Petrographical and geochemical characterization of lignites, sub-bituminous coals and carbonaceous sediments from the Erin Formation, Southern Basin, Trinidad – Implications on microfacies, depositional environment and organic matter alteration

Baboolal, Anastasia; Littke, Ralf; Wilson, Brent; Stock, Alexander T.; Knight, Joscelyn

doi:10.1016/j.coal.2016.06.020

Cited by 11 publications

(3 citation statements)

References 27 publications

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“…The two studied coaly shales from the glauconitic shale-mudstone unit have high HI and very low OI values. While the HI values are in the range that can be expected for lignites (Baboolal et al, 2016), the low oxygen indices were not expected in view of the high oxygen contents of the coals. This effect has often previously been observed and is mainly related to the generation of carbon monoxide (CO) rather than carbon dioxide (CO 2 ) during pyrolysis (Lafargue et al, 1998).…”

mentioning

confidence: 77%

Source Rock Potential and Depositional Environment of Middle – Upper Jurassic Sedimentary Rocks, Blue Nile Basin, Ethiopia

Mohammedyasin

Littke

Wudie

et al. 2020

Journal of Petroleum Geology

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This study investigates the hydrocarbon generation potential, kerogen quality, thermal maturity and depositional environment of Middle – Upper Jurassic sedimentary rocks in the Blue Nile Basin, Ethiopia, using organic petrography, Rock‐Eval pyrolysis and molecular organic geochemistry. Thirty‐seven outcrop samples were analysed for their total organic carbon (TOC) and inorganic carbon (TIC) contents. The samples came from a Toarcian – Bathonian transitional glauconitic shale‐mudstone unit, the overlying Upper Bathonian Gohatsion Formation, and the Lower Callovian – Upper Tithonian Antalo Limestone Formation. Thirteen samples with sufficient TOC contents for further analysis of the organic matter, eight from the Antalo Limestone Formation and five from the glauconitic shale‐mudstone unit, were selected and analysed using Rock‐Eval pyrolysis. Vitrinite reflectance (VRr) was measured on random particles, and qualitative maceral analysis was performed under normal incident and UV light. Nine samples were selected for molecular organic‐geochemical analyses. All the samples originating from the Gohatsion Formation showed TOC values which were too low for further analyses of the organic matter. The TOC contents of shales and limestones from the Antalo Limestone Formation and and of shales from the glauconitic shale‐mudstone unit were 3.43‐6.43% (average 4.85%) and 0.76‐3.15% (average 1.72%), respectively, and two coaly shale samples from the latter unit have average TOC values of 18.48%. HI values are very high for shales in the Antalo Limestone Formation (average 575 mg HC/g TOC) but lower for the shales in the glauconitic shale‐mudstone unit. The vitrinite reflectance of shales from the Antalo Limestone Formation ranged between 0.21% and 0.47%; coaly shales from the glauconitic shale‐mudstone unit have VRr% of between 0.29% and 0.35%. Pr/Ph ratios for samples of the Antalo Limestone Formation shales ranged from 0.8 to 1.1, indicating anoxic to suboxic depositional conditions; while shales in the glauconitic shale‐mudstone unit show higher values of up to 4.9. In terms of organic petrography, the Antalo Limestone Formation samples are dominated by finely dispersed liptinite particles and alginite; the organic material in the glauconitic shale‐mudstone unit is of higher land plant origin, with abundant vitrinite and inertinite. Sterane and hopane biomarker ratios suggest an anoxic/suboxic depositional environment for the Antalo Limestone Formation shales and limestones. These values together with Rock‐Eval Tmax (average 414 °C), the high ratio of pristane and phytane over the n‐alkanes C17 and C18, and hopane biomarker ratios indicate that the Middle – Upper Jurassic succession is of low thermal maturity in the central parts of the Blue Nile Basin. The Antalo Limestone Formation shales have a high petroleum generation potential, making them a viable target for future exploration activities.

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confidence: 77%

Source Rock Potential and Depositional Environment of Middle – Upper Jurassic Sedimentary Rocks, Blue Nile Basin, Ethiopia

Mohammedyasin

Littke

Wudie

et al. 2020

Journal of Petroleum Geology

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“…highly mineral-containing) would be less informative, as these materials occur in both South America (e.g. Orndorff, 1985) and the Caribbean, where they are found in Trinidad (Orndorff, 1985;Babalool et al, 2016) and throughout the Greater Antilles, eastwards from Cuba, across parts of Jamaica, Haiti, the Dominican Republic, and Puerto Rico (e.g. Orndorff, 1985;Iturralde-Vinent and Hartstein, 1998;Iturralde-Vinent, 2001;Sealey, 1986;Graham, 1996) (Figure 4).…”

Section: Geological Materialsmentioning

confidence: 99%

“…Figure 4: Map of the Caribbean, indicating locations of finds of black Pre-Columbian carvings (white circles) and known locations of lignite (black markers) (e.g. Orndorff, 1985;Babalool et al, 2016;Iturralde-Vinent and Hartstein, 1998;Iturralde-Vinent, 2001;Sealey, 1986;Graham, 1996).…”

Section: Geological Materialsmentioning

confidence: 99%

Dark materials: Pre-Columbian black lithic carvings from St Vincent and the wider Caribbean

Brock

Ostapkowicz

Collinson

et al. 2020

Journal of Archaeological Science: Reports

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A small number of pre-Columbian black lithic carvings are known to have been found at archaeological sites across the Caribbean, as well as in parts of neighbouring mainland South America. The identity of the material used to create these artefacts is often unknown, but suggestions include lignite, wood, petrified wood, manja(c)k, jet (or 'jet-like' materials) and hardened asphalt.These identifications are often historical and lacking any scientific basis, and as such can be unreliable. However, identification of the material has the potential to inform on the source of the carving and thereby pre-Columbian trade routes within the circum-Caribbean region. Four analytical techniques (reflectance microscopy, FTIR, Py-GC/MS, x-ray fluorescence) were applied to samples taken from two carvings found on St Vincent and five comparative materials. Both artefacts were found to be most likely to be carved from cannel coal, indicating that they originated in South American (where cannel coal is found extensively in locations in Colombia and Venezuela), as the material is not found within the Caribbean region.

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Assessment of Thermal Maturity, Source Rock Potential and Paleodepositional Environment of the Paleogene Lignites in Barsingsar, Bikaner–Nagaur Basin, Western Rajasthan, India

Singh

Kumar

2019

Nat Resour Res

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Petrographical and geochemical characterization of lignites, sub-bituminous coals and carbonaceous sediments from the Erin Formation, Southern Basin, Trinidad – Implications on microfacies, depositional environment and organic matter alteration

Cited by 11 publications

References 27 publications

Source Rock Potential and Depositional Environment of Middle – Upper Jurassic Sedimentary Rocks, Blue Nile Basin, Ethiopia

Source Rock Potential and Depositional Environment of Middle – Upper Jurassic Sedimentary Rocks, Blue Nile Basin, Ethiopia

Dark materials: Pre-Columbian black lithic carvings from St Vincent and the wider Caribbean

Assessment of Thermal Maturity, Source Rock Potential and Paleodepositional Environment of the Paleogene Lignites in Barsingsar, Bikaner–Nagaur Basin, Western Rajasthan, India

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