title: Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging.
abstract: This study presents a cross-correlated surface and near surface investigation of two phlogopite polytypes from Kasenyi kamafugitic rocks (SW Uganda) by means of advanced Atomic Force Microscopy (AFM), confocal microscopy and Raman micro-spectroscopy. AFM revealed comparable nanomorphology and electrostatic surface potential for the two mica polytypes. A widespread presence of nano-protrusions located on the mica flake surface was also observed, with an aspect ratio (maximum height/maximum width) from 0.01 to 0.09. Confocal microscopy showed these features to range from few nm to several μm in dimension, and shapes from perfectly circular to ellipsoidic and strongly elongated. Raman spectra collected across the bubbles showed an intense and convolute absorption in the range 3000-2800 cm-1, associated with weaker bands at 1655, 1438 and 1297 cm-1, indicating the presence of fluid inclusions consisting of aliphatic hydrocarbons, alkanes and cycloalkanes, with minor amounts of oxygenated compounds, such as carboxylic acids. High-resolution Raman images provided evidence that these hydrocarbons are confined within the bubbles. This work represents the first direct evidence that phlogopite, a common rock-forming mineral, may be a possible reservoir for hydrocarbons.
authors.affiliation: Università di Bologna, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Piazza di Porta S. Donato 1, 40126 Bologna, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Moro
authors.affiliation: Università di Bologna, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Piazza di Porta S. Donato 1, 40126 Bologna, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Valdrè
authors.affiliation: Università degli Studi di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Via E. Orabona 4, 70125 Bari, Italy.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Mesto
authors.affiliation: Università degli Studi di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Via E. Orabona 4, 70125 Bari, Italy.
authors.forename: Fernando
authors.initials: F
authors.lastname: Scordari
authors.affiliation: Università degli Studi di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Via E. Orabona 4, 70125 Bari, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Lacalamita
authors.affiliation: Università Roma Tre, Dipartimento di Scienze, Largo S. Leonardo Murialdo 1, 00146 Rome, Italy.
authors.forename: Giancarlo Della
authors.initials: GD
authors.lastname: Ventura
authors.affiliation: Università Roma Tre, Dipartimento di Scienze, Largo S. Leonardo Murialdo 1, 00146 Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Bellatreccia
authors.affiliation: Università degli Studi di Catania, Dipartimento di Scienze Chimiche, Viale A. Doria 6, 95125 Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Scirè
authors.affiliation: Università degli Studi di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Via E. Orabona 4, 70125 Bari, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Schingaro