Cryogenic cave carbonates from the Ural Mountains (Russia)
Coarsely crystalline cryogenic cave carbonates (CCCcoarse) are widely used indicators of past permafrost conditions. Nevertheless, details of their formation with respect to macroscopic morphology, stable isotope evolution and potential metastable precursor phases are poorly understood. CCCcoarse we...
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ftunivinnsbruck:oai:diglib.uibk.ac.at/:2532693 2023-10-01T03:56:35+02:00 Cryogenic cave carbonates from the Ural Mountains (Russia) Töchterle, Paul Innsbruck 38.95 38.32 38.30 TI 5160 UI:GA:GP 24.04.2018 vi Blätter, 83 Seiten, 8 Blätter text/html Illustrationen, Diagramme, Karten https://resolver.obvsg.at/urn:nbn:at:at-ubi:1-23016 eng eng vignette : https://diglib.uibk.ac.at/titlepage/urn/urn:nbn:at:at-ubi:1-23016/128 urn:nbn:at:at-ubi:1-23016 https://resolver.obvsg.at/urn:nbn:at:at-ubi:1-23016 local:99144771203703331 system:AC15125910 InC_1 Höhle Permafrost Kalzit Text Thesis Hochschulschrift MasterThesis 2018 ftunivinnsbruck 2023-09-04T22:02:07Z Coarsely crystalline cryogenic cave carbonates (CCCcoarse) are widely used indicators of past permafrost conditions. Nevertheless, details of their formation with respect to macroscopic morphology, stable isotope evolution and potential metastable precursor phases are poorly understood. CCCcoarse were found in 5 caves located along a north-south transect of the Ural Mountains, Russia. A comprehensive data set was generated including results of carbonate stable isotope composition, stable isotopic composition of fluid inclusion water, stable oxygen isotope thermometry, trace element composition, X-ray diffraction and transmission properties and U/Th disequilibrium dating. Detailed petrographic characterization of the samples allows for the proposal of a morphological classification scheme for CCCcoarse. Non-crystallographic branching of crystallites, also referred to as crystal splitting, is identified as the mechanism enabling morphological variety in CCCcoarse. Splitting propensity is likely related to physico-chemical properties of the mineral forming solution such as Mg++ concentration and supersaturation with respect to carbonate minerals. Numerical modelling of C and O stable isotope evolution shows that open system style degassing of CO2 during CCCcoarse formation accounts for 10 – 20% of the observed isotopic trends. These results support a model of slow and continuous degassing of CO2 via nucleation of gas bubbles in co-precipitating ice in compliance to freezing experiments. Fluid inclusion analyses suggest that early stages of CCCcoarse formation take place at isotopic equilibrium between carbonate minerals and the parent solution. However, oxygen isotope fractionation (??(????−??????????)18=1.0318 ±0.0005) appears to be smaller than expected from literature values extrapolated to 0°C. Diffraction properties of a CCCcoarse specimen indicate that it formed via non-classical crystallisation pathways. Crystallisation by particle attachment (CPA) of poorly crystalline, or even amorphous precursor phases ... Master Thesis Ice permafrost University of Innsbruck: Digital Library (Universitäts- und Landesbibliothek Tirol) |
institution |
Open Polar |
collection |
University of Innsbruck: Digital Library (Universitäts- und Landesbibliothek Tirol) |
op_collection_id |
ftunivinnsbruck |
language |
English |
topic |
Höhle Permafrost Kalzit |
spellingShingle |
Höhle Permafrost Kalzit Töchterle, Paul Cryogenic cave carbonates from the Ural Mountains (Russia) |
topic_facet |
Höhle Permafrost Kalzit |
description |
Coarsely crystalline cryogenic cave carbonates (CCCcoarse) are widely used indicators of past permafrost conditions. Nevertheless, details of their formation with respect to macroscopic morphology, stable isotope evolution and potential metastable precursor phases are poorly understood. CCCcoarse were found in 5 caves located along a north-south transect of the Ural Mountains, Russia. A comprehensive data set was generated including results of carbonate stable isotope composition, stable isotopic composition of fluid inclusion water, stable oxygen isotope thermometry, trace element composition, X-ray diffraction and transmission properties and U/Th disequilibrium dating. Detailed petrographic characterization of the samples allows for the proposal of a morphological classification scheme for CCCcoarse. Non-crystallographic branching of crystallites, also referred to as crystal splitting, is identified as the mechanism enabling morphological variety in CCCcoarse. Splitting propensity is likely related to physico-chemical properties of the mineral forming solution such as Mg++ concentration and supersaturation with respect to carbonate minerals. Numerical modelling of C and O stable isotope evolution shows that open system style degassing of CO2 during CCCcoarse formation accounts for 10 – 20% of the observed isotopic trends. These results support a model of slow and continuous degassing of CO2 via nucleation of gas bubbles in co-precipitating ice in compliance to freezing experiments. Fluid inclusion analyses suggest that early stages of CCCcoarse formation take place at isotopic equilibrium between carbonate minerals and the parent solution. However, oxygen isotope fractionation (??(????−??????????)18=1.0318 ±0.0005) appears to be smaller than expected from literature values extrapolated to 0°C. Diffraction properties of a CCCcoarse specimen indicate that it formed via non-classical crystallisation pathways. Crystallisation by particle attachment (CPA) of poorly crystalline, or even amorphous precursor phases ... |
format |
Master Thesis |
author |
Töchterle, Paul |
author_facet |
Töchterle, Paul |
author_sort |
Töchterle, Paul |
title |
Cryogenic cave carbonates from the Ural Mountains (Russia) |
title_short |
Cryogenic cave carbonates from the Ural Mountains (Russia) |
title_full |
Cryogenic cave carbonates from the Ural Mountains (Russia) |
title_fullStr |
Cryogenic cave carbonates from the Ural Mountains (Russia) |
title_full_unstemmed |
Cryogenic cave carbonates from the Ural Mountains (Russia) |
title_sort |
cryogenic cave carbonates from the ural mountains (russia) |
publishDate |
2018 |
url |
https://resolver.obvsg.at/urn:nbn:at:at-ubi:1-23016 |
op_coverage |
Innsbruck 38.95 38.32 38.30 TI 5160 UI:GA:GP |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_relation |
vignette : https://diglib.uibk.ac.at/titlepage/urn/urn:nbn:at:at-ubi:1-23016/128 urn:nbn:at:at-ubi:1-23016 https://resolver.obvsg.at/urn:nbn:at:at-ubi:1-23016 local:99144771203703331 system:AC15125910 |
op_rights |
InC_1 |
_version_ |
1778526565334777856 |