Submarine Karst of Croatia - Evidence of Former Lower Sea Levels

Med zadnjo, to je pleistocensko-holocensko transgresijo, je naraščajoča morska gladina zalila velike dele dinarskega krasa. Ker porečja rek na vzhodni jadranski obali sestavljajo pretežno karbonatne kamnine, te reke prenašajo le okoli 20 % sedimentov v obliki suspenza, vse ostalo pa kot raztopljeni tovor. Zaradi tega je pod morsko gladino še vedno mogoče ugotavljati značilne kraške oblike, kot so škraplje, vrtače, polja, jame in brezna, kot tudi rečne doline in soteske. Poleg teh preprostih potopljenih oblik so zaradi dvigajoče se gladine nastale tudi nove: podmorski izviri imenovani vrulje, zaslanjeni obalni izviri in morska jezera. Najpomembnejši dokazi o nekdanjem kopnem okolju so kapniki v potopljenih jamah in lehnjak v potopljenih nekdanjih rekah. Te oboje je mogoče uporabiti za ugotavljanje nekdanje niæje morske gladine.During the last, Late Pleistocene-Holocene transgression, rising sea flooded a vast part of the Dinaric karst. Due to prevalence of carbonate rocks in the drainage area of most of the rivers on Eastern Adriatic coast, those rivers carry only approximately 20% of particulates as suspended matter and the rest is dissolved. Consequently, many typical karst features such as karrens, dolines, poljes, caves, pits and river valleys and canyons as well, presently under the sea, can still be recognized. Beside these simply drowned features, some new ones were formed by the sea level rise. Those are submarine springs, so called vruljas, brackish coastal springs and marine lakes. The most significant evidences of former subaerial conditions are speleothems in submerged caves and calc tufa deposits of drowned paleo rivers. Both of them could be used for determination of the former low sea level stands

Challenges in cave monitoring and sampling – experiences from speleothem-based researches in Croatian caves

Speleothem-based research aimed to the reconstruction of the Quaternary environment in Dinaric karst has been conducted in several Croatian caves. As the interpretation of the palaeoenvironmental signal archived in speleothems relies on identifying and understanding processes between atmosphere and cave precipitates, especially hydrological behaviour, cave monitoring is crucial. Despite relatively simple sampling and monitoring protocols, series of problems and complications has arisen, caused by different natural and technical reasons. Extreme weather events such as enormous precipitation, prolonged drought or snow drifts, each in their own way can cause sample loss, while technical issues associated with equipment failures can lead to data loss. Even biological threats occurred, both man-induced and of natural origin. Although the later cannot be eliminated, as well as extreme weather, experience gained substantially helps to minimize negative effects. On the other hand, most of the technical issues are resolvable, and suggested solutions have been regularly implemented

Late Pleistocene – Holocene environmental changes – records from submerged speleothems along the Eastern Adriatic coast (Croatia)

U-Th and 14C dating, and X-ray diffraction of the parts of 16 submerged speleothems taken from the depths of 1.5−41.5 m from 7 submarine caves and pits along the Eastern Adriatic coast, provided insight to the sea-level fluctuations during the last 220 ka and to the palaeogeographic changes caused by sea-level changes. Due to the climate changes, palaeoenvironmental settings also varied, but not so abrupt and intensive as in the rest of Europe. Namely, owing to the Alps and Dinarides acting as orographic barriers, Eastern Adriatic coast was the border region between periglacial Europe and temperate Mediterranean region. It was, also, refuge area for plant species from the north. This study showed that appropriate temperature, humidity and vegetation cover ensured favourable conditions for karstification and speleothems formation processes even during Last Glacial Maximum.</p

Kraška hidrologija hrvaške obale v delih Alberta Fortisa (1741-1803)

Alberto Fortis (1741-1803) was an Italian naturalist who had a wide range of scientific interests from linguistics and ethnology to geology, geography and hydrology. This paper presents an overview of hydrological features that Fortis recorded in two of his works: Saggio d'Osservazzioni sopra l'Isola di Cherso ed Osero (1771) and Viaggio in Dalmazia (1774). These works were a result of several Fortis' travels in the region and were noted in European scientific literature of that time. Fortis revealed to European public the eastern Adriatic coast, a then little-known part of Europe with its wide variety of natural features. Despite the scarce appearance of surface water in karst, numerous interpretations of hydrological features can be found in Fortis’ descriptions of the East Adriatic coast. He often shows a remarkable understanding of karst hydrology even though some of his ideas and explanations are dubious from the present point of view. Although Fortis is not considered a karstologist in the strict sense, his works contain elements of what will eventually become karstology.Alberto Fortis (1741-1803) je bil italijanski naravoslovec s širokim razponom znanstvenih interesov od jezikoslovja in etnologije do geologije, geografije in hidrologije. V članku predstavljava pregled hidroloških pojavov, ki jih je Fortis opisal v dveh svojih delih: Saggio d'Osservazzioni sopra l'Isola di Cherso ed Osero (1771) in Viaggio in Dalmazia (1774). Deli, ki sta rezultat Fortisovih potovanj po vzhodni jadranski obali, sta  bili opaženi v evropski znanstveni literaturi tistega časa. Fortis je z njima evropski javnosti predstavil naravno pestrost tega, takrat malo poznanega območja. Kljub odsotnosti površinskih voda, Fortis predstavi in razloži  številne hidrološke pojave in pri tem pokaže  za tisti čas izjemno razumevanja kraške hidrologije. Seveda pa so nekatere ideje in razlage z današnjega vidika naivne. Fortisa sicer ne velja za krasoslovca v ožjem pomenu besede, a njegova dela nedvomno vsebujejo  gradnike bodočega krasoslovja

Potopljeni krš – živ ili mrtav? Primjeri s istočne obale Jadrana (Hrvatska)

Numerous karst features submerged by the Late Pleistocene-Holocene transgression are found along the Eastern Adriatic (Croatian) coast. Generally, most of karstification processes cease at the base level, that is, in case of coastal karst, the sea level. However, evidence of continued karstification (corrosion) and related processes (mechanical erosion and bioerosion), as well as remarkable change in hydrogeological settings of some hydrological systems, are quite common in Croatian submarine and coastal area.U podmorju duž cijele istočne obale Jadrana nalaze se brojni krški oblici potopljeni posljednjom gornjopleistocensko-holocenskom transgresijom. Općenito, većina procesa u okviru okršavanja prestaje na razini erozijske baze koja je u slučaju priobalnog krša apsolutna erozijska baza – razina mora. Međutim, u podmorju i priobalnom dijelu istočnog Jadrana brojni su primjeri gdje se i ispod morske razine djelomično nastavilo okršavanje (korozija) i okršavanju bliski procesi (mehanička erozija i bioerozija), a poznati su i primjeri značajne promjene hidrogeoloških funkcija pojedinih priobalnih hidroloških sustava uzrokovanih izdizanjem morske razine