Hypogene caves in the Plavecký hradný vrch Hill (Western Slovakia, Central Europe) were formed by waters ascending along faults in fractured Triassic carbonates related to the horst-graben ...structure at the contact of the Malé Karpaty Mountains and the NE part of the Vienna Basin. The Plavecká jaskyňa and Pec caves mostly contain horizontal passages and chambers with flat corrosion bedrock floors, fissure discharge feeders, wall water-table notches, replacement pockets, as well as a few other speleogens associated with sulfuric acid speleogenesis. The low-temperature sulfuric acid development phases of the Plavecká Jaskyňa are also indicated by the presence of sulfate minerals (i.e., gypsum and jarosite).Subaerial calcite popcorn rims were precipitated from water condensation at the edges of feeding fissures that were still active as thermal vents when the water table dropped. Hydrogen sulfide involved in the sulfuric acid speleogenesis was likely derived from anhydrites and/or hydrocarbon reservoirs with sulfate-saline connate waters in the fill of the adjacent Vienna Basin. It ascended to the surface along deep-rooted sub-vertical fault zones at the contact of the Vienna Basin with neighboring mountains. Three cave levels at 295 to 283 m asl in the Pec Cave, and five levels at 225 to 214 m asl in the Plavecká jaskyňa corresponded to phases of stable local erosional base levels in the bordering part of the Vienna Basin, most likely during periods of strongly decelerated and/or interrupted subsidence. Cave levels separated by vertical differences of only a few meters may also be related to the Pleistocene climatic cycles. The subhorizontal parts of the Pec Cave are probably of late Early Pleistocene age (˃0.99–1.07 Ma?). The two highest levels of the Plavecká jaskyňa developed during the early Middle Pleistocene (˃600 ka). Fine-grained sediments in the passage at 225 m asl with normal magnetic polarity contain jarosite. The middle level of the Plavecká jaskyňa at 220 m asl was formed in the mid-Middle Pleistocene, while the lower and lowermost levels formed in the late Middle Pleistocene (˃270 ka). The water table in the lowermost cave level probably dropped after the tectonic reactivation of the Podmalokarpatská zníženina Depression just in the front of a marginal horst structure of the Malé Karpaty Mountains.
In this contribution we examine and discuss recently published magnetostratigraphic data from the Nordvik section (north Siberia) around the Tithonian–Berriasian (J/K) boundary, with a special ...emphasis on calibration with biostratigraphy and the reliability of both the fossil and magnetic records, as well as sedimentation rates. Specifically, we discuss original new interpretations by Bragin et al. (2013) and the commentary on that work by Guzhikov (2013). We consider some limitations of the Nordvik section, and conclude that the base of M18r, because it is in a condensed part of the sequence, makes a poor contender for precise long-range correlation. We discuss the lack of ammonites at several magnetozone boundaries, and whether the bases of the local zones of
and
can be used to bracket the correlative horizon of
, a widespread marker in the middle of M19n.2n in Tethys.
The Ochtiná Aragonite Cave (Western Carpathians) represents an unique natural phenomenon. It originated under particular lithological and hydrogeological conditions of the Ochtiná Karst in which ...several isolated lenses of Paleozoic crystalline limestone (marbles), partly metasomatically altered to ankerite, are enclosed by phyllites. Meteoric water seepage through non-carbonate rocks dissolved limestone and caused the oxidation of ankerite to Fe oxyhydroxides. Carbon dioxide produced during ankerite oxidation enhanced limestone dissolution. The maze cave consists of parallel fault-controlled linear passages and chambers interconnected by transverse horizontal passages. Phreatic and epiphreatic solution morphologies resulted from slowly moving or standing water. These include flat ceilings (
Laugdecken
), facets (planes of repose,
Facetten
), lateral notches, convection ceiling cupola-shaped depressions, and spongework-like hollows. Flat ceilings were developed in several altitude positions, each of them probably closely below the slightly oscillated water table. Primary phreatic cupola-shaped depressions, truncated by flat ceilings, represent relics of the oldest cavities (pre-Quaternary? to Early Pleistocene). Inward-sloping smooth facets were not developed only in passages with flat ceilings, but also in the passages and halls with a vaulted ceiling. The asymmetrical shape of cusped depressions above the facets were documented in detail by a high-resolution cave topography with terrestrial laser scanning and digital photogrammetry. Middle–Late Pleistocene accumulation phases, identified by magnetostratigraphy of cave sediments and U-series dating of speleothems, are associated with phreatic and later epiphreatic development. The deposition on the bottom bedrock began before 1.8 Ma. The Brunhes/Matuyama boundary (0.773 Ma) and Jaramillo magnetozone (0.990–1.071 Ma) were recorded in the profile in the Oválna chodba Passage. Slow depositional rate (~0.09 cm/kyr) calculated from magnetostratigraphy resulted from slow water movement in confined conditions in marbles completely enclosed by phyllites and no direct relation to the surface. Only occasionally turbid water was loaded in extremely fine-grained infiltration material and autochthonous Fe oxyhydroxides. The depositional rate in Mn-rich layer was much slower (~0.03 cm/kyr). Additional U-series dating confirmed that old aragonite generations (with ages about 500–450 ka and 143–121 ka) were partly corroded by repeated floods during Late Pleistocene humid episodes. Aragonite younger than 13.5 ka is not corroded.
This paper discusses the results of a study of the Le Chouet section, its lithologies, facies, magnetic properties and fossil record (ammonites, calcareous nannofossils, calpionellids and calcareous ...dinoflagellates). Data obtained have been applied to give a precise biostratigraphy for this carbonate sequence as well as a paleoenvironmental reconstruction. Its relationship to magnetostratigraphy, based on a modern study of a French site, is important. Investigation of the micro- and macrofossils shows that the site comprises a sedimentary sequence in the Microcanthum to Jacobi ammonite Zones, and the Chitinoidella, Crassicollaria and Calpionella Zones. Several calpionellid and nannofossil bioevents have been recorded on the basis of the distribution of stratigraphically important planktonic organisms. The site allows us to calibrate the levels of various biomarkers and biozonal boundaries, and correlate them with the magnetozones M20n, M19r and M19n.
The Jurassic/Cretaceous transition was accompanied by significant changes in palaeoceanography and palaeoenvironments in the Tethyan Realm, but outside the Tethys such data are very scarce. Here we ...present results of a study of the most complete section in the Panboreal Superrealm, the Nordvik section. Belemnite δ
18
O data show an irregular decrease from values reaching up to +1.6‰ in the Middle Oxfordian and from +0.8 to −1.7‰ in the basal Ryazanian, indicating a prolonged warming. The biodiversity changes were strongly related to sea-level oscillations, showing a relatively low belemnite and high ammonite diversity during sea-level rise, accompanied by a decrease of the macrobenthos taxonomical richness. The most prominent sea-level rise is marked by the occurrence of open sea ammonites with Pacific affinities. Peak abundances of spores and prasinophytes correlate with a negative excursion in organic carbon δ
13
C near the J/K boundary and could reflect blooms of green algae caused by disturbance of the marine ecosystem.
This study reports on a approximately 150 m thick macrofossil-barren sequence of siliciclastic sediments from a Burdigalian age (Early Miocene) freshwater lake. The lake was located within an ...incipient rift system of the Most Basin in the Ohre (Eger) Graben, which was part of the European Cenozoic Rift System, and had an original area of ≈ 1000 km2. Sediments from the HK591 core that cover the entire thickness of the lake deposits and some of the adjacent stratigraphic units were analysed by X-ray fluorescence spectroscopy (a proxy for element composition) and magnetic polarity measurement. The element proxies were subjected to frequency analysis, which provided estimated sedimentation rates, and allowed for sediment dating by magnetostratigraphy and orbital tuning of the age model. Based on the resulting age model and the known biostratigraphy, the lake was present between 17.4 and 16.6 Ma, which includes the onset of the Miocene Climatic Optimum in the latest Early Miocene. The identification of orbital forcing (precession, obliquity and short eccentricity cycles) confirms the stability of the sedimentary environment of the perennial lake in an underfilled basin. The dating allowed the sediment record to be interpreted in the context of the current knowledge of the European climate during that period. The stability of the sedimentary environment confirms that precipitation was relatively stable over the period recorded by the sediments.
Budimirica Cave is a small cave located in the southern part of the Republic of Macedonia, in the Kamenica Valley, a tributary to the Crna Reka and part of the Vardar river drainage network. The ...response of the cave to Late Pleistocene environmental changes is interpreted based on a detailed study of cave sediments, with previous data being supplemented, reinterpreted and compared to the Ohrid Lake palaeoclimate record. The oldest exposed speleothems in the Budimirica sediment profile were deposited during the MIS 5a (radiometric age of ca 83 ka). Sands to clays in the overburden are characterized by cycles separated by short-lived interruptions in deposition. They were deposited from a number of repeated flood events likely during the MIS 4 stage, the Weichselian (Wurmian) Glaciation, correlating to aggradation in the Kamenica Valley. The top flowstone is correlated with a warmer climate excursion at 45-50 ka (MIS 3) recorded from the Ohrid Lake deposits. The whole section was extensively eroded during the MIS 2 stage, due to strong incision in the Kamenica Valley, indicated by knickpoint retreat. The erosion surface is overlain by a fossil-bearing breccia (with Ursus spelaeus) derived from frost shattering of the cave walls close to the entrance due to climate deterioration and enlargement of the entrance by slope retreat during the MIS 2 stage. Budimirica Cave sediments reflect changes in the Kamenica Valley, as well as the environmental changes during the last glacial-interglacial cycle, with clastic cave sediments deposited during glacial stadials, and erosion and flowstone deposition characteristic of the interstadials. They also allow reconstruction of the evolution of the Kamenica Valley during the Late Pleistocene, with a general trend of valley incision hindered by climate influenced river aggradation, but reinforced by river knickpoint retreat.
Trije profili jamskih sedimentov (v fosilni jami blizu Divače, v Divaški jami in v Trhlovci) so bili preučeni na Krasu blizu Divače. Mineraloška analiza izpričuje relativno enotno sestavo lahke ...frakcije in kaže na glavni izvor v preperelih ostankih eocenskega fliša. Nekaj mineralov je produkt preparevanja (npr. gibbsit). Podrobna magnetostratigrafska raziskava treh profilov kaže na normalno in reverzno polarnost magnetocon in kaže na korelacijo med profiloma v Divaški jami in Trhlovci. Ozke normalne magnetocone verjetno sovpadajo z Jaramillo polarnostjo (0.90 do 0.97 Ma) v Matuyama epohi. Podatki kažejo na precejšnjo starost jame, v kateri je nastopilo zadnje obdobje zapolnjevanja pred 0,97 Ma in se končalo pred mejo med Brunhes/Matuyama, pred približno 0.73 Ma. Magnetostratigrafski podatki profila pri Divači so zabeležili dve ozki normalni magnetoconi v dolgi reverzni polarni coni, kar verjetno sovpada z Olduvai oz. Reunion (okrog 1.67 do 1.87 Ma) reverzne Matuyama epohe ali z normalnimi magnetoconami (okrog 3.8 d0 5.0 Ma) v reverzni Gilbert epohi. Podatki nakazujejo možnost, da je jama nastala v mesinski stopnji, za katero je značilen padec morske gladine in razvoj globokega krasa v Mediteranu. Three profiles of caves sediments (Divača fossil cave, Divaška Jama and Trhlovca Cave) were studied in the Kras near Divača village. Mineralogical study proved relatively uniform mineral composition of the light fraction indicating the main source from weathered sediments of Eocene flysch. Some minerals are derived from weathering profiles and crusts (e.g. gibbsite). Detailed magnetostratigraphic investigations of three profiles defined normal and reverse polarity magnetozones and shows the correlation between the profiles in the Divaška Jama and Trhlovca Cave. The narrow normal magnetozones probably correlate with the Jaramillo polarity event (0.90 to 0.97 Ma) of the Matuyama epoch. Those data indicate the substantial age of cave in which the last phase of filling started before 0.97 Ma and finished before the Brunhes/Matuyama boundary, i.e. around 0.73 Ma. Magnetostratigraphic data of the Divača profile detected two narrow normal magnetozones in the long reverse polarity zone which probably correlate with Olduvai and Reunion polarity events (about 1.67 to 1.87 Ma) of reverse Matuyama epoch or with some of normal magnetozones (about 3.8 to 5.0 Ma) within reverse Gilbert epoch. Data indicate the possibility that the cave was originated during the Messinian period characteristic by sea-level fall and evolution of deep karst in the Mediterranean Basin.
Snežna jama je velika vodoravna fosilna epifreatična jama. Leži v grebenu Raduhe, V delu Kamniško Savinjskih Alp v SV Sloveniji. V bližini vhoda je v jami v okrog 3 m visok prerezu razgaljeno ...zaporedje plasti sig s številnimi prekinitvami rasti in izdatno terigeno komponento v spodnjem delu. V 2,4 m dolgem zveznem profilu smo vzeli zaporedne vzorce , ki smo jih proučili z termalno demagnetizacijsko metodo in metodo spreminjajočega magnetnega polja. Magnetostratigrafske analize so pokazale 7 normalnih in 6 reverznih magnetocon. Magnetne lastnosti se dobro ujemajo z litološko mejo v profilu sige. Spodnji del profila kaže večjo magnetno susceptibilnost in močnejšo remanentno magnetizacijo. Sprememba lastnosti v profilu nakazuje pomembno paleogeografsko spremembo v času nastajanja sige. Starost sige sega izven dosega datacijske metode alfa spektrometrične analize U razpadne vrste; ravnotežje U izotopov pa nakazuje starost večjo od 1,2 Ma. Najbolj verjetna starost sige, ki jo dobimo z korelacijo s primerjavo z geomagnetno časovno skalo je bodisi 3,0 do 5,0 ali 1.8 do 3.6 Ma. Starost jame lahko primerjamo z nekaterimi brezstropimi jamami na krasu v JZ Sloveniji, kjer sedimentacijo v jamah postavljamo v mesinsko obdobje. Snežna jama je bila dvignjena v sedanjo višino z mlajšimi (plio-pleistocenskimi) dvigovanji Alpskega loka. The Snežna jama Cave is located in the Kamnik-Savinja Alps, NE Slovenia, in a Raduha Ridge. The cave is a huge, more or less horizontal fossil phreatic/epiphreatic conduit. It is penetrated by vertical shafts – invasion vadose (proglacial) caves. Close to the cave entrance, there is about 3 m high wall composed of speleothems - a complex sequence of flowstone with numerous breaks in deposition, six of them are principal. The lower part of the profile (about 85 cm) contains abundant terrigenous component (terra rossa-derived clay). Stalagmites developed in several periods are completely buried by nearly horizontal younger sequences of flowstone. Continuous speleothem log was recovered from the profile in a total length of about 2.4 m. The rock column was cut to cubes in the laboratory (2x2x2 cm) and studied both by thermal demagnetisation (23 samples, 12 steps - 20 to 620 ¡C) and alternating field method (98 samples, 14 steps - 1 to 100 mT). Magnetic properties identified the lithological boundary. In contrast to the upper part, the lower one shows both higher magnetic susceptibility and higher remanent magnetisation. The turn point can indicate important palaeogeographical change. Magnetostratigraphic log is composed of 7 normal and 6 reverse polarised magnetozones. The age of speleothems detected by the U-series alpha-counting spectrometry falls outside the method range, i.e. over 350 ka. Uranium isotopic equilibria indicate the age over 1.2 Ma. The age of the fill is pre-Quaternary, clearly older than 1.77 Ma. The most probable age from correlation with geomagnetic polarity timescales is about 3.0 to 5.0 or 1.8 to 3.6 Ma. Both possibilities can indicate the growth rate of speleothems of about 1.1 to 1.3 m per 1 Ma. The age of speleogenesis can be compared to some of unroofed caves in the area of the Classical Karst (SW Slovenia) connected with the Messinian period. Snežna jama was uplifted to high altitudes by younger (Plio-Pleistocene) uplift of the Alpine chain.
Proučena je bil 9 m visoka sekvenca jamskih sedimentov Črnotiče II. V spodnjem delu grade profi l ciklično urejene plasti fluvialnih sedimentov (konglomerati, peski, melji in gline), v zgornjem pa ...laminirane ali pasovite plasti melja in gline. Oba dela profi la loči dobro izražena prekinitev, ki je povezana z močno erozijo v spodnjem delu profi la in tektonskimi premiki . Fluvialna zapolnitev je prekrita s kaotično blokovno brečo z rdečim ilovnatim matriksom – porušenim stropom. Na enem delu sten votline so številne drobne cevke, ki pripadajo polihetnim črvom. Podobne so cevkam recentnega jamskega cevkarja Marifugia cavatica. Oba dela profi la imata normalno polariteto, v vsakem pa je tudi kratka reverzna ekskurzija. Iz pridobljenih magnetostratigrafskih podatkov lahko sklepamo, da so se sedimenti odlagali v Gaussovi (2,5 do 3,6 Ma) ali kateri drugi dolgi dobi z normalno polariteto. Profi l Črnotiče II je bil odložen v zelo kratkem času. Planota Podgorskega krasa je od miocena doživela komplicirano geomorfološko evolucijo, ki so jo povzročili tektonski dvig, nagibanje in rotacija ozemlja.Več obdobjem razvoja freatičnih in epifreatičnih jam je sledil nastanek vadoznih brezen, zapolnjevanje jam, denudacija in uravnavanje površja. The sequence of interior cave facies 9 m high is composed of cyclically arranged fl uvial sediments (conglomerates, sands, silts, clays) in the lower part and by laminated to banded silts to clays in the upper part. Both parts are separated by pronounced unconformity associated with deep erosion of the lower part of the profi le and tectonic tilting. The fi ll is covered by chaotic fl owstone boulder breccia with red loamy matrix. One segment of the cavity wall was covered by tiny tubes of polychates worms comparable to recent fresh-water Marifugia cavatica. Both profi les show normal magnetozone with only one narrow reverse excursion in each. The correlation of the obtained magnetostratigraphy log can indicate the Gauss chron (ca 2.5 to 3.6 Ma) or the other long normal chron. Črnotiče II site was fi lled in a substantially short time. Gemorphological evolution of the Podgorski karst plateau (Classical Karst, Karst Edge) since Miocene underwent complicated development with distinct phases of repeating phreatic speleogenesis (horizontal caves), vadose evolution (drawdown shafts), filling, fossilisation, exhumation, block tilting and rotation, uplift and planation.
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