Characterization of bituminite in Kimmeridge Clay by confocal laser scanning and atomic force microscopy

Објеката

Тип
Рад у часопису
Верзија рада
објављена верзија
Језик
енглески
Креатор
Paul C. Hackley, Jolanta Kus, João Graciano Mendonça Filho, Andrew D. Czaja, Angeles G. Borrego, Dragana Životić, Brett J. Valentine, Javin J. Hatcheries
Извор
International Journal of Coal Geology
Издавач
Elsevier BV
Датум издавања
2022
Сажетак
This work investigates bituminite (amorphous sedimentary organic matter) in Upper Jurassic Kimmeridge Clay source rock via confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM). These petrographic tools were used to provide better understanding of the nature of bituminite, which has been historically difficult to identify and differentiate from similar organic matter types in source rocks. As part of an International Committee for Coal and Organic Petrology (ICCP) working group, an immature (0.42% vitrinite reflectance), organic-rich (44.1 wt% total organic carbon content) sample of Kimmeridge Clay was distributed to multiple laboratories for CLSM characterization. The primary observations from CLSM imaging and spectroscopy include: 1) the interpreted presence of Botryococcus algae as a contributor to bituminite precursors; 2) color red-shift of sulfide reflectance and bituminite auto-fluorescence from below the sample surface; 3) positive alteration of bituminite from laser-induced photo-oxidation of the sample surface, including fluorescence blue-shift; 4) fluorescence blue-shift associated to higher fluorescence intensity regions in bituminite indicative of compositional (fluorophore) differences; 5) the need for fluorescence spectroscopy standardization as applied via CLSM; and 6) the suitability of CLSM fluorescence spectroscopy to predict solid bitumen reflectance from bituminite spectral emission via calibration to an extant dataset. Secondary CLSM observations include detection of reflected laser light from highly reflective inclusions in bituminite, including sulfides and fusinite, and radiolytic alteration of bituminite caused by substitution of U for Fe in sulfides. Findings from AFM include the observation that surface roughening or surface flattening of bituminite are induced by differential broad ion beam (BIB) milling and are dependent on the location and scale of AFM topology measurement. This result highlights our still limited understanding of the effects of BIB milling on sedimentary organic matter and indicates the need for further research before this technique can be advanced as a standard practice in petrographic sample preparation. Collectively, the results of this study illustrate the general applicability and versatility of AFM and CLSM as tools for organic petrology research, specifically for better understanding of the nature and properties of the bituminite maceral.
Број
251
број страница
17
doi
10.1016/j.coal.2022.103927
issn
0166-5162
Subject
Битуминит, Kонфокална ласерска скенирајућа микроскопија, Mикроскопија атомских сила, Органска петрологија, Термичка зрелост
Bituminite, Confocal laser scanning microscopy, Atomic force microscopy, Organic petrology, Thermal maturity
Шира категорија рада
M20
Ужа категорија рада
М21а
Је дио
OI176007 - Геохемијска испитивања седиментних стена - фосилна горива и загађивачи животне средине
Права
Затворени приступ
Лиценца
All rights reserved
Формат
.pdf
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Драгана Животић
Radovi istraživača

Paul C. Hackley, Jolanta Kus, João Graciano Mendonça Filho, Andrew D. Czaja, Angeles G. Borrego, Dragana Životić, Brett J. Valentine, Javin J. Hatcheries. "Characterization of bituminite in Kimmeridge Clay by confocal laser scanning and atomic force microscopy" in International Journal of Coal Geology, Elsevier BV (2022). https://doi.org/10.1016/j.coal.2022.103927

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