Pulicchio di Gravina (in the local dialect ''Pulícchie'' or ''Pulidde'') is the second-largest doline in the

Murge The Altopiano delle Murge (Italian for "Murge plateau") is a karst topographic plateau of rectangular shape in southern Italy. Most of it lies within Apulia and corresponds with the sub-region known as Murgia or Le Murge. The plateau lies mainl ...

plateau (in Apulia, southern

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

) after

Pulo di Altamura Pulo di Altamura is a doline located on the Murge plateau ( Apulia, Italy). It is the largest doline in that region and it is located about north-west of the city of Altamura. It shares the local toponym ''pulo'' with other large dolines of the ...

. It falls into the territory of

Gravina in Puglia Gravina in Puglia (; nap, label= Barese, Gravéine ; la, Silvium; grc, Σιλούϊον, Siloúïon) is a town and ''comune'' of the Metropolitan City of Bari, Apulia, southern Italy. The word ''gravina'' comes from the Latin ''grava'' or from ...

, being located about north of the latter, close to the border with Altamura's territory. It shares the local toponym ''pulo'' with other large dolines of the region, i.e.

Pulo di Molfetta Pulo di Molfetta is a doline located on the Murge plateau, in Apulia, southern Italy, around south-west of the city of Molfetta. It originated due to the collapse of the ceiling of one or more caves. It shares the local toponym ''pulo'' with ot ...

and Pulicchio di Toritto. The doline is very close to other two karst landforms,

Gurio Lamanna Gurio Lamanna (also incorrectly called Gurlamanna) is a doline shaped like a coat of arms located in the Murge plateau and falling into Gravina in Puglia's territory, on the border with Altamura, Apulia, southern Italy. It is "one of the largest ...

and Tre Paduli.

Dimensions

The doline is shaped like an egg and it is highly regular, with the slope almost constant on all its sides (as shown on the map's level curves). The biggest length (in direction NNW-SE) is equal to . The doline is somewhat wider in the northern part () than in the southern part (). Its perimeter is approximately , while the maximum depth is . The lowest point has height from the sea level. Therefore, the doline turns out to be smaller but a little deeper than

Etymology

The etymology of toponym ''pulo'' is currently unknown. It is used only in the

plateau to denote a doline, while it is unused in other regions of Apulia. The term is also used for the nearby dolines

, and Pulicchio di Toritto (''pulicchio'' means small ''pulo''), and it is attested as early as in the 17th century, since Domenico Santoro in 1688, referring to

, wrote "luogo detto dalli Cittadini lo Pulo" (place called by Altamura people 'Pulo'). storie-inedite, page 47

History of scientific research on Pulo di Altamura

Te first thorough scientific study on Pulicchio di Gravina (until then completely unknown among

geologists A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

and naturalists) dates back to Carmelo Colamonico (1917). C. Colamonico (1917), page 4, notes 1 and 2 Previously, a few other scientists and

had only cited a natural cavity near Altamura. For instance, F. Virgilio (1900) briefly mentions the doline calling it "pulicchio" and incorrectly traces its origin to an unspecified "underground water erosion". According to Virgilio, the absence of rock masses at the bottom of the doline proves that subsidence occurred due to "underground water erosion". Carmelo Colamonico refutes F. Virgilio's theory pointing out that the absence of rock masses at the bottom of the doline proves, instead, that the origin is due to "superficial erosion". C. Colamonico (1917), page 9

Origin and evolution

In the same way as

and

, the origin of Pulicchio di Gravina can be explained through karst processes, i.e. the physical (erosion) and chemical (dissolution) action of rainwater, that the fractured limestone rock of the

plateau underwent over the millennia (and it still continues). Unlike other karst dolines of the region (such as

), Pulicchio di Gravina is the endpoint of a very small

drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

and therefore the amount of rainwater collected inside the doline is very little. Carmelo Colamonico points out that not even the rainwater falling on the area close to the doline manages to reach it (at least not superficially). The scarce rainwater is absorbed very quickly. Some farmers of that region stated that "there is never water at the bottom of Pulicchio di Gravina". Furthermore, no noteworthy

sinkholes A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

have been discovered inside the doline. Carmelo Colamonico argues that Pulicchio di Gravina originated mainly due to superficial erosion (and, partly, also the chemical dissolution of the limestone). Nevertheless, just the superficial erosion would not explain both its large size and the proximity to other two dolines,

and Tre Paduli. It cannot be excluded the

of Pulicchio di Gravina may have been larger than today's and it may have been reduced due to the formation of the other two nearby dolines. Nevertheless, the absence of

lamas Lamas may refer to: * the plural form of Lama, a title for a teacher of the Dharma in Tibetan Buddhism. Places *Lamas Province, Peru **Lamas District ** Lamas, Peru, the capital of Lamas Province and seat of Lamas District *Lamas (Braga), a paris ...

near Pulicchio di Gravina does not seem to confirm this hypothesis. The lama (or lamas) may have been eroded due to the formation of the nearby Gurio Lamanna and Tre Paduli. Another hypothesis is that it might be a "collapse doline", i.e. a doline generated due to the collapse of the ceiling of a pre-existing cave. Even if it is assumed that the origin of the doline was caused by the collapse of a cave, the initial size of it would have been so small that in any case it is necessary to introduce karst action (rainwater) in order to explain the origin of the doline.

Afforestation

As shown on the photo published by Carmelo Colamonico (1917), C. Colamonico (1917), page 5 Pulicchio di Gravina originally did not have any trees inside. In the 1950s, a forest has been established.

References

Bibliography

* * * * {{Cite book, title=Storie inedite della città di Altamura , first=Tommaso , last=Berloco , year=1985 , publisher=ATA - Associazione Turistica Altamurana Pro Loco , url=https://www.scribd.com/document/371395521/Tommaso-Berloco-Storie-inedite-della-citta-di-Altamura , place=Altamura , language=it , ref=storie-inedite Karst Landforms of Apulia Sinkholes of Italy