Ponor
Encyclopedia
A ponor is a natural surface opening that may be found in landscapes where the geology and the geomorphology is characterized by some kind of karst
.
Whereas a sinkhole
is a depression (doline
) of surface topography with a pit or cavity directly underneath, a ponor is kind of a portal where a surface stream or lake flows either partially or completely underground into a karst groundwater
system. Steady water erosion may have formed or enlarged the portal in (mainly limestone
) rock, in a conglomerate, or in looser materials.
Ponors are found worldwide, but only in some karst regions. There are several places in southeast Europe (Bulgaria, Croatia, Czech Republic, Hungary, Romania, Montenegro) with the name Ponor due to associated karst openings. There are significant geological ponors in the Carpathian Mountains
, the Dinaric Alps
, Greece, Turkey, and parts of the southern U.S.
The term ponor has become the international geological term for larger karst-induced surface water inlets. The word derives from the proto-Slavic
nora 'pit, hole, abyss'.
Karst topography
Karst topography is a geologic formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite, but has also been documented for weathering resistant rocks like quartzite given the right conditions.Due to subterranean drainage, there...
.
Whereas a sinkhole
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...
is a depression (doline
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...
) of surface topography with a pit or cavity directly underneath, a ponor is kind of a portal where a surface stream or lake flows either partially or completely underground into a karst groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
system. Steady water erosion may have formed or enlarged the portal in (mainly limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
) rock, in a conglomerate, or in looser materials.
Ponors are found worldwide, but only in some karst regions. There are several places in southeast Europe (Bulgaria, Croatia, Czech Republic, Hungary, Romania, Montenegro) with the name Ponor due to associated karst openings. There are significant geological ponors in the Carpathian Mountains
Carpathian Mountains
The Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...
, the Dinaric Alps
Dinaric Alps
The Dinaric Alps or Dinarides form a mountain chain in Southern Europe, spanning areas of Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Kosovo, Albania and Montenegro....
, Greece, Turkey, and parts of the southern U.S.
The term ponor has become the international geological term for larger karst-induced surface water inlets. The word derives from the proto-Slavic
Proto-Slavic language
Proto-Slavic is the proto-language from which Slavic languages later emerged. It was spoken before the seventh century AD. As with most other proto-languages, no attested writings have been found; the language has been reconstructed by applying the comparative method to all the attested Slavic...
nora 'pit, hole, abyss'.