Pulicchio di Gravina


Useful Information

Location: Near Altamura.
From Altamura center follow Via Gravina, which becomes SP238, to the south, signposted Corato. After 13 km on the left side, parking lot with outlook.
(40.906101, 16.423935)
Open: no restrictions.
[2022]
Fee: free.
[2022]
Classification: KarstTiankeng KarstDoline
Light: n/a
Dimension: L=530 m, W=400 m, VR=100 m, VRmin=90 m, Ar=280,000 m², V=15.0 M m³.
Guided tours: self guided
Photography: allowed
Accessibility: no
Bibliography: F. Virgilio (1900): Geomorfogenia della provincia di Bari Terra di Bari (in Italian). Trani: Vecchi. 3.
Carmelo Colamonico (1917): Il pulicchio di Gravina Rivista geografica italiana (in Italian). Udine (XXIV).
Address: Pulicchio di Gravina, SP238, 70024 Gravina di Puglia BA.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.

History

1900 mentioned by F. Virgilio.
1917 first thorough scientific study by Carmelo Colamonico.

Description

The Pulicchio di Gravina is located at the local road SP238 between Altamura and Corato. There is a parking lot at the road with an outlook, which is easy to miss as the signs are simply white. It seems they had a flaw and the colour is gone, bleached by the sun or washed away by the rain. Nevertheless, it is a parking lot 13 km from Altamura and 28 km from Corato, and if you look for it, you will not miss it. There is also a single lane gravel road along the rim, so if you want, you can make a half hour 1.7 km easy hike around the doline.

This doline is less impressive than nearby Pulo di Altamura, as the ground is covered by a forest, which makes it difficult to see the exact form of the doline. The forest is artificial, the pine trees were planted in the 1950s because the inside of the depression is suitable for trees. On the other hand the steep walls make farming inside the doline difficult. We are not sure how they planned to get the wood out of the doline, probably by pulling them on ropes. While the forest is not good for the geotope, it is quite helpful for the plants and animals in the depression, which are quite exceptional. The site is listed for various rare plants.

This place was long overlooked by science, the doline was first actually mentioned in 1910 by F. Virgilio. He calls it pulicchio and guesses it's a result of subsidence which occurred due to "underground water erosion", which was proven by the absence of rock masses at the bottom of the doline. This is, while not completely wrong, a rather simplistic description. Carmelo Colamonico refuted F. Virgilio's theory in 1917, by pointing out that the absence of rock masses at the bottom of the sinkhole instead proves that the origin is due to "superficial erosion". Actually both theories are somewhat strange. A doline is a result of the dissolution of soluble limestone by water. Collapse dolines are a result of a cave or numerous caves which collapse. Solutional dolines are the result of rainwater entering the limestone through cracks widening the cracks and also dissolving the limestone downwards from the surface. In reality both processes happen in general at the same time, the lack of rock masses does not explain anything, and this discussion has not been solved until today.

In many cases its quite simple to determine if a doline is a collapse doline. It has steep walls and often there is a cave at the bottom, speleothems on the walls, or a huge pile of debris. However, there are dolines which were formed by a combination of both processes, and dolines where it is quite difficult to determine which process formed it. That's actually the main reason why two different things have the same name, both are dolines, because that's what you can easily see.

There have been rather recent researches with quite logical theories about its formation. It may have formed by multiple collapses and disintegration of a network of small caves or by paleokarst dissolution. But they still lack the final proof, which would require something like drilling inside the doline to examine the underground. This is quite expensive, and as most people do not care about this question, there is no funding.

We classified this doline as a KarstTiankeng, which means it has a diameter and depth greater than 100 m. However, if you define tiankengs as collapses of huge caverns, this is most likely not a tiankeng. We use the simpler definition only by size and classify this as tiankeng though. However, the dimensions we found in different publications differ very much, Tony Waltham lists it as a huge doline which is not a tiankeng and gives its depth with 100 m. The wikipedia page for example gives 85 m. In any case it is quite impressive and well worth a visit. If you are in Puglia, spend the hour to visit this site.

In the Murge of Gravina, one of the largest karstic cavities in Apulia is known by the simple name of "pulicchio"... The pulicchio is found, a little more than 10 km from Gravina, on the left-hand side of the provincial road that leads from this town to Corato and Ruvo... In this section, before heading decisively northwards in the middle of the wider flat area of the Murge alte, the carriage road - having passed the steep slope with which the step rises from the Plio-Pleistocene pre-murgian ditch - winds for over five kilometres in a NW direction, even flanking the very edge of the plateau. Almost in the middle of this section of the south-western balcony of the Murgia, the Gravina pulicchio is excavated: from its western edge, in fact, an immense flat area dominates, about 150 metres below it, corresponding to the "Pantano" of the I.G.M. map and largely called "Maricello", today almost all of it reclaimed... Therefore, the pulicchio, which, although at the end of the terraced step, opens up in the higher area, assumes, both in the area that constitutes it and in the region that surrounds it, the characteristics of the mostly monotonous landscape, typical of this higher part of the Murge, without life and without notable physical accidentality, arid and almost steppe-like, desolate, rocky, with very permeable soil. The ovoid-shaped cavity extends from the NNW to the SSE for about 530 metres and is 400 metres wider to the north and 360 metres wider to the south; its outline is almost entirely formed by broken lines, which bring its development to over 1600 metres; it is more elevated in the northern section, where the edge coincides in various points with the route of isohyssic route 565; it reaches its lowest point at an altitude of 477.50 metres, so that the maximum difference in height is 87.50 metres; it occupies an area of 175,000 square metres. The geographical coordinates of the midpoint are: 40°54'13" lat. N, 3°58'18" long. E from Rome and 478 m. above sea level. For its size and shape, the cavity is evidently ascribed to the dolines; and it is one of the largest dolines, slightly smaller than the pulo of Altamura but much larger than the pulo of Molfetta; from both, however, it is distinguished by the gentler steepness of the walls, and therefore, by the less marked individuality it assumes, by the absolute lack of caves and caverns and by its greater depth. On the whole, the pulicchio di Gravina has a very regular shape and a uniform slope on all its sides, as can be seen from the tracing of the isohypses on the map I have drawn. In fact, from all sides, except in the section closest to the rocky edge and not a few times very steep, the slope of the land is less in the highest and lowest part of the basin, and is greater in the middle part; the difference is not remarkable, however, obtained as it is from the figures of 50% in the first case, and 60% in the second case. The rocky section of the eastern side has even vertical slopes, sometimes over ten metres high.
Carmelo Colamonico (1917): Il pulicchio di Gravina Rivista geografica italiana (Italiano - Italian). Udine (XXIV).