Variation in Organic-Matter Composition and its Impact on Organic-Carbon Preservation in the Kimmeridge Clay Formation (Upper Jurassic, Dorset, Southern England)

2005 ◽  
pp. 261-278 ◽  
Author(s):  
RICHARD D. PANCOST ◽  
BART E. VAN DONGEN ◽  
AMY ESSER ◽  
HELEN MORGANS-BELL ◽  
HUGH C. JENKYNS ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Upper Jurassic ◽  
Southern England ◽  
Organic Matter Composition ◽  
Clay Formation

scholarly journals Volgian–Ryazanian ‘hot shales’ of the Bo Member (Farsund Formation) in the Danish Central Graben, North Sea: stratigraphy, facies and geochemistry

2003 ◽  
Vol 1 ◽  
pp. 403-436 ◽  
Author(s):  
Jon R. Ineson ◽  
Jørgen A. Bojesen-Koefoed ◽  
Karen Dybkjær ◽  
Lars H. Nielsen
Keyword(s):  
Organic Carbon ◽  
North Sea ◽  
Upper Jurassic ◽  
Fine Grained ◽  
Carbon Burial ◽  
Anoxic Environments ◽  
Organic Carbon Burial ◽  
Bottom Waters ◽  
Northern North Sea ◽  
Clay Formation

Upper Jurassic – lowermost Cretaceous marine mudstones represent the most significant source of hydrocarbons in the Central and Northern North Sea. Of particular importance in the Danish sector of the Central Graben is a succession of radioactive ‘hot shales’ referred to the Bo Member, in the upper levels of the Farsund Formation (Kimmeridge Clay Formation equivalent). This mudstone-dominated succession is typically 15–30 m thick and has a total organic carbon (TOC) content of 3–8%, though locally exceeding 15%. Although truncated on some structural highs, the Bo Member is a persistent feature of the Danish Central Graben. Lateral variation in both thickness and organic richness is attributed to intrabasinal structural topography and to the location of sediment input centres. Detailed study of the dinoflagellate cyst biostratigraphy of 10 wells indicates that the onset of enhanced organic carbon burial began in the middle–late Middle Volgian in this portion of the Central Graben. The Bo Member, representing the peak of organic carbon enrichment, is largely of Early Ryazanian age. Core data (Jeppe-1, E-1 wells) indicate that the organic-rich shales of the Bo Member are not wholly of hemipelagic origin, as commonly assumed, but may locally be dominated by fine-grained turbidites. Absence of bioturbation, well-preserved lamination and high TOC values suggest that bottom waters were predominantly anoxic although the presence of in-situ benthic bivalves at discrete horizons in the E-1 well suggests that suboxic conditions prevailed on occasion. The Bo Member is a good to very good source rock, showing very high pyrolysis yields (10–100 kg HC/ton rock) and Hydrogen Index (HI) values in the range 200–600. In particular, the Bo Member is characterised by an abundance of 28,30 bisnorhopane (H28), a compound that is indicative of anoxic environments. These new data from the Danish sector of the Central Graben are compatible with the model of Tyson et al. (1979) in which the accumulation of organic-rich mudstones was controlled primarily by bottom-water anoxia beneath a stratified watermass. A number of factors probably contributed to the development of watermass stratification, both intrinsic such as the tectonic morphology of the graben system and extrinsic including climate and sea-level stand.

scholarly journals Dynamic climate-driven controls on the deposition of the Kimmeridge Clay Formation in the Cleveland Basin, Yorkshire, UK

2019 ◽  
Author(s):  
Elizabeth Atar ◽  
Christian März ◽  
Andrew Aplin ◽  
Olaf Dellwig ◽  
Liam Herringshaw ◽  
...  
Keyword(s):  
Organic Matter ◽  
Trace Metals ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Distal Part ◽  
Hadley Cell ◽  
Redox Conditions ◽  
Climate Modelling ◽  
Lower Variability ◽  
Clay Formation

Abstract. The Kimmeridge Clay Formation (KCF) is a laterally extensive, total organic carbon-rich succession deposited throughout Northwest Europe during the Kimmeridgian–Tithonian (Late Jurassic). Here we present a petrographic and geochemical dataset for a 40 metre-thick section of a well-preserved drill core recovering thermally-immature deposits of the KCF in the Cleveland Basin (Yorkshire, UK), covering an interval of approximately 800 kyr. The new data are discussed in the context of depositional processes, sediment source and supply, transport and dispersal mechanisms, water column redox conditions, and basin restriction. Armstrong et al. (2016) recently postulated that an expanded Hadley Cell, with an intensified but alternating hydrological cycle, heavily influenced sedimentation and total organic carbon (TOC) enrichment, through promoting the primary productivity and organic matter burial, in the UK sectors of the Boreal Seaway. Consistent with such climate boundary conditions, petrographic observations, total organic carbon and carbonate contents, and major and trace element data presented here indicate that the KCF of the Cleveland Basin was deposited in the distal part of the Laurasian Seaway. Depositional conditions alternated between three states that produced a distinct cyclicity in the lithological and geochemical records: lower variability mudstone intervals (LVMIs) which comprise of clay-rich mudstone, TOC-rich sedimentation, and carbonate-rich sedimentation. The lower variability mudstone intervals dominate the studied interval but are punctuated by three ~ 2–4 m thick intervals of alternating TOC-rich and carbonate-rich sedimentation (here termed higher variability mudstone intervals, HVMIs). During the lower variability mudstone intervals, conditions were quiescent with oxic to sub-oxic bottom water conditions. During the higher variability mudstone intervals, highly dynamic conditions resulted in repeated switching of the redox system in a way similar to the modern deep basins of the Baltic Sea. During carbonate-rich sedimentation, oxic conditions prevailed, most likely due to elevated depositional energies at the seafloor by current/wave action. During TOC-rich sedimentation, anoxic-euxinic conditions led to an enrichment of redox sensitive/sulphide forming trace metals at the seafloor and a preservation of organic matter, and an active Mn-Fe particulate shuttle delivered redox sensitive/sulphide forming trace metals to the seafloor. In addition, based on TOC–S–Fe relationships, organic matter sulphurisation appears to have increased organic material preservation in about half of the analysed samples throughout the core, while the remaining samples were either dominated by excess Fe input into the system or experienced pyrite oxidation and sulphur loss during oxygenation events. New Hg/TOC data do not provide evidence of increased volcanism during this time, consistent with previous work. Set in the context of recent climate modelling, our study provides a comprehensive example of the dynamic climate-driven depositional and redox conditions that can control TOC and metal accumulations in the distal part of a shallow epicontinental sea, and is therefore key to understanding the formation of similar deposits throughout Earth's history.

scholarly journals Receptor modelling of fine particles in southern England using CMB including comparison with AMS-PMF factors

2015 ◽  
Vol 15 (4) ◽  
pp. 2139-2158 ◽  
Author(s):  
J. Yin ◽  
S. A. Cumberland ◽  
R. M. Harrison ◽  
J. Allan ◽  
D. E. Young ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Fine Particles ◽  
Sea Salt ◽  
Oxidation Products ◽  
Substantial Contribution ◽  
Vehicle Exhaust ◽  
Source Contribution ◽  
Southern England ◽  
Biogenic Source

Abstract. PM2.5 was collected during a winter campaign at two southern England sites, urban background North Kensington (NK) and rural Harwell (HAR), in January–February 2012. Multiple organic and inorganic source tracers were analysed and used in a Chemical Mass Balance (CMB) model, which apportioned seven separate primary sources, that explained on average 53% (NK) and 56% (HAR) of the organic carbon (OC), including traffic, woodsmoke, food cooking, coal combustion, vegetative detritus, natural gas and dust/soil. With the addition of source tracers for secondary biogenic aerosol at the NK site, 79% of organic carbon was accounted for. Secondary biogenic sources were represented by oxidation products of α-pinene and isoprene, but only the former made a substantial contribution to OC. Particle source contribution estimates for PM2.5 mass were obtained by the conversion of the OC estimates and combining with inorganic components ammonium nitrate, ammonium sulfate and sea salt. Good mass closure was achieved with 81% (92% with the addition of the secondary biogenic source) and 83% of the PM2.5 mass explained at NK and HAR respectively, with the remainder being secondary organic matter. While the most important sources of OC are vehicle exhaust (21 and 16%) and woodsmoke (15 and 28%) at NK and HAR respectively, food cooking emissions are also significant, particularly at the urban NK site (11% of OC), in addition to the secondary biogenic source, only measured at NK, which represented about 26%. In comparison, the major source components for PM2.5 at NK and HAR are inorganic ammonium salts (51 and 56%), vehicle exhaust emissions (8 and 6%), secondary biogenic (10% measured at NK only), woodsmoke (4 and 7%) and sea salt (7 and 8%), whereas food cooking (4 and 1%) showed relatively smaller contributions to PM2.5. Results from the CMB model were compared with source contribution estimates derived from the AMS-PMF method. The overall mass of organic matter accounted for is rather similar for the two methods. However, appreciably different concentrations were calculated for the individual primary organic matter contributions, although for most source categories the CMB and AMS-PMF results were highly correlated (r2 = 0.69–0.91). In comparison with the CMB model, the AMS appears to overestimate the biomass burning/coal and food cooking sources by a factor of around 1.5 to 2 while estimates of the traffic source are rather similar for each model. The largest divergence is in the primary/secondary organic matter split, with the AMS estimating an appreciably smaller secondary component. Possible reasons for these discrepancies are discussed, but despite these substantial divergences, the strong correlation of the two methods gives some confidence in their application.

scholarly journals The non-conservative distribution pattern of organic matter in Rajang, a tropical river with peatland in its estuary

2019 ◽  
Author(s):  
Zhuoyi Zhu ◽  
Joanne Oakes ◽  
Bradley Eyre ◽  
Youyou Hao ◽  
Edwin Sien Aun Sia ◽  
...  
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Anthropogenic Activities ◽  
Field Investigation ◽  
Organic Matter Composition ◽  
Doc Concentration ◽  
Nitrogen Ratio ◽  
Export Pattern

Abstract. South-east Asian peatland-draining rivers have attracted much attention due to their high dissolved organic carbon (DOC) yield and high CO2 emissions under anthropogenic activities. In August 2016, we carried out a field investigation of the Rajang river and estuary, a tropical system located in Sarawak, Malaysia. The Rajang has peatland in its estuary while the river basin is covered by tropical rainforest. DOC δ13C in the Rajang ranged from −28.7 ‰ to −20.1 ‰ and a U-shaped trend from river to estuary was identified. For particulate organic carbon (POC), the δ13C ranged between −29.4 ‰ to −31.1 ‰ in the river and a clear increasing trend towards more δ13C -enriched with higher salinity existed in the estuary. In the estuary, there was a linear conservative dilution pattern for dissolved organic matter composition (as quantified by D/L amino acids enantiomers) plotted against DOC δ13C, whereas when plotted against salinity dissolved D/L amino acids enantiomers values were higher than the theoretical dilution value. Together, these data indicate that the addition of DOC in estuary (by peatland) not only increased the DOC concentration, but also altered its composition, by adding more bio-degraded, 13C-depleted organic matter into the bulk dissolved organic matter. Alteration of organic matter composition (adding of more degraded subpart) was also apparent for the particulate phase, but patterns were less clear. The Rajang was characterized by DOC / DON ratios of 50 in the river section, with loss of DON in the estuary increased the ratio to 140, suggesting the unbalanced export pattern for organic carbon and nitrogen, respectively. Under anthropogenic activities, further assessment of organic carbon to nitrogen ratio is needed.

Diagenesis in Upper Jurassic marine sandstones from the North Sea Well 14/26-1 and its significance

Clay Minerals ◽  
1986 ◽  
Vol 21 (4) ◽  
pp. 513-535 ◽  
Author(s):  
C. V. Jeans ◽  
M. J. Fisher
Keyword(s):  
Organic Matter ◽  
North Sea ◽  
Upper Jurassic ◽  
Immature Stage ◽  
Maximum Temperature ◽  
Burial Depth ◽  
Hydrocarbon Generation ◽  
Clay Formation ◽  
Later Phase ◽  
Ferroan Dolomite

AbstractA tightly cemented series of marine sandstones, interbedded with shales and mudstones, occurs in the lower part of the Kimmeridge Clay Formation (Kimmeridgian to Ryazanian) of Arco Well 14/26-1 (Core No. 5, 8067–8085 ft). The well is on the northern flank of the Fraserburgh Spur Basement Ridge. The sediments are in the immature stage of hydrocarbon generation and are now at their maximum temperature and burial depth: the bottom hole temperature is 75°C. The sandstone diagenesis was complex, essentially of an intrinsic type, and took place under considerable overpressures. Initially a series of early cements was precipitated (minor chalcedony, quartz, feldspar, ferroan calcite, non-ferroan dolomite and major ferroan dolomite). A later phase of diagenesis embraced two periods of intrastratal solution (each affecting both the silicate and the carbonate components of the sediment) separated by a phase of calcite precipitation and followed by a phase of kaolinite cementation. The early cements are interpreted as being of the intrinsic miagenetic type. The later phase of diagenesis (alternating intrastratal solution and cement precipitation) resulted from the interaction of (i) the biotic breakdown of organic matter by thermophyllic micro-organisms and (ii) the abiotic thermal alteration of organic matter with the mineral components of the sediment: of particular importance were varying PCO2 and the generation of carboxylic and phenolic acids. The diagenetic pattern is closely comparable to that known from various Upper Jurassic sandy shelf sediments in other parts of the northern North Sea which have very different burial histories.

scholarly journals The nonconservative distribution pattern of organic matter in the Rajang, a tropical river with peatland in its estuary

2020 ◽  
Vol 17 (9) ◽  
pp. 2473-2485
Author(s):  
Zhuo-Yi Zhu ◽  
Joanne Oakes ◽  
Bradley Eyre ◽  
Youyou Hao ◽  
Edwin Sien Aun Sia ◽  
...  
Keyword(s):  
Organic Matter ◽  
Amino Acid ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Anthropogenic Activities ◽  
Field Investigation ◽  
Carbon And Nitrogen ◽  
Organic Matter Composition ◽  
Doc Concentration ◽  
Amino Acid Enantiomer

Abstract. Southeast Asian peatland-draining rivers have attracted much attention due to their high dissolved organic carbon (DOC) yield and high CO2 emissions under anthropogenic influences. In August 2016, we carried out a field investigation of the Rajang River and its estuary, a tropical system located in Sarawak, Malaysia. The Rajang has peatland in its estuary, while the river basin is covered by tropical rainforest. DOC-δ13C in the Rajang ranged from −28.7 ‰ to −20.1 ‰, with a U-shaped trend from river to estuary. For particulate organic carbon (POC), δ13C ranged between −29.4 ‰ and −31.1 ‰ in the river, and there was a clear increasing trend towards more enriched δ13C values with higher salinity. In the estuary, there was a linear conservative dilution pattern for dissolved organic matter composition (as quantified by D- and L-amino acid enantiomers) plotted against DOC-δ13C, whereas when plotted against salinity, dissolved D- and L-amino acid enantiomer values were higher than the theoretical dilution value. Together, these data indicate that the addition of DOC to the estuary (by peatland) not only increased the DOC concentration but also altered its composition, by adding more biodegraded, 13C-depleted organic matter into the bulk dissolved organic matter. Alteration of organic matter composition (addition of a more degraded subpart) was also apparent for the particulate phase, but patterns were less clear. The Rajang was characterized by DOC to DON (dissolved organic nitrogen) ratios of 50 in the river section, with loss of DON in the estuary increasing the ratio to 140, suggesting an unbalanced export of organic carbon and nitrogen. Where affected by anthropogenic activities, further assessment of organic carbon to nitrogen ratios is needed.

scholarly journals Dynamic climate-driven controls on the deposition of the Kimmeridge Clay Formation in the Cleveland Basin, Yorkshire, UK

2019 ◽  
Vol 15 (4) ◽  
pp. 1581-1601 ◽  
Author(s):  
Elizabeth Atar ◽  
Christian März ◽  
Andrew C. Aplin ◽  
Olaf Dellwig ◽  
Liam G. Herringshaw ◽  
...  
Keyword(s):  
Organic Matter ◽  
Trace Metals ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Hydrological Cycle ◽  
Hadley Cell ◽  
Climate Modelling ◽  
Recent Climate ◽  
Lower Variability ◽  
Clay Formation

Abstract. The Kimmeridge Clay Formation (KCF) is a laterally extensive, total-organic-carbon-rich succession deposited throughout northwest Europe during the Kimmeridgian–Tithonian (Late Jurassic). It has recently been postulated that an expanded Hadley cell, with an intensified but alternating hydrological cycle, heavily influenced sedimentation and total organic carbon (TOC) enrichment by promoting primary productivity and organic matter burial in the UK sectors of the Boreal Seaway. Consistent with such climate boundary conditions, petrographic observations, total organic carbon and carbonate contents, and major and trace element data presented here indicate that the KCF of the Cleveland Basin was deposited in the Laurasian Seaway under the influence of these conditions. Depositional conditions alternated between three states that produced a distinct cyclicity in the lithological and geochemical records: lower-variability mudstone intervals (LVMIs) which comprise clay-rich mudstone and higher-variability mudstone intervals (HVMIs) which comprise TOC-rich sedimentation and carbonate-rich sedimentation. The lower-variability mudstone intervals dominate the studied interval but are punctuated by three ∼ 2–4 m thick intervals of alternating TOC-rich and carbonate-rich sedimentation (HVMIs). During the lower-variability mudstone intervals, conditions were quiescent with oxic to suboxic bottom water conditions. During the higher-variability mudstone intervals, highly dynamic conditions resulted in repeated switching of the redox system in a way similar to the modern deep basins of the Baltic Sea. During carbonate-rich sedimentation, oxic conditions prevailed, most likely due to elevated depositional energies at the seafloor by current–wave action. During TOC-rich sedimentation, intermittent anoxic–euxinic conditions led to an enrichment of redox-sensitive and sulfide-forming trace metals at the seafloor and a preservation of organic matter, and an active Mn–Fe particulate shuttle delivered redox-sensitive and sulfide-forming trace metals to the seafloor. In addition, based on TOC–S–Fe relationships, organic matter sulfurization appears to have increased organic material preservation in about half of the analysed samples throughout the core, while the remaining samples were either dominated by excess Fe input into the system or experienced pyrite oxidation and sulfur loss during oxygenation events. New Hg∕TOC data do not provide evidence of increased volcanism during this time, consistent with previous work. Set in the context of recent climate modelling, our study provides a comprehensive example of the dynamic climate-driven depositional and redox conditions that can control TOC and metal accumulations in a shallow epicontinental sea, and it is therefore key to understanding the formation of similar deposits throughout Earth's history.

scholarly journals Receptor modelling of fine particles in Southern England using CMB including comparison with AMS-PMF factors

2014 ◽  
Vol 14 (17) ◽  
pp. 24523-24572 ◽  
Author(s):  
J. Yin ◽  
S. A. Cumberland ◽  
R. M. Harrison ◽  
J. Allan ◽  
D. E. Young ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Fine Particles ◽  
Sea Salt ◽  
Oxidation Products ◽  
Substantial Contribution ◽  
Vehicle Exhaust ◽  
Source Contribution ◽  
Southern England ◽  
Biogenic Source

Abstract. PM2.5 was collected during a winter campaign at two southern England sites, urban background North Kensington (NK) and rural Harwell (HAR), in January–February 2012. Multiple organic and inorganic source tracers were analysed and used in a Chemical Mass Balance (CMB) model, which apportioned seven separate primary sources, that explained on average 53% (NK) and 56% (HAR) of the organic carbon (OC), including traffic, woodsmoke, food cooking, coal combustion, vegetative detritus, natural gas and dust/soil. With the addition of source tracers for secondary biogenic aerosol at the NK site, 79% of organic carbon was accounted for. Secondary biogenic sources were represented by oxidation products of α-pinene and isoprene, but only the former made a substantial contribution to OC. Particle source contribution estimates for PM2.5 mass were obtained by the conversion of the OC estimates and combining with inorganic components ammonium nitrate, ammonium sulphate and sea salt. Good mass closure was achieved with 8% (92% with the addition of the secondary biogenic source) and 83% of the PM2.5 mass explained at NK and HAR respectively, with the remainder being secondary organic matter. While the most important sources of OC are vehicle exhaust (21 and 16%) and woodsmoke (15% and 28%) at NK and HAR respectively, food cooking emissions are also significant, particularly at the urban NK site (11% of OC), in addition to the secondary biogenic source, only measured at NK, which represented about 26%. In comparison, the major source components for PM2.5 at NK and HAR are inorganic ammonium salts (51 and 56%), vehicle exhaust emissions (8 and 6%), secondary biogenic (10% measured at NK only), woodsmoke (4 and 7%) and sea salt (7 and 8%), whereas food cooking (4% and 1%) showed relatively smaller contributions to PM2.5. Results from the CMB model were compared with source contribution estimates derived from the AMS-PMF method. The overall mass of organic matter accounted for is rather similar for the two methods. However, appreciably different concentrations were calculated for the individual primary organic matter contributions, although for most source categories the CMB and AMS-PMF results were highly correlated (r2 = 0.69–0.91). In comparison with the CMB model, the AMS appears to over-estimate the biomass burning/coal and food cooking sources by a factor of around 1.5 to 2 while estimates of the traffic source are rather similar for each model. The largest divergence is in the primary/secondary organic matter split, with the AMS estimating an appreciably smaller secondary component. Possible reasons for these discrepancies are discussed, but despite these substantial divergences, the strong correlation of the two methods gives some confidence in their application.

Earth’s Middle Ages: What Came after the GOE

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Middle Ages ◽  
Atmospheric Oxygen ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Dissolved Iron ◽  
Great Oxidation Event ◽  
Low Levels ◽  
Substantial Rise

This chapter considers the aftermath of the great oxidation event (GOE). It suggests that there was a substantial rise in oxygen defining the GOE, which may, in turn have led to the Lomagundi isotope excursion, which was associated with high rates of organic matter burial and perhaps even higher concentrations of oxygen. This excursion was soon followed by a crash in oxygen to very low levels and a return to banded iron formation deposition. When the massive amounts of organic carbon buried during the excursion were brought into the weathering environment, they would have represented a huge oxygen sink, drawing down levels of atmospheric oxygen. There appeared to be a veritable seesaw in oxygen concentrations, apparently triggered initially by the GOE. The GOE did not produce enough oxygen to oxygenate the oceans. Dissolved iron was removed from the oceans not by reaction with oxygen but rather by reaction with sulfide. Thus, the deep oceans remained anoxic and became rich in sulfide, instead of becoming well oxygenated.

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