Cave & Karst Terminology
Artesian spring: An artesian spring is formed when underground water that is under hydrostatic pressure, rises above the land surface.

Breakdown: Cave breakdown is the enlargement of a cave system due to rocks falling from ceilings and walls forming heaps of rock called breccia.

Carbonate bedrock: Rock formations consisting of one or more carbonate minerals where carbonate rock is dominant.

Carbonic acid: Carbonic acid is formed from the dissolution of calcium carbonate by carbon dioxide in an aqueous solution.

Chert: Black, brown or grey rock, consisting of fine-grained silica that can be found as horizons of nodules and or layers in many limestones. It may form passages, ledges and waterfall lips.

Depositional flow: The movement of sediment and mineral deposits as they settle within a pore space.

Disappearing stream: A sinking stream is a small stream that disappears underground, it terminates abruptly by flowing or seeping into the ground. Disappearing streams are evidence of disrupted surface drainage and indicate the presence of an underground drainage system.

Fault: A fracture in the earth's crust where rock movement has occurred.

Flowstone: Layered deposits of calcium carbonate, gypsum, and other mineral matter which have precipitated and accumulated on the walls or floors of caves at places where water trickles or flows over the rock.

Grike: A vertical or sub-vertical, large, steeply inclined joint in the surface of a karstland, extending for up to a few meters into the limestone.

Glacial till: An assorted mixture of glacial drift (sediment material contained, transported, and deposited by glaciers.

Insurgence: Insurgence describes a point of inflow for surface water into subsurface conduits.

Joint: A break of geological origin in the continuity of a body of rock occurring either singly or more frequently in a set or system.

Keyhole passage: A cross-sectional shape of a cave passage that consists of a rounded top (pheateric tube), constricted middle, and rectangular canyon cut in its floor.

Lava cave: A cave that forms in a partly cooled, basaltic or phonolitic lava by molten material flowing away.

Limestone: Sedimentary rock containing at least 50% calcium carbonate. Some purer limestones consist of almost entirely of calcite.

Master cave: A low level trunk streamway cave with may tributaries.

Occluded sink: A point where a stream or river disappears underground in the form of a depression which is closed up or blocked off.

Resurgence: Re-emergence of karst ground water, a point at which an underground stream reaches the surface and becomes a surface stream.

Scallop: A spoon-shaped depression carved in a cave wall, floor or ceiling caused by the erosion of eddies in flowing water. Scallops are closely packed together, range from 10mm to 1m in length, are generally smaller when formed by fast flowing water, can be used to determine direction and velocity of water flow.

Sediment: Material recently deposited by water, ice or wind, or precipitated from water.

Shelter cave: A small cave in which the maximum horizontal extension seldom exceeds the width of its mouth. Sinkhole: Closed basin, funnel, or cylindrical shaped depressions where a stream or river disappears underground.

Siphon: A section of flooded cave passage in the form of an inverted 'U' with water moving only under pressure when the siphon has completely filled up. A cave passage where the ceiling dips below a water surface.

Solution: A homogeneous mixture of two or more components.