Evaporite karst and caves of Emilia Romagna Region

Description

The Emilia-Romagna evaporite karst outcrops consist of two different lithologies: Triassic anhydrites (with a total area of ~ 20 km²) and Messinian gypsum (~ 30 km²).

Despite their reduced dimensions, these areas host well developed and varied surface forms and over 700 caves have been explored and mapped so far.

The outcrop of Triassic Anhydrites in the Upper Secchia Valley is a rare, perfectly preserved, example of evaporite, still partially active, diapir, hosting the world deepest anhydrite cave and the largest salt karst spring in Italy with an average discharge of over 250 1/s.

The Emilia-Romagna anhydrite caves are the only epigenichypogeanhe world hosting also a completely new kind of cavity: the "'`hypogean bend", the development of which is strictly controlled by the hydration of anhydrite.

Gypsum outcrops exhibit spectacular monoclinal structure which has been exposed by the differential erosion of the overlying impervious deposits. The gypsums underwent two different speleogenetic cycles: the first was intra-Messinian, while the second started over 500.000 years BP and is still going on today.

Some of the hosted gypsum caves are among the world's deepest and longest epigenetic caves in these lithologies. Moreover, they host peculiar solution-corrosion forms, speleothems and cave minerals, important paleontological and archeological remains, while some endemic organisms can be found only there.

To date, with over 2.000 printed papers, the evaporite areas of Emilia Romagna are by far the best explored, documented, and studied evaporite karst in the world.

Moreover the properties host rare geologic and karst landscapes which are very important from the aesthetic point of view. They attract thousands of visitor years as well as the gypsum caves open to the public. Some of the caves within the property are also important archaeological sites for the copper, bronze, and iron ages, during which they were used as places of settlement, burial or cultic sites, as well as for some perfectly preserved roman aged mine-caves of "Lapis Specularis".

From the Biological point of view some of the properties host peculiar on-going ecological and biological processes. In particular, it is worth mentioning the Poiano Springs in the Upper Secchia Valley and its related brackish aquifer, hosting several rare and/or new to science organisms like the endemic amphipod Niphargus poianoi. These organisms probably represent phylogenetic relicts, survived in an area where anhydrite karst aquifers are characterized by high sodium chloride content.

Finally the Emilia-Romagna gypsum and anhydrite caves are extremely important biological shelters, hosting some of the largest and varied Bat colonies of Europe, and several peculiar endemic troblobitic species, restricted to these environments. Moreover, the gypsum and anhydrite outcrops influence the local microclimate allowing the presence of rare botanic associations. Over 500 different botanic species have been detected in the Triassic Anhydrites of the Upper Secchia Valley. Over 1000 different botanic species have been detected in the Messinian gypsum, including Mediterranean Tortilla revolvens and the fern Cheilanthes (Notholaena) persica, that in Italy can be found only on the Vena del Gesso, the only growing area in Western Europe.

Coordinates:
Triassic anhydrites of the Upper Secchia Valley:
From 10°26'49,284"E to 10°22'04,29"E; from 44°23'56,005"N to 44°21'30.81'N

Messinian Gypsum of Zola Predosa:
From 11°13'30,016"E to 11°12'57,749"E; from 44°28'05,666"N to 44°27'47.035"N

Messinian Gypsum of Bologna:
From 11°25'48,668"E to 11°22'19,339'T; from 44°27'19.226"N to 44°25'11,108"N

Gypsum Vein of Romagna:
From 11°46'37,985"E to 11°33'25,681"E; from 44°16'47,945"N to 11°33'25,681"E

Justification de la Valeur Universelle Exceptionnelle

The Emilia-Romagna anhydrite caves are the single epigenic ones in the world; they host the world deepest anhydrite cave and the largest salt karst spring of Italy, while some of the gypsum caves are among the deepest and longest world epigenetic caves in these lithologies. The lithological variability (anhydrite and gypsum), the presence of two different (intra­Messinian and actual) speleogenetic cycles, the richness of epigean and hypogean karst forms, the huge dimensions of both anhydrite and gypsum caves, together with their peculiar ecosystem, which gives shelter to endangered or peculiar species, ecological and biological processes, mineralogy and paleontology and archaeology are significant factors supporting their candidature.

The evaporite areas of Emilia Romagna are by far the best explored, documented and studied evaporite karst in the world since 16^th Century.

Criterion (viii): The lithological variability (anhydrite and gypsum), the presence of two different (intra-Messinian and actual) speleogenetic cycles, the richness of epigean and hypogean karst forms, the rare/new speleothems and/or cave minerals (some of them restricted to these properties), and the huge dimension of both anhydrite and gypsum caves are important requirements for this candidature. Geomorphological and mineralogical features, however, are not the only outstanding aspects of the Emilia-Romagna gypsum karst and caves. Indeed, in these areas were found some rare and well preserved paleontological remains of intra-Messinian and upper Pleistocene.

Déclarations d’authenticité et/ou d’intégrité

Most of the properties (over 95%) fall within the boundaries of the Alto Appennino Tosco-Emiliano National Park (Triassic anhydrites of the Upper Secchia Valley), and of two Regional Parks: the Gessi Bolognesi Park (Messinian gypsum of Bologna) and the Vena del Gesso Romagnola Park (Gypsum vein of Romagna).

All the properties are geosites officially catalogued by Emilia-Romagna Region, thanks to the Regional Law n.9/2006 "Norme per la conservazione e valorizzazione della geodiversità dell 'Emilia-Romagna e delle attività ad essa collegate".

Consequently, all the proposed properties are protected by law. Moreover, these three Parks are still expanding their territories by acquiring new private areas and these acquisitions will be further enhanced if these properties will be nominated WH. Moreover all the proposed properties, from 2010 to 2016, were interested by LIFE 08 NAT/ IT/000369 project "Gypsum: protection e management of the habitats associated with the gypsum formations of Emilia-Romagna", which increased protection and awareness of these areas.

Comparaison avec d’autres biens similaires

No anhydrite and/or gypsum karst area has been submitted to attain the rank of WH since then. No other gypsum and/or anhydrite karst area is present in the Tentative List. Gypsum, and to a lesser extent, anhydrite, outcrop in many places around the world and often lie buried at a shallow depth. Occurrences are particularly extensive in the Russian Federation, Ukraine and North America (Klimchouk, et al. 1996). Huge Messinian evaporitic (gypsum, and halite), often well karstified, deposits are present all around the Mediterranean sea. Anyway, only few of them have been explored and studied yet and even less have a protection suitable to be considered for a WH application.

Anhydrite karst
Presently the single Country in which caves in this lithotype are known and explored is Germany. Their genesis is hypogenic, while that of Emilia Romagna is epigenic and therefore the two karsts are hardly comparable. Anyway, concerning criterium (viii) a single speleogenetic mechanism is responsible for their development and therefore the resulted forms are few, while those in Emilia Romagna are much more and complex. Moreover the cave size, the hosted speleothems and cave minerals, their hydrogeology, make the Emilia Romagna Anhydrite karst much more interesting. Concerning criterium (ix) the German anhydrites were dried by mining activities only a couple of century ago, therefore they had not the possibility to develop outstanding examples representing significant on-going ecological and biological processes which in turn are present in the Emilia Romagna ones. The same can be said for criterium (x). While they have no interest at all with respect to criterum (iii).

Gypsum karsts
Many gypsum karst areas exist in the world and some of them have been at least partially explored and studied. Here the most important of them are shortly described in comparison with the Gypsum Karsts of the Emilia Romagna.

1. Gigantic caves of Podolia, Ukraine
These maze cave are by far the longest gypsum caves of the world. Anyway regarding criterium (viii) it must be stressed that morphological varieties and hosted speleothems o f the Podolia caves exhibit, by far, less variability with respect to those of Emilia Romagna, moreover in Podolia a single karst cycle is present.
Regarding criteria (ix) and (x) it must be said that nothing is actually known on the hosted ecosystems and their in time evolution and no paleontological remains at all are hosted in those caves. While they have no interest at all with respect to criterum (iii). Finally Podol is gypsum karst still lacks of a suitable protection.

2. Sorbas Gypsum Karst Almeria, Spain
This karst area is very similar to the gypsum properties of the Emilia-Romagna being developed in the same Messinian Gypsum formations. The karst and caves are well explored documented and studied. Regarding the criterium (viii): they are less interesting because their dimension are smaller and only the actual karst cycle is represented. Moreover they lack of several forms and speleothems (those of calcite are practically absent) as well as cave minerals. Regarding criteria (ix) and (x) their ecosystems, at least on the basis of the actual knowledges, are by far poorer than that of Emilia Romagna Region. No paleontological remains at all are hosted in those caves. They have no interest at all with respect to criterum (iii). In conclusion the interests of the Almeria is restricted to abiotic phenomena of a Messinian Gypsum where only a single karst cycle is represented, moreover only a partial protection is actually imposed to a portion of that area.

3. Santa Ninfa, Sicily, Italy
The Messinian gypsum of Santa Ninfa hosts several surface and deep karst forms. resulting the most interesting among the gypsum karst areas of Sicily. Regarding the criterium (viii) it must be said that the variability of forms and deposits is far less than in the Emilia Romagna gypsum karst. Most of the karst forms and of the speleothems of the Santa Ninfa area are similar to those present in the Emilia Romagna area. Regarding criteria (ix) and (x) extremely few is known on cave ecosystems and their evolution in time. No paleontological remains are present in that area and only scarce evidence of a roman mine of lapis specularis. They have no interest at all with respect to criterum III. Finally only the Santa Ninfa cave is a Regional Natural Preserve, while the other parts of the gypsum outcrop have no protection at all.

4. Pinega, Russia
Permian gypsum is covered by thick fluvio-glacial deposits and occupies a large portion of territory several km NE of Arkangelsk. The Pinega gypsum karst is inserted in a Natural Park characterized by a huge taiga forest with practically no inhabitants, therefore its safeguard is optimal. Regarding the criterium (viii) surface karst forms are rare and represented only by a few vertical sinkhole where water sinks during the short thaw period and by seasonal springs along the main river cutting the area. Caves are very recent (most of them developed after the last glaciation) and are partially frozen all the year. The single hosted morphologies are related to the early summer floods. Only a very few speleothems and practically no cave minerals beside ice have been reported from the caves of this region. Regarding criteria (ix) and (x) nothing is known on cave ecosystems and its evolution in time. They have no interest at all with respect to criterum (iii).

5. Kungur, Russia
The huge Permian gypsum outcrop around the Kungur village hosts lot of sinkholes, several different small karst forms (karren etc..) and a few caves, the most renown of which is the Kungur Ice Cave. Regarding the criterium (viii) the main characteristic of Kungur Ice Cave is given by the hosted huge ice deposits giving rise to formations and large crystals while speleothems are restricted to few and small gypsum ones. This cave hosts also some ephemeral minerals segregated by the freezing lakes in the winter time. In any case its morphological and mineralogical interests are by far less and less interesting than those of the Emilia Romagna ones.
Regarding criteria (ix) and (x) it must be said that probably the underground lakes host peculiar ecosystems but they are still totally unknown. As the cave has low paleontological and/or archaeological value, it is characterized by a poor protection policy. Moreover, the cave is open to the public with very few restrictions, therefore it is not well preserved. In any case, our opinion is that even if in the near future more detailed informations on this karst area will be available, we think that the importance and interest of the Gypsum caves of Emilia Romagna will remain by far higher.

6. New Mexico, USA
In the desert of New Mexico there is a large peneplanar area of outcropping gypsum characterized by flat extremely large dolines at the bottom of which sometimes sinkholes allow the access to even large caves (Chiesi & Forti, 1996). This karst area has been only partially explored and mapped but no specific analyses and studies have been  performed over it. Probably the cave ecosystem will be of noticeable importance because the cavities represent a shelter against the extremely dry weather conditions of that area. Anyway, at least in the near future, the quite total lack of knowledge on their characteristics avoid the possibility to consider them for a possible WH candidature.

7. Darhedi, Algeria
The area hosts a rather large cavity (Bir al Ganham) with a few speleothems and cave minerals. Nothing else is presently known on this area. At the moment no kind of safeguard exists for the whole karst area.

8. Neuquén, Mendoza Argentina
In this area of Argentina there are several relatively small gypsum outcrops which host time by time dolines, karren-fields and some peculiar forms like small chimneys. Some gypsum caves are also known but their size is generally small. Only a minor part of these areas have been at least partially explored. Nothing is known about their ecosystems.

9. Punta Alegre, Cuba
The gypsum karst area of Punta Alegre is very small, consisting of a diapir in which few  very small gypsum caves (never exceeding 20-30 m in length) are present. All the karst form are controlled by the peculiar tropical climate, which allows also the development of a few interesting speleothems and cave minerals. A couple of caves (locally named Cuevas do Calor) host huge bat colonies during the breeding seasons. This area has no specific safeguard rules and the karst aquifer is hardly polluted by a factory of a traditional liquor from sugar can.

10. Verzino, Calabria, Italy
The small Messinian gypsum outcrop hosts a single important and relatively long (a couple of km) karst system with a rather complex hydrogeology. Along the underground river small sulphide springs allowed the development of peculiar speleothems and a few cave minerals. Presently this area has no specific safeguard.

At the end of this recognition on the main actually known gypsum and anhydrite karsts of the world, it is evident that the Evaporite karst and caves of Emilia Romagna, is by far the best, among these properties and therefore it should be considered for attaining the rank of WH.