ruin-shaped (ruiniforme) relief features (in a sense used by Migoń et al. , as well as diversified cavernous weathering features (Fig. 8b, c) like tafoni and ledges (Groom et al. 2015). Lower relief zones, especially around water streams, show a profusion of weathering pits or gnammas (Twidale and Bourne, 2018), variously shaped and, sometimes, filled in with pebbles (Fig. 8d). ...
Article
The municipality of Caçapava do Sul, in southernmost Brazil, is a future candidate for the certification as a UNESCO Global Geopark (the Caçapava Aspiring Geopark). Proving the international, scientific value of geoheritage in any given territory is a fundamental pre-requisite to be fulfilled for this certification. Representativeness, rarity, integrity, geodiversity of elements and processes, limitations for use, relevance as key locality, and available/published scientific knowledge are the criteria usually applied to evaluate the scientific value of geosites. Thus, in the first place, this paper reviews, demonstrates, and discusses the relevance of the most outstanding geological context of the Caçapava territory: the ‘Camaquã basin’ sedimentary, volcanic, and associated sulphide ore deposits, as a unique stratigraphic record on a Brazilian, South American and Gondwanan scale. Moreover, the relevance of three individual geosites (the Guaritas, Serra do Segredo, and Minas do Camaquã geosites) for international science in the fields of Gondwana tectonics, copper mining, and cavernous weathering research is also demonstrated. Besides their geoscience importance, those geosites share cultural, ecological, aesthetic, functional, and educational values. This paper, based on a comprehensive and thorough literature review, is also an attempt to fill the gap between the context-, theme-, age- or unit-based approach of traditional geology and the site-based and territory-based strategies adopted in geoheritage research, geoconservation, and geoparks.
... The island Vågsøy on the outermost Atlantic coast in west-central Norway features both cavernous weathering forms and saprolites ( Fig. 7a, b). We follow Groom et al. (2015) and Paradise (2015), and term caverns of all sizes on inclined to sub-vertical rock faces 'tafoni' (singular: tafone), and caverns on horizontal to slightly dipping surfaces 'weathering pits (gnammas)'. Where tafoni occur in groups, often covering whole bedrock outcrops, the elaborate, cell-like pattern is termed honeycomb structure (Mustoe, 1982;Turkington and Phillips, 2004). ...
Article
Full-text available
Quantifying bedrock weathering rates under diverse climate conditions is essential to understanding timescales of landscape evolution. Yet, weathering rates are often difficult to constrain, and associating a weathered landform to a specific formative environment can be complicated by overprinting of successive processes and temporally varying climate. In this study, we investigate three sites between 59°N and 69°N along the Norwegian coast that display grussic saprolite, tafoni, and linear weathering grooves on diverse lithologies. These weathering phenomena have been invoked as examples of geomorphic archives predating Quaternary glaciations and consequently as indicators of minimal glacial erosion. Here we apply cosmogenic nuclide chronometry to assess the recent erosional history. Our results demonstrate that all three sites experienced sufficient erosion to remove most cosmogenic nuclides formed prior to the Last Glacial Maximum. This finding is inconsistent with preservation of surficial (<1–2 m) weathered landforms under non-erosive ice during the last glacial period, while simultaneously demonstrating that post-glacial weathering and erosion rates can be locally rapid (4–10 cm kyr⁻¹) in cold temperate to subarctic coastal locations.
... As a type of cavernous weathering features, tafoni (sing. tafone) are widely developed in various rock substrates in different climates around the world, especially in granular rock types such as sandstone and granite (Twidale and Bourne 1975;Paradise 2013a;Groom et al. 2015;Huang and Wang 2017;Chen et al. 2019). They often appear in groups on vertical cliffs with a charming network-like structure, attracting attention from geomorphologists and tourists. ...
Article
Tafoni are a type of cavernous weathering features widespread in different climate zones around the world, but their origin has not been fully understood. Little attention was paid on tafoni in conglomerates. Danxiashan UNESCO Global Geopark, located within the subtropic humid region of South China, has a landscape of large tafoni that occur on cliffs of red conglomerates. Both the Dinosaur Rock and Pagoda Peak of the geopark were selected to investigate the formation mechanisms of tafoni in conglomerates. During the field investigation, the size, rock hardness, and the external and internal meteorology of tafoni were measured and tested. The texture and composition of rock samples were observed, and the ion chromatography experiments were performed as well. Results show that tafoni have well ellipsoidal openings. Clasts of the conglomerates are largely sub-rounded and poorly sorted, and the cement is dominantly composed of calcite and iron oxide. The hardness of the lips is almost equal to that of the columns, and both are slightly higher than the backwalls. Compared with the external intense environmental changes, the interior of the tafoni is characterized by smaller temperature and relative humidity ranges and windless condition. Therefore, the porous and permeable conglomerates provide favorable lithology for tafoni development, and the micro-environment within the caverns is conducive to improving water utilization efficiency and enhancing salt weathering. The salts mainly consist of sulfates and nitrates, which might be derived from frequent raining, water evaporation and red beds as well. Consequently, tafoni are the result of the synergistic effects by multiple factors, rather than a single mechanism.
... Los tafoni (en singular tafone) son cavidades semiesféricas de distintos tamaños que se desarrollan en superficies rocosas de variadas litologías (a excepción quizás de rocas foliadas), pero que no se restringen a contactos, sino que ocupan diversas posiciones en los afloramientos (Fig. 1B). Se consideran poligenéticos, resultado de procesos de desagregación mecánica y desintegración química por meteorización y, secundariamente, por acción de la erosión (Turkington 2004;Groom et al. 2015;Chen et al. 2019). Las diferencias microclimáticas creadas en el reparo interior de los tafoni pueden acelerar los procesos de meteorización, reforzados por una retroalimentación positiva (Turkington y Phillips 2004). ...
Article
Full-text available
Resumen Este trabajo forma parte de un proyecto cuyo objetivo principal consiste en realizar un análisis geoarqueológico de aleros y cuevas someras ubicados en diferentes regiones y contextos geológicos de la Argentina, con el fin de evaluar patrones y pe-culiaridades en el desarrollo de sus morfologías y estratigrafías. Dichos sitios constituyen ambientes restringidos con una dinámica particular que se forman, evolucionan, colmatan y/o colapsan de maneras diferentes y que deben estudiarse a escala regional para interpretar el registro arqueológico y tafonómico que contienen. En un mismo sector se pueden
... The origin of both forms remains under discussion (e.g., Turkington 2004, Bruthans et al. 2018 and their distinction is mainly based on shape and size; honeycombs have commonly a diameter of few centimeters and a width less than 1 m, while tafoni can reach several meters in size (e.g., Roqué et al. 2013, Migoń & Maia 2020. Due to these discrepancies and the different characterization among researchers, Groom et al. (2015) proposed for all of these forms the use of the single term 'tafoni'. In this work, we adopt the distinction of these eschweizerbart_xxx weathering features based on their size and shape and discuss our findings accordingly. ...
Article
Along the semi-arid coast of northern Patagonia (Golfo San Matías, Río Negro) mountain ranges composed of rhyolites illustrate different stages in the evolution of rock cavities. A comparative study carried out in the Punta Pórfido area allows us to evaluate rockshelter formation processes and their sedimentary fillings. Cavity morphology in this sector results from the romboidal pattern of joints in the volcanic rock and weathering processes, mainly the development of tafoni. The fillings are made up of gravel and blocks derived from the weathering of the rhyolite, with the contribution of fine sediments originating from wind and marine salts that have collaborated in the preservation of unusual organic remains. At the main cavity surveyed, Alero 2, two excavations were carried out and four radiocarbon dating samples determined the ages on charcoal to be between ca. 2200 and 7500 years cal. AP. In this contribution, we present the initial results of the geoarchaeological study of these cavities in the coastal area of Punta Pórfido to understand their development and some properties of the archaeological and taphonomic record contained in their fillings.
Chapter
Representing countless societies and cultures, rock imagery and cultural stone are diverse and valuable resources that are, despite their perceived resilience, incredibly fragile and vulnerable to copious geomorphological processes. This article discusses various multidisciplinary theoretical frameworks and field assessment research tools that have been employed to better understand the dynamic nexus of heritage sciences, geomorphology, archeology, material sciences, and more. Additional information on ethical considerations scholars must take when researching sensitive materials is also provided.
Article
Tafoni-like cavernous weathering forms have been encountered at 21 locations in Finland. Their size vary from caverns 1–6 m in diameter to pits a few centimetres deep and wide. The cavernous forms have been developed in a great variety of rocks: gneisses, granitoids, amphibolites and breccias. The weathering is physico-chemical. The weathering material usually contains some clay minerals, among which illite, kaolinite, vermiculite and mixed-layer clay minerals predominate. In a few places the formation of gypsum seems to cause salt weathering. The weathering processes in ceilings and walls are flaking and granular disintegration. They seem mostly to be caused by water freezing in micro-fractures combined with chemical weathering. The big tafoni are results of a two-step development. The original forms were weathering pockets in the basal parts of the preglacial weathering crust. The glacier dislodged blocks comprising weathering pockets and transported these erratics, which remained unbroken because the crust, filling the pockets, was frozen. After glaciation the pockets were emptied, and the weathering proceeded and alveolar weathering controlled by the ventilation in the tafoni. Small cavernous forms may evolve differently. Structural weaknesses of the rock, such as inclusions, breccia fragments, accumulation of easily weathered minerals and miarolitic cavities, might have developed small-scale tafoni-like forms during postglacial time, particularly in the coastal zone. The bottom deposits of some tafoni enclose microfossils. The interpretation of these deposits is complicated because of the exceptional sedimentation conditions and the possible mixing with older microfossils.