Download PDF - Speleogenesis

4
NCKRI Special Paper Series No.1
Significant advances in understanding of
speleogenesis in hypogene (deep-seated) and confined
(artesian) settings made during recent years remain
somewhat fragmented and uncoordinated. This is partly
because discussions of the particular cases of “atypical”
speleogenesis (sulfuric acid, hydrothermal, in some sense
– speleogenesis in evaporites) focus attention on
geochemical processes of solutional porosity creation
with the hydrogeologic framework of cave formation
often remaining poorly understood. There is a misleading
trend to label particular types of speleogenesis, or even
types of karst, by the dissolutional mechanism assumed to
have created the caves. This obscures the fact that most
hypogenic/confined karst systems share many major
common features in their geo/hydrogeological settings,
patterns and morphologies. Although geochemical
attributes and dissolution mechanisms are indispensable
components of the speleogenetic environment, the
principal component is groundwater flow. Other attributes
largely depend on the position of a given karst system in
the basinal groundwater flow system and evolution of
boundary conditions. By way of analogy, in creating
dissolutional porosity the groundwater flow system is a
“master,” the type of recharge is a “tool” and
dissolutional mechanisms are the “fuels” to power the
tools. The shape, pattern and size of holes produced by a
tool (dentist drill, hand drill, borehole drill bit, bulldozer
or excavator) depend more on the intentions of a master
and the type of tool rather than on the fuel that drives it.
This paper intends to give an overview of the
principal environments, main processes and
manifestations of hypogenic speleogenesis, in order to
show the place of hypogenic karst systems in the basinal
groundwater flow systems, thus demonstrating the
common genetic background of various styles of
hypogenic karst and caves that were previously
considered unrelated, specific either to lithologies and/or
chemical mechanisms. I intend to demonstrate the
fundamental importance of the type of flow system in the
formation of hypogenic (confined) karst and caves, and
establish hypogenic karst as one of two major types of
karst systems.
The appreciation of the widespread occurrence of
hypogenic karst systems, marked specifics in their origin
and development, and their scientific and practical
importance, calls for revisiting and expanding the current
paradigm of karst and cave science.