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HYPOGENIC CAVE FEATURES
Cueva de Villa Luz in Tabasco, Mexico, has received
much attention during recent years as an example of active
and dynamic, presently unconfined hypogenic development
(Hose and Pisarowicz, 1999; Hose and Macalady, 2006).
The cave is a 2-km long maze of passages lying almost
horizontally 10-20 m below the surface, connected to it by
numerous skylight entrances (Figure 51). The cave has
more than 20 underground springs rising from conduits (up
to 1 m x 2 m in width) in the floor and coalescing into a
surface resurgence spring. Spring discharge (~270-300 L/s)
is remarkably steady. Together with elevated temperature
(28 o C) and high H2S and CO2 content of the water, this
suggests a deep flow system possibly related to the
magmatic system of El Chichon volcano, 50 km to the
west. Springs inside the cave release H2S and CO2 into the
cave atmosphere at concentrations that vary, respectively,
from 1 to 120 ppm and from 0.03 to >3.2%. Replacement
gypsum coats most walls throughout the cave. Fallen
gypsum forms piles up to 1 m thick and is partially
removed by the stream. The cave has many cupolas which
are presumed to be actively growing due to chemical
stoping. The origin of the cave is presumed to be largely
due to subaerial dissolution at the stage of underground
hypogenic springs (Hose and Macalady, 2006).
Figure 51. Map of Cueva de Villa Luz, Tabasco, Mexico (from Hose
and Pisarowicz, 1999).
Sistema Zacatón (also known as Los Cenotes de
Tamaulipas or Los Cenotes de Aldama) in the Sierra de
Tamaulipas, northeastern Mexico, is one of the most
outstanding examples of deep hypogenic karst, expressed as
a series of extremely deep, phreatic megasinkholes, some of
them being sealed with travertine precipitating at the water
table (Figures 52 and 53, Plate 19 upper photo). Recently
published results of the ongoing study of Sistema Zacatón
provide a detailed description of the system and discussion
of its origin (Gary et al., 2003; Gary and Sharp, 2006).
Besides megasinkholes – deep phreatic shafts – the system
also includes ramiform, currently vadose cave passages,
sub-horizontal phreatic conduits, broad overland travertine
flows and relict spring flow travertine. El Zacatón is the
deepest of the sinkholes, and the second deepest underwater
shaft in the world with its measured depth of at least 329 m
(dove to -284 m).
Figure 52. Profile view of southernmost sinkholes of Sistema
Zacatón showing zones of varying water types and travertine
morphology. The Verde pit is hypothesized to have a travertine
floor formed during periods of low water-table levels (~50 m). This
cap now serves as a flow barrier (from Gary and Sharp, 2006).
Figure 53. Aerial photograph of Sistema Zacatón showing the
major features of the area. Numerous travertine-filled sinkholes are
labeled and water-filled areas appear as black. Water flows
underground from El Zacatón to the resurgence of El Nacimiento
through a phreatic cave passage and then flows overland until
becoming dispersed through broad honeycomb travertine deposits
south of the area (from Gary and Sharp, 2006).
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