Vashegyite from Gaura cu Muscă Cave (Locvei Mountains, Romania): a new and rare phosphate occurrence

Bogdan P. Onac; Luminiţa Zaharia; Joe Kearns; Daniel Veres

doi:10.5038/1827-806X.35.2.2

Vashegyite from Gaura cu Muscă Cave (Locvei Mountains, Romania): a new and rare phosphate occurrence

Bogdan P. Onac, Luminiţa Zaharia, Joe Kearns, Daniel Veres

University of South Florida

Research output: Contribution to journal › Article › peer-review

Abstract

This study investigated the occurrence of vashegyite from a guano-rich deposit located in the Gaura cu Musc&abreve; Cave, Romania. Analytical methods used include optical microscopy, X-ray powder diffraction (XRD), scanning electron-microscopy (SEM), inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermal investigations and Fourier-transform infrared (FT-IR) analyses. Vashegyite occurs as friable, chalky white, irregular nodules of up to 2.5 cm in diameter, within a 15 cm thick sequence of organic and minerogenic sediments. The chemical structural formula is: (Al 10.91 Fe 3+ 0.06 Na 0.1 Ca 0.02 Mg 0.08 ) Σ=11.17 [(PO 4 ) 8.78 (SiO 4 ) 0.056 ] Σ=8.83 (OH) 6.17 ·43.79H 2 O. Electron microscope images show vashegyite crystals to be flattened on (001). The orthorhombic lattice constants of vashegyite determined by XRD are a = 10.766(2) Å, b = 15.00(4) Å, c = 22.661(1) Å, and V = 3660.62 Å 3 ( Z = 4). The major weight loss, reflected in 3 endothermic peaks, was observed between 40° and 200°C, corresponding to the removal of water molecules. Vashegyite FT-IR absorption bands are comparable in position and relative intensity to other Al-phosphates. Water percolating through guano becomes strongly acidic and reacts with the clay-rich sediment laid down by the underground stream to form vashegyite. In the lower part of the investigated profile, crandallite and ardealite were also found.

Original language	American English
Journal	Default journal
DOIs	https://doi.org/10.5038/1827-806X.35.2.2
State	Published - Jan 1 2006

Keywords

vashegyite
phosphate
guano
cave minerals
Romania

Disciplines

Earth Sciences
Geology
Physical Sciences and Mathematics

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10.5038/1827-806X.35.2.2License: CC BY

Vashegyite from Gaura cu Musc Cave (Locvei Mountains Romania)Final published version, 521 KBLicense: CC BY

Cite this

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title = "Vashegyite from Gaura cu Musc{\u a} Cave (Locvei Mountains, Romania): a new and rare phosphate occurrence",

abstract = " This study investigated the occurrence of vashegyite from a guano-rich deposit located in the Gaura cu Musc&abreve; Cave, Romania. Analytical methods used include optical microscopy, X-ray powder diffraction (XRD), scanning electron-microscopy (SEM), inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermal investigations and Fourier-transform infrared (FT-IR) analyses. Vashegyite occurs as friable, chalky white, irregular nodules of up to 2.5 cm in diameter, within a 15 cm thick sequence of organic and minerogenic sediments. The chemical structural formula is: (Al 10.91 Fe 3+ 0.06 Na 0.1 Ca 0.02 Mg 0.08 ) Σ=11.17 [(PO 4 ) 8.78 (SiO 4 ) 0.056 ] Σ=8.83 (OH) 6.17 ·43.79H 2 O. Electron microscope images show vashegyite crystals to be flattened on (001). The orthorhombic lattice constants of vashegyite determined by XRD are a = 10.766(2) Å, b = 15.00(4) Å, c = 22.661(1) Å, and V = 3660.62 Å 3 ( Z = 4). The major weight loss, reflected in 3 endothermic peaks, was observed between 40° and 200°C, corresponding to the removal of water molecules. Vashegyite FT-IR absorption bands are comparable in position and relative intensity to other Al-phosphates. Water percolating through guano becomes strongly acidic and reacts with the clay-rich sediment laid down by the underground stream to form vashegyite. In the lower part of the investigated profile, crandallite and ardealite were also found.",

keywords = "vashegyite, phosphate, guano, cave minerals, Romania",

author = "Onac, {Bogdan P.} and Lumini{\c t}a Zaharia and Joe Kearns and Daniel Veres",

year = "2006",

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doi = "10.5038/1827-806X.35.2.2",

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journal = "Default journal",

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TY - JOUR

T1 - Vashegyite from Gaura cu Muscă Cave (Locvei Mountains, Romania): a new and rare phosphate occurrence

AU - Onac, Bogdan P.

AU - Zaharia, Luminiţa

AU - Kearns, Joe

AU - Veres, Daniel

PY - 2006/1/1

Y1 - 2006/1/1

N2 - This study investigated the occurrence of vashegyite from a guano-rich deposit located in the Gaura cu Musc&abreve; Cave, Romania. Analytical methods used include optical microscopy, X-ray powder diffraction (XRD), scanning electron-microscopy (SEM), inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermal investigations and Fourier-transform infrared (FT-IR) analyses. Vashegyite occurs as friable, chalky white, irregular nodules of up to 2.5 cm in diameter, within a 15 cm thick sequence of organic and minerogenic sediments. The chemical structural formula is: (Al 10.91 Fe 3+ 0.06 Na 0.1 Ca 0.02 Mg 0.08 ) Σ=11.17 [(PO 4 ) 8.78 (SiO 4 ) 0.056 ] Σ=8.83 (OH) 6.17 ·43.79H 2 O. Electron microscope images show vashegyite crystals to be flattened on (001). The orthorhombic lattice constants of vashegyite determined by XRD are a = 10.766(2) Å, b = 15.00(4) Å, c = 22.661(1) Å, and V = 3660.62 Å 3 ( Z = 4). The major weight loss, reflected in 3 endothermic peaks, was observed between 40° and 200°C, corresponding to the removal of water molecules. Vashegyite FT-IR absorption bands are comparable in position and relative intensity to other Al-phosphates. Water percolating through guano becomes strongly acidic and reacts with the clay-rich sediment laid down by the underground stream to form vashegyite. In the lower part of the investigated profile, crandallite and ardealite were also found.

AB - This study investigated the occurrence of vashegyite from a guano-rich deposit located in the Gaura cu Musc&abreve; Cave, Romania. Analytical methods used include optical microscopy, X-ray powder diffraction (XRD), scanning electron-microscopy (SEM), inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermal investigations and Fourier-transform infrared (FT-IR) analyses. Vashegyite occurs as friable, chalky white, irregular nodules of up to 2.5 cm in diameter, within a 15 cm thick sequence of organic and minerogenic sediments. The chemical structural formula is: (Al 10.91 Fe 3+ 0.06 Na 0.1 Ca 0.02 Mg 0.08 ) Σ=11.17 [(PO 4 ) 8.78 (SiO 4 ) 0.056 ] Σ=8.83 (OH) 6.17 ·43.79H 2 O. Electron microscope images show vashegyite crystals to be flattened on (001). The orthorhombic lattice constants of vashegyite determined by XRD are a = 10.766(2) Å, b = 15.00(4) Å, c = 22.661(1) Å, and V = 3660.62 Å 3 ( Z = 4). The major weight loss, reflected in 3 endothermic peaks, was observed between 40° and 200°C, corresponding to the removal of water molecules. Vashegyite FT-IR absorption bands are comparable in position and relative intensity to other Al-phosphates. Water percolating through guano becomes strongly acidic and reacts with the clay-rich sediment laid down by the underground stream to form vashegyite. In the lower part of the investigated profile, crandallite and ardealite were also found.

KW - vashegyite

KW - phosphate

KW - guano

KW - cave minerals

KW - Romania

UR - https://digitalcommons.usf.edu/ijs/vol35/iss2/2

U2 - 10.5038/1827-806X.35.2.2

DO - 10.5038/1827-806X.35.2.2

M3 - Article

JO - Default journal

JF - Default journal

ER -

Vashegyite from Gaura cu Muscă Cave (Locvei Mountains, Romania): a new and rare phosphate occurrence

Abstract

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