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depositional or constructional forms (Vidal RomanĂ­ and Twidale, 1998). The most noticeable one,
due to being unknown up to now, are the small siliceous speleothems widely developed in partings
and other opened discontinuities of the granitic massifs (Fig. 10.11a). They are here called, as
their congeners in soluble rocks, speleothems though they are different as to size and appearance
frequency to the ones in the karstic systems. Their forms are very similar, and thus in the literature
they have, as far as possible, the same names when the form is the same. There may be distin-
guished two types of deposits. The first type is the cylindrical speleothems: appear associated to
some water dripping points of the fissure system. Within this type of speleothems two subtypes
may be differentiated: stalactites, which are formed in the roof of rock fissures in the dripping
point of the water that circulates through the fissure. False stalagmites or antigravitational
speleothems: are due to antigravitational growths on the base of the cavities. Its lineal develop-
ment is limited. The second type of speleothems is developed as layers or coatings and is produced
by trickling of water through the rock fissure system. They are called flowstone, dripstone, gour-
dams or rimstone as their congeners in limestone (Finlayson and Webb, 1985). The elemental
(a)
(b)
Figure 10.11.
(a) Siliceous speleothems from Kokerbin Hill, Western Australia. (b) Siliceous speleothems
from Tcharkuldu Hill, Southern Australia.
 
 
 
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