scholarly journals Hummocks in alpine tundra, northern British Columbia, Canada: distribution, morphology and organic carbon composition

2019 ◽  
Vol 5 (3) ◽  
pp. 127-147
Author(s):  
Marjolaine Verret ◽  
Yifeng Wang ◽  
Jean Bjornson ◽  
Denis Lacelle
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Organic Carbon ◽  
Late Holocene ◽  
Organic Content ◽  
Alpine Tundra ◽  
Carbon Density ◽  
Freezing And Thawing ◽  
Fine Grained ◽  
Alkyl Groups

Hummocks develop by cryoturbation in fine-grained frost-susceptible soils and their stage of maturity may affect the translocation of organics in Cryosols. This study examines the distribution and morphology of hummocks in the Chuck Creek Trail Valley (northern British Columbia) and determines the quantity, distribution, and composition of organic matter in their soils. Hummocks occupy about 5%–20% of the valley and their morphology is largely affected by their silt content. Cryoturbated intrusions, radiocarbon dated to 2814 and 1648 cal year B.P., suggest that hummock development was initiated during the cooler late Holocene. Hummocks have an average soil organic carbon density of 16.3 kg m−2 in the uppermost 1 m, with 62% stored in the top 25 cm. Organics are mainly present as particulate organic matter in the O-horizon (25%–80%), characterized by degradable alkyl C and O/N-alkyl groups, but occur as mineral-associated organic matter (96%–98%) composed of recalcitrant aromatic and aliphatic C groups in the underlying B and C horizons. Minor differences in organic content and composition occur between hummock tops and troughs, and between hummocks showing different stages of maturity. In the absence of an observed frost table, contemporary hummock activity is attributed to seasonal freezing and thawing.

scholarly journals A global hotspot for dissolved organic carbon in hypermaritime watersheds of coastal British Columbia

2017 ◽  
Vol 14 (15) ◽  
pp. 3743-3762 ◽  
Author(s):  
Allison A. Oliver ◽  
Suzanne E. Tank ◽  
Ian Giesbrecht ◽  
Maartje C. Korver ◽  
William C. Floyd ◽  
...  
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Organic Carbon ◽  
Stream Water ◽  
Coastal Ocean ◽  
Stream Discharge ◽  
Coastal Margin ◽  
Doc Concentration ◽  
Small Catchments ◽  
Dom Composition

Abstract. The perhumid region of the coastal temperate rainforest (CTR) of Pacific North America is one of the wettest places on Earth and contains numerous small catchments that discharge freshwater and high concentrations of dissolved organic carbon (DOC) directly to the coastal ocean. However, empirical data on the flux and composition of DOC exported from these watersheds are scarce. We established monitoring stations at the outlets of seven catchments on Calvert and Hecate islands, British Columbia, which represent the rain-dominated hypermaritime region of the perhumid CTR. Over several years, we measured stream discharge, stream water DOC concentration, and stream water dissolved organic-matter (DOM) composition. Discharge and DOC concentrations were used to calculate DOC fluxes and yields, and DOM composition was characterized using absorbance and fluorescence spectroscopy with parallel factor analysis (PARAFAC). The areal estimate of annual DOC yield in water year 2015 was 33.3 Mg C km−2 yr−1, with individual watersheds ranging from an average of 24.1 to 37.7 Mg C km−2 yr−1. This represents some of the highest DOC yields to be measured at the coastal margin. We observed seasonality in the quantity and composition of exports, with the majority of DOC export occurring during the extended wet period (September–April). Stream flow from catchments reacted quickly to rain inputs, resulting in rapid export of relatively fresh, highly terrestrial-like DOM. DOC concentration and measures of DOM composition were related to stream discharge and stream temperature and correlated with watershed attributes, including the extent of lakes and wetlands, and the thickness of organic and mineral soil horizons. Our discovery of high DOC yields from these small catchments in the CTR is especially compelling as they deliver relatively fresh, highly terrestrial organic matter directly to the coastal ocean. Hypermaritime landscapes are common on the British Columbia coast, suggesting that this coastal margin may play an important role in the regional processing of carbon and in linking terrestrial carbon to marine ecosystems.

scholarly journals Effects of Igneous Intrusion on the Organic Content of Irati Formation, Paraná Basin, in Sapopema (PR)

2020 ◽  
Vol 43 (4) ◽  
Author(s):  
Werlem Holanda ◽  
Anderson Costa dos Santos ◽  
Camila Cardoso Nogueira ◽  
Sérgio Bergamaschi ◽  
René Rodrigues ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Organic Matter Content ◽  
Organic Content ◽  
Insoluble Residue ◽  
Sem Images ◽  
Igneous Intrusion ◽  
Irati Formation ◽  
Paraná Basin ◽  
Parana Basin

The thermal effects of an igneous intrusion on organic-rich sedimentary rocks can be considering an important source of maturation of organic matter. The Permian Irati Formation of Paraná Basin (Brazil) is a carbonatic and organic-rich shale sequence intruded by Jurassic-Cretaceous basic rocks. This study reports possible effects of igneous intrusion on the organic matter content of Irati Formation, in Sapopema region (Paraná State). Total organic carbon (TOC), total sulfur (S) and insoluble residue (IR) data were combined with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The relatively low TOC values recorded in well where Irati Formation is in contact with 60 m of diabase sill (SP-58-PR) are residuals, associated with the depletion of organic carbon, caused by the thermal effect from the overlying intrusive rock. It was responsible to promote the cracking of the organic matter and reduced those values in relation to the original ones, observed in SP-32-PR (without thermal influence). When comparing the TOC peaks of the Assisting Member in both wells, it was observed that there was a decrease between 80.7 and 84% in the SP-58-PR. SEM images reveal that organic matter in Taquaral Member is sub-rounded and regular shape, while the organic matter in Assistência Member presents a characteristic pattern of thermally evolved organic matter.

scholarly journals Organic-carbon-rich sediments: benthic foraminifera as bio-indicators of depositional environments

2019 ◽  
Vol 16 (21) ◽  
pp. 4183-4199 ◽  
Author(s):  
Elena Lo Giudice Cappelli ◽  
Jessica Louise Clarke ◽  
Craig Smeaton ◽  
Keith Davidson ◽  
William Edward Newns Austin
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Content ◽  
Benthic Foraminifera ◽  
Organic Content ◽  
Depositional Environments ◽  
Organic Carbon Content ◽  
Carbon Burial ◽  
Actual Change ◽  
Freshwater Inputs

Abstract. Fjords have been described as hotspots for carbon burial, potentially playing a key role within the carbon cycle as climate regulators over multiple timescales. Nevertheless, little is known about the long-term fate of the carbon that may become stored in fjordic sediments. One of the main reasons for this knowledge gap is that carbon arriving on the seafloor is prone to post-depositional degradation, posing a great challenge when trying to discriminate between an actual change in the carbon deposition rate and post-depositional carbon loss. In this study, we evaluate the use of modern benthic foraminifera as bio-indicators of organic carbon content in six voes (fjords) on the west coast of Shetland. Benthic foraminifera are known to be sensitive to changes in organic carbon content in the sediments, and changes in their assemblage composition therefore reflect synchronous variations in the quantity and quality of carbon reaching the seafloor. We identified four environments based on the relationship between benthic foraminiferal assemblages and organic carbon content in the sediments: (1) land-locked regions influenced by riverine and/or freshwater inputs of organic matter, namely the head of fjords with a restricted geomorphology; (2) stressed environments with a heavily stratified water column and sediments rich in organic matter of low nutritional value; (3) depositional environments with moderate organic content and mild or episodic current activity; and (4) marginal to coastal settings with low organic content, such as fjords with an unrestricted geomorphology. We conclude that foraminifera potentially provide a tool to disentangle primary organic carbon signals from post-depositional degradation and loss of organic carbon because of their environmental sensitivity and high preservation potential in the sedimentary record.

scholarly journals Distribution of Arsenic with Iron, Manganese and Copper in Borehole Sediments of the River Tista and Jamuna

2013 ◽  
Vol 61 (2) ◽  
pp. 207-210 ◽  
Author(s):  
Mohammad Arifur Rahman ◽  
Md Jahangir Alam ◽  
Nur-E-Alam Siddique ◽  
AM Shafiqul Alam
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Chemical Analysis ◽  
Arsenic Concentration ◽  
Sediment Layer ◽  
Fine Grained ◽  
Lower Depth ◽  
Iron Manganese ◽  
Clay Type

Boreholes sediments (1-6 m depth) of the river Tista and Jamuna in Bangladesh were collected for the analysis of As, Fe, Mn, Cu and organic carbon. Chemical analysis reveals that Mn and Fe hydroxides and organic matter are the major leachable solids which carrying As. High levels of arsenic concentration in aquifers are associated with fine grained sediments at the lower depth of the sediment layer. The highest As containing sediment was gray and texture of sediment was clay type. The colour of the least As containing sediment was white and texture of sediment was sandy. In addition, this study indicate that As is closely associated with Fe and slightly correlated with Mn and Cu in the sediment of the river Tista and Jamuna. Arsenic was distributed regularly DOI: http://dx.doi.org/10.3329/dujs.v61i2.17072 Dhaka Univ. J. Sci. 61(2): 207-210, 2013 (July)

scholarly journals A Mineralogical Context for the Organic Matter in the Paris Meteorite Determined by A Multi-Technique Analysis

Life ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 44
Author(s):  
Manale Noun ◽  
Donia Baklouti ◽  
Rosario Brunetto ◽  
Ferenc Borondics ◽  
Thomas Calligaro ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Content ◽  
Parent Body ◽  
Chemical Extraction ◽  
Fine Grained ◽  
Tof Sims ◽  
Mineral Phases ◽  
Amorphous Silicate ◽  
Chemical States

This study is a multi-technique investigation of the Paris carbonaceous chondrite directly applied on two selected 500 × 500 µm² areas of a millimetric fragment, without any chemical extraction. By mapping the partial hydration of the amorphous silicate phase dominating the meteorite sample matrix, infrared spectroscopy gave an interesting glimpse into the way the fluid may have circulated into the sample and partially altered it. The TOF-SIMS in-situ analysis allowed the studying and mapping of the wide diversity of chemical moieties composing the meteorite organic content. The results of the combined techniques show that at the micron scale, the organic matter was always spatially associated with the fine-grained and partially-hydrated amorphous silicates and to the presence of iron in different chemical states. These systematic associations, illustrated in previous studies of other carbonaceous chondrites, were further supported by the identification by TOF-SIMS of cyanide and/or cyanate salts that could be direct remnants of precursor ices that accreted with dust during the parent body formation, and by the detection of different metal-containing large organic ions. Finally, the results obtained emphasized the importance of studying the specific interactions taking place between organic and mineral phases in the chondrite matrix, in order to investigate their role in the evolution story of primitive organic matter in meteorite parent bodies.

Evolution of organic-mineral interactions and implications for organic carbon occurrence and transformation in shale

2019 ◽  
Vol 132 (3-4) ◽  
pp. 784-792 ◽  
Author(s):  
Xiaojun Zhu ◽  
Jingong Cai ◽  
Yongshi Wang ◽  
Huimin Liu ◽  
Shoupeng Zhang
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Burial Depth ◽  
Hydrocarbon Generation ◽  
Petroleum Systems ◽  
Fine Grained ◽  
Sedimentary Environments ◽  
Organic Mineral ◽  
Organic Fractions ◽  
Sequential Treatments

Abstract Organic-mineral interactions are pervasive in sedimentary environments; however, the extent of these interactions is not constant and has a significant impact on organic carbon (OC) occurrence and transformation. To understand the evolution of organic-mineral interactions and the implications for OC occurrence and transformation in fine-grained sediments, several shale samples were selected and subjected to physical and chemical sequential treatments. The samples were subjected to pyrolysis, Fourier transform infrared spectrophotometry (FTIR), and adsorption measurements to determine the organic parameters and the mineral surface area (MSA) of the shale samples. The results show that the organic fractions derived from sequential treatments have varying pyrolysis and FTIR characteristics. The correlation between the total OC content and MSA is positive, but it is split according to organic fractions with different attributes. Correlations between the different organic fractions and MSA indicate that the organic matter in shale is mainly adsorbed on mineral surfaces, while a certain portion of organic matter occurs in the pores and is adsorbed on the organic-mineral aggregates, suggesting variable interactions between the organic fractions with different attributes and minerals. From the pyrolysis and FTIR analysis, the organic fractions of different occurrence sites vary in their OC proportion, proclivity to form organic functional groups, and hydrocarbon generation potential. With increasing burial depth, the MSA and hydrogen index as well as OC loading per unit MSA are reduced, and the OC proportions of organic fractions with different attributes have regular trends. These observations indicate that the extent of organic-mineral interactions that can stabilize organic matter gradually decreases, resulting in transformation of the tightly mineral-combined OC into free OC. Our work reveals the heterogeneity in organic matter occurrence and the effect of the evolution of the organic-mineral interactions on OC occurrence and transformation, which is significant in the global carbon cycle and in petroleum systems.

scholarly journals Characterization of organic matter in bottom sediments of Ivashkina Lagoon, Laptev Sea

2019 ◽  
Vol 98 ◽  
pp. 06006
Author(s):  
Elena Gershelis ◽  
Ivan Goncharov ◽  
Oleg Dudarev ◽  
Alexey Ruban ◽  
Igor Semiletov
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Bottom Sediments ◽  
Laptev Sea ◽  
Terrestrial Vegetation ◽  
Fine Grained ◽  
The Core ◽  
Volatile Organic ◽  
The Laptev Sea

Here we present lithological and geochemical characteristics of the core drilled in coastal part of the Laptev Sea (Ivashkina Lagoon, Bykovsky Peninsula). It is shown that for sediments accumulated in specific lagoon conditions the increased content of organic carbon is confined to fine-grained lacustrine and lagoonal sediments in the uppermost layers. Pyrolytic analysis results indicate a sharp variability in the content of total organic carbon and volatile organic compounds across the studied horizons. The distribution of n-alkanes is characterized by the dominance of high molecular weight homologues, which indicates the ubiquitous contribution of higher terrestrial vegetation discharged with river and coastal thermo abrasion fluxes to the organic matter of bottom sediments.

scholarly journals Comparative study of the methods for the determination of organic carbon and organic matter in soils, compost and sludge

2019 ◽  
Vol 51 (3) ◽  
pp. 342-347 ◽  
Author(s):  
V. R. Angelova ◽  
V. I. Akova ◽  
K. I. Ivanov
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Content ◽  
Organic Content ◽  
Correction Coefficient ◽  
Organic Carbon Content ◽  
Wide Range ◽  
High Organic Content ◽  
Very High

The aim of this study was to compare the most commonly used methods for the determination of organic carbon (OC) and organic matter (SOM), and evaluate the capability of LOI (loss on ignition method) to estimate OC, using reference soils, compost and sludge as standards. The use of a titrimetric endpoint (adding phosphoric acid prior to titration) is more suitable for assessing the level of organic carbon in soils with low, medium, high and very high content. The use of a photometric endpoint is more appropriate for samples of medium and high carbon content. LOI 400 and LOI 450 may also be used for the determination of samples with a high organic content whereas LOI 450 - in the determination of samples with an average organic content. LOI 450 can be used to evaluate SOC in a wide range of organic matter concentrations (3-55%). Indirect assessment of the organic carbon content or organic matter using a correction coefficient is not very accurate for samples with average organic carbon content. Keywords: methods, organic carbon, organic matter, certified samples

scholarly journals Multiple Controls on the Accumulation of Organic-Rich Sediments in the Besa River Formation of Liard Basin, British Columbia, Canada

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Jiyoung Choi ◽  
Hyun Suk Lee ◽  
Yuri Kim ◽  
Omid H. Ardakani ◽  
Sung Kyung Hong
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
High Resolution ◽  
Organic Carbon ◽  
Sea Level ◽  
Shale Gas ◽  
Biogenic Silica ◽  
Gas Production ◽  
Geochemical Data ◽  
Geographic Variations

The Late Devonian Besa River Formation is an organic-rich shale sequence in Liard Basin, northeastern British Columbia, Canada, with significant natural gas reserves. High-resolution elemental geochemistry of three long continuous cored intervals of the Besa River Formation was used to better understand the paleodepositional environment of organic-rich intervals in this thick marine shale. The studied core intervals were divided into five chemostratigraphic units based on organic and inorganic geochemical proxies. The highest total organic carbon (TOC) content (up to 13 wt.%) was identified in the upper part of the Patry member (Unit III) within the Liard Basin. During the deposition of Unit III, low clastic influx and euxinic bottom conditions mostly contributed to the high accumulation of organic carbon. Moreover, a high productivity and organic influx may have increased organic-rich basinal sediments, which further depleted the seawater column oxygen content in the presence of a large amount of organic matter. This took place within the oxygen-deficient bottom water from the Patry–Exshaw stratigraphic units. This high TOC interval was most likely deposited through abundant biogenic silica production by radiolarians, thereby utilizing the supply of nutrients from the upwelling. Sea level change was also an important factor that controlled organic matter accumulation in the Besa River Formation. The transgression in sea level changed the residence time of the organic matter in oxic zones within the water column, which limited its supply in deeper water; this decreased the TOC content in Unit IV. Before the deposition, silica production collapsed and was replaced by terrestrial sedimentation of clay minerals in the upper part of the Exshaw member, which caused organic matter dilutions in Unit V (under 5 wt.%). These results provide new insights into the effects of relative sea level changes on redox conditions, productivity, and detrital flux, which are related to organic matter enrichment patterns and their geographic variations. Unit III is characterized by an organic-rich interval as well as an abundance of biogenic silica that is closely related to fracturing. Thus, Unit III is expected to have the highest shale gas potential in the Devonian Besa River Formation. The high-resolution geochemical data integrated with well log and/or seismic data can be used to determine the distribution of the perspective interval for shale gas production in the Liard Basin.

Late Holocene sedimentation in Saanich Inlet, British Columbia, and its paleoseismic implications

1997 ◽  
Vol 34 (10) ◽  
pp. 1345-1357 ◽  
Author(s):  
A. Blais-Stevens ◽  
J. J. Clague ◽  
P. T. Bobrowsky ◽  
R. T. Patterson
Keyword(s):  
British Columbia ◽  
Debris Flows ◽  
Late Holocene ◽  
Earthquake Activity ◽  
Proxy Record ◽  
Varved Sediments ◽  
Fine Grained ◽  
Saanich Inlet ◽  
Cesium 137 ◽  
Large Earthquakes

Eight piston cores of sediment spanning the last 1500 years were collected from Saanich Inlet, an anoxic fiord on southern Vancouver Island, to obtain information on sedimentation and prehistoric earthquake activity. The cores consist mainly of fine-grained varved sediments, but include massive layers deposited by subaqueous debris flows. The debris flows may have been triggered by earthquakes or by the buildup of fine sediment on the walls of the inlet. Cesium-137 and 210Pb data, 14C ages, and varve counts were used to date and correlate massive layers in the eight cores. The uppermost massive layer in two cores may record a magnitude 7.2 earthquake that occurred in 1946 near Comox, British Columbia, 200 km north-northwest of Saanich Inlet. Seven older layers are found in two or more cores and are about 200, 440, 550, 800–850, 1050–1100, 1100–1150, and 1450–1500 years old. Two of these older layers may correlate with previously documented earthquakes in the region. There is an average of one massive layer per 116 varves in the core with the greatest number of such layers, which is broadly consistent with the expected periodicity of moderate to large earthquakes in the region, on average, one earthquake producing local Modified Mercalli Intensity VII or VIII per century. Saanich Inlet may contain a proxy record of all moderate and large earthquakes that have affected southwestern British Columbia during Holocene time, but some of the massive layers do not appear to correlate from core to core and undoubtedly are nonseismically generated deposits.

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