REE patterns in latest Neoproterozoic–early Cambrian phosphate concretions and associated organic matter

Felitsyn, S. B.; Morad, S.

doi:10.1016/s0009-2541(02)00046-3

Cited by 71 publications

(24 citation statements)

References 24 publications

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“…The proportions of LREE (La-Nd) over HREE (Ho-Lu) were calculated via (La/Yb) SN ratios as proposed by Kucera et al [44]. The proportions of MREE (Sm-Dy) was calculated using (Sm/La) SN and (Sm/Yb) SN ratios [45] over LREE and HREE, respectively.…”

Section: Methodsmentioning

confidence: 99%

Diagenetic Pore Fluid Evolution and Dolomitization of the Silurian and Devonian Carbonates, Huron Domain of Southwestern Ontario: Petrographic, Geochemical and Fluid Inclusion Evidence

2020

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Core samples from two deep boreholes were analyzed for petrographic, stable and Sr isotopes, fluid inclusion microthermometry and major, minor, trace and rare-earth elements (REE) of different types of dolomite in the Silurian and Devonian carbonates of the eastern side of the Michigan Basin provided useful insights into the nature of dolomitization, and the evolution of diagenetic pore fluids in this part of the basin. Petrographic features show that both age groups are characterized by the presence of a pervasive replacive fine-crystalline (<50 µm) dolomite matrix (RD1) and pervasive and selective replacive medium crystalline (>50–100 µm) dolomite matrix (RD2 and RD3, respectively). In addition to these types, a coarse crystalline (>500 µm) saddle dolomite cement (SD) filling fractures and vugs is observed only in the Silurian rocks. Results from geochemical and fluid inclusion analyses indicate that the diagenesis of Silurian and Devonian formations show variations in terms of the evolution of the diagenetic fluid composition. These fluid systems are: (1) a diagenetic fluid system that affected Silurian carbonates and was altered by salt dissolution post-Silurian time. These carbonates show a negative shift in δ18O values (dolomite δ18O average: −6.72‰ VPDB), Sr isotopic composition slightly more radiogenic than coeval seawater (0.7078–0.7087), high temperatures (RD2 and SD dolomite Th average: 110 °C) and hypersaline signature (RD2 and SD dolomite average salinity: 26.8 wt.% NaCl eq.); and (2) a diagenetic fluid system that affected Devonian carbonates, possibly occurred during the Alleghenian orogeny in Carboniferous time and characterized by a less pronounced negative shift in δ18O values (dolomite δ18O average: −5.74‰ VPDB), Sr isotopic composition in range with the postulated values for coeval seawater (0.7078–0.7080), lower temperatures (RD2 dolomite Th average: 83 °C) and less saline signature (RD2 dolomite average salinity: 20.8 wt.% NaCl eq.).

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Section: Methodsmentioning

confidence: 99%

Diagenetic Pore Fluid Evolution and Dolomitization of the Silurian and Devonian Carbonates, Huron Domain of Southwestern Ontario: Petrographic, Geochemical and Fluid Inclusion Evidence

2020

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“…9) and positive log 10 (Eu/Eu*) value (Table 3). The MREE enrichment can be attributed to the mobilization of the MREE from organic matter and biogenic phosphates during diagenesis (Cruse et al 2000;Felitsyn and Morad 2002;Kiddler et al 2003). Positive Eu anomalies in pore water are produced under strongly anoxic conditions (McLennal 1989, MacRae et al 1992.…”

Section: Diagenetic Setting Sources Of Bicarbonatementioning

confidence: 99%

Origin of Siderite Concretions In Microenvironments of Methanogenesis Developed In A Sulfate Reduction Zone: An Exception Or A Rule?

Bojanowski

Clarkson

2012

Journal of Sedimentary Research

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The Mississippian shales from Wardie (Scotland) were deposited in a large normally brackish-water basin. They host siderite concretions with d 13 C values ranging from 23.5 to 12.1% which show that sulfate reduction and methanogenesis contributed to the production of bicarbonate. Fossils are found within each of the concretions, suggesting that the decay of these organic remains provided a catalyst for concretionary growth. The pore water was freshened, which is indicated by the very negative d 18 O values (from 212.8 to 24.7%). Many features indicate that the concretions are very early-diagenetic, precompactional precipitates.The concretions are mostly homogeneous; only a few exhibit complex concentric zoning. The microstructure of the homogeneous concretions indicates a pervasive growth. However, their isotopic composition reveals a clear trend towards lighter d 13 C and d 18 O values from the center to the edge. It is proposed that the concretions grew due to methanogenesis in microenvironments around large organic remains, which acted as nuclei. We suggest that this process may be one of the reasons for the very common occurrence of cements as mineral concretions, not as disseminated precipitates along beds. These microenvironments developed entirely within the sulfate reduction zone, which resulted in the establishment of isotopic gradients in bicarbonate dissolved in the pore water across these microenvironments. These gradients were caused by fast consumption of sulfate by the intensive oxidation of organic remains. This resulted in the isotopic trends preserved in the homogeneous concretions. The formation of the zoned concretions proceeded generally concentrically, but detailed observations suggest that pervasive growth also contributed to their formation. Afterwards, all the concretions were deeply buried, probably within the oil window, where late-diagenetic phases crystallized (mainly kaolinite, quartz, and sulfides).

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“…Oil-source correlation obtained from analysis of REE was not consistent with correlation conclusions based on biomarker data Coal extracts (Wang et al, 2008) TD2 heavy oil YM2 oil Siberia crude oil (Felitsyn and Morad, 2002) Lacustrine oils from China (This study; Zhang et al, 2009) Niger Delta crude oils (Akinlua et al, 2008) Devonian-Mississippian marine oils from USA (Ramirez-Caro, 2013;McIntire, 2014;Kwasny,2015) Marine oils from Tarim Basin (Jiao et al, 2010) Dushanzi oil seeps (Nakada et al, 2010) LaN/YbN and trace element ratios (V/Ni and Ni/Co). Only one pair of oilsource rock relationship was established successfully using REE.…”

Section: Discussionmentioning

confidence: 64%

“…However, Manning et al (1991) indicated that REE in crude oil were organically bound rather than carried in clays because a low concentration of Al was found in crude oil and oil fractions. Felitsyn and Morad (2002) found that a heavy, asphaltene-rich crude oil from western Siberia showed a concave-shaped shale-normalized REE pattern with substantial depletion of middle rare earth elements (MREE: Sm-Ho) which was ascribed to the preferential bounding between MREE and oxygenated groups of the humic polymer, because asphaltene represented an oxygen-poor component of crude oil. Wang et al (2008) studied the REE geochemistry of coal organic extracts, and suggested that REE in the extracts were probably adsorbed by hydrogen-containing functional groups or directly bonded by carbon.…”

Section: Occurrence Of Ree In Crude Oilsmentioning

confidence: 99%

“…16), including flat (Dushanzi oil seeps and this study), left-inclined (coal extracts and Niger Delta crude oils), right-inclined (Devonian-Mississippian crude oils and shale oils), convex (TD2 heavy oil), concave (Siberian crude oil) and zig-zag patterns (YM2 and Dongying crude oils). Although various authors have proposed various inferences for the origin of these patterns (Felitsyn and Morad, 2002;Wang et al, 2008;Ramirez-Caro, 2013;McIntire, 2014;Kwasny, 2015), direct evidence is still lacking. A cross-plot of P REE values against the La N /Yb N ratio, commonly used for characterization of REE patterns (Henderson, 1984;Wang et al, 2008), is shown in Fig.…”

Section: Lumentioning

confidence: 99%

See 1 more Smart Citation

Evaluating rare earth elements as a proxy for oil–source correlation. A case study from Aer Sag, Erlian Basin, northern China

Gao

Liu

Jia

et al. 2015

Organic Geochemistry

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REE patterns in latest Neoproterozoic–early Cambrian phosphate concretions and associated organic matter

Cited by 71 publications

References 24 publications

Diagenetic Pore Fluid Evolution and Dolomitization of the Silurian and Devonian Carbonates, Huron Domain of Southwestern Ontario: Petrographic, Geochemical and Fluid Inclusion Evidence

Diagenetic Pore Fluid Evolution and Dolomitization of the Silurian and Devonian Carbonates, Huron Domain of Southwestern Ontario: Petrographic, Geochemical and Fluid Inclusion Evidence

Origin of Siderite Concretions In Microenvironments of Methanogenesis Developed In A Sulfate Reduction Zone: An Exception Or A Rule?

Evaluating rare earth elements as a proxy for oil–source correlation. A case study from Aer Sag, Erlian Basin, northern China

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