Characterization of Carbonate Crust from a Recently Discovered Methane Seep on the North Atlantic Continental Margin of the USA

Source at https://doi.org/10.3390/min9030138 . This study is focused on mineralogical and chemical characterization of an authigenic carbonate rock (crust) collected at a recently discovered cold seep on the US North Atlantic continental margin. X-ray diffraction (XRD) and scanning electron microsco...

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Bibliographic Details
Published in:Minerals
Main Authors: Gabitov, Rinat, Borrelli, Chiara, Buettner, Jacob, Kirkland, Brenda, Skarke, Adam, Trail, Dustin, Garner, Brittany, Testa, Maurice, Wahidi, Mahnaz, Hoff, Christopher, Khasanov, Salavat, Panieri, Giuliana, Thirumalai, Roobanvenkatesh, Thomas, Jay, Weremeichik, Jeremy, Zverkova, Irina
Format: Article in Journal/Newspaper
Language:English
Published: MDPI 2019
Subjects:
VDP::Mathematics and natural science: 400::Geosciences: 450::Mineralogy
petrology
geochemistry: 462
VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Mineralogi
petrologi
geokjemi: 462
Authigenic carbonates
Aragonite
Methane seep
Magnesium
Sulfur
Strontium
Barium
Carbon isotopes
North Atlantic
Online Access:https://hdl.handle.net/10037/14795
https://doi.org/10.3390/min9030138
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Summary:Source at https://doi.org/10.3390/min9030138 . This study is focused on mineralogical and chemical characterization of an authigenic carbonate rock (crust) collected at a recently discovered cold seep on the US North Atlantic continental margin. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate that the carbonate rock is composed of microcrystalline aragonite cement, white acicular aragonite crystals (AcAr), equant quartz crystals, small microcrystalline aluminosilicates, and trace amounts of iron sulfide microcrystals. Element/calcium ratios were measured with laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) using a calcite standard, which was prepared by annealing USGS certified carbonate powder (MACS-3). The occurrence of microscopic, non-carbonate inclusions precluded evaluation of trace elements in the aragonite cement, but allowed for in situ analysis of AcAr crystals. Carbon and oxygen isotopes were analyzed via isotope ratio mass spectrometry (IRMS) and expressed as δ 13C and δ 18O. Low δ 13C values suggest that aragonite grew as a result of anaerobic oxidation of methane and observed δ 18O values indicate that the temperature of aragonite crystallization was 1.7–1.9 ◦C.

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