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NCKRI Special Paper No. 1
Figure 50. Longitudinal profile of the Guadalupe ridge (along the
escarpment) from southwest (left) to northeast, with locations,
elevations and vertical ranges of major caves. Age dates from
alunite from four caves, and elevation of samples, are indicated
(from Polyak and Provencio, 2000).
could receive better lateral integration. The development
during the water table stage was unlikely to produce most
of the cave volume as assumed by proponents of water
table/condensation corrosion speleogenesis. There is no
unambiguous evidence in cave patterns and morphology
suggesting the prominent speleogenetic role of water table
development. There are no truly horizontal levels in
structural organization of most individual caves, nor
noticeable correlation between quasi-levels in adjacent
caves or in different parts of the same caves. There are no
distinct, laterally continuous, marks in cave mesomorphology
(such as horizontal notching, truncated
partitions, etc.) even at those levels, which are assumed to
be a result of water table development. In contrast, many
parts of complex cave systems and individual caves
demonstrate inclined stories of maze development (Figure
46), which apparently do not fit the water table concept. As
shown by many examples throughout this book, such
stories (including quasi-horizontal ones) are controlled by
distribution of initial porosity structures. This is evident for
stratigraphically concordant stories but is also an
alternative to the water table) explanation for the beddingdiscordant
stories. The study of Koša and Hunt (2006)
suggests that clusters of syndepositional fractures are often
confined to certain elevation levels discordant to bedding
(Figure 48; see also Plate 16). The quasi-levels in cave
development are in many cases related to this control.
The total decline in the water table between the
southwestern and northeastern sectors of the Guadalupe
ridge is estimated to exceed 1000 m (Polyak et al., 1998;
DuChene and Cunningham, 2006), while the vertical
ranges of individual 3-D cave systems vary from 20-30 to
250-490 m. Widespread correlation of cave stories within
the water table concept would not be expected between
caves scattered along the lengthwise direction of the ridge,
as these caves experienced water table conditions at
different times. However, it would be expected between
caves for which elevation ranges overlap, located in
proximity within the same transversal segments of the
ridge. Palmer and Palmer (2000a) noted the lack of level
correlations even between nearby caves and concluded that
the confidence with which cave development (in the water
table sense – A. K.) can be related to regional geomorphic
events is limited. Instead, they suggested an elegant view
in favor of the water table control on levels, namely that
releases of H2S from depth were episodic and occurred in
different times and places. Horizontal levels were
produced when these releases coincided with rather static
water tables, so that bursts of cave enlargement occurred
there. However, given that H2S supply is associated with
regional flow systems and events, it is unlikely that the gas
releases occurred in such an individualized manner to
caves located in close proximity, or only to particular
major feeders within the same large caves. Other
researchers argue that water table effects on cave
development were not focused at particular levels but were
distributed over the vertical range of caves due to water
table fluctuations. This is certainly a sound possibility, but
it gives no ground to claim the major speleogenetic role of
water table development, as morphologic evidence of
rising flow has not been overprinted by new, water-table
related morphologies.
It follows from the above discussion that the origin of
caves in the Guadalupe Mountains fits well with the
broader class of ascending hypogenic transverse
speleogenesis defined on a hydrogeological basis. The
proposed refinement of the regional speleogenetic model is
sufficient to explain virtually any features of cave patterns,
morphology, and mineralogy observed in the region. The
main speleogenetic stage of confined development
probably involved both hydrothermal and sulfuric acid
dissolution mechanisms and was quite prolonged in the
geologic time scale. This discussion, taken within the
overall context of this book, also suggests that caves of the
Guadalupe Mountains, although being outstanding
examples, are not unique, and that most of their
characteristics (except geochemical and mineralogical) are
not exclusive to sulfuric acid dissolution, as many works
have suggested.
Central and South America
It is apparent from publications and exploration reports
that Central and South America have a remarkable
diversity of hypogenic karst. Detailed studies, however, are
still scarce. Below only a few examples are referred to in
order to highlight the diversity and some related
speleogenetic issues.