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Resinite macerals at various degrees of weathering, Upper Cretaceous (Nigeria), in kerogen concentrate. Width of field 200 μm. (Photomicrograph W. Pickel)
Source publication
The liptinite maceral group has been revised by ICCP in accordance with the ICCP System 1994. After the revision of the classifications of vitrinite (ICCP, 1998), inertinite, (ICCP, 2001) and huminite (Sykorova et al., 2005) this liptinite classification completes the revised ICCP maceral group classifications. These classifications are collectivel...
Citations
... Pyrolysis was carried out using a HAWK programmed pyrolysis equipment (Wildcat Technologies LLC, USA) being uniquely designed with the ability to start analysis at temperatures as low as 50 C, which enables the measurement of early volatiles, such as C 4 and C 5 . The data obtained using HAWK programmed pyrolysis is extremely consistent and comparable to traditional Rock-Eval II and VI data (both capable of (ICCP, 1998ICCP, 2001;Sýkorov a et al., 2005;Pickel et al., 2017). As the organic matter content of the samples was low, point counting for absolute maceral quantification was meaningless; hence, the maceral composition was semi-quantitatively determined. ...
... Normalization allows for a standardized comparison of different samples. The terminology used in the analysis aligns with the International Committee for Coal and Organic Petrology (ICCP) classification system [17][18][19]. ...
The Upper Miocene–Pliocene Kampungbaru Formation crops out in the easternmost part of the Lower Kutai Basin, Indonesia. The sedimentological analysis of seven outcrops was carried out, and a total of twenty-five samples from these outcrops was analyzed for bulk geochemistry, organic petrography, and bulk and clay mineralogy to assess the effect of the climate and depositional environment on organic matter enrichment. The Kampungbaru Formation consists of interbedded sandstone, siltstone, claystone, and thick coal beds, which were classified into eleven lithofacies. Subsequently, seven facies associations were identified, namely the fluvial-dominated distributary channel, sheet-like sandstone, tide-influenced distributary channel, mouth bar, crevasse splay, delta plain, and delta front. The coal facies generally have a high amount of total organic carbon (TOC, 5.1–16.9; avg. 10.11 wt.%), and non-coal layers range from 0.03 to 4.22 wt.% (avg. 1.54 wt.%). The dominant maceral is vitrinite, while liptinite occurs only rarely in the samples. Organic matter is inferred to have originated from terrestrial plants growing in mangrove swamps. Identified clay minerals include varying proportions of kaolinite, illite, chlorite, and mixed layer illite/smectite (I/S). Kaolinite, which commonly constitutes up to 30% of the clay volume, indicates intensive chemical weathering during a warm and humid climate. In accordance with the Köppen climate classification, the paleoclimate during the deposition of the Kampungbaru Formation is classified as type Af, which is a tropical rainforest. Tropical climate was favorable for the growth of higher plants and deposition of organic matter under anoxic conditions and led to higher amounts of TOC in the Kampungbaru Formation.
... Macerals were identified primarily by their morphology, level of reflectance, and fluorescence intensity under ultraviolet light (Taylor et al., 1998;ICCP, 1998;ICCP, 2001;Suárez-Ruiz et al., 2012). The terminology applied follows the classification and nomenclature of the International Committee for Organic Petrology (ICCP) (ICCP, 1998(ICCP, , 2001Pickel et al., 2017). Additionally, solid bitumen present in the rock matrix was identified (Suárez-Ruiz et al., 2012). ...
The Claromecó foreland Basin (Carboniferous–Permian; southern Buenos Aires province, Argentina) is key to
understanding the paleotectonic evolution of the southwestern Gondwana margin and is relevant to energy
resource exploration. This study reconstructs the thermal and burial history of the Claromecó Basin by integrating
geochemical data, organic petrology, and thermal modeling techniques. Cores samples of the Tunas
Formation (Pillahuincó Group, Early Permian) were studied. A 1D thermal model was constructed, calibrated
with vitrinite reflectance measurements (VRo %), and corroborated with fluid inclusion and apatite fission track
data from previous studies. Rock-Eval pyrolysis results show TOC% values ranging from 0.13 to 60.35 wt%. The
Hydrogen index (HI < 50 mg HC/g TOC) and Oxygen index (OI < 50 mg CO2/g TOC) indicate the dominance of
Type III and Type IV kerogens, most likely resulting from the thermal maturation of an original Type III kerogen.
Petrologic observations confirm the presence of macerals from the inertinite group, as well as minor amounts of
vitrinite and liptinite. The Tmax displays a temperature range mostly from 460 to 610 ◦C. The VRo % values
range from 1.5 to 2.0%. Geochemical data combined with VRo % measurements confirm a late catagenesis to
metagenesis stage within the wet to dry gas window for coals and organic-rich strata.
In order to constrain the thermal evolution of the basin infill, different scenarios were tested by varying the
heat flow and the missing section thickness associated with the uplift and erosion of the basin (Permian–Cenozoic
unconformity). The best calibration results were obtained with an erosion thickness of 3000 up to 4200 m and
paleo heat flow peaks of either 60 or 80 mW/m2 during the Lower Permian–Lower Cretaceous. The Tunas
Formation was deposited and buried during the Permian–Triassic (Gondwanides Orogeny phase), reaching a
maximum temperature of 180 ◦C. The results obtained by combining geochemical analysis, organic petrology,
and thermal modeling techniques indicate that the coal beds of the Tunas Formation could have a current potential
as gas-prone source rocks. Despite that, the hydrocarbon generation capacity of coal levels is currently low
due to the high percentage of residual (Type IV) kerogen. Further research could help clarify if the hydrocarbons
potentially expelled by these source rocks have been lost due to migration or could be trapped somewhere in the
basin.
... The identification of organic components was carried out under reflected white light (vitrinite and inertinite macerals) and blue light (liptinite macerals). The dispersed organic matter found in the analysed samples was classified using the terminology recommended by the International Committee for Coal and Organic Petrology (ICCP 1998(ICCP , 2001 and Pickel et al. (2017). The measurements of mean organic matter reflectance were carried out on vitrinite (R o ), solid bitumen (BR o %), fusinite (R f %) and semifusinite (R sf %) particles in accordance with the ASTM D 7708-11 (ASTM 2011) guidelines. ...
New inorganic and organic geochemical data from thucholite in the Upper Permian (Wuchiapingian) Kupferschiefer (T1) shale collected at the Polkowice-Sieroszowice Cu-Ag mine in Poland are presented. Thucholite, which forms spherical or granular clusters, appears scattered in the T1 dolomitic shale at the oxic-anoxic boundary occurring within the same shale member. The composition of thucholite concretions and the T1 shale differs by a higher content of U- and REE-enriched mineral phases within the thucholite concretions compared to the T1 shale, suggesting a different mineralising history. The differences also comprise higher Ntot, Ctot, Htot, Stot contents and higher C/N, C/S ratios in thucholite than in the T1 shale. The hydrocarbon composition of the thucholite and the surrounding T1 shale also varies. Both are dominated by polycyclic aromatic compounds and their phenyl derivatives. However, higher abundances of unsubstituted polycyclic aromatic hydrocarbons in the thucholite are indicative of its pyrogenic origin. Pyrolytic compounds such as benz[a]anthracene or benzo[a]pyrene are more typical of the thucholite than the T1 shale. Microscopic observations of the thucholite and its molecular composition suggest that it represents well-rounded small charcoal fragments. These charcoals were formed during low-temperature combustion, as confirmed by semifusinite reflectance values, indicating surface fire temperatures of about 400 °C, and the absence of the high-temperature pyrogenic polycyclic aromatic hydrocarbons. Charred detrital particles, likely the main source of insoluble organic matter in the thucholite, migrated to the sedimentary basin in the form of spherical carbonaceous particulates, which adsorbed uranium and REE in particular, which would further explain their different contents and sorption properties in the depositional environment. Finally, the difference in mineral content between thucholite and the T1 shale could also have been caused by microbes, which might have formed biofilms on mineral particles, and caused a change in the original mineral composition.
... A minimum of 500 distinct points were recorded on each polished block to determine maceral and mineral assemblages (SANS/ISO 7404-3 2016). The macerals were classified following the International Committee for Coal and Organic Petrology, ICCP System 1994(ICCP 1998Pickel et al. 2017). The pellets were also used to measure mean random vitrinite reflectance (%RoV), following SANS/ISO 7404-5 (2016). ...
This study investigates the paleodepositional conditions of the No. 6 Seam of the Madzaringwe Formation in Makhado and Voorburg south area of the Soutpansberg Coalfield (Limpopo Province, South Africa) utilizing organic petrography and inorganic geochemical proxies. The coals are predominantly high-volatile bituminous B-A rank with high ash yields (avg. 36.1 wt%), characterized by high-vitrinite (~ 41.5 vol%), moderate-to-high inertinite (9.8 vol%–33.7 vol%) and low liptinite (~ 2.3 vol%). The distribution of inertinite varies among different coal horizons (from bottom-lower to middle-upper), suggesting differential oxidation conditions and/or paleofire occurrence. Vitrinite-to-inertinite (V/I) ratio, tissue preservation–gelification index (TPI–GI), and groundwater–vegetation index (GWI–VI) plots, indicate that the peat-forming forest-swamp vegetation accumulated under mesotrophic-to-rheotrophic hydrological conditions. The presence of structured macerals (i.e., telinite, collotelinite, fusinite, and semifusinite) suggests well-preserved plant tissues, whereas framboidal pyrite and sulphur content (0.24 wt%–2.16 wt%) point to brackish-water influence at the peat stage. The coals contain quartz, kaolinite, siderite, muscovite, dolomite, calcite, and pyrite minerals, most of which were likely sourced from felsic igneous rocks. The Al/(Al+Fe+Mn) and (Fe+Mn)/Ti ratios for the studied samples range between 0.24–0.97 and 0.57–70.10, respectively. The ratios, Al–Fe–Mn plot, and presence of massive botryoidal-type pyrite imply some influence of meteoric waters or fluids from hydrothermal activity post-deposition. Moreover, the chemical index of alteration (CIA: 98.25–99.67), chemical index of weathering (CIW: 92.04–97.66), and A–CN–K ternary diagram suggest inorganic matter suffered strong chemical weathering, indicating warm paleoclimatic conditions during the coal formation.
... mm was prepared through deconstruction into pulverized coal bricks and diamond polishing fluid was used for polishing. Based on the ICCP System 1994 [34][35][36][37], the maceral composition of seven samples was identified and photographed using fluorescence optical microscopy (Imager M1 m, Carl Zeiss, Jena, Germany), and the liptinite was identified using fluorescence light attachment. According to the Chinese national standard GB/T 6948-2008 [38], the random reflectance of vitrinite was determined by microphotometer (MV-SP, Leica, Wetzlar, Germany), with sapphire as the standard samples. ...
This study investigated the differences and correlation between the occurrence characteristics of alkali and alkaline earth metals (AAEMs) among different maceral groups in high-alkali, high-inertinite coal, and provides scientific guidance for the co-separation of AAEMs and inertinite groups in Xinjiang coal. The total AAEMs of inertinite-enriched samples were significantly higher than those in raw coals and vitrinite-enriched samples. Five-step sequential extraction showed that Na mainly occurs as water-soluble sodium (Na-Water) in raw coal and inertinite-enriched samples, accounting for about 53% of the total content, while it exists as organic sodium (Na-NH4Cl and Na-EDTA) in vitrinite-enriched samples, accounting for about 52% of the total content. Ca and Mg are both mainly present in organic form (Ca/Mg-NH4Cl and Ca/Mg-EDTA) in all the samples, with slightly higher proportions present in vitrinite-enriched samples. The contents of K are low in all the samples, which exist in an insoluble state (K-I). Combined microscopy and SEM-EDS analyses have revealed that the localized enrichment of Na in raw coal and inertinite-enriched samples occurs in the inertinite cell cavity, which primarily exists as NaHCO3 combined with quartz crystals, with a maximum content of up to 5.85 wt%. In this study, although EDS spectra could not directly characterize organic Ca and Mg, dolomite and calcite minerals were repeatedly found in the inertinite cell cavity. Moreover, the contents of Ca and Mg in the vitrinite-enriched samples were significantly lower than those in the other samples, which suggests that Ca and Mg are enriched with the inertinite groups. The localized enrichment of AAEMs could not be detected in any of the vitrinite-enriched samples. In summary, though there are significant differences between the occurrence modes of AAEMs in different maceral groups of high-alkali coal, AAEMs have a strong affinity with inertinite, which may be due to the inertinite’s abundant pore structures.
... Coal petrography analyses were done according to the ASTM D2797/D2797M standard [12]. The maceral identifications were done following ICCP [13,14] and Pickel et al. [15]. Random vitrinite (collotelinite) reflectance (%Ro) values were measured, as indicated by the ISO 7404-5 standard [16], for rank determination. ...
The Çankırı-Çorum Basin is economically important basin in north Anatolia due to the presences of economic coal seams within Eocene deltaic-shallow marine sequences and especially Miocene lacustrine sequences. The Eocene coals form a good example of upper deltaic coal formation of the Bayat Formation in order to work mineralogic and petrographic features of the Eocene coals in the Karakaya coalfield. The studied coal samples have on a dry basis variable ash yields (8.9–42.6%), gross calorific (4145–7241 kcal/kg), total C (42.1–73.5%), and high total S contents (2.9–4.2%). Based on the mean random vitrinite reflectance (%Ro) and proximate analyses, the samples are bituminous-D coal in rank. The identified
minerals in the raw samples by XRD analyses are clay minerals, quartz and pyrite. Maceral compositions and coal facies indices of the samples suggest that the palaeomires were accumulated limno-telmatic conditions, and mixed peat-forming vegetation was developed. Although the peat surface seemed to be
constantly covered by the mire water, the sediment-laden water influx took place. Hence, ash yields are variable, and illitic clay mineral aggregates were commonly identified. The framboidal pyrite grains could be indicators of anoxic conditions in the palaeomire; however, the lagoonal conditions were occurred in the study area during the Middle Eocene could also cause seawater influence during late stages of peatification and/or diagenetic stages. Thus, the total S contents are high. Overall, the Karakaya coals displays similar features to coal seams within deltaic sequences, which were open to seawater influence.
... Representative particles were captured by photomicrographs using a digital camera. The categorization of palynomacerals into vitrinite and liptinite macerals using TWL microscopy was conducted according to the ICCP System [23,24]. More details about the sample preparation for vitrinite reflectance measurements are illustrated in the online supplementary Appendix 2. ...
... (www.preprints.org) | NOT PEER-REVIEWED | Posted: 14 May 2024 doi:10.20944/preprints202405.0957.v124 ...
This study investigates the petroleum potential of the Middle Jurassic Khatatba Formation (Fm) in the Matruh Basin, northwestern Egypt. This formation shows in situ dual source and reservoir characteristics, where alternations of fine and coarse clastics were deposited during semi-arid and semi-humid conditions due to climate changes and Tethyan sea level fluctuations. The organic-rich shales and argillaceous siltstones are fair to very good/excellent (TOCm wt%: 0.91–3.07) source rocks. They are rich in late mature to early postmature mostly gas-prone organic facies C, which sourced the juxtaposing intraformational coarse clastics of the Lower Safa Member with gas and condensates. The source rocks show poor to fair gas generation potential (S2: 0.38–1.96, mg HC/g rock). The middle part of the Lower Safa Member shows excellent organic richness (TOCm wt%: 5.39 and 22.90) of early postmature gas-prone carbonaceous material and coal deposits. These coaly shale layers exhibit fair to excellent wet gas and condensate generation potential (S2: 4.51–27.43, mg HC/g rock). Maturation of the source rocks was related to the Late Jurassic–Early Cretaceous Tethyan rifting. The onset of oil generation occurred in the Early Cretaceous (~ 116 Ma ago), while the onset of gas generation occurred in the Oligocene (~ 24 Ma ago). Shales of the Lower Cretaceous Alam El Bueib Fm are primary sealing rocks, while carbonates and shales of the Khatatba Fm are secondary sealing rocks. Trap types are structural, formed during the Late Jurassic and Early Cretaceous rifting of the Matruh Basin. Sandstones of the Upper Safa Member show upward increases in kaolinite and exhibit low-quality tight sandstone reservoirs. The Lower Safa Member sandstones show better gas reservoir quality with lower shale volumes. Operationally, the Lower Safa sandstone reservoirs in the Imhotep W-1X well are not suitable for gas production because they are ductile and show a high decline in production and pressure. Overall, the petroleum system of the Khatatba Fm shows mainly fair hydrocarbon potential in the study area.
... Photomicrographs were captured under incident white light and blue-light excitation using a Leica digital fluorescence camera DC 300 F at 1.300 × 1030 pixels and were stored using Image Access Premium 09 software. The maceral nomenclature applied in this paper follows ICCP System 1994 adopted by the International Committee for Coal and Organic Petrology (Sýkorová et al., 2005;Pickel et al., 2017). ...
... In isorank coals, the proportion of principal carbon types (aliphatic vs. aromatic) varies for the three maceral groups, leading to differences in microcrystalline structures (Guedes et al., 2010;Chen et al., 2012;Li et al., 2019Li et al., , 2020; in turn, the macerals are the main building blocks of coal macromolecular structure (van Krevelen, 1993). In low and medium-rank coals, liptinite is the main aliphatic and inertinite the aromatic constituent; vitrinite has intermediate fractions of both aromatic and aliphatic structures (ICCP, 1998(ICCP, , 2001O'Keefe et al., 2013;Pickel et al., 2017). Therefore, maceral composition directly impacts the coal macromolecular structure and suitability for various applications. ...
... The maceral composition and reflectance analysis were determined on block pellets prepared following South African National Standard (SANS)/International Organization for Standardization (ISO) standard 7404-2 (2015). Macerals were identified based on the International Committee for Coal and Organic Petrology System 1994(ICCP, 1998, 2001Pickel et al., 2017), using a Zeiss Axio Imager.M2m reflected white light microscope fitted with Hilgers Diskus Fossil components and software, at a total magnification of x500 using immersion oil (Zeiss Immersol 518 N, refractive index of 1.518 at 23 • C), following South African National Standards (SANS) 7404-3 (2016). ...
