Petrographic and micro-Raman spectroscopy study of inertinite discrete structureless bodies, fusinite, secretinite, and 'ovoid' bodies infilling fusinite

• Type: Article in International Scientific Journal
• Date: 2020

Authors

Moreira, KS (Author) Other; Guedes, A (Author) FCUP; Ribeiro, H (Author) FCUP; B. Valentim (Author) FCUP

Journal

Title: International Journal of Coal Geology

Vol. 221

ISSN: 0166-5162

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 1 Citation

Other information

Authenticus ID: P-00R-WHR

DOI: 10.1016/j.coal.2020.103444

Abstract (EN): In 1982 and 1986, Lyons and co-authors defined secretinite as one of the two types of sclerotinite (the other being funginite) and established its origin based on its occurrence inside the secretory ducts of medullosan seed ferns. However, in 2001, the International Committee for Coal and Organic Petrology implicitly classified many materials whose derivation is not clear (e.g. inertinite discrete structureless bodies (IDSBs)) as secretinite. By using a combination of coal petrography and micro-Raman spectroscopy (MRS), fusinite, secretinite, IDSBs, and 'ovoid' bodies infilling fusinite were compared in a set of coals within the same rank. Coal petrography allows to identify and quantify macerals of the basis of their shape, internal structure, reflectance, relief, and size. The reflectance of these materials can be determined and then calculate the reflectance indicating surfaces (RIS) main axes (i.e. R-MAX, R-INT, and R-MIN) and parameters (i.e. R-am and R-ev); moreover, the Raman spectra and parameters (i.e. the full width at half maximum intensity of the G band (FWHMG) and the integrated intensity ratio of the S band to G band (I-S/I-G)) reflect changes in their structures. Many of the results obtained from the analysis of secretinite did not correspond to those of fusinite and IDSBs. These data suggest different origins/derivations for these materials and justify further discussions about the classification of secretinite and macrinite. The results obtained for the 'ovoid' bodies indicate that their reflectance and Raman parameters can vary within a broad range. We infer that such bodies could represent sclereids; however, when they occur disassociated from fusinite, they should represent IDSBs.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14