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Z. Geomorph. N.F., Vol. 22 (1978), 44-67 TAFONI WEATHERING, WITH EXAMPLES FROM TUSCANY, ITALY I. PETER MARTINI Department of Land Resource Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
 Tafoni
is a type of cavernous weathering of granular rocks. Tafoni-like features
of smaller scale are known as alveoli and honeycomb weathering. The
processes that form tafoni and tafoni-like alveoli relate to differential
outside of hooded cavities. The inside has more uniform temperature and
higher moisture. This, plus the fact that the outside is frequently
weathering due to microclimatological differences between the inside and
protected by a mineralized coating leads to higher rates of weathering in
the inside through reactions sum as hydrolysis, hydration and salt
weathering predominantly of micaceous and argillaceous minerals. Once they
are initiated under special conditions sum as hot Mediterranean, semi-arid
climates, and in coastal warm and cold deserts, where saline moistures
exist, tafoni can persist as long as outcrops are not shadowed and the
inside-outside microclimatological differences persist.In Tuscany, Italy two areas relatively close to each other have well-developed tafoni. One, the isle of Elba, has them in granitic rocks where they are very active, as indicated by fresh inner surfaces, abundant flaking, and absence of alveoli and of limonite cover. The second area, Mt. Pisani, near Pisa, displays tafoni in slightly metamorphosed conglomerates, where they are for the most part inactive and actively losing their monk-like hoods. This latter activity is indicated by fresh detachment surfaces of flakes only around the rim. The main differences between the two areas are distance from seacoast, exposure to saline airflow, and insolation. The Mt. Pisani area was close to the coast in early Quaternary times; it is now twenty kilometers away, and is developing a forest that shadows parts of the outcrop.
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