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Muriel Pacton - One of the best experts on this subject based on the ideXlab platform.
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the role of microorganisms in the formation of a Stalactite in botovskaya cave siberia paleoenvironmental implications
Biogeosciences, 2013Co-Authors: Muriel Pacton, Sebastian F M Breitenbach, Franziska A Lechleitner, Anton Vaks, Claire Rollionbard, Oksana S Gutareva, Alexander V Osintcev, Chris VasconcelosAbstract:Calcitic speleothems in caves can form through abiogenic or biogenic processes, or through a combination of both. Many issues conspire to make the assessment of biogenicity difficult, especially when focusing on old speleothem deposits. This study reports on a multiproxy analysis of a Siberian Stalactite, combining high-resolution microscopy, isotope geochemistry and microbially enhanced mineral precipitation laboratory experiments. The contact between growth layers in a Stalactite exhibits a biogenic isotopic signature; coupled with morphological evidence, this supports a microbial origin of calcite crystals. SIMS δ13C data suggest that microbially mediated speleothem formation occurred repeatedly at short intervals before abiotic precipitation took over. The studied Stalactite also contains iron and manganese oxides that have been mediated by microbial activity through extracellular polymeric substance (EPS)-influenced organomineralization processes. The latter reflect paleoenvironmental changes that occurred more than 500 000 yr ago, possibly related to the presence of a peat bog above the cave at that time. Microbial activity can initiate calcite deposition in the aphotic zone of caves before inorganic precipitation of speleothem carbonates. This study highlights the importance of microbially induced fractionation that can result in large negative δ13C excursions. The microscale biogeochemical processes imply that microbial activity has only negligible effects on the bulk δ13C signature in speleothems, which is more strongly affected by CO2 degassing and the host rock signature.
Chris Vasconcelos - One of the best experts on this subject based on the ideXlab platform.
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the role of microorganisms in the formation of a Stalactite in botovskaya cave siberia paleoenvironmental implications
Biogeosciences, 2013Co-Authors: Muriel Pacton, Sebastian F M Breitenbach, Franziska A Lechleitner, Anton Vaks, Claire Rollionbard, Oksana S Gutareva, Alexander V Osintcev, Chris VasconcelosAbstract:Calcitic speleothems in caves can form through abiogenic or biogenic processes, or through a combination of both. Many issues conspire to make the assessment of biogenicity difficult, especially when focusing on old speleothem deposits. This study reports on a multiproxy analysis of a Siberian Stalactite, combining high-resolution microscopy, isotope geochemistry and microbially enhanced mineral precipitation laboratory experiments. The contact between growth layers in a Stalactite exhibits a biogenic isotopic signature; coupled with morphological evidence, this supports a microbial origin of calcite crystals. SIMS δ13C data suggest that microbially mediated speleothem formation occurred repeatedly at short intervals before abiotic precipitation took over. The studied Stalactite also contains iron and manganese oxides that have been mediated by microbial activity through extracellular polymeric substance (EPS)-influenced organomineralization processes. The latter reflect paleoenvironmental changes that occurred more than 500 000 yr ago, possibly related to the presence of a peat bog above the cave at that time. Microbial activity can initiate calcite deposition in the aphotic zone of caves before inorganic precipitation of speleothem carbonates. This study highlights the importance of microbially induced fractionation that can result in large negative δ13C excursions. The microscale biogeochemical processes imply that microbial activity has only negligible effects on the bulk δ13C signature in speleothems, which is more strongly affected by CO2 degassing and the host rock signature.
Norbert Frank - One of the best experts on this subject based on the ideXlab platform.
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A Stalactite record of four relative sea-level highstands during the Middle Pleistocene Transition
Quaternary Science Reviews, 2017Co-Authors: Paolo Stocchi, Fabrizio Antonioli, Paolo Montagna, Fabrizio Pepe, Valeria Lo Presti, Antonio Caruso, M. Corradino, Gino Dardanelli, Pietro Renda, Norbert FrankAbstract:Ice-sheet and sea-level fluctuations during the Early and Middle Pleistocene are as yet poorly understood. A Stalactite from a karst cave in North West Sicily (Italy) provides the first evidence of four marine inundations that correspond to relative sea-level highstands at the time of the Middle Pleistocene Transition. The speleothem is located ∼97 m above mean sea level as result of Quaternary uplift. Its section reveals three marine hiatuses and a coral overgrowth that fixes the age of final marine ingression at 1.124 ± 0.2, thus making this speleothem the oldest Stalactite with marine hiatuses ever studied to date. Scleractinian coral species witness light-limited conditions and water depth of 20–50 m. Integrating the coral-constrained depth with the geologically constrained uplift rate and an ensemble of RSL scenarios, we find that the age of the last marine ingression most likely coincides with Marine Isotope Stage 35 on the basis of a probabilistic assessment. Our findings are consistent with a significant Antarctic ice-sheet retreat.
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investigation of marine and continental layers in a Stalactite older than 1 million years custonaci north western sector of sicily
Bollettino Della Societa Geologica Italiana, 2012Co-Authors: Fabrizio Antonioli, Paolo Montagna, Valeria Lo Presti, Antonio Caruso, Norbert Frank, Rosario Ruggieri, Sergio Silenzi, Eric Douville, Catherine PierreAbstract:Ricerche su una stalattite a livelli marini e continentali piu antica di un milione di anni, Custonaci, Sicilia NW.Questo lavoro si basa sul ritrovamento, in una grotta carsica, a 100 metri di quota a Custonaci in provincia di Trapani, di una stalattite di notevole interesse paleo climatico, ricoperta da coralli marini, la cui sezione rivela la presenza di 3 iatus che denotano una interruzione della deposizione di carbonato continentale presumibilmente in seguito a trasgressioni marine. Il carbonato, datato attraverso la metodologia 230Th/U MC-ICPMS (NeptunePlus), ha fornito una eta piu antica del limite temporale massimo di applicabilita del metodo (~ 600 ka). I coralli, che ricoprono il livello continentale piu giovane, analizzati usando il rapporto 87Sr/86Sr, hanno fornito una eta di 1.1±0.2 Myrs. Alcune considerazioni sui risultati delle analisi δ18O sui livelli continentali dello speleotema indicano una deposizione durante il MIS 27-31.
Yondri Lutfi - One of the best experts on this subject based on the ideXlab platform.
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GUA KETUK DI KAWASAN KARST PASIR PAWON : KANDUNGAN BUDAYA DAN PERTANGGALAN C-14
'Badan Penelitian dan Pengembangan Kemdikbud', 2016Co-Authors: Siregar Darwin, Yondri LutfiAbstract:Ketuk Cave complext as apart of Pawon karstic area. It located at the eastern side of Pawon Cave. The collecting data from Ketuk Cave complex had been down by survey and excavation. The conclusion based on the research is some of cave on Ketuk Cave complex had some indication about human activity in the past on it location. The artifactual remains had found such as in Ketuk Cave 3, 4, and Ketuk Cave Above. The carbon dating analysis C-14 from the sample sand and Stalactite had been shown about it chronology, 1560 + 140 BP (sand) and 3260 + 120 BP (Stalactite). That mean a while, the human activity there is not in the same era with in Pawon Cave. Pawon Cave had the carbon dating chronology during 5660 + 180 BP until 9525 + 200 BP.Gua Ketuk merupakan gugusan gua yang terdiri dari enam ruang gua. Terletak satu kawasan dengan Gua Pawon, termasuk dalam lingkungan karst Pasir Pawon. Pengumpulan data arkeologi di Gua Ketuk dilakukan dengan menerapkan metode survei dan ekskavasi. Berdasarkan hasil penelitian yang dilakukan dapat disimpulkan tidak semua ruang gua memiliki indikasi pernah dimanfaatkan sebagai tempat beraktivitas oleh masyarakat masa lalu. Tinggalan artefaktual antara lain ditemukan di Gua Ketuk Ruang 3, 4, dan Gua Ketuk Atas. Analisis pertanggalan karbon (C-14) yang diambil dari sampel tanah dan stalaktit telah dilakukan pada Gua Ketuk Ruang 4 dengan hasil pertanggalan 1560 + 140 BP untuk sampel tanah, sementara itu dari stalaktit diperoleh pertanggalan sekitar 3260 + 120 BP. Dari pertanggalan tersebut dapat disimpulkan bahwa aktivitas manusia di gua tersebut jauh lebih kemudian dibanding yang berlangsung di Gua Pawon dengan rentang pertanggalan antara 5660 + 180 BP sampai 9525 + 200 BP
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GUA KETUK DI KAWASAN KARST PASIR PAWON KANDUNGAN BUDAYA DAN PERTANGGALAN C14 KETUK CAVE AT PASIR PAWON KARST AREA: CULTURES AND ITS C14 CHRONOLOGY
'Balai Arkeologi Jawa Barat', 2016Co-Authors: Yondri Lutfi, Siregar, Darwin AAbstract:ABSTRACTKetuk Cave complext as apart of Pawon karstic area. It located at the eastern side of Pawon Cave. The collecting data from Ketuk Cave complex had been down by survey and excavation. The conclusion based on the research is some of cave on Ketuk Cave complex had some indication about human activity in the past on it location. The artifactual remains had found such as in Ketuk Cave 3, 4, and Ketuk Cave Above. The carbon dating analysis from the sample sand and Stalactite had been shown about it chronology, 1560 + 140 BP (sand) and 3260 + 120 BP (Stalactite). That mean a while, the human activity there is not in the same era with in Pawon Cave. Pawon Cave had the carbon dating chronology during 5660 + 180 BP until 9525 + 200 BP. Keywords : cave, cultural remaints, chronological analysis, carbon dating, inhibitant ABSTRAKGua Ketuk merupakan gugusan gua yang terdiri dari enam ruang gua. Gua ini terletak satu kawasan dengan Gua Pawon, termasuk dalam lingkungan karst Pasir Pawon. Pengumpulan data arkeologi di Gua Ketuk dilakukan dengan menerapkan metode survei dan ekskavasi. Berdasarkan hasil penelitian yang dilakukan dapat disimpulkan tidak semua ruang gua memiliki indikasi pernah dimanfaatkan sebagai tempat berkativitas oleh masyarakat masa lalu. Tingallan artefaktual antara lain ditemukan di Gua Ketuk Ruang 3, 4, dan Gua Ketuk Atas. Analisis pertanggalan karbon (C14) yang diambil dari sampel tanah dan stalaktit telah dilakukan pada Gua Ketuk Ruang 4 dengan hasil pertanggalan 1560 + 140 BP untuk sampel tanah, sementara itu dari stalaktit diperoleh pertanggalan sekitar 3260 + 120 BP. Dari pertanggalan tersebut dapat disimpulkan bahwa aktivitas manusia di gua tersebut jauh lebih kemudian dibandingkan dengan yang berlangsung di Gua Pawon dengan rentang pertanggalan antara 5660 + 180 BP sampai 9525 + 200 BP. Kata Kunci: gua, tinggalan Budaya, analisis kronologi, umur karbon, hunian gua
Raymond E Goldstein - One of the best experts on this subject based on the ideXlab platform.
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Stalactite growth as a free boundary problem a geometric law and its platonic ideal
Physical Review Letters, 2005Co-Authors: Martin B Short, James C Baygents, Warren J Beck, David Stone, Rickard Toomey, Raymond E GoldsteinAbstract:The chemical mechanisms underlying the growth of cave formations such as Stalactites are well known, yet no theory has yet been proposed which successfully accounts for the dynamic evolution of their shapes. Here we consider the interplay of thin-film fluid dynamics, calcium carbonate chemistry, and CO2 transport in the cave to show that Stalactites evolve according to a novel local geometric growth law which exhibits extreme amplification at the tip as a consequence of the locally-varying fluid layer thickness. Studies of this model show that a broad class of initial conditions is attracted to an ideal shape which is strikingly close to a statistical average of natural Stalactites.
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Stalactite growth as a free boundary problem
05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, 2005Co-Authors: Martin B Short, James C Baygents, Raymond E GoldsteinAbstract:Stalactites, the most familiar structures found hanging from the ceilings of limestone caves, grow by the precipitation of calcium carbonate from within a thin film of fluid flowing down their surfaces. We have recently shown [M. B. Short, J. C. Baygents, J. W. Beck, D. A. Stone, R. S. Toomey III, and R. E. Goldstein, “Stalactite growth as a free-boundary problem: A geometric law and its Platonic ideal,” Phys. Rev. Lett. 94, 018501 (2005)] that the combination of thin-film fluid dynamics, calcium carbonate chemistry, and carbon dioxide diffusion and outgassing leads to a local geometric growth law for the surface evolution which quantitatively explains the shapes of natural Stalactites. Here we provide details of this free-boundary calculation, exploiting a strong separation of time scales among that for diffusion within the layer, contact of a fluid parcel with the growing surface, and growth. When the flow rate, the scale of the Stalactite, and the chemistry are in the ranges typically found in nature, ...