What is the deepest limestone bed that a cave could penetrate to?

Answer 1

Sedimentary deposits are thought to exist up to 9 kilometers deep. From 9 kilometers to about 18 kilometers metamorphic layers likely exist. However, temperatures would be very high, along with toxic gases like sulfur. So explorable cave passage at that depth is unlikely. Drill cores in Wyoming have found limestone nearly 26,000 feet deep. Can anyone verify if that Mississipian layer is soluble enough to form explorable caves?

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Caves at that depth are not very likely but may form by dissolution by very deep, acidic, geothermal fluids. The normal limit really is not ever so deep below the base level - the altitude of the resurgence for their formative streams. Although they can form deep "sumps" like the U-bend under a sink, the limestone formation's own depth sets the limit, whatever the rock below it. So although sedimentary rock may be 9km deep, the cavernous limestone is likely to be far less.

Also, it's not the solubility of the limestone that's the problem. It's the physical nature of the formation, the relationship to basement and cover rocks, and hydrology of its region that matter.

Answer 2

The depth to which a cave can penetrate limestone bedrock depends on various factors such as the type of limestone, geological processes, and local tectonic activity. In general, caves can penetrate several hundred meters into limestone formations, with some systems extending over thousands of meters. However, the maximum depth is typically limited by factors such as the strength of the bedrock and the presence of groundwater.